Key Concepts in MIN - Intracerebral Hemorrhage Evacuation: Volume 2: Basics 2 (Key-Concepts in MIN, 2) 3030906280, 9783030906283

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Key-Concepts in MIN 2 Series Editor: Klaus Dieter Maria Resch

Klaus Dieter Maria Resch

Key Concepts in MIN Intracerebral Hemorrhage Evacuation Volume 2: Basics 2

Key-Concepts in MIN Series Editor Klaus Dieter Maria Resch Department of Neurosurgery Nuevo Hospital Civil\Dr. Juan I. Menchaca; Hospital Escuela de la Universidad de Guadalajara Guadalajara Mexico

More information about this series at http://www.springer.com/series/16498

Klaus Dieter Maria Resch

Key Concepts in MIN - Intracerebral Hemorrhage Evacuation Volume 2: Basics 2

Klaus Dieter Maria Resch Department of Neurosurgery (MIN) Hospital Civil University of Guadalajara Guadalajara, Mexico

ISBN 978-3-030-90628-3    ISBN 978-3-030-90629-0 (eBook) https://doi.org/10.1007/978-3-030-90629-0 © Springer Nature Switzerland AG 2022 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Foreword

In this second volume of Key Concepts in MIN, Prof. Dr. Klaus Resch has drawn attention to morphology as a key concept of minimally invasive neurosurgery (MIN). He describes, for the first time, the clinical application of plastination over an entire career in neurosurgery, and moreover, offers different perspectives on plastination’s scientific meaning. I first met Klaus over 40 years ago, during a rather heated faculty council meeting in the University of Heidelberg, where we both worked at the time. I was a research assistant to Prof. Wilhelm Kriz, who had just been appointed to the first chair of the university’s Anatomical Institute. Klaus also worked under Prof. Kriz, who employed him as a preliminary preparator with a student assistant contract, as a table assistant in macroscopic dissection courses. At this meeting, our anti-­ authoritarian views aligned, self-confidently believing in ourselves to effectively represent the interests of the voters in the faculty. My first experience with Klaus’ eccentric personality was when witnessing him at this meeting accusing a famous Prof. of anatomy of neglecting his work and in return received a strong critical retaliation for his courageous attempt. This was the birth of a remarkable friendship, comrades in our joint endeavors in anatomy, benefited by the permanent professional support of my revered boss at the time, Professor Kriz always held his protective hand over us and predicted the innovative potential of my unique colleague. In 1979, Klaus visited my plastination laboratory at the Institute of Anatomy in the University of Heidelberg. He was thrilled with the results he discovered there and appeared to have found something he was looking for a long time. He began working in the basement of the anatomical institute during the semester holidays, spending many hours preparing cephalic material for clinical anatomical teaching and research. We plastinated his work to provide life-long preservation of his impressive results. Klaus always maintained strong aspirations in the fields of clinical anatomy and neurosurgery, but not involving his goals, at that time, in plastination directly. However, he watched the progress of plastination closely and accompanied me in 1986 to the Third International Conference of Plastination in San Antonio, Texas, where he gave an excellent lecture on clinical anatomy of the cranial base and plastination. In 1987, Klaus surprised me with a project to prepare an extraordinary head-­ plastinate on neurotological skull base approaches for Prof. Ugo Fisch’s (RIP), otolaryngology clinic in the University of Zürich. In 1988, the plastinate was v

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demonstrated at the First International Congress on Skull Base Surgery in Zürich and subsequently delivered to the otolaryngology department. Meanwhile, my plastination technique evolved markedly, and by that time, whole-body plastinates were already possible, providing new insights and esthetic capabilities. Klaus participated in lectures at the Fifth Plastination Conference in Heidelberg, Germany, and at the Seventh Conference in Graz, Austria. Klaus’ mission becomes quite clear when reading chapters three through to six, where he provides a new perspective on the role of plastination in clinical anatomy for MIN. He has effectively elaborated on the meaning of plastination in this context and furthermore, has pioneered in differentiating and discriminating 12 clinical applications of plastinates. It is also emphasized that all radiological institutions should have a three-planar set of sheet plastinates as a real-world reference for interpreting diagnostic imaging, such as CT and MRI scans. The book is richly illustrated with clinical cases, with their meaning in practical clinical life, and where virtual images are easily misinterpreted due to a lack of effective resources and knowledge to inform the morphological reality. This three-dimensional anatomical understanding of real human anatomy is imperative for future generations of doctors; therefore, the book should receive a warm welcome in medicine. From a scientific perspective, Klaus has expanded upon plastination’s contributions to science under the following headings: thanatology, the highest precision preservation, an analogous medium, a storage medium of qualities, and the utmost important preservation of the ever-fading Gestalt-characteristics. Plastination is now present in hundreds of universities and institutions around the globe, with BODY WORLDS exhibitions having attracted over 50 million visitors across more than 140 cities worldwide. With this book, Klaus continues to profoundly contribute to plastination, describing not only its universal utility, but its unrivaled clinical importance in neurosurgery. Prof. Dr. Klaus Resch, inventor, pioneer, and possessor of the greatest talent worldwide in MIN, to whom many patients owe their lives to, has carved a path for future neurosurgeons to follow. A truly triumphant book for the bright future of MIN. 

Gunther von Hagens

Foreword (from Vol. 1)

Congratulation to this outstanding book. I have known the author since his time as a medical student in Heidelberg starting in 1989. He attracted my attention during the dissecting course in human anatomy. His enthusiasm and his ability in dissecting even complex regions of the body were outstanding. After his preclinical exam, he asked me if I was willing to become the supervisor of his medical thesis. He explained that his desire to become a neurosurgeon had already come up at his time in high school and the work in the dissecting course had reinforced his plan. He also proposed a topic for his thesis himself. He wanted to examine in human corpses trans-oral pathways to the brainstem, at that time still a no mans’ land. His enthusiasm and his skill in dissecting convinced me that I allocated him cadavers donated for medical research to start with his work. From then on, when a cadaver was available, he spent days and nights in the basement of the department checking the possibilities for trans-oral routes to the brainstem. His thesis “Beitrag zum transoralen Zugang zum Hirnstamm” has been highly awarded by the Medical Faculty of the University of Heidelberg. Thereafter, as a young physician in the Department of Neurosurgery in Heidelberg, he maintained his close relationships to anatomy continuing his work refining several variants of trans-oral pathways to the basal aspect of the brain. By dissecting non-fixed specimens, he demonstrated the intact subarachnoid cisterns in relationship to the arteries on the basal aspect of the brainstem; finally, he extended his work to pathological situations. He always had his whole heart in his work. During his subsequent residency at the Department of Neurosurgery at the University of Mainz, we lost contact with each other. It came as a real surprise, when in 1993 he sent me the book by Perneczky, Tschabitscher, and Resch Endoscopic anatomy for neurosurgery. It was evident that my former thesis student had succeeded in reaching a position in the leading group of neurosurgeons at that time. During the many subsequent years, he developed with others the concept of Minimally invasive neurosurgery (MIN), the success of which, as he emphasizes, would have not been possible without a thorough knowledge of the anatomy, precise anatomical-planning, and accurate performing of an exact design procedure. It was at that time when imaging and computer-aided navigation came up in neurosurgeries. This led to the belief that thorough direct knowledge of the anatomy is of less importance. This has turned out to be wrong. No question, imaging-guided surgery represents a great advance, but nevertheless the new techniques required profound vii

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anatomical experience to control and understand the images delivered by the new tools. It has become necessary as ever to have a second look into the anatomical training laboratory to get the clinical anatomy knowledge in order to be able to underlay this knowledge to the virtual pictures of imaging techniques. Fundamentally, the further evolution of MIN and the description of the MIN-key techniques for neuro-microsurgery, neuro-sonography, and neuro-endoscopy (presented in Volume I and II) became a full success. These techniques need an adapted anatomical understanding, which strongly relies on the primary anatomical basis. Each new technique requires the knowledge of specific anatomical features and recognition permitting the intracranial orientation. This is the basis for the final success of a surgery. Taking together, the clinical success of MIN, here described in four volumes, will always depend on profound knowledge of the anatomy that, as Klaus Resch always has emphasized, can be learnt and must be learnt by anybody who pursues the career of a neurosurgeon. I am sure this book will have the resounding success that it deserves. Anatomy and Cell-Biology University of Heidelberg Heidelberg, Germany

Wilhelm Kriz

Preface

The Da Vinci Principle was the cooperation and interaction of all counterparts of his brain to a coherent system, causing the Gestalt-Effect. He developed within his bicameral mind system (Jaynes 1976) a 4D-mind and 4D-awareness. By being poly-minded and by his extraordinary skills of extremely precise drawing and painting, he created and documented a 4D-imagination. He could see everything as a mental clip. Moreover, he synchronized and converged all adverse poles to a coherent interactive system reaching a new level of awareness: the 4D-awareness. He was the owner of a mental “computer,” a new interface of mind and reality. The left-handed mirror writings transformed his experiences to science, far ahead to the temporary aristocratic science, moreover, founding science by meaningful and systematic experiences.

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The challenge of this work is to create future reality out of past and present, which is creating knowledge and science out of experience. All knowledge, findings, and facts are concentrated in Key Concepts. For these book volumes that means: to form MIN-Keys, elaborated within a scientific structure, which can be seen and does function as an axiomatic web. In Chaps. 1 and 2, completion of the Key-Techniques of Vol. 1 (Mouth-tracked microscope; Neuro-sonography and Neuro-endoscopy) are described, and Vol. 2 starts with LASER and Sealing. Then the three major chapters of Vol. 2 are as follows: Key Concepts for MIN: Chap. 3 Anatomy, Chap. 4 Training, and Chaps. 5 and 6 Plastination. Since Einstein described the quantum-physics of radiation (1916), the medical application of LASER needed half a century, but never played a major role in neurosurgery. For MIN, however, the LASER is a Key-Technique. A MIN procedure is functioning like a chain, and all elements have to function perfectly, no matter if they play a big or a small role. Such a small element is Sealing. Without sealing, one has to expect complications by CSF-leakage in small approaches, where suturing is hardly possible. This fact makes Sealing a Key-­ Technique in MIN also. These two, actually small elements of the MIN-chain, deserve, each one, an own chapter. Chapter 3 deals with the Evolution of Anatomy to a Key Concept of MIN. In 1978, W. Seeger followed the idea of adapting anatomy to microneurosurgery. He sent his pupils with a program of analytical drawings into the OR, giving them a schedule of imaginations for most procedures. In a time of fast and immature results of technical opportunities, he insisted on safe ground of morphology and created a new clinical anatomy. He fulfilled the call of Benninghoff, to get an

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anatomical education level, that surgeons can directly take over the anatomical knowledge into the OR. However, Seeger wanted to inspire each one of us by starting with once own program of clinical anatomy, but not just enjoying his drawings (pers. communication 26.10.1989 Freiburg). In the daily morning meetings, each surgeon of the OR program had to show the concept and strategy he has planned to apply, presenting all steps of surgery. Seeger taught that planning starts from inside with a highly precise anatomical description of the lesion and its vascular supply, progressing to the surface and defining accordingly the approach. This was a true academic school.

For MIN, we need to come back to this point, and we have to show: the evolution of the clinical anatomy to a Key Concept for MIN. Creating the context to visualization and surgical technique leads to a new kind of surgical anatomy. However, the theoretical basics of why this kind of anatomy works for MIN comes from Gestalt-Theory. Meaning and applications of this theory are explained intensively because of its extraordinary power and its lasting existence as a secret in medicine.

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t e B

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• This Gestalt contains all symbols to recognize a famous composer. We will meet him again in the part on Gestalt-Theory (Chap. 3). • Gestalt-Phenomena will play a major role as a basis to understand, why a new kind of anatomy is necessary to make anatomy a Key Concept for MIN (Chap. 3). • Without this key concept, MIN cannot be understood, neither really mastered. Imitations of MIN without this context will not work. The different types of Gestalt-Phenomena will be demonstrated and anatomical applications of Gestalt-Theory will be shown in the examples: optic chiasm/ supra-sellar space and basilar head. One can learn the principles of planning and the geometrical Gestalt-phenomena: to understand an anatomical structure within its context and consecutive surgical meaning. This will form the basis for approach-­ analysis and approach-design in MIN. Paradigmatically, application of approach-analysis and approach-design is then shown in “the trans-oral route to the ventral brainstem.” Defining and precision of extended anatomical considerations and techniques will give a feeling for analyzing and creating approaches in MIN. Such principles are working when creating a MIN approach out of imaging and clinical data. In summary, anatomy must be elaborated according to Gestalt-Theory to become a Key of MIN. Still anatomy is the “House of Medicine,” giving a mental place to all knowledge, theories, and biological functions. Chapter 4 presents the Surgical Simulation Concept and Training in MIN.

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In this chapter, we draw the line from Gestalt-Anatomy to a Surgical Simulation Application in Pathological Anatomy of aneurysm cases. We can see a training setup dealing with all morphological and manual aspects of MIN, applied in aneurysm cases. Why do even the most attractive virtual training methods not provide surgical abilities in the end result? How can the most precise anatomical drawings not contain the information necessary for safe intracranial working? How can we train a neurosurgeon’s brain according to micro-/endo-surgical needs before surgery finally takes place? What makes training work shall be answered according to the results of previous Chap. 3. The main aspects will be the application of Gestalt-theory and the extension from anatomy to pathology, in our cases: SAH and aneurysms. There were four different working situations classified, and 74 cases analyzed. In each of these classified conditions, there were different topics that one can learn and get trained in. According to ergonomics (Vol. 1), the training setup will be described and characterized to understand how training does work. Ergonomics will be described as the major factor for training and the future evolution guideline. The para-endoscopic dissection concept will introduce a precursor of endoscopic-­ assisted microsurgical dissection. Most relevant techniques and manual haptic tasks are addressed; mainly: imaging- and approach-analysis,

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clipping-­ training, burr-hole surgical simulation, endoscopic pathology training, multiple approach analysis to the same lesion, and others. A summary of analysis of all aneurysm cases according to clinical routine and 13 illustrative cases will be analyzed according to indication of method, application, and results. The summary and conclusion will show an overview of the benefits of the interdisciplinary method for neuro-pathology, neuro-radiology, and MIN. The interactivity of the three ergonomics paradigms (s. Vol. 1) within the training concept is underlined. Finally, the role as a test-environment for evolution of innovations is pointed out. The Surgical Simulation Concept is a Key Concept in MIN. Chapter 5 deals with the role of Plastination for MIN. This technique is very precise and easy to handle and also helps in preserving anatomical material. The history and technique are shortly outlined, and then the steep evolution of the concept of Plastination, in 40 years, is mentioned. These topics have been already presented in detail elsewhere in many publications. However, in the first part, a new analytical focus is directed on the scientific meaning of Plastination, selectively, to promote this underestimated reality, in the shadow of the well-known and famous exhibition-activity worldwide. The unique contributions of Plastination to thanatology, high-precision preservation, analogous storage, quality storage, and Gestalt-storage are differentiated according to the meaning in science.

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The anatomy-concept of high-end plastinates is described and correlated with concepts of Plato, Da Vinci, and Vesalius. In the second part, the applications of plastinates during 33 years by the author in MIN are described in detail. During this period, 12 applications were created and established: Head-Plastinates for systematic-, topographic-, and surgical-anatomy were produced. Organ-Plastinates and Plastinates of special findings were done. Use as testphantoms for CT-Imaging evolution had been started. One education use as a congress-demonstration phantom is shown, for example, and also routine use in endoscopy courses are described. Plastinates as a training tool for monitor 2D, monitor 3D, and HMD 3D laboratory are presented. In clinical neuronavigation training, head-plastinates were incomparably effective and motivating. For 3D CT-resolution and reconstruction-testing, head-plastinates with real MIN approach became an innovation tool for MIN. Moreover, head-plastinates were the best test-environment for new techniques and instruments with a close to reality experience. They can also be used as test phantoms for endoscopy-towers and adaptation and adjustment of its components. Most recent test-environment was provided by plastinates in a new generation of exoscope-type. Finally, the Plastination Gallery (Chap. 6) gives an insight into art and brilliance, showing mainly high-end sheet-plastinates. They are perfect to be compared with CT- and MR-scans and to remember the difference between digital anatomy and real anatomy. Moreover, this comparison enables anatomy to be used as a learning tool for the difference of real science to unreal science, which becomes more and more the usual kind of science. We can experience that it is wise to go forward to reality in science again.

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In overall summary: Plastinates are Innovation Tools for MIN. Together with Vol. 1, this Vol. 2 of the Series Key Concepts in MIN presents the Key-Techniques and Key Concepts. Vol. 3 will address clinical pathophysiology and clinical procedures preoperatively. Vol. 4 is dedicated to case illustrations according to a classification of ICH-types. A pioneering group around a great teacher in medicine also should care about the consolidation of the innovative route and secure the new way, enabling that others can follow. To create a street along a trail is one of the obligations of the pupils of a master. Maybe it is, like in the snow, only possible to keep the trail of the masters’ footprints visible. Stronger pupils may not only describe the trail, but also the landscape they are seeing around, as their teacher did see it before, and they may even have new perspectives; however, this remains time-consuming. But, if all pupils take a different direction, there will be no safe way into future and no evolution of a safe street for others to follow; it may cause stagnation or perish a brilliant idea path. This multiple Volumes Series is intended to keep the idea of MIN alive and to make the trail to a street others can follow.

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Volume 2 of this series of “Key Concepts in MIN” contains experiences and knowledge gained during a period of four decades. Of course, a lot of support had been accepted as a present for being able to create this volume today, and I am thankful to each one of them: Prof. Dr. F.  Pampus and PD Dr. B.  Atay gave me the first insight into neurosurgery. Many of my academic teachers became a mental fundament of this book, namely Prof. Dr. W. Kriz and Prof. Dr. K. Tiedemann (Anatomy), the late Prof. Dr. Dr. h. c. mult. W. Dörr (Pathology), and Prof. Dr. Dr. Dr. h. c. mult. H. Schipperges (History of Medicine). Prof. Dr. G. v. Hagens invited me generously to become early experiences in Plastination, supporting new ways of clinical anatomy of the head (Plastination). He also supported Plastination (Chap. 5) and provided the photographs of high-end plastinates for the gallery at the end of this chapter. Prof. Dr. M. G. Yasargil and Prof. Dr. U. Fisch opened my mind for the Art of Surgery of Highest Performance. (Microneurosurgery; ENT-Skull-base Surgery) Dr. H. Huebschmann represented me to the school of V. V. Weizäcker (Psychosomatology), then Prof. Dr. W. Koos, Prof. Dr. St. Kunze, and Prof. Dr. A. Aschoff (Neurosurgery), and Dr. J.  Bohl (Neuro-pathology) acknowledged and supported my work in the early clinical training. They all became idols to me and realized a true tradition: which is to deliver knowledge and experience directly from one hand to the other. I thank Prim. Univ. -Doz. Dr. M. Cejna for supporting the recent 3D-CT imaging in head-plastinates. Without the technical support of medical companies, this work would not have been possible. My thanks go to Richard Wolf GmbH; Zeppelin Instruments GmbH; Aesculap AG; Aloka/Hitachi Co.; Takeda GmbH & Co.KG/Tachosil and Lisa Laser OHG; finally, Carl Zeiss AG. The red guideline of these successful experiences came true because of free interdisciplinary cooperation and communication. We can actually learn, due to the Corona-Management-Disaster, which disturbed also making of this book, what missing of free cooperation and communication causes. However, the best medicine against corona blues was creativity and resistance. Remembering of all appreciated persons mentioned? kept me strong to keep the goal intuitively in mind and to invest into the future by giving this experience as innovative knowledge and with non-dogmatic theories to the younger generation. Keep going the way!

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Guadalajara, Mexico

Preface

Klaus Dieter Maria Resch

Errata

Vol. 1: Chap. 1, p. 34–39 Within guest obituaries for A.  Perneczky, by lay-out mistake, Figs.  1–7 of the paper by T. Fukushima page 40–49 were pushed into the paper of R. Reisch page 31–40. (which has no Figs.)

 orrections: Minimally Invasive Keyhole Concept in Spinal C Tumor Surgery Robert Reisch Centre for Endoscopic and Minimally Invasive Neurosurgery, Clinic Hirslanden Zurich Zurich, Switzerland Email: [email protected] Abstract  On account of their space-occupying effect, intraspinal tumors may become symptomatic causing severe neurological deficits. The gold standard of treatment is the total removal of the lesion. However, extended dorsal and dorsolateral approaches may cause late complications due to iatrogenic destruction of posterolateral elements of the spinal column. In this article, Axel Perneczky’s concept in minimally invasive spinal tumor surgery is described. Two illustrative cases demonstrate the safety and feasibility of keyhole fenestrations, exposing the intraspinal space. The first case is a 67-year-old woman with a one-year history of severe back pain and slight gait disturbances. Neuroimaging revealed a right-sided extradural T11/12 schwannoma with compression of the spinal cord and laterally extension through the intervertebral foramen. The tumor was removed through a contralateral left-sided hemilaminectomy. The second case is a 38-year-old man with progressive spinal ataxia according to an intramedullar C6/8 ependymoma. Here, bi-segmental interlaminar fenestrations were performed, allowing safe and minimally invasive tumor resection. In both cases, postoperative MR imaging demonstrated complete tumor removal, the patients showed no neurological deterioration and no vertebral instability or pain syndromes. xix

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Keywords: Contralateral hemilaminectomy, Interlaminar fenestration, Keyhole spinal surgery, Preoperative planning, Spinal schwannoma, Spinal ependymoma

Introduction The main problem is well known: despite the benign biological behavior, natural history of intraspinal tumors is unfavorable on account of their space-occupying effect and subsequent neurological deterioration among patients (1). The gold standard is total removal of the lesion without postoperative neurological worsening. In order to achieve optimized visualization of the intraspinal structures, bilateral extended laminectomy has traditionally been recommended (2). However, numerous clinical and biomechanical studies reported late complications after extensive dorsal approaches with postoperative spinal instability, severe kyphoscoliosis or epidural scarring, and spinal arachnoiditis; importance of the loss of the posterior bony protection has also been published (3–6). In the case of lateral extension of the tumor, the laminectomy may be enlarged by partial costo-transversectomy; however, this exposure can be complicated by postoperative pneumothorax and may cause denervation of the paraspinal muscles over several segments (7). Furthermore, using extended approaches the incidence of postoperative local pain is higher with subsequent use of analgesics, longer hospitalization, and delayed rehabilitation.

 xel Perneczky’s Concept in Minimally Invasive Spinal A Tumor Surgery The aim of minimally invasive neurosurgery is not to harm the patient by creating a tailor-made limited less traumatic approach based on skilled preoperative planning and detailed neuroanatomical and neurofunctional knowledge. The interlaminar fenestration approach is par excellence of this concept in spinal tumor surgery. The keyhole exposure offers minimal soft tissue injury and restricted osteo-destruction, thus achieving the clear benefit of keyhole neurosurgery: the minimal approach-related traumatization. However, limited approaches offer important restrictions in spinal surgery that should also be considered in a critical way. The major limitations are (1) the predefined surgical corridor, (2) the difficult intra-operative orientation, (3) the insufficiency of available micro-instruments, and (4) the decreased illumination in the deep-seated field. Therefore, the spinal approach should be performed in an exact and individual way, according to the individual pathoanatomical situation. Two preconditions of a precisely tailored surgery are (1) the distinguished preoperative approach planning and (2) personal “self-made” performance of the surgery by the surgeon himself. Note that this personal performance should include positioning of the patient, skin incision, interlaminar fenestration, and surgical exposure of the target region.

Illustrative Cases

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The second drawback of keyhole procedures is the difficult intra-operative orientation. Real-time imaging and intra-operative use of navigation systems may increase surgical safety if the limited approach leads to a confusing situation. In addition, meticulous neuromonitoring with continuous SSEP/MEP measurements must be performed in every spinal tumor case, allowing careful protection of neurological functions. The narrow viewing angle and almost coaxial control of dissection causes an additional problem. Intra-operative use of slim and tube-shaft designed micro-­ instruments may help to overcome this limitation in spinal keyhole surgery. The fourth and probably main difficulty of keyhole approaches is the significantly reduced optical control during surgery. For this purpose, surgical microscopes can be effectively supported by endoscopes with the advantages of (1) increased light intensity, (2) extended viewing angle, and (3) clear depiction of details in close-up position.

Illustrative Cases Case 1: Epidural Schwannoma Patient’s presentation. This 67-year-old woman was admitted with a 1-year history of severe back pain with extension to the right side of the chest and slight gait disturbances. Clinical examination revealed radicular pain with paresthesia, hypesthesia, and hypalgesia in accordance with the right T11 nerve root, and a slight gait ataxia without paresis of the lower extremities. No disturbance of bladder function was detected. Magnetic resonance image demonstrated a right-sided intra-­ extraspinal situated extradural hourglass schwannoma at T11/12. The intraspinal part caused severe compression of the spinal cord; lateral extension through the intervertebral foramen showed close connection to the pleura (Fig. 1a). Approach planning. The following approaches were discussed taking into consideration the individual pathoanatomical situation. Bilateral laminectomy with wide exposure of the ipsi- and contralateral side. This approach allows good visualization of the tumor removal, however, with destruction of the vertebral lamina on both sides, spinous process, interspinous ligaments, yellow ligaments, and facet joints. Using ipsilateral hemilaminectomy approach the dorsal static structures are less likely to be injured than by a conventional laminectomy. However, in this case on account of the lateral extension of the tumor, a partial costo-transversectomy would be necessary. Using contralateral hemilaminectomy approach, the exposure of the tumor is equivalent to that after laminectomy, however, without necessity of an ipsilateral costo-transversectomy (Fig. 2). According to the use of keyhole concept in spinal microsurgery, the surgical dissection along the tumor axis allows minimal destruction of eloquent vertebro-muscular and neural structures. Surgery: After longitudinal median skin incision, the paravertebral muscles and ligaments were stripped sub-periostally on the left side and reflected laterally. A limited hemilaminectomy was carried out at level T11, the facet joints were not

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exposed. Using a high-speed drill and small Kerrison punches, the base of the spinous process and the contralateral vertebral arch were carefully undermined to gain optimal access to the opposite side (Fig.  3). The dissection along the tumor axis allowed minimal manipulation of the spinal cord could and neighboring structures. The tumor could be totally removed via extradural approach, and complete resection was controlled with endoscope-assisted technique. The histopathological examination showed a benign schwannoma; intra-operative monitoring showed no changes in SSEP/MEP. Postoperative course. On the first postoperative day, the patient showed hypesthesia in accordance with the T11 nerve. The patient did not reveal paresis of the lower extremities, gait, or vegetative disturbances. A slight local wound pain could be managed with analgesics. Three weeks postoperatively, after neuro-­physiological training the patient could subsequently return to her previous employment. Postoperative MR imaging demonstrated that the schwannoma was completely removed (Fig. 1b).

Case 2: Intramedullary Situated Ependymoma C6/8 Patient’s presentation. This 38-year-old man developed progressive gait disturbances without back pain. Neurological evaluation revealed severe medullar ataxia without paresis of the lower extremities and radicular paresthesia according to the right C8 nerve root. No disturbance of bladder function was detected. Magnetic resonance image revealed an intraspinal situated tumor C6/8 (Fig. 4). Approach planning. The following approaches were evaluated. Multilevel laminectomy with wide intraspinal exposure: This approach allows wide visualization; however, approach-related destruction of the vertebral lamina can cause postoperative late deformity. Multilevel laminoplasty avoids postoperative loss of posterior bony protection; however, the exposure causes wide bilateral muscular injury. A unilateral approach with hemilaminectomy or multi-segmental interlaminar fenestrations offers comparable intraspinal exposure, however with minimal muscular destruction and without injury of the dorsal static structures (Fig. 5). Surgery. After longitudinal median skin and fascia incision, the paravertebral muscle was reflected laterally to the right side. Using the operating microscope, interlaminar fenestrations were performed in the levels C5/6, C6/7. With the high-­ speed drill and Kerrison rongeurs, the contralateral vertebral arches were gently undermined, achieving optimal access into the spinal canal. After dural opening, the tumor was removed under continuous neuromonitoring. Under the preserved C6 lamina, complete tumor resection was controlled with endoscope-assisted technique (Fig. 6). The histopathological examination showed a benign ependymoma. Postoperative course. Direct postoperative patient showed minor impairment of gait ataxia without vegetative disturbances. During the 5-days postoperative stay, patient recovered completely and could return to his previous employment 4  weeks after surgery. Postoperative MR imaging showed complete tumor removal (Fig. 7).

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Discussion There is agreement among authors that the treatment of choice of spinal schwannomas is the complete surgical removal. However, concerning operative exposure, opinions vary. Since the first dorsal laminectomy, described by Smith in 1829, the diagnostic and therapeutic possibilities have been developed enormously (8). However, the operative methods have not been changing markedly for almost 200 years and laminectomy is described in recent publications as the most commonly performed neurosurgical procedure (9). Otherwise, the importance of preserving the posterior bone elements with the attached ligaments and muscles is widely recognized (6). In order to reduce these postoperative complications, Raimondi (10) recommended osteoplastic laminotomy, Eggert (4), Yasargil (11), and Sarioglu (12) unilateral hemilaminectomy. Perneczky popularized a more limited approach, using multi-­ segmental inter-arcuar fenestrations to observe intraspinal lesions (13). In this article, two cases with intraspinal tumors were demonstrated, operated through minimally invasive spinal keyhole approaches. After preoperative planning of surgical treatment taking into consideration, the individual pathoanatomical situation, both lesions were approached by effective limitation of iatrogenic destruction of posterior elements of the spinal column. The contralateral hemilaminectomy approach allowed optimal visualization along the tumor axis and safe surgical preparation in the opposite intraspinal area without extended laminectomy or costo-­ transversectomy. To our knowledge, there has been no previous report of a spinal schwannoma treated successfully by contralateral exposure.

Addendum Both operations were performed from the author in 2001 as neurosurgical resident under the fruitful assistance and intra-operative support of Prof. Axel Perneczky. This paper is addressed to him with infinite respect and gratitude. Acknowledgments: We express our gratitude to Stefan Kindel for his artistic assistance.

Minimally Invasive Neurosurgical Treatments (MINT) Takanori Fukushima Carolina Neuroscience Institute, Raleigh, NC, USA Division of Neurosurgery, Duke University Medical Center, Durham, NC, USA Professor Axel Perneczky and the author were cooperating to promote Minimally Invasive Neurosurgical Techniques and Treatments in the 1980s and

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1990s. For over two decades, we maintained good colleagueship as well as a personal and professional friendship. I have been pioneering the development of innovative neuro-endoscopes and of minimally invasive keyhole microsurgical techniques. Professor Perneczky possessed an extremely agreeable and warm personality and had excellent microsurgical skills and neurosurgical knowledge. Professor Perneczky was a man of science and academy, publishing a number of scientific articles and textbooks. In commemoration of Professor Perneczky’s great clinical neurosurgical contribution and promotion of minimally invasive neurosurgical concept, I will discuss the idea of minimally invasive neurosurgical techniques and the development of keyhole micro-operative procedures. I started neurosurgery in 1968 and my first specialization was stereotactic treatment of parkinsonism. I performed stereotactic thalamotomy in over 300 cases with Parkinsonism and at the same time I developed the neuro-fibro-endoscope as well as transsphenoidal pituitary microsurgical technique and keyhole supermicroneurosurgery. Over the past four decades of my entire career, I devoted myself to the development of Minimally Invasive Neurosurgical Technique and concept. In this article, I present the development of an innovative neuro-fibro-endoscope, establishment of a keyhole microsurgical approach for hemifacial spasm, trigeminal neuralgia, and glossopharyngeal neuralgia as well as the development of a mini-craniotomy and lateral supra-orbital minimally invasive approach.

Development of the Neuro-Fibro-Endoscope Since the first description of a ventriculoscope by Walter Dandy in 1922, various kinds of ventriculoscopes have been reported by Fay, Putnam, Guiot, and Scarff. Most of these ventricular endoscopes were used for the endoscopic cauterization of the choroid plexus in the treatment of hydrocephalus. All of the previous neuro-­ endoscopes were rigid endoscopes with large caliber and were restricted for the visual diagnosis and management of hydrocephalus. In 1968, I developed a 3 mm and 4 mm ventriculo-fiberscope with a 68-degree wide viewing angle lens. The tip of the fiberscope could be bent 30° up and 130° down angle with electric bending control.1 The fiberscope has a channel for irrigation, aspiration, and insertion of an electrocautery probe. The results of the clinical application of this ventriculo-fiberscope were published in Journal of Neurosurgery in February 1973 with the operative results in 37 clinical cases.2 This neuro-fibro-­ endoscope was mounted on a supporting stand and the entire scope was sterilized. The insertion of the biopsy probe and coagulating probe were inserted with a special Y connector in the middle of the fiberscope tube with irrigation and suction control. Photograph and motion pictures could be taken for recording of the operative event. Figure  1 illustrates the supporting system and the fiberscope (Fig.  1a) and the

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bending section of the tip controlled electronically with the foot lever (Fig.  1b). Figure 2 demonstrates various pictures of the intraventricular lesions. Figure 3 illustrates a special 2 mm catheter endoscope for spinal endoscopy and Figure 4 illustrates the needle endoscope (Fig.  4a), which was used for spinal endoscopy and particularly C1–C2, lateral endoscopy.3 This Celfoc needle endoscope was also used for CP angle endoscopy4 through the retromastoid burr-hole (Fig.  4b). The clinical results of Celfoc needle endoscopy and spinal endoscopy were reported in Neurochirugica in 1975.3 Results of endoscopic biopsy for intraventricular tumors were reported in Neurosurgery in 1978.5 Because of the development of a keyhole microneurosurgical technique and minimally invasive craniotomy with innovative supermicrosurgical instruments, I stopped using these neuro-endoscopic techniques by the end of the 1970s. I never imagined that the revival and revitalization of neuroendoscopy could occur in the middle of the 1980s by Perneczky and others. a

b

Fig. 1 (a) Innovative operating neurofiberscope mounted on the supporting stand with Xenon cool light supply (Olympus model 1969). (b) Tip of the bending portion of the neurofiberscope (3 mm), 30° up and 130° down automatic electric control by the foot pedal

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Fig. 2  (cases from 1968 to 1969). (a) typical picture of foramen of Monro with septal and thalamostriate veins and the choroid plexus. (b) typical appearance of cystic craniopharyngioma. (c) example of pineoblastoma

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xxvi Fig. 3  Development of a 2 mm soft catheter endoscope for cisterna magna and intraspinal investigation

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Fig. 4 (a) Celfoc glass rod neuro-endoscope of needle type (outer diameter 0.8 mm–1.2 mm). (b) A picture of C-P angle endoscopy showing the abducens nerve and the Dorello’s foramen

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 ime-Size Keyhole Microsurgery: Microvascular Transposition D (MVT) for Hemifacial Spasm, Trigeminal Neuralgia and Glossopharyngeal Neuralgia It should be highly commended of the effort and research of Professor Perneczky for the popularization of the neuro-endoscopy, endoscope-assisted microsurgery and keyhole microsurgical approaches. Since 1978, Fukushima developed a keyhole microneurosurgical approach and microvascular transposition (MVT) procedure in the surgical management of hemifacial spasm, trigeminal neuralgia, and glossopharyngeal neuralgia. Hemifacial spasm, trigeminal neuralgia, and glossopharyngeal neuralgia are distinctive clinical entities and are extremely annoying and distressing disorders that cannot be cured by any other medical management. With the clinical neurosurgical work by Peter Jannetta since 1970, the pathophysiology and etiological mechanism have become clear that hemifacial spasm, trigeminal neuralgia, and glossopharyngeal neuralgia are caused by vascular loop compression onto the exitentry zone of the cranial nerves. I started to perform vascular loop transposition surgery in September 1978. I performed 400 operative procedures from 1978 to 1980, and I established a dime-opening keyhole retrosigmoid approach. A superior dimesize opening is used for trigeminal neuralgia and an inferior retrosigmoid keyhole for hemifacial spasm and glossopharyngeal neuralgia. A number of the previous literature make an inappropriate or wrong surgical approach to the cisternal segment of the seventh and eighth cranial nerves where either the PICA or AICA loop were manipulated with high risk of hearing complications. I noted that vascular loop compression is not around the cisternal portion of the seventh nerve. The compression site for hemifacial spasm exists at the nerve root exit zone on the lower pons over the proximal ninth nerve. Previous microvascular decompression procedures of inserting prosthesis material such as Ivalon sponge, Dacron or Teflon pledget are totally inappropriate procedures. Surgery is not the insertion of prostheses in between the facial nerve and the vessel, but mobilization and transposition of the compressing vascular loop towards the jugular foramen and fixation with shredded Teflon tape and fibrin glue. Nothing should touch the nerve root. This is the correct microsurgical procedure for hemifacial spasm. This keyhole microsurgical curative treatment should not be called a Microvascular Decompression (MVD) but should be designated as Microvascular Transposition (MVT). Figure 5 illustrates the patient positioning and location of the one-inch skin incision and a dime-size keyhole bone opening. Operative techniques of vascular loop transposition and fixation with shredded Teflon tape sling and fibrin glue is shown in Fig. 6a for AICA-­MVT and in Fig. 6b for VA PICA-MVT. I performed the MVT procedure in over 3300 cases from 1978 until 2008, over 30 years with a one-time surgical cure of 96%.6 Throughout my 30-year surgical experience, my keyhole microvascular transposition operation carries 0.1% major risks and 1 or 2% of minor risks. The offending vascular loop was the AICA branch in 35% of cases, PICA branch in 30% of cases, and vertebral artery compression in 20% of cases. For trigeminal neuralgia, it is noteworthy that in my series of 2300, 10% of typical class 1 genuine trigeminal neuralgia showed the presence of a brain tumor, mostly epidermoid tumor (9%) and acoustic neuroma and meningioma (1%). In

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Fig. 5  Lateral position and the location of the trigeminal (upper) and the facial nerve (lower) keyholes (1-inch skin incision and the dime-size bone opening)

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Fig. 6 (a) shredded Teflon tape sling method and fibrin glue fixation for AICA loop transposition. (b) shredded Teflon tape sling and covers for mobilization and repositioning of VA and PICA loops

addition, I had 12 cases of cryptic angiomatous malformation in and around the trigeminal nerve root. The other 80% of patients had typical vascular loop compression mostly by the superior cerebellar artery, 7% by the vertebro-basilar artery trunk and an additional 8% by an AICA loop compression. Throughout these vascular loop transposition procedures, an initial one-time surgical cure was obtained in 96% of cases. In typical hemifacial spasm cases, there was no negative exploration and all patients had vascular loop compression. In typical trigeminal neuralgia cases, despite typical tic douloureux syndrome, 10% had no vascular loop compression. For these negative cases, the cause was unknown. I performed glossopharyngeal neuralgia surgery in 60 patients and the results were excellent. Long-term follow-up

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data over 20 years shows my vascular loop transposition in glossopharyngeal neuralgia was excellent with over a 95% cure rate.7

 evelopment of a Mini-Craniotomy and a Lateral Supra-Orbital D Keyhole Approach In 1980, I developed a midline keyhole interhemispheric approach for the clipping repair of ACOM aneurysms (Fig. 7a, b). I developed the lateral supra-orbital keyhole approach (Fig. 8) for anterior circulation aneurysms such as internal carotid PCOM aneurysms and MCA aneurysms. In 1981, I made the first report of the lateral supraorbital keyhole pterional approach for aneurysms (Fig. 9). For this type of keyhole procedure, I developed keyhole aneurysm clip appliers (Fig. 10) which are about half size of a standard Yasargil clip applier. I have been continuously using these keyhole aneurysm appliers for over a 30-year period. In 1982, I switched from the U-shaped or horseshoe craniotomy flap to the straight incision and trephine minimally invasive craniotomy technique for calvarial lesions and subcortical tumors (Fig. 11). In 1982, I developed an ultrasound B-scope neurosurgical imaging device with a one-inch mini-probe9 for visualization of subcortical lesions such as brain tumors and cavernous hemangiomas (Fig. 12). In 1995, I developed a keyhole ultrasonic aspirator which is less than half the size of the American CUSA hand piece (Fig. 13).8 I also developed a needle ultrasonic aspirator for percutaneous aspiration and removal of gliomas.8 All of these ultrasound developments were published in the 1980s and 1990s as a scientific article.9 Although my current specialty of skull base surgery for treating large and extensive cranial base tumors may require wide surgical exposure, I still maintain a minimally invasive or less invasive philosophy. My previous technical developments, microsurgical Fukushima instruments and special Fukushima Retraction Holder System10, 11 facilitate accurate performance of Minimally Invasive Neurosurgical Treatment (MINT). In conclusion, I hope the next generation of neurosurgeons in the world will follow and maintain our effort of minimally invasive neurosurgical concept and technique for the benefit of patients. a

b

Fig. 7 (a) midline interhemispheric keyhole approach for Acom aneurysm clipping (3  cm trephine opening). (b) midline interhemispheric keyhole approach via forehead crease incision repairing Acom and A2-3 aneurysms

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Fig. 8  Lateral supra-orbital 3 cm incision and keyhole bone opening for clipping of Pcom aneurysm (1981)

Fig. 9  Illustration of lateral supra-orbital skin incision and a case operated for ruptured MCA aneurysm (1981)

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Fig. 10  Fukushima designed keyhole aneurysm clip appliers; double joint model and angled groove models (13 with various angles)

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Fig. 11  Straight incision and mini-craniotomy for calvarial subcortical lesions

Fig. 12  One-inch mini-probe for linear electronic ultrasound imaging (TOSHIBA model, 1982)

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Fig. 13  Development of a keyhole ultrasonic aspirator with a small light-weight hand piece (Olympus 1995) and needle type tips, utilizing a special technology of electrostriction transducer and not electromagnetic type (American CUSA)

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Results of Imaging The complete spectrum of neurosurgical diagnoses presented applicable assistance for therapy in our experience. In 376 intra-operative applications, ultrasound proved to be an excellent neuro-navigation system providing the surgeon with real-time imaging and targeting capabilities. Resection control in 221 tumor cases with targeting in 29 small lesions was very satisfying and in four cases craniotomy correction was possible before opening of dura mater. Compensation of computer-­ navigation failures was possible in 14 cases preventing possible disasters. The 584 cases of application at the ICU showed a bedside use, resulting in a decrease of risky out-door examination reduce stress for our patients and logistic efforts for the professionals. Investigations are running in innovative applications like: brain death diagnosis (54 cases), bedside-sono-CT (92 cases), aneurysm-monitoring (50 cases), bridging-­ vein monitoring (15 cases), sono-pupillometry (23 cases). Intra-operatively we examined sono-angiography in tumors and for clipping control of aneurysms. Compensation of computer-navigation pitfalls was frequently necessary and always successful representing the real-time lack of computer-neuro-navigation. With the new trans-endoscopic use, which was introduced by the senior author in 1996 into neurosurgery, it is possible to intuitively navigate endoscopes serving like a “brain-radar.” (see the following) The clinical benefit of intra-operative ultrasound has become widely known from works published by several authors. Since the era of CT and MR, ultrasound did not have a chance to be widely accepted in neurosurgery. However, the brain is an ideal organ for ultrasound and neurosurgery can learn today from neighbor disciplines with a large experience. Moreover, we can take over the technical evolution of two decades resulting in a wide field of uncharted territory. In this chapter, the daily use of high-end ultrasound in neurosurgery is presented and a first series of 1084 examinations (2002–2006) evaluated in a broad variety of lesions and indications. The main goal of consequently using ultrasound was to minimize the trauma to the patient and to assist in minimally invasive techniques in neurosurgery. The transcranial sonography applied via the typical fronto-temporal, temporal, or suboccipital windows was only in four cases not possible because of thick bone. The postoperative cases additional presented small bone defects enabling excellent quality of imaging at bedside. After decompression craniectomy, ultrasound scanning was compared to CT in imaging quality. During 1084 examinations, 1053 diagnoses with a large variety were found and were appropriate for ultrasound technique (Table  3). In addition to the diagnosis and the morphology, we examined physiological and pathophysiological parameters especially of the blood circulation. Intra-operatively, in this series, we had in 376 examinations a lot of different applications.

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xxxiv Table 3 (2006) Diagnose Aneurysm Tumor ICH Trauma SDH Infarction Dysontogen lesion Spinal lesion NPH Cavernoma Aqueduct stenosis Abscess Angioma Epilepsy Others ∑

No 353 221 148 95 43 31 27 28 24 16 13 11 12 2 29 1053

Position of craniotomy was controlled through the first burr-hole to be optimized if needed. Before opening the dura, targeting and examining the lesion in comparison to the pre-op imaging was always done. Blood supply and main feeders of tumors with the surrounding edema were imaged from the actual surgical perspective. Such information offered actual information to decide or in case change the operative strategy. Details could be localized through the operative approach and targeting was able in real time. During the ultrasound assisted procedures, orientation, real-time navigation and resection control of tumor cases and clipping control of aneurysm cases was able in all such examinations. In a few cases, even the pre-op diagnosis had to be corrected with severe consequences for the operative strategy. All emergency cases were assisted by ultrasound for completion of diagnostics concerning the reason and site of bleeding or because assistance in targeting the lesion was necessary. Peri-operatively also many applications were seen during 646 examinations: At ICU in 584 examinations, monitoring of morphological and pathophysiological parameters were routinely done. Vasospasm and blood circulation follow-ups, obliteration of vessels, and developing of hydrocephalus or hematomas were regularly controlled. CT or MRT indications were proven by bedside sono-CT in 92 examinations decreasing numbers of risky out-door CTs and all that consecutive logistic disaster (Figs. 2 and 3). In 24 investigations, a follow-up by high-end ultrasound, during 4  years was used to reduce MR examinations. This was done through small bone defects after craniotomy. Innovative applications (Table 4) were possible in 521 examinations with different indications. Bedside sono-CT as a substitute for CCT was applied 92 times, Sono-angiography was investigated 65 times to evaluate aneurysms pre- and

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post-­op and to examine the cerebral blood circle in different diagnoses. Aneurysm monitoring was applied 50 times to follow up stress parameters for the aneurysm sac and to estimate the risk of rupture and to get a more precise timing of operation and intensive care measurements. Intra-operatively in six cases, a clipping control was done applying sono-angiography pre- and post-clipping to see patience of parent vessels and exclusion of the aneurysm. This intra-operative sono-angiography allows the surgeon to react during operation and correct clip position in the same procedure.

Fig. 3  International ultrasound course group at bedside training

Compensation of computer-neuro-navigation pitfalls was able in 14 cases for different reasons of failures of the soft- or hardware. Decompression craniectomy effect on the cerebral perfusion was measured in 15 examinations by bridging-vein monitoring at bedside. In normal pressure, hydrocephalus shunting procedure effect on perfusion was controlled in 23 cases. Finally, pupillomotor measurements were documented by sono-pupillometry in 23 examinations enabling objective documentation of anisocoria in selected cases of interest. A new intra-operative application and introduction into neurosurgery was the use of transendoscopic ultrasound in 75 highly selected cases. In these cases imaging, neuro-navigation and targeting in neuro-endoscopy was evaluated clinically after a

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period of laboratory testing (Fig. 5). It was shown that navigation of endoscopes is possible in real time and imaging and targeting of lesions with high resolution was able in each case of application. (s. case 14 and end of this chapter) Endo-Sono Correlation 3

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Fig. 5  The endoscope view (left) shows the right lateral ventricle with the choroid plexus (2), pellucid septum (3), and the transendoscopic mini-probe (4) in tough with the plexus. The ultrasound scan (right) represents the sono-probe by a spot (1) in tough with the plexus (5) and shows in addition to the right ventricle (2) the left ventricle (3), the septum (4), and the thalamic parenchyma. This scan is a real-time land map looking like a “mini-CT” and enabling navigation of the endoscope as each moving of the endoscope is visible on the ultrasound scan by the moving of the spot (1) in real time and in relation to anatomical landmarks not visible in the endoscope. Due to its 360° geometry presentation, we call it “brain radar.” Ultrasound in neurosurgery is still not widely used in times of CT and MR. A retrospective analysis of a complete spectrum of application in neurosurgery (1084 examinations) using high-end ultrasound technique has not been reported. Few papers presented results of the intra-operative spectrum of applications. Most of them are dealt with a special application applied in a very few examinations. In addition to intra-operative application also the peri-operative use is presented, and the first unexpected result of analysis is the broad variety of the applied spectrum. The main goal of application in the present series was to assist in minimally invasive technique of neurosurgery with single high-end equipment. This goal can only be reached by small probes and proper selection regarding size, shape, and frequency. Moreover, it does not make sense in our opinion to enlarge the approach and the trauma just for applying a big ultrasound probe. Table 4  Problem-solving by ultrasound in MIN Intraoperatively: •  Imaging (Additional Information about the Lesion) •  Targeting (Find a Small Lesion, Direction of Approach) •  Neuronavigation (Real-Time Orientation) •  Pathophysiology (Vasospasm, Perfusion, Shift) •  Emergency (Angioma? Aneurysm? Main Feeders?) •  Diagnosis (Vascularisation? Type of Tumor? etc.) •  Reorientation (Complex Lesion, Confusing Changes to preop.) •  Resection Control (Tumor Borders) •  Clipping Control (Patency of Parent Vessels)

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Recent papers reported mostly on rather complex combination of ultrasound with other techniques like neuro-navigation. In the present series, we focused applications using only technical equipment that compete principles of ergonomics in neurosurgery avoiding “technical overkill.” There was no single case in which ultrasound use needed assistance by neuro-navigation system. This is not surprising as the ultrasound is a navigation tool itself and the only technique that competes the definition of navigation, namely a real-time feedback. We had 14 cases in our series of neuro-navigation, where the ultrasound had to compensate pitfalls of neuro-­ navigation systems (Table 4). In this 1084 examinations, one third were intra-operative and two third were peri-operative use. However, it was seen during daily work that neurosurgical therapy outside the OR can be markedly assisted by ultrasound (Figs. 2 and 3). These applications differ a lot from neurological applications as there were different problems to be solved and as neurosurgical ultrasound applications can use the bone gaps left in postoperative cases enabling bedside imaging which even might substitute CT or MR. A convincing learning curve was the integrated investigation of anatomical structures together with physiological parameters which gave a complete different decision-making as usual when using only MR or CT. Intra-operative control of craniotomy position was an easy and helpful use enabling precise dimensioning of craniotomy in a minimally invasive strategy. However, consequent epidural examination of lesions created much more safety for consecutive decision-making in favor of a minimally invasive strategy. In this series of 376 cases, the ultrasound was used like a surgical instrument always at hand and serving like a “personal intra-operative neuroradiologist.” In no single case neuro-­navigation was needed for targeting feeders; moreover, in contrast to the three orthogonal computer planes the ultrasound did present the vascular supply in relation to the surgeon’s perspective through the surgical approach resulting in an intuitive understanding during the targeting. The main disadvantage of neuro-navigation systems is the lack of real time, and actually there are efforts to overcome this by ultrasound integration to neuro-navigation systems. Three different technical realizations are going on: first, several platforms offer an integration of an ultrasound probe into the navigation system. The second realization is that ultrasound equipment is supported by integration of navigation components. The third realization is that navigation system and ultrasound equipment is combined by registration of the ultrasound probe like a pointer in the 3D-data of the navigation system. However, the problem of mathematical description of brain shift is not solved. All these systems can just enable to show the shift on a display in relation to the off-line imaging. In other words, the navigation system serves as an interpretation interface of the ultrasound imaging. In our opinion, this solution seems rather expensive just to display a shift which is for pure ultrasound use; no problem at all as ultrasound enables the real-time imaging. Moreover, it has been observed by the author that the imaging management task for the surgeon impairs neurosurgical ergonomics

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of the environment as well as mental management. Investigative applications (Table 4) have been usual in this series (521 examinations) as neurosurgery can benefit today from neighbor disciplines with large experience and the new developed techniques. However, examination numbers are still low, and more experience is needed to avoid premature reports. The transendoscopic ultrasound however has been used with very strict indication for a long time after introduction into neurosurgery by the senior author. Results in general have been documented and presented already. (s. below) The limitations of ultrasound imaging are: worsening of the image quality by physical changes of the brain tissue during surgery. In resection control, a typical echo density of the resection planes can be regularly observed. Differentiation of the borders of low-grade gliomas is difficult and also resection control; however, in this series targeting was always possible and resection control in low-grade gliomas is difficult in all imaging techniques. The commonly used term of limitation in ultrasound is the “strong user dependence.” During over 40 years of experience with neuroimaging techniques and their neurosurgical use in the daily work it must be recognized that the user dependence is true for all imaging techniques but well known in ultrasound than in the other “anatomistic” imaging methods like MR or CT. Moreover, our experience in this series was also that generating of imaging, interpretation, and decision-making on the one hand was a major advantage in the use of ultrasound compared to CT and MR. A special intra-operative condition for using ultrasound was to position the patient with regard to the need of fluid overlay as contact medium. Absolutely clean working field is also essentially; however, these needs are generally prerequisites of good neurosurgery. In summary, routine use of high-end ultrasound in neurosurgery enables a broad variety of applications and indications intra- and peri-operatively. Ultrasound contributes to minimally invasive techniques with realization of good ergonomics in neurosurgery. Most limitations can be avoided by correct usage and sufficient experience and training (Tables 5, 6, 7, and 8).

Table 5  Intra-operativ sono-targeting in MIN Targeting: •  Small Lesion •  Tumor Remnant • Slitventricles • Distance + Angle • Volume

Corrections: Vol. 1, Chap. 4: p. 169–182: History of Ultrasound in Neurosurgery Table 6  Peri-operative sono-monitoring in MIN Monitoring extra-op • Vasospasm •  Aneurysm Remnant • Vessel-Occlusion •  Ventricular Size •  Edema and Shift • Rebleeding? Table 7  Intra-operative imaging in MIN Intra-operative Imaging: •  Size and Correction of Craniotomy • Cyst/Tumor? • Tumorborders • Edemborders • Tumordignity •  Resection Control • Sono-Angiography •  Clipping Control and Patency of Parent Vessels •  Shifting and all intracranial Changes •  Ventricular Size and Changes •  Unexspected Findings!  –  Cause of Bleeding (Aneurysm, Angioma?)  –  Actual Tumor size (fast growing)  –  Perfusion Amount of the Lesion •  Physiological Parameters

Table 8  Intra-operative sono-navigation in MIN Neuronavigation: •  to the Target •  Pitfalls of Computer-Neuronavigation  –  Shift  –  Registration Failure  –  Technical Failure (soft, hard) •  Cysts Distribution + Parenchymatous Topographic Anatomy • Orientation •  Correlations Texture •  Early Detection of Dangers

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Goal: Planning and Controlling a MIN Approach

Ultrasound can be used in a wide spectrum of applications and indications. But within MIN, it is applied as a key technique to enable minimally invasive strategies. One of the most obstacles for MIN came from the question: “Can I control the procedure through a small precisely adapted MIN approach?” To decide the strategy, one has to know which information for planning is needed and which ultrasound application can deliver this information. Once the learning curve gives the experience that the key information can be acquired regularly, insecurity will decrease and precision of approaching and security of managing difficulties will grow. It is impossible to imagine the MIN approach without this experience. It should become normal by training. In the case above, analysis of feeders and vascularization by duplex-sonography convinced during planning that this strategy will work and can be applied in the handicapped old lady. Standard concepts came to the decision: inoperable due to the trauma and high risk expected for the multimorbid lady. The spectrum of applications and problem solutions by ultrasound, however, can best be demonstrated by typical cases. Such cases are presented, each standing for a certain capacity of ultrasound-assisted solutions:

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Cases Case 1: Sono-assisted Angioma-ICH Evacuation Emergency

In this emergency case with a dramatic deterioration of rising ICP to a comatous status during MR, it was not possible to get a sufficient diagnostic about the av-­ angioma regarding architecture and flow. Within short time, it was clear; the reason for bleeding and the life-threatening clinical status. This is one of the most satisfying applications of high-end ultrasound giving the surgeon during emergency situation and incomplete imaging the safety to complete the imaging intra-operatively and to target the evacuation precisely. How to evacuate the hematoma without hurting the angioma and provocating a dangerous rebleeding while releasing the high ICP to normal level and to save the life? This can only be done fast and safe enough with the assistance of high-end ultrasound in the duplex mode and if needed with triplex mode to identify the danger of angioma. The boy was operated fast through a single burr-hole and was sent to further investigations by the interventional neuroradiologists in a normal neurological status.

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Case 2: Duplex-Sono-assisted ICH Evacuation

The CTA in this lateral ganglia-ICH showed close proximity to the ICA bifurcation in coronal and lateral view. Transdural burr-hole duplex-ultrasound showed a plane of cerebral tissue between the vessels and the hematoma in coronal and lateral view, as well as the consistency of the bleeding with a liquid and a thrombosed compartment. The deep hematoma was evacuated through a 1€-approach after the ultrasound findings that there is no reason for dangerous bleeding and that the liquid part of the hematoma will enable a fast and easy release of ICP. This means, that the evacuation of the thrombus will then be possible, safe, and controlled. The somnolence, headache, and severe hemiparesis disappeared within few days and perifocal edema also. After rehabilitation stay, she surprised the author, 2 month since the stroke, with a video clip in which she is skiing. The husband, who became desperate during the stroke-unit days, because she got worse every day, urged the neurologists to call the neurosurgeon. This was not usual after the STICH-trial period, a disaster still taking place.

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Case 3: ICH Evacuation in Severe Coagulopathy Case

This is an example showing that sono-assisted MIN enables operations under bad conditions like high age and severe coagulopathia. While she still was in substitution MIN surgery already was started to prevent brainstem compression. After duplexsonography epidural did not present a danger bleeding pathology intracranial, the procedure could be done safely and fast through a 1€-approach with minimal irritation for the coagulation physiology. Sono-imaging shows a liquid part of the hematoma superficial and a deep thrombosed part compressing the lateral ventricle. After a very fast decompression of the ICP, the sono-control did not present pathological vessels in normal ICP conditions. The hematoma was easy and very carefully sucked out but without any explorative actions, the evacuation amount was only checked by ultrasound. This can shorten the procedure and prevent to evoke rebleeding. Opening and closure are maximally fast in such MIN procedure also. The patient recovered fastly and kept a slide paresis of one arm being full accepted life quality and well cared in her glad family.

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Case 4: Supra-orbital ICH-Evacuation and Cavernoma Extirpation

This case of a large ICH offered the option to approach it through a lateral supra-­ orbital window which is a challenging task and need a precise planning. In MIN, volumes should be approached always along the long axis. To be sure not to meet a dangerous bleeding cause, in such a strategy of approaching, ultrasound assistance is absolutely indispensable. You must be aware of managing the complete space into the depth of about 100 mm with safe focus and visualization. This is only possible with mouth-switch tracking of the microscope having an online focus with similarly maximum of magnification. (s. Chap. 4) The intra-operative ultrasound imaging promptly showed some clear pathological vessels which could have been a relative contraindication for a supra-orbital approach and which were not visible in the CTA! Ultrasound is much more sensitive for presenting vessels in a raised ICP situation, than CTA or even MRA. A fast second look by duplex-sono will show vessels in a released ICP situation, giving sometimes surprises in negative CTA findings! Here, the ultrasound showed a cavernoma before opening the dura, the final information to go on with the supra-orbital approach strategy without choosing an enlarged approach or surgical variation.

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 ase 5: Near-Fatal ICH/IVH with Ventricular Tamponade from Left C Frontal Ganglia

In this dramatic case of a near-fatal ICH in a 19-year-old girl, the role of peri-­ operative ultrasound can be demonstrated. After 3 frustran operations (two drainages and craniectomy), coma, mydriasis, and high ICP persisted and no therapy was suggested anymore. Next morning through the large craniotomy a precise and extended three-planar duplex examination was undertaken surprisingly presenting a still sufficient real flow imaging. The contralateral insular vessels and the bridging veins could be shown. No bleeding cause was seen at this stage in concordance with MR imaging. This gave the basics for a final MIN strategy: 3 cm of the suture and the dura 2 × 2 cm were re-opened, and with the safety of a real-time imaging assistance by ultrasound (in connection with mouth-switch tracked microscope/s (Chap. 4)) the hematoma was evacuated, and under ultrasound control to detect vascular pathologies and volume reduction over 90% evacuation was realized within about 1 h. She recovered completely and went back to her profession (s. Vol. 4). Post-op sono-control showed near-complete evacuation and patent perfusions.

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Case 6: Intra-op Sono-Angio of Meningioma

This “swimming”-tumor showed in MRT an appearance which allowed different diagnoses from cystic tumor types or meningioma. The change from angiography as main diagnostic tool to CT and MR caused a decrease of imaging solution and a loss of knowledge about vascular patterns. The capillar fingerprint of lesions got lost in only one generation of radiologists and surgeons. Ultrasound provides, with several modes, to analyze the vascular information and localizations of details about the lesion before opening the dura. In this case, the vascular supply presented the typical pattern of a meningioma. But more important is the existence of a pial feeder which has a major impact on operative strategy. It was essential for the outcome to approach the pial feeder first and to coagulate and cut it. Otherwise in case of extirpation, a bleeding and neurological deficit can occur. Also, the primary coagulation of the arterial supplied from the dura can make surgery fast and easy. Ultrasound can inform about the best tactic and strategy of the surgery before opening the dura.

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Case 7: Intra-op Sono-Imaging a. com. Ant. aneurysm

This vascular case shows an a. com. Ant. aneurysm in comparison between radiological CTA and DSA with surgical Duplex-Sono and PW-Sono. The sono-imaging provides the imaging through the surgical (pterional, blue arrows) approach and additional with physiological parameters. Ultrasound can intra-operatively give essential information about the blood circle and the aneurysm. Post-clipping these parameters can be compared to pre-clipping both intra-operatively to see if clip correction is necessary and if all vessels are patent, and also the reaction of the parenchyma. In contrast to ICG fluorescein-angiography control, the vessels are visible in sono-control independently if they are visible through the microscope or not. Ultrasound can compensate ICG control problems. The aneurysm can be seen within the edematous tissue, and the aneurysm wall can be analyzed as well as intra-aneurysmal thrombus and flow-parameters. All these information before opening of dura and during the whole operation make the challenging procedure safer, faster, and less stressful.

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 ase 8: Giant Aneurysm: Multiple Parameters of Pathoanatomy C and Pathophysiology

In this case of a giant M-bifurcation aneurysm, the sono-examination of aneurysm wall and flow characteristics like turbulences and direction of flow are shown exemplarily which is not so clearly visible in medium or small aneurysms. In the duplex, the typical yin-yang (blue-red) appearance and screw-turbulence are well demonstrated. The fine calcification of the carrier vessel wall and the thick thrombus inside the aneurysm are precisely presented. All morphological and physiological parameters are essential for understanding the lesion and the dangers during therapeutic procedure whatever it may be. This information can not only be acquired transcranially pre-op and transdurally intra-op but also during the procedures. This information cannot be provided by CT or MR. By triplex mode, quantitative measurements of flow-parameters can be visualized, and calculations of stress of aneurysm wall and timing of procedures can be derived.

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Case 9: Glioma (Astrocytoma II) Resection Control

Glioma resection control was one of the first special applications of advanced intra-­ operative ultrasound in times, when there was no “neuro-navigation” by computer-­ assistance systems available. Neurosurgeons had to recognize tumor by tissue consistency, color, morphology, vascularization, necrosis, perifocal edema, and the tendency to bleed. Tumor resection control was difficult as the tissue changes during surgery and shift progress occurs. Imaging in real-time to estimate character of tissue, real-time sono-navigation for re-orientation, and targeting tumor remnants were applications which came with ultrasound into neurosurgery. The vascularization pattern as a “fingerprint” of different tumors is only in use by duplex-ultrasound and triplex-sonography. As the only real-time technique, without radiation side-effects ultrasound is independent of shifting of tissue intra-operatively, a promise that never has been kept by computer “neuro-navigation.” Resection control needs a clean surgery and correct positioning of the head, which are preliminaries for MIN.  Sono-application must not be an excuse to enlarge the approaching for MIN, with high precision.

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Case 10: Sono-Navigation of the Fourth Ventricle

The real-time imaging of ultrasound makes it the only true navigation tool; hence, it is independent of all changes during surgery; moreover, it can detect and visualize these changes. Whenever changes cause uncertainty to the surgeon, ultrasound can truly navigate during surgery for orientation, correction of direction, and distance to the target. In this case of a child, the very experienced surgeon was afraid to enter the brainstem while searching for a pathway to the fourth ventricle. The burr-hole probe (ALOKA) gave safe information on how to go on and the small-part probe (ALOKA) showed, compared to MR-quality, in axial and sagittal, the complete anatomical overview of posterior fossa content. The burr-hole probe with tough plane 8  ×  8  mm can be used like a “seeing micro-instrument,” fast and handy throughout the surgery. In cases of less imaging quality, using duplex mode will show further landmarks by the vessels presented. Moreover, once the liquor pathway is open, the flow will be visible by color artifacts showing velocity and direction of flow. The small sono-­ probes (s. Graph 6) fit elegantly and with good ergonomics into the surgical workflow.

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Case 11: Navigation of a Small Lesion—Targeting

Cavernomas are well visible even when they are very small hence being targets. However, due to the small size, there is no chance for them to be safe from computer-“navigation.” Most of these sono-navigation cases are computer-navigation pitfalls, leaving the surgeons in desperation if they have no compensation by ultrasound. The reasons are sometimes below the surgical precision range of the navigation systems misleading surgeons into the wrong direction. One cannot rely on the xanthochromia of the perifocal tissue as the small cavernomas do not always have this sign. Draining veins and DVAs can be identified and preserved as they are easily differentiated from supplying arteries. In this temporo-polar position, the cavernous sinus serves as a safe landmark and final medial border of the surgical field. Also, tentorial notch and mesencephalon as well as the basilar system will be well visible.

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Case 12: Metastasis Posterior Fossa

Standard approaches to the posterior fossa are very invasive because of the deep and strong muscle masses. Only in a small area between superior nuchal line and transverse sinus, the approach design is minimally invasive with regard to approach trauma. Transdural duplex-sono with burr-hole probe will inform about sufficient positioning and size of the approach. Moreover, the visualization of main-feeders location and the vascularization will inform whether the lesion can be surgically managed safely through a small approach. Sono-findings indicate if any adaptations of the planned approach is finally needed, and sono-findings also will show how exactly this adaptation is needed. Surgeons used to standard working overestimate the need of approach size in general. According to the senior authors’ experience and case analyses over 30 years, a MIN approach, detailed by sono-assistance, measures one third of approach size. Sono-assisted correction are in the range of some millimeters. Post-op function of neck muscles will not be impaired by this strategy, which is important for the post-op morbidity and the frequency of complications. Liquor collections in MIN approaches usual need no surgical revision.

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 ase 13: Preterm Hydrocephalus Post-bleeding C Sono-Assisted Procedures

MIN in preterm is convincing as all condition call for minimally invasive strategies and techniques, ultrasound assistance and guidance is most satisfactory there. All procedures must be seen by the patients with a view into future. The prize of standard procedures is much higher in this group compared to grown-ups. Working space is extremely limited and tissue premature. The problems are often biological simple in this type of hydrocephalus—compared with neoplasma—but the application is very difficult due to the mentioned conditions. Therefore, a strong focus must be given to the way of application and to the timing and planning of application. Only ultrasound assistance can realize this challenge, the frequent extraordinary problems that arise should not be answered by standards rather than by individual decisions and MIN strategies and techniques. Even a simple placement of drainage or reservoir should be sono-assisted with a minimal opening. Each revision and additional surgery can be the beginning of a disaster in the near future or a lifelong burden to the patient. Ultrasound-assisted surgeries need an innovative mind and strong education and training.

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Correction: Vol. 1: p. 351–373: Clinical Cases The first clinical case presented all conditions in ventricular endoscopy: The eye of the surgeon (KDMR) is fixed on the monitor, which is still in an uncomfortable lateral position. Camera cable, light cable, irrigation- and drainage line need to be controlled and kept sterile. The heavy camera and too long endoscope could only be controlled safe by 4 hands. A good overview of the third ventricle was possible, no obstructive membrane was found in this dysmorphic brain, and a shunt was implanted. Before going into endoscopic neurosurgery, it is indispensable to know and follow some rules given below: 1. Always fix your eyes on the monitor, whatsoever may happen! 2. Do everything inside the brain very slowly. 3. Stop moving the endoscope if you do not understand the image on the monitor. 4. In case of a bleeding never, leave the intracranial space/ventricle. 5. Advance the tip of the endoscope close to the bleeding origin. 6. If the irrigation pressure does not stop the bleeding, carefully press the lens on it and wait for some time and then prepare the transendoscopic bipolar. 7. Continuously control patency of irrigation and the free outflow. 8. End of outflow line must not be placed below foramen of Monro. 9. One canal of the endoscope must always stay open. 10. In bleeding accident cases, leave a drainage at the end of the procedure.

Graph 36  Case 1

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It was the anatomist S. T. v. Soemmerring, who described the cranial nerves, but also believed that the soul of human is located in the CSF.  Regarding the clinical symptoms of hydrocephalus patients, this was a logical concept. It represents the effects of liquor dynamics to the peri-ventricular regions of the third ventricle, the location of human soul functions according to recent results of neurobiology (G. Roth). Patients of this group are neglected usually, regarding hydrocephalus therapy.

Graph 37  Case 2

Case 2 shows a 49-year-old woman with chronic headache and NSAR abuse presented with gait walking, stress incompliance, and decline in performance. She could only sleep in semi-sitting position. Concentration and memory became worse. Intermittent scotomas during last year; atrophy of optic nerve OS>OD without glaucomatous excavation; visual field defects left > right with new central scotoma, as well as central oculomotor disturbance were present. Pre-existent congenital strabismus and nystagmus were additionally found. MR showed giant hydrocephalus and AV-shunt dysfunction due to displacement of cardiac catheter. Moreover, a functional aqueduct-stenosis can be diagnosed. Emergency lumbar punction (LP) to release ICP was done after a severe attack of raised ICP. According to the patients’ preference, an endoscopic repair of liquor pathway by ETV was performed.

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During endoscopy (Graph 2), a caudal second arachnoid membrane was found (5) and a deep stomy (6) was performed. This should be done only by experienced endo-neurosurgeons. The view into the fourth ventricle through the aqueduct was obscure (4). Though the third ventricle seems small in sagittal view on the MR, the distance of mammillary bodies (1–3) represents clearly the enlargement of the third ventricle. Visual field and also RFNL recovered soon after LP. All other symptoms disappeared finally after ETV and she received good feedback for her new mental appearance at work and in privacy. Chronic hydrocephalus causes multiple ophthalmological, neurological, neuro-­ psychological, and endocrinological signs and symptoms. Often these are misunderstood due to their complexity. Neuro-ophthalmological symptoms may be decisive but are mostly overseen and not understood as a hydrocephalus symptom. It is necessary to recognize and believe the complains of the patient. This patient had to wait 10 years to get her problem solved. All of these patients with neuro-­ psychological findings present an odyssey of misunderstandings, wrong diagnoses, and abuse of medicaments, especially psycho-pharmacological drugs, causing severe side-effects. Regularly, these side-effects are later misunderstood as part of the disease. With meticulous detection and documentation in a close co-working, difficult neuro-ophthalmological-neurosurgical cases can be solved.

Graph 38  Case 3

In Case 3, we see comorbidity of chromosomal pathology (M.  Perthes) and aqueduct-stenosis. Such conditions that cause hydrocephalus symptoms were overseen or mixed up with the main disease.

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Despite the diagnosis of aqueduct-stenosis, it is common to implant a shunt system and ignore the “evidence.” This will be followed in a course of shunt-revisions because of two main reasons. It is difficult to differentiate the symptoms of shunt-­ disease from those of the main disease. More important is the fact that disabled patients’ brains use to have a small compliance window to compensate the on–off effect of the shunt system. Even if there is no aqueduct-stenosis, it is wise to start liquor dynamic regulation by ETV and add a shunt only in the less number of cases, when ETV is not enough. This patient had to wait for 30 years, under control, to get the liquor dynamic regulated and to prevent further cerebral changes of the hydrocephalus. The deterioration was mainly neuro-psychological making integration and inclusion more and more impossible. Post ETV morphological changes (s MR, Graph 38) were extraordinary strong, but the symptoms changed very slowly, indicating that the disturbance of the liquor flow pathology lasted too long. However, she recovered fully within few months and she could change to a private and near independent life. Here endocrinological functions normalized, and she even went through a late puberty. All the communication functions improved and she developed cognitively, being more alert with better self-­control. This was also represented in her mimic appearance. In summary, a complete spectrum of improvements, even in this disabled life, leading to nearindependency in a chronic hydrocephalic pathology was possible by ETV.

Graph 39  Case 4

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Case 4: The variations of symptoms in liquor dynamic pathology are many and may not fulfill the rules of medical knowledge book: “Nature does not read our books!” Especially cases of dominant psychological symptoms cases may present far away from the classical Hakim’s triad of normal pressure hydrocephalus (NPH), and curiously complains and symptoms may dominate the clinical presentation. The patients may live a normal life for a long time and the symptoms estimated are not in relation to the documented or unknown hydrocephalus. But seemingly suddenly the compensation mechanisms may break down and deterioration occurs. Quite commonly, the patients may have a long psycho-pathological history using psycho-pharmacological drugs for a long time; like in case 4, it is nearly impossible to differentiate the primary symptoms from the drug side-effects and the secondary reactive course. Neither neuro-psychological test series nor lumbar drainage may show up with convincing results, but the patient is in a desperate situation. Only small beneficial results may keep them away from dependency or high-cost therapeutic situation. The clinical history often is unbelievable and very sad and intolerable, and whole lives and families are destroyed. However, case 4 patient presented all symptoms of NPH in a low expression, but psychological symptoms were very dominant, and the relatives are completely deteriorated. Though the diagnosis was quite clear by Hakim’s triad and the typical MR, she was kept in a gerontopsychiatric unit under drugs causing a difficult pre-op time and handling. Finally, the ETV was successfully done and she recovered fast from NPH symptoms and within weeks from depression changing her complete appearance in mimic, moving, and behavior. The major difficulty was the reduction of psycho-­ pharmacological drugs. It is one of the most impressive clinical courses, which are presented by these patients psychologically and to free them from the pharmacological straight jacket. (s. also Graph 3).

Graph 40  Case 5

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Case 5: Population in industrial countries are becoming older and the multimorbid fraction of patient is growing fast. Endoscopy as a minimal invasive key technique is playing an important role, avoiding trauma and enabling procedures in old people, which otherwise would be contraindicated. A 77-year-old patient was first admitted by his ophthalmologist to clarify vertical diplopia with hypotropia of OD. cMR showed an acoustic neuroma (AKN) on his right side. The patient decided for follow-up strategy. Five months later, he appeared again with several new problems: (Graph 40) For several months, the patient had experienced changing visual field defects and actually, surprisingly showed dramatic papilledema on both sides combined with signs and symptoms of normal pressure hydrocephalus (NPH) with complete Hakim’s triad. Emergency lumbar punction (LP) to release ICP was performed. Lumbar liquor drainage proved a high positive effect of recovery and shunt implantation indication. A standard liquor shunt procedure was not possible due to very high albumin levels in the liquor. A shunt procedure was contraindicated and an endoscopic repair of the liquor pathway (ETV) was performed. However, configuration of a supratentorial hydrocephalus indicated a functional aqueduct-­ stenosis. MR showed sudden stop of flow signal at the entrance of third ventricle! Qualitative changes of flow signal in the aqueduct are often ignored. During endoscopy (Graph 40), an opaque liquor and strong changes of arachnoid membranes were found. The cisternal route was followed until the view of foramen magnum showed free liquor pathways. View of fourth ventricle through aqueduct was obstructed. Results: LP was followed by a fast recovery in visual fields and NPH symptoms. ETV saved the results and improved them additionally without shunt-system implantation. After radiation of the acoustic neuroma (an operation was refused and also not convenient regarding overall conditions), the albumin level decreased to half and the papilledema decreased fast. NPH symptoms decreased markedly, but only after ending the neuroleptic medication waking became normal. All visual problems recover completely. Shunting one year later resulted in complications and revisions and did not improve the post-ETV and post-radiation results, but the patient lost his gross independency. In summary: Neuro-ophthalmological findings led to diagnosis and fast therapy of a complex multimorbid case. Close cooperation of ophthalmology and neurosurgery prevented decompensation of vision and NPH. In cases of functional aqueduct-stenosis and shunt contraindication, ETV can solve the problems of liquor dynamics disturbance. Minimally invasive neurosurgery (MIN) can face complex pathologies in old patients.

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Graph 41  Case 6

Case 6: Large cystic craniopharyngiomas are challenging multidisciplinary as well as for neurosurgery. Even the best series in literature report 15% overall mortality. A supra-sellar located tumor injure the visual pathway at its most vulnerable site functionally: compression of the chiasm, less than a half of cubic centimeter, causes blindness! There is a narrow window of time for acting to save vision! This is also true for endocrinological and neurological preservation of function. The time is the major factor for preserving function. Time is not visible on imaging but in the clinical course. Intense interdisciplinary interaction, and application of minimally invasive concepts and techniques, preserved vision and visual field, endocrinological and neurological symptoms in each of the four phases of therapy in this case. Finally, also the liquor pathway was kept intact. In this case of a 53-year-old female, acute decrease of vision and visual field was diagnosed by ophthalmologist followed by emergency MRI and immediately sending to neurosurgery. Visual acuity and perimetry as well as MRI and endocrinological laboratory pre- and post-op were analyzed retrospectively in all four phases of therapy. Neurosurgical micro- and endo-surgical operations assisted by neuro-­sonography and LASER were applied according to minimal invasive concept (Table 1).

Intact with finally no hydrocortison substitution 1 y.

Complete resection without recurrency since 6y.

Endocrinological:

Tumor status:

Radiation:

Non

Status of hydrocephalus: No shunt necessary.

Complete recovery (risk: hypothalamic/thalamic coma vigile!). Recovery of both eye (MD (dB):OD24,3 -> 5,1 OS14,4 -> 5,6).

During the 4 Phases good visual acuity again after all operations.

OS 0,3-->0.6

0,6 4/2015

L 0,4 0,5*0,8 0,4*0,6 0,5 0,4 0,3*0,4 0,6 0,5* 0,4 11/2013 3/2014 5/2014 8/2014

OD 0,10.4

0,4

R 0,4 0,25*0,6 0,1*0,6 0,5 0,25 0,3*0,3 0,4 0,3*0,25

Vigilance: Perimetry:

Visus-Amplitude:

Visual ac.:

RESULTS of:

Table 1  Postop clinical findings

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Recovery of visual function after all four surgical intervention and finally complete resection of tumor was achieved. Return to normal vigilance without disturbance of liquor dynamics and minor hydrocortisone substitution post-op during 1 year could be accomplished. In summary, immediate, direct, and systematically interaction between ophthalmology, endocrinology, neurology, neuroradiology, neuro-anesthesia, and neurosurgery prevented visual loss in all four phases of therapy in this case of a large cystic craniopharyngioma of the third ventricle. Ophthalmology gained a trigger function to get neurosurgical intervention in time. Minimal invasive concept and staged therapy resulted in excellent outcome. In this cystic case, the new concept of stepwise approaching, starting with cyst control by endoscopy and advancing with endoscopy assisted microsurgery. This MIN concept allows the extremely sensitive and disabled tissue to recover before the next step is done. Especially normalization of liquor pathway and release of ICP for better perfusion and decompression is essential. As shown by Yasargil, attention must be drawn to the anterior circle of Willisii obstructing the visual pathways from superior during the growing from inferior.

Graph 42  Case 7

Arachnoid cysts are benign congenital cystic lesions, a duplication of arachnoid membranes. Most frequently, they appear in the Sylvian fissure (15%) but also in

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the pineal recess (10%), CPA (10%), cerebellar vermis (10%), and interhemispheric (5%). Lesions of supra-sellar location do protrude into the third ventricle, causing neurological, neuro-psychological, ophthalmological, and endocrinological symptoms. Complexity of clinical appearance may lead to misinterpretation of single symptoms, and diagnostic procedure may be delayed. Sometimes the diagnosis is made accidently, but when it comes to liquor dynamic problems, deterioration may occur and emergency situations can happen, sometimes with severe outcome. Ophthalmological dysfunctions can lead to the diagnostic actions finally, or just in time. In case 7 (Graph 42), the 16-year-old pupil experienced a 2-h speech arrest, paresthesia at the tongue, hypesthesia at the right hand, and severe cephalgia with vomiting attacks for the past 5 years. Visual disturbance with diplopia and arterial hypertension were present, and she developed adipositas. Finally, problems at school with difficulties to concentrate and memory deficits led to presenting her to an ophthalmologist, to neuro-imaging and to neurosurgery. Intermittent visual field deficits appeared, and MR showed a big supra-sellar cyst of the 3rd ventricle and prepontine extension, compressing trigeminal nerves, optic pathways, and obstruction of aqueduct, causing tree-ventricular hydrocephalus. Finally, an ETV was successfully performed on superior and inferior level of cyst membranes and a subtotal resection of the cyst. The neuro-psychological and ophthalmological problems disappeared within weeks and she could finish her college in time. However, a reduction of peri-papillary retinal fiber layer (RFNL) nasal inferior (left  >  right) was now present as a remnant of the chronic hypertension of liquor. During endoscopy, in addition to the cyst she had a membranous stenosis with a small hole of the aqueduct, explaining the typical extraordinary “jet-flow” in such cases, usually misdiagnosed as normal aqueduct because of flow signal. This membranous stenosis of aqueduct can only be seen in CISS sequence (T2 flow) sagittal. After ETV, the “jet-flow” disappeared and a very strong flow signal through the stomies is visible. Bulging of the cyst is not present anymore and cyst wall in the third ventricle is also not visible anymore. In Summary, the case shows a chronic and complex symptomatology due to a supra-sellar arachnoid cyst of the third ventricle. The membranous stenosis of the aqueduct was radiologically hidden by the huge finding of the cyst, but only indirectly announced by the typical “jet-flow” in this type of stenosis with a small hole in the membrane. This compensates peaks mostly, leading to a very slow chronic course, but with the possibility to suddenly decompensate with deterioration and emergency situation. The deficits may be seen very late and misinterpreted.

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Graph 43  Case 8

Case 8: This woman, 69 year old at admission, is a complex case, representing the abilities of endoscopy to anyway realize a good result, after a series of traumatic operations in two university departments of neurosurgery, with complications followed by functional deficits. In Graph 43, the skull shows a battle field of approaches. After five procedures, the sixth one by ultrasound-assisted endoscopy through a burr-hole stopped the progress of neurological deficits and seizures. Now, after 6 years, the multi-cystic lesion became bigger again and some of the old symptoms appeared again. Hemiparesis and nonconvulsive local seizures were in progress. MR showed that the endoscopic cysto-ventriculostomy has closed again. Approach planning became essential with regard to all the former results of operations and the changes of morphology. Using the given condition without transgression of brain tissue, through cysts and scarfs, connecting all volumes into the ventricle was the goal to reach. It was soon clear that endoscopy alone would be dangerous, and computer-neuro-navigation cannot serve with real-time capacity. The only real-time imaging is ultrasound with a true navigation capacity and without bias by shift or loss of liquor. Moreover, ultrasound is applied through the surgical approach with the perspective of the surgeon fitting easily into the workflow (ergonomics) of the procedure. Through a small approach ( ) (Graph 43), leaving all bone-flaps in place, the endoscope was introduced through inter-flap scarf tissue and guided from one cyst to the other by perforating the membranes at the needed point by transendoscopic bipolar. Finally, the connection was done until the lateral ventricle. Post-op the hemiparesis improved fast and the focal seizures within 1 month and she was fully mobilized.

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The post-op imaging showed air in the cysts, marking the endoscopy route; the cyst decreased and a flow signal into the ventricle was documented. To avoid a shunt system, the patient had to travel outside her city and country in Europe. Six of the seven procedures were done after 1996; that means after the International Congress of MIN in 1993 and after the major publications were done. This problem has not changed yet and patients have to search long and far to find a well-trained endo-neurosurgeon. The manual difficulties are of medium level, but the concept and the planning are of high level. Judgment of level should be done according to difficulty managing intra-operative and peri-operative complication. Complications do not disclose endoscopy rather than the typical complication need to be known and managed. In cystic lesions, endoscopy is always an option.

Graph 44  Case 9

Liquor dynamic problems in complex constellations should not be answered by standard procedures. The 34-year-oldman of case 9 (Graph 44) suffers from a battered-child syndrome with ICH and hydrocephalus as well as optic nerve injury (right amaurosis, left decreased visual acuity). He got a ventricular and subdural shunt with complications and revisions. Actually, he was admitted with visual acuity of 0.1 and intermittent amaurosis fugax attacks on one eye. Retinal severe atrophies of capillaries and optic nerves were present. One week before, he experienced hypakusis and NPH syndrome (Hakim) and had to stop working. He showed a progredient change of behavior and Parkinson’s signs on the left side. A lumbar drainage was applied (danger!) with minus pressure syndrome forcing him to bed, but the visual acuity recovered to 0.4, which was not a benefit in that situation.

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MR showed an aqueduct-stenosis and a chronic slit ventricle syndrome due to long time over-drainage. After worsening of lumbar over-drainage and visual acuity to 0.1, an emergency ETV was performed. Due to the slit ventricles and variations of strong midline vessels, endoscopy through the midline route transcallosal was a master task, not recommended for unexperienced endo-neurosurgeons. The very short route through corpus callosum is the best way in a handicapped brain functionality. First view hours, the patient did not see anything. Within 1 day he recovered to 0.6 visual acuity and his visus normalized for the patient on his last eye. All NPH symptoms disappeared fast and performance improved markedly and visibly. His mimic and personal expression changed positively and was back to work. The most difficult change was the slow exit from his (contraindicated and misused) neuroleptic medication. With the help of his fabulous grandmother, he mastered this, and Parkinson’s symptom on the left side disappeared and showed only remnants in very stressful situations. The newly gained vigilance and self-awareness led to irritating observation on his disabled short memory. The critical selfjudgment of remnants must not be misinterpreted as failure of ETV rather than expectable course of inhomogeneous recovery. However, the strong recovery of visual function and NPH symptom as well as better overall life quality made ETV successful. Such success needs a close interdisciplinary cooperation and the understanding that complex pathology does need an individual solution and not a standard procedure. Disabled brains cannot compensate shunt disease.

Graph 45  Case 10

Case 10 represents a major conceptual problem regarding indication of endoscopy because it is the combination of aqueduct-stenosis and ICH.  The ideology,

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implemented since STICH-tails, caused a prohibitive environment for ICH surgery, and in case of IVH or additional liquor involvement, drainage strategy with series of surgeries, predictable complications, and days in bed, or even prolonged stay at ICU, are preferred to endoscopy strategies. This causes human tragedies and a lot of money. This 57-year-old patient was admitted to ICU with stroke symptoms of the brainstem. She was somnolent and complained of headache and visual problems. Speaking was difficult and slow and the right side showed dysmetria. Ophthalmological follow-up diagnosed incomplete Parinaud syndrome and paresis of abducens and trochlear nerves. Dysarthria, dysphagia, and hemi-dysmetria were found initially. Emergency CT showed an obstructive hydrocephalus and MR presented an ICH, dorsal to the upper brainstem with compression of aqueduct and superior medullary velum. As usual, a ventricular drainage was inserted and changed one times, when liquor became signs of infection. Moreover, it became clear by control imaging that the blood clot will not be solved soon, and by laboratory results of liquor, that shunting will also not be able for a long unpredictable time. Under this condition, an indication for EVD could be pushed through, according additional with the authority of the wish from the relatives. This strategy allows to shorten the drainage (when already placed), the ICU time, and the bed-rest time, last but not least, it shortens hospital stay and costs of the therapy ethically. The ETV was successful and she could be mobilized soon thereafter and sent to rehabilitation as earlier as usual. During endoscopy (Graph 45), an injury from the ventricular catheter was seen close to the fornix (1), as already visible in the coronary MR ( ) post-drainage. There was an extraordinary strong choroid plexus (2), narrowing the foramen of Monro. The anatomy of the floor of third ventricle was normal and well developed (3) with a narrow infundibular recess, a well resent impression of optic chiasm and lamina terminalis was also visible in the 30° view. The stomy was placed rather ventral (4) close to the infundibulum, according to the planning at the sagittal MR, where the interpeduncular cistern was small due to the dorsal ICH volume. The gap for perforation was small and close to the dorsum of sellae. The arachnoid membrane of the prepontine cisterns showed already xanthochromia (4) In all of these cases, an early ETV is recommended and drainage should be avoided to get the patient out of bed and to avoid infections, as well as multiple surgeries. Minimally invasive evacuation of the bleeding was not necessary, as she recovered fast after ETV and was mobilized. Ophthalmological and neurological symptoms recovered, and CT showed release of the blood clot by the liquor transportation rather early. An optimistic indication of ETV is not only rectified in such cases from the viewpoint of pathophysiology, but also from view of psychology and humanism (ethical). Of course, equipment and trained surgeons need to be on the side.

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Graph 46  Case 11

The case 11 represents aqueduct-stenosis by tumor with the indication of ETV at the ventral third ventricle and biopsy at the posterior third ventricle. Usually this is done, if endoscopically, by planning and performing two surgeries with two different trajectories, causing a lot of trauma and surgical, logistical, and financial efforts. At the sagittal MR, it can be calculated and planned (Graph 16), in relation to the diameter of the foramen of Monro and the diameter of the endoscope if both procedures can be done with one trajectory only. However, this concept is theoretical because there are more parameters involved like the size of the ventricles (especially the third) and the rigidity of the brain. The anatomical variation of plexus and veins of the foramen of Monro (1) also plays a critical role. For 1 year, she had headache attacks, sometimes with vomiting and even with visual symptoms. These attacks and waveform symptoms are often underestimated, and experienced surgeons remember tragic cases, for example, in colloid cyst cases. During endoscopy foramen of Monro showed well present veins (1), and the vein most underestimated and without a name, and the main bleeding cause (not the plexus as always believed) at the foramen of Monro during endoscopies. This vein may be hidden by ependyma and by the fibers of stria terminalis of lateral ventricle (part of the limbic system), may cause bleedings, which are difficult to coagulate, being in an unfavorable angle to the working canal of the endoscope. Especially in the 30° endoscope, it can be in the blind angle, when the lens is directed anteriorly. Turned 180° dorsally, which is difficult to navigate free-handed, this area is well

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visible and the favorable way to coagulate the vein, but also to view into the posterior par of third ventricle. Mostly, in such circumstances, a very slight compression with the endoscope-shaft may serve as first aid is often sufficient. However, this is a holy area, as the paraventricular nucleus is nearby, which is the “switch of awareness”! The cinereum, entrance to the infundibular recess and pre-mammillary located, was still parenchymatous (2) which tends to have vessels for bleedings, but the stoma (3) could be placed in the usual typical place. A highly placed head of the basilar artery was not visible (predictable by sagittal MR), but the strong basilar trunk just below the origin of superior cerebellar artery is well seen (4). Turning the 30° endoscope 180° posterior with a light carefully minimal angling of the endoscope-shaft gives view to the posterior part of third ventricle and the entrance of aqueduct (5+6). One has to decide to go anterior to the inter-thalamic adhesion or posterior. The latter route (7) is dangerous and should only be used after carefully proving the anatomy regarding veins and plexus. An injury of the angle of the veins, mostly hidden by the plexus, can end-up in a disaster. Biopsy (6) was uneventful and astrocyte tissue (no tumor) was found. Pre- and post-op MR showed the lifting of floor ( ) of the third ventricle to normal level, increasing interpeduncular cistern, and the change of the chiasma-angle (most unaware), in this case only minimally ( ). A typical flow void through the stomy became visible but is not necessary to prove the patency of the stoma, only in the positive case it is predictive.

Graph 47  Case 12

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Errata

Case 12 represents the task always present in surgery to control and preserve coagulation on a level allowing surgery and safety regarding bleeding on one side and thrombosis on the other side. To balance this parameter is a major issue and became very difficult due to multimorbidity and complexity of recent thrombosis prophylaxis with new drugs coming up. In this case of a mechanic heart valve, anticoagulation is indispensable and surgery becomes a balancing act. The triad of Virchow seems not to be aware anymore and drugs, anti-drugs, and laboratory values rule over the surgical field. The 88-year-old patient had already two operations on both sides (1). During rehab-therapy she deteriorated, and CT presented a subdural rebleeding left (2) with severe midline-shift and somnolence. An emergency operation was necessary under unfavorable coagulation conditions. Under these circumstances, a usual blind drainage procedure with an insufficient irrigation effect was not recommended rather than to control subdural procedure endoscopically and to avoid trauma. Also, it seemed wise to avoid a persistent catheter and to control also endoscopically the completeness of evacuation. In such a case, planning of burr-hole position is totally different to usual strategy. In MIN, any intracranially volume should be approached from the small side if possible (3). In the hype-time of endoscopy, subdural hematomas were evacuated frequently under endoscopic control. During this phase, experiences were possible about the visual appearance of the subdural space under CSH conditions. We have learned what curiosities Jackson-Pratt catheters can show and how they can injure the cortex and bend or tear bridging veins. The change of color of the meninges and the kind of compartmentation by membranes could be studied. During endoscopy, in this case something new was experienced. Additionally, different changes and membranes (4 + 5) and the appearance of the capsule (6), very tiny “bridging veins” at unusual sites, were encountered and, moreover, venous aneurysms were visible (8–10). Remnants of blood clot (7) could be made visible in deep regions and a visually controlled decision is made, if to evacuate radically or not. The severe vulnerability regarding bleeding could be seen, supporting the strategy not to leave a drainage in such circumstances, to control completeness visually and by decision-making and to avoid unnecessary trauma like craniotomy. It became clear that the balance between heart and brain was critical in this case, and a bit in favor for the heart, because of the danger of sudden death. Rebleeding, in contrast, would cause another operation. Finally, in this case, after 2 weeks, another rebleeding occurs, but without a servere symptom. Prognosis depends on the above-mentioned balance, and the multimorbidity in the old patient, however, craniotomy would be far too dangerous, and MIN strategies is the only way to go, or to give up. In conclusion, endoscopy is especially helpful in the elderly patient group.

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Graph 48  Case 13

Case 13 represents the situation to do an emergency endoscopy procedure. In addition, it teaches again that deterioration in posterior fossa pathology can occur unpredictably and without the symptom cascade of supra-tentorial lesions. However, we have learned also, that neuro-ophthalmological signs and symptom, but also such complains of the patient, are often the only and last warning sign before sudden emergency happens. A crucial balance, it might be for a long time, should never be the reason to neglect the life-tethering danger. In this case, the danger was visible by warning signs in the MR: cerebellar were already herniated deep into foramen magnum. The brainstem was severely compressed and shifted. Several cranial nerves showed symptoms, and this was present since some weeks, evoking standstill instead of surgical alarming. This type of gaming behavior can be observed more and more. The patient even was allowed to have meal in the evening. But neurological deterioration happens suddenly and is unpredictable. Ophthalmological signs and symptoms are often decisive to predict developing of emergency. A 17-year-old boy suffers from intermittent headache, dizziness, and ataxia for about 2 weeks; he was admitted with diplopia and vomiting.

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Ophthalmological findings: Visual acuity OD 0,9 OS 1,0 without RAPD, IOD 17/14 mmHg. Edema of the optic nerve OU with radial hemorrhage OD. Ptosis OD, palsy of abducens nerve OU, trochlear nerve OS, pathological saccades, upgaze nystagmus and nystagmus to both sides. Anterior eye segment and ocular fundus moreover normal OU. Imaging findings: Big cystic tumor of the cerebellum, compressing fourth ventricle causing obstructive hydrocephalus. Herniation of tonsils and midline shift with compression of the prepontine cistern were visible. Torsion and dislocation of optic chiasm with compression of the stalk at the dorsum sellae. To decrease the raised ICP in this case of obstructive hydrocephalus, an endoscopic emergency procedure was done. Perforation of the floor of third ventricle and the roof of the interpeduncular cistern created a new pathway for the liquor to flow, releasing the raised ICP to normal and decreasing the risk of hydrocephalus posttumor operation to 50%. Vomiting and headache disappeared immediately and diplopia resolved within few days. The overall condition was normalized without external drainage having 50% less risk for post-op shunt dependency. After a sudden increase of diplopia, followed by headache and vomiting, at midnight, an emergency ETV had to be done. The procedure was uneventful, but it lasted longer than usually during day-surgery does. The liquor ICP intra-operatively was 30 cm H2O. The tumor histology was cystic astrocytoma WHO I. This case shows impressively ophthalmological symptoms as typical warning signs before neurological deterioration in case of tumor of the posterior fossa. The ophthalmology gets a trigger function before neurosurgical emergency operation. Close and routine cooperation between ophthalmology and neurosurgery can best manage these cases in time and the ophthalmological warning signs should never ever be neglected.

Graph 49  Case 14

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This case 14 represents a planned ETV indication to resolve acute symptomatic in the first step, before going into the main surgery of a big tumor causing an obstructive hydrocephalus. This strategy, avoiding a ventricular drainage, enables to do the main surgery at an optimal timing, without keeping the patient in bed and having the infection risk in addition. The patient and the tissue can recover under relaxed ICP. Endoscopy was not of average difficulty, as the brainstem and basilar artery were shifted ventrally. The tumor was visible in the posterior part of the third ventricle because the space between venous angle and inter-thalamic adhesion was large (1), and the tumor tended to bleed. The perforation was done rather ventrally (2) and due to the shift, all the thalamo-perforators were stretched (3). The way along the clivus and pons showed the bulging tissue of pons on both sides of basilar artery (4) and compression of the pontine subarachnoid veins (5). The patient recovered well from the main surgery 14 days later, which was successful. After radiation, this pinealoblastom WHO 4° disappeared completely without recurrency and no hydrocephalus thereafter. The stepwise strategy by MIN in lesions, in and around the brainstem and third ventricle, is well tolerated and prepares the patient for the main surgery without acute symptoms. After this experience, the patient will have a strong trust to the following therapeutic steps.

Graph 50  Case 15

This case 15 represents, in contrast to case 6, an adjuvant indication, having a severe clinical course for 1 year after primary surgery of a craniopharyngioma. Also, it represents the extremely anatomical and tissue changes in such a case, making orientation and identification difficult.

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Finally, it is an indication of ventriculoscopy and lavage of IVH in a situation, when shunting is contraindicated for an unpredictable time. MIN should be applied in desperate cases rather than a complication promising shunt procedure. This patient had, at the end, a list of 16 diagnoses with several sub-diagnoses in a multimorbid and minimal conscious state, after two operations of a craniopharyngioma. Eight months before the second operation, an IVH has occurred causing an incomplete obstructive hydrocephalus. After growing of the remnant, visible in the MR, the second operation was indicated; the patient was in an absolute dependent status. The neuro-endocrinological deterioration did not recover and led to the above-described situation. During the ventriculoscopy for irrigation of the ventricles, and to prove the communication of the third ventricle into basal cisterns, until the level of C2, all the severe changes of arachnoid membranes, bleeding remnants, and tumoral changes of the ependymal tissue were visible. The wall of prepontine cistern was, in addition, fenestrated into subdural (epi-arachnoidal) space, to further promote free flow into the spinal canal for compensating liquor peaks. During ICU stay and the many problems coming up, the concept of solving the liquor dynamics by MIN in a desperate situation was not followed and a shunt was placed before he died. Here, we see finally an ethical question, which can be answered in different ways. The author would always prefer an individual decision over a standard decision in such a situation, recommending only MIN strategies in such a late phase, if not to stop therapy at all.

Graph 51  Case 16

This case 16 of a preterm (24 SSW/700 g) baby represents a very rare compensation mechanism of an obstructive hydrocephalus due to obliteration of the aqueduct,

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and within peri-natal infection and bleeding. Moreover, it represents the need to analyze in each shunt-revision situation the possibility to substitute the shunt by an endoscopic procedure or to combine both concepts. A complex dysplasia of the brain, compromising corpus callosum and cerebellum showed a cystic lesion supra-cerebellar (B). In only 15 months, the baby experienced already several operations with reservoir implantation, multiple shunts and shunt-revisions, and several drainages. The baby was born in 2016, that means, more than 23 years after the first MIN Congress in Wiesbaden 1993 and appearance of the major papers of MIN, also 15 years after the founding of IFNE, primarily as a research worldwide net for neuro-endoscopy. It needed 2 years after the first shunt to indicate an endoscopy through an already given approach in this difficult case, at least, to verify the unusual findings in the imaging: from the ventricular trigone left side an invagination into the posterior fossa has developed during the first year of life (axial MR), indicating a chronic obstructive hydrocephalus. It would be difficult to explain this in a communicating hydrocephalus. Even the pre-existence of an arachnoid cyst supra-cerebellar would not support communication in the aqueduct; moreover, the aqueduct is obliterated completely (B, C, F). Even in CT, the trajectory to the naturally developed stoma was given from the existing burr-hole of former operations (A). The pressure and shift in the posterior fossa was well visible in the pre-op MR for the endoscopy procedure (B). Post-op MR (E, F) showed release of the supra-sellar arachnoid cyst and invagination of the left trigone of lateral ventricle. The fourth ventricle is visible again and the prepontine cisterns are present normally. The ETV flow is not only seen (C) but also the flow through the invagination pathway to the posterior fossa (E, F). The insufficient shunt was substituted by a new one during the same operation to meet, additional to the obstruction (ETV), the post-bleeding and post-infection situation. During endoscopy, one first came into a mono-ventricle giving view to the fornix on both side and the left enlarged foramen of Monro. The right one was not visible due to a blood clot by a recent drainage catheter (1, 2). Directing the endoscope towards the trigone of the left ventricle, in the depth the natural developed stoma was visible soon (4). Approaching closer (5), it could be seen that it is not artificial, and entering gave a view on the dorsal ambient cistern (6) with arachnoid covered pineal gland and the superior colliculi of quadrigeminal lamina. Back in the frontal horn and passing a wide open foramen of Monro on the right side (3), the broad unusual overview of the third ventricle (7) with immature hypothalamic walls and typical signs of former bleedings in the ependyma are visible. Mammillary bodies are well in size, but ventricle width and floor was five times too broad. During the first perforation, a vein of the cinereum (pre-mammillary membrane) started to bleed (8) and could be easily stopped by blowing up the balloon again (10). Thereafter, the arachnoid trabecula of the Liliequist membrane (roof of the interpeduncular cistern) became visible (11). After complete opening, the view goes along the basilar artery with remnants of the Liliequist membrane (12). Finally, after

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taking away the blood clot with the biopsy forceps (13), the origin of that bleeding and primary catheter injury became visible. It is quite typical that even soft catheters cause, sometimes severe, injuries in the premature tissue. At the end, the ventricular system, with obstructive and infect and post-bleeding changes, has three pathways to compensate: the naturally developed into posterior fossa through an absolute rare stoma, the ETV, and the shunt system. According to the recent imaging controls, the stoma has a strongly flow, the ETV less used, the shunt is at 130 cm H2O adjusted. Function of cerebellum and visual function will most sensitively show if the system is balanced well. Anyway, each case of surgical revision of the shunt system must be used to re-evaluate, if the shunt is necessary, or even, if the stoma must be closed, of course endoscopically. The traumatized head of the baby tells us that we do not recognize MIN well enough, even not in our youngest patients. But they need it most!

Graph 52  Case 17

This recent case 17 (2/2019) represents, together with case 1, a period of 32 years of endoscopic procedures. It is, at the end of this series with few examples (what can I do with endoscopy?), an easy and benign case, the usual case one can meet at congresses and in industry-launched brochures. It is the case often done with

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6.5 mm endoscopes with wonderful images done with fixed endoscopes, stereotactically or by any kind of rigid holding device, a technique with which you can do such cases, but not that once seen above (case 1–16). However, even these cases are not free of long time missing a diagnosis and therapy, mostly and everywhere solved by implantation of shunt systems. By accident, and because the patient refused constantly a shunt implantation, in case 17 of the series, it was rather easy to get the indication brought through and to do the procedure within 40  min. Even in the convincing changes of the third ventricle (Graph 52) and the typical three-ventricular constellation of the ventricular system, the jet-flow of the aqueduct caused the primary advice for a shunt procedure. (Aqueduct is believed to be patent according to flow void signal) During endoscopy, we look into a ventricular system of a 22-year-old young lady, which looks like that of an 80-year-old man after misuse of alcohol (1, 2). All the peri-ventricular tissue is atrophic and the floor of the third ventricle is only a membrane (3, 4). The complete posterior circle of Willis is visible through the slightly opaque membrane pulsating strongly. The transparency is surgically of benefit because one can choose the perfect place to perforate under visual control, knowing well that this kind of membrane may be very tough, and it is easy to run into the pons and hurt it. Here, it was surprisingly easy to perforate the membrane (4). However, with the correct angle and a given pathway from basilar tip (5) along the basilar trunk (6) and through an enlarged cisternal hiatus (7), a visual control until foramen magnum (8) could be done. This can guaranty that no second or third membrane is overseen and obstruct the liquor flow at a deep caudal level. The subarachnoid space always has a complex compartmentation with openings to let the major vessels pass through different compartments. These cisterns have therefore hiatus construction, and well known is that of basilar artery close to the meeting point of all six ventral cisterns of the brainstem (Graph 53). However, this control tour through the basal cisterns along the basilar artery should only be done with good reasons and by very experienced endoscopic neurosurgeons (with laboratory training, and over 100 cases). Nobody can know which destructions, acquired for 22 years, this brain of our patient case 17, has to compensate, so that the she looks and functions normal during daily life. The tiny flow through ETV in the post-op imaging is not a problem as we know from the endoscopy journey that the liquor pathway is open. The signs and symptoms disappeared soon and further recoveries in neuro-psychological field might be encountered in the near future. Such changes were observed regularly after ETVs.

Errata

lxxviii C. präpontis

clivus-Fenster c. pontocerebellaris (sup)

a b 8

b

7

c

c

10 11 12

c

C. cerebellomedullaris lateralis dura-Fenster

c.pramedullaris

a b

b

c

c d

Graph 53  Compartmentation of ventral cisterns posterior fossa

I hope, the corrections of lay out will make the content much more comprehensive.

Contents

1 Laser������������������������������������������������������������������������������������������������������������   1 1.1 History������������������������������������������������������������������������������������������������   1 1.2 For MIN the LASER Is One of the Key-Techniques and Has a Unique Meaning����������������������������������������������������������������   2 1.3 Equipment and Ergonomics����������������������������������������������������������������   6 1.4 Illustrative Cases ��������������������������������������������������������������������������������  12 1.4.1 Typical Applications of LASER Trans-endoscopically����������  12 References����������������������������������������������������������������������������������������������������  32 2 Sealing/Tachosil������������������������������������������������������������������������������������������  35 2.1 Recommended Dose ��������������������������������������������������������������������������  36 2.2 Administration������������������������������������������������������������������������������������  37 2.3 Mechanism of Action��������������������������������������������������������������������������  38 2.4 Pharmacokinetics��������������������������������������������������������������������������������  39 2.5 Storage and Stability ��������������������������������������������������������������������������  39 2.6 Tachosil Product Characteristics��������������������������������������������������������  39 2.6.1 Fibrinogen ������������������������������������������������������������������������������  39 2.6.2 Thrombin��������������������������������������������������������������������������������  39 2.6.3 Collagen Sponge ��������������������������������������������������������������������  40 2.6.4 TachoSil����������������������������������������������������������������������������������  40 2.7 Neurosurgical Application������������������������������������������������������������������  40 2.8 Illustrative Cases ��������������������������������������������������������������������������������  43 2.8.1 Case 1. ICH Left Par-Occ with HP, Aphasia, Hemi-Anopsia, Pre-coma, and Limbic Syndrome������������������  43 2.8.2 Case 2. ICH Left Par-Occ after Stroke with HP and Limbic Syndrome������������������������������������������������������������  45 2.8.3 Case 3. ICH Left Central, Double Anticoagulation, Functional Hemiplegia, Dura Closure without Suture, Indication: Preservation of Function��������������������������������������  49 2.8.4 Case 4. Bullet Injury and ICH, Evacuation Via Exit-Hole and Sealing Pernasal����������������������������������������  51 2.8.5 Case 5��������������������������������������������������������������������������������������  54 2.8.6 Case 6. Per-cutan-transorbital Perforation with CSF Leakage������������������������������������������������������������������  57 lxxix

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Contents

2.9 Other Techniques for MIN as Probable MIN-Key Option������������������  60 2.9.1 Sono-thrombolysis������������������������������������������������������������������  60 2.9.2 Focused Ultrasound FUS/HIFU����������������������������������������������  61 2.9.3 Integration of Multiple Min Key-Techniques ������������������������  62 Suggested Readings ������������������������������������������������������������������������������������  67 3 Evolution of Anatomy to a Key of MIN ��������������������������������������������������  71 3.1 Anatomy/Topographic Anatomy/Surgical (Gestalt) Anatomy������������  71 3.1.1 Approach-Analysis and Approach-Design ����������������������������  71 3.2 Gestalt: Theory for MIN ��������������������������������������������������������������������  79 3.2.1 Examples��������������������������������������������������������������������������������  80 3.2.2 The Perneczky Pyramid����������������������������������������������������������  87 3.2.3 Preparation Concept����������������������������������������������������������������  99 3.3 Case Application According to Gestalt-Anatomy������������������������������ 102 3.3.1 Approach-Analysis and Approach-Design ���������������������������� 102 3.3.2 Dissection Steps���������������������������������������������������������������������� 108 3.3.3 Anatomy and Modern Imaging: 3D CT, Microscopy, and Endoscopy������������������������������������������������������������������������ 129 3.3.4 Discussion ������������������������������������������������������������������������������ 137 3.4 Conclusions���������������������������������������������������������������������������������������� 147 References���������������������������������������������������������������������������������������������������� 148 4 Laboratory: Surgical Simulation and Training for MIN ���������������������� 157 4.1 Introduction���������������������������������������������������������������������������������������� 158 4.1.1 Recalling Some Problems ������������������������������������������������������ 161 4.2 Learning from History������������������������������������������������������������������������ 162 4.3 Classification of Post-mortal Inspection/Training (PMI)Settings�������������������������������������������������������������������������������������� 162 4.4 Understanding of Patho-anatomic Gestalt Phenomena���������������������� 163 4.5 Training Topics ���������������������������������������������������������������������������������� 165 4.5.1 Analysis of Imaging���������������������������������������������������������������� 165 4.5.2 Approach-Analysis and Approach-Design ���������������������������� 167 4.5.3 Para-endoscopic Dissection Concept�������������������������������������� 169 4.5.4 Clipping���������������������������������������������������������������������������������� 171 4.5.5 Analyzing Ergonomics of the Setup and Instruments������������ 172 4.5.6 Analyzing Imaging Findings and Navigation ������������������������ 174 4.5.7 Analyzing Approaches������������������������������������������������������������ 177 4.5.8 Analyzing the Ergonomics of the Setting and Instrumentation ���������������������������������������������������������������������� 178 4.5.9 Training Programs and Education������������������������������������������ 180 4.6 Cases �������������������������������������������������������������������������������������������������� 181 4.6.1 Case-Analysis ������������������������������������������������������������������������ 181 4.6.2 Preparation Concept���������������������������������������������������������������� 184 4.6.3 Cases of all 4 Classifications�������������������������������������������������� 185 4.7 Final Reflections on Training for MIN ���������������������������������������������� 230 References���������������������������������������������������������������������������������������������������� 233

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5 The Role of Plastination for Research, Planning Strategies, Surgical Simulation and Training for MIN �������������������������������������������� 237 5.1 History������������������������������������������������������������������������������������������������ 237 5.2 Technique of Plastination�������������������������������������������������������������������� 245 5.2.1 Fixation & Anatomical Dissection������������������������������������������ 245 5.2.2 Removal of Body Fat and Water �������������������������������������������� 246 5.2.3 Forced Impregnation �������������������������������������������������������������� 247 5.2.4 Positioning������������������������������������������������������������������������������ 248 5.2.5 Curing (Hardening)���������������������������������������������������������������� 249 5.3 Concept of Plastination ���������������������������������������������������������������������� 249 5.4 Scientific Meaning of Plastination������������������������������������������������������ 251 5.5 Anatomical-Concepts: Topography, Gestalt-Anatomy and Surgical Anatomy������������������������������������������������������������������������ 257 5.6 Applications of Plastinates During 33 Years in MIN�������������������������� 258 5.6.1 Topographic- and Surgical-Anatomy of Head-Plastinates (1982–1987) ������������������������������������������ 259 5.6.2 Organ Plastination and Preservation of Special Findings������ 266 5.6.3 Research: CT Resolution and Imaging Evolution (1983) �������������������������������������������������������������������� 281 5.6.4 Plastinate Demonstrations at Congresses: “Neurological Surgery of the Ear and the Skull Base” 1988 ­Zürich/Switzerland (U. Fisch; A. Valavanis; M. G. Yasargil)������������������������������������������������������������������������ 285 5.6.5 Endoscopy Courses���������������������������������������������������������������� 290 5.6.6 2D Video/Monitor Endoscopy Training���������������������������������� 293 5.6.7 3D Endo HMD Training �������������������������������������������������������� 294 5.6.8 Microscope-Navigation Training in Head-Plastinates (2006) ���������������������������������������������������� 296 5.6.9 Endoscopy Roboter-Arm Prototype Testing �������������������������� 307 5.6.10 Light Depth-Range Testing of an Endo Tower (2018)������������ 312 5.6.11 Exoscope: Kinevo 900 System (Zeiss) Testing (2019) ���������� 319 Suggested Reading�������������������������������������������������������������������������������������� 328 6 Plastination Gallery ���������������������������������������������������������������������������������� 331 6.1 Body- Plastinates (I–IV) �������������������������������������������������������������������� 331 6.2 Head- Plastinates�������������������������������������������������������������������������������� 334 6.3 Cerebral Sheet- Plastinates ���������������������������������������������������������������� 339 6.3.1 Sagittal Sheet- Plastinates ������������������������������������������������������ 341 6.3.2 Coronal Sheet- Plastinates������������������������������������������������������ 350 6.3.3 Axial Sheet- Plastinates���������������������������������������������������������� 355 6.3.4 Injection Sheet- Plastinates ���������������������������������������������������� 365 6.3.5 Detail Sheet- Plastinates �������������������������������������������������������� 372

1

Laser

1.1

History

It was Albert Einstein, who described the quantum theory of radiation in 1916 and published it in 1917, AL Schawlow described the fundaments of LASER 1940 and TH Maiman constructed the first LASER in 1960. But it needed until 1989 that “LASER in Neurosurgery”, Springer, was published by EF Downing, PW Ascher et al. presenting of the start-up of LASER use in neurosurgery during the 1970th and 1980th. However, while LASER played a major role in other disciplines in medicine, neurosurgery did never accept it widely. There have been a broad variety of applications like stereotactic percutaneous thermotherapy (LITT), LASER in open neurosurgery, photodynamic brain tumor therapy, percutaneous intervertebral disk therapy, laser-based diagnostic tools,

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_1

1

2

1 Laser

biodynamics transcranial therapy and LASER neuro-endoscopy. These were excellently and extensively presented by E. Belykh et al. (Surg Neurol Int. [2017]; 8: 274). Here the application within MIN techniques and strategies are described. These neurosurgical applications have the capacity to become standard with broad acceptance.

1.2

 or MIN the LASER Is One of the Key-Techniques F and Has a Unique Meaning

Principally the LASER is a nonmechanical surgical tool with multiple properties, like coagulation, ablation, vaporization, cutting, heating, bio-effectivity, diagnostic tool and excellently applicable in combination with neuro-endoscopy. The future of surgery is nonmechanical aiming at minimally invasive strategies. Therefor the LASER will be within the spectrum of techniques in the future of MIN, but already in the present with rather rare applications. The hype of LASER in neurosurgery took place in the 1970th and 80th. However, it ended with writing the name of the surgeon on the tumor, but then starting surgery of extirpation of the tumor really. After some pitfalls in spinal surgery the LASER was practically forgotten in neurosurgery. After introduction of the modern video-chain in neuro-endoscopy (s. Chap. 6, Vol 1) the LASER had a short come-back but never gained that interest which it should have due to its properties. LASER needs a solid training in theory and practically. Once you have experienced how a LASER teacher sets a newspaper 10 m away on fire, and a LASER is transgressing a glass of water without a reaction of the water but burning the surface of the table where it is standing on, you can understand the dangers for the tissue by LASER. The first general generation of LASER machines were weapons and not easy to handle as they lack appropriate presets to avoid the most danger risks in application. Moreover, there were and there are many different LASERS and each one has very specific properties and application spectrums. In some circumstances the LASER can do things, that cannot be provided by any alternative techniques, and it can also do many things that can be done very elegantly by nonmechanical effects. In summary LASER is one of the key-techniques of MIN: As mentioned, the LASER can provide many applications, but what it makes so interesting for MIN, despite which indication, is:

1.2 For MIN the LASER Is One of the Key-Techniques and Has a Unique Meaning

3

• the application through a very thin fiber excellently applied trans-endoscopically • the multi-tasking ability: vaporization, coagulation, cutting, ablation, heating, biodynamic effects, multiple diagnostic tool • the non-mechanical functioning which compensate the weak point of trans-­ endoscopic working, causing haptic disadvantages • the machines providing neurosurgical applications became small, cheap and mobile according to the needs of ergonomics in MIN • the variety of LASER enabling a spectrum of properties and effects for different applications These factors are the reasons, why LASER is not replaceable for many tasks in MIN especially in neuro-endoscopy. Furthermore, it is one of those techniques of the future surgery, which will completely be non-mechanical. The lack of many surgical maneuvers in endoscopy need “all in one”—instruments with a variety of properties to make endo-neurosurgery as safe as microneurosurgery. The tool should be based on visual control rather than on mechanical and haptic control, which is perfectly the case in LASER-tools (Fig. 1.1). Fig. 1.1  The view of the third ventricle floor shows directly how thin the LASER fiber is, leaving a nearly undisturbed view of the working field and the tissue. The typical perforation during ETV can be done without any mechanical force while the pure energy of the beam does the effect. Even tough membranes must not be pushed into the direction of the basilar tip, enabling coagulation of vessel at the same time. This must be seen as a paradigmatic MIN-tool

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1 Laser

Like always in MIN, geometrical conditions are of major impact and a main factor of planning. LASER can go beyond the spatial possibilities of mechanical tools due to its’ size (Graphs 1.1 and 1.2).

3. Ventricle Mammillary bodies Foramen Monroi Endoscope Endo-Tool LASER

Graph 1.1  (related to Figs. 1.2 and 1.3) Fig. 1.2  A usual applied Forgathy-catheter cannot be placed correctly in this foramen of Monroe in the approach angle that was used for biopsy of a thalamus-tumor in the same case, trans-septal at the opposite side. A new trajectory would cause an enlargement of the surgical trauma

1.2 For MIN the LASER Is One of the Key-Techniques and Has a Unique Meaning

5

Fig. 1.3  With the thin LASER-fiber a very small pathway at the border of the visible field was enough to apply an ETV by LASER without mechanical stress for the tissue and safe coagulation ability at the limits of spatial conditions, avoiding an enlargement of surgical trauma by a second trajectory and surgical approach

a

b

c

Graph 1.2 (a–c) During the PICO-project (EU 2005-7), the non-mechanical property of the LASER was represented in the Logo with the atom- model of Niels Bohr and a thin LASER-fiber. This Logo represents also the evolution of mechanical surgery to non-mechanical surgery. (s. Chap. 4, Vol 1, Graph 13). The LASER-fiber is so thin, that it has a lot space within all kind of neuro-endoscopes, weather block-shaft or holo-shaft type. Even in the block-shaft type with several channels, the LASER-fiber is still mobile and can be maneuvered within the channels of suction, rinsing and working. It can be angled with special types of endoscopes mostly used in urology

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In summary these are the reasons why LASER is a key-technique in MIN and not the different tool of applications, where usually alternative techniques are already in use. At the end of the chapter we will see cases which could not be done by alternative techniques, so the indication was drawn quite strictly.

1.3

Equipment and Ergonomics (Graph 1.3, Figs. 1.4 and 1.5)

Graph 1.3  Due to the small size of new LASER machines for neurosurgery and the long application fibers, the ergonomics of LASER is perfect as it does not disturb the emergent orbits red, orange and yellow thus fulfilling recommendations for each equipment for MIN

1.3 Equipment and Ergonomics

7

Fig. 1.4  Compared with the High-end-Sono-­ Machine and the Endoscopy-Tower, the LASER for neurosurgery is very small. This is important to accomplish the need for ergonomics in MIN

Sono

Fig. 1.5  H: 16 cm, W: 46 cm, L: 63 cm and 20 kg weight are rather good dimensions compared to many techniques

Endo

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1 Laser

The properties of this machine are perfect in neurosurgery because of its presets, not being too dangerous intracranially, due to low energy at the tip and due to only 0.5 mm penetration depth. With these parameters, for example, one can open the floor of the third ventricle without opening the interpeduncular cistern thus preserving even high-positioned basilar arteries. The cistern can be opened selectively under view on the basilar artery and parent vessels as well as the oculomotor nerves (Graphs 1.4 and 1.5, Table 1.1).

Graph 1.4  This ETV-sketch shows the geometry of the surgical situation in a high basilar artery tip. Moreover, the dimension of the LASER-fiber enables a variety of moving possibilities in the limited pace of the third ventricle, which was not able by any mechanical tool. The LASER will enable to open the floor of the third ventricle by energy only without pressure and separately without opening the arachnoid membrane forming the roof of interpeduncular cistern (Liliequist membrane)

1.3 Equipment and Ergonomics

9

Graph 1.5  LASER Endo-Third-Ventricular Cisternostomy Table 1.1  LASER-Physiks regarding absorption

Laser system Wavelength Power at fibre tip Chopped mode Frequency Beam delivery Aiming beam Mains supply Cooling system Dimensions Weight Environmental conditions

continuous wave DPSS laser continuous wave DPSS laser 2013 nm 2013 nm 1 - 15 Watt cw (adjustable) 1 - 30 Watt cw (adjustable) 50 - 1000 ms 50 - 1000 ms 0.5 - 10 Hz 0.5 - 10 Hz wide range of fibres wide range of fibres 635 nm (red) or 532 nm, (green) max. 1.3 mW (adjustable), laser class 3R 100 - 240 VAC 50/60 Hz, 6 A max. 100 - 240 VAC 50/60 Hz, 6 A max. Air cooling Air cooling H 160 x W 460 x L 630 mm H 160 x W 460 x L 630 mm 20 kg 20 kg 15 - 28 °C / 10 - 90 % humidity (non-condensing)

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1 Laser

The most characteristic parameter of the laser for MIN is its resorption in water and the following penetration-depth. The table above shows one of the most important physical properties of LASER effects, which is, that the result is not just due to the property of the LASER one uses, but due to the interaction between the laser and the tissue and its resorption of that LASER used. This is the basis, why the education and training are so important, as LASER behaviors quite different to all, what surgeons’ usual knew before using LASER (Graph 1.6, Fig. 1.6). Light Interaction with a Turbid Medium Input

Specular Reflection

Diffuse Reflection

Scattering

Absorption

Direct Transmission

Diffuse Transmission

Graph 1.6  The Interaction between LASER and tissue must be known and regarded in the field of use. All LASER that produce effects in the depth without being visible at the surface are not recommended in the CNS. The main issue in neurosurgery is the penetration depth and the energy that is transmitted. The Tu-YAG Laser has only 0.5  mm penetration depth and 1–5  W energy application amount. The surgeon can see and judge the effect on the tissue

1.3 Equipment and Ergonomics

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Fig. 1.6  LASER in combination with endoscopy and sonography needs a special training and management in the operation environment. The mastery of all three tools depends from a well-organized work- flow at the table. Reliable interpretation of endoscopic and ultrasound images in parallel is necessary and knowledge of all physical and surgical effects of the LASER within the brain. In addition, surgical strategies and results must be clear in advance. A precise planning must be applied before

In future, to routinely enable cases as following below, further evolution of single rack combination tools will be needed to improve ergonomic for this challenging kind of surgery. In addition, all the tools have special technical and safety conditions, which need to be followed. It seems very attractive to get the results of these MIN key techniques, but an intense training and experience is needed to get such results. However, as such results cannot be reached otherwise, it is worth to go this way and also to train the next generation. Many diseases and handicaps of these patients and children may elicited doubts about the steps that can be reached, but for them small steps mostly rise the life quality into a self-controlled future and release the life for the relatives. Shunting and standard concept mostly have worse results with a never-ending course of complications and re-operations. To hide behind standards and to wait for “evidences” that will not appear for such an extraordinary minority of patients at the border of view. These Patient are impressive teachers for our profession.

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1.4

1 Laser

Illustrative Cases

1.4.1 Typical Applications of LASER Trans-endoscopically 1.4.1.1 Case 1: ETV in a High Basilar Tip Case (Graph 1.7) Cases and Clinical Application 1

2

1b

3

High basiar tip case: complete symptom trias (Hakim) LASER ETV

4 5

Graph 1.7  High basilar artery ETV

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1.4 Illustrative Cases

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This 70y old Lady was admitted by her daughter with a complete Hakim-Triasfor 2  years, which was primarily diagnosed as dementia without neuropsychological testing. Because of the rising walking-and incontinent-problems additionally, a normal pressure hydrocephalus (NPH) was discussed and an MRT (1) was indicated. Her daughter complained, that her mother mostly was impaired with the walking, while for all relatives the memory weakness was more disturbing. Neither urologists nor orthopedics found pathologies. Neurologists did not see any reason to contact a neurosurgical colleague. Finally, an article on NPH brought the daughter to present her mother in our unit. After the MRT was successful organized, including CISS (flow sensitive T2 sequences) and a positive testing pre- and post LP, the indication for ETV was given. MRT presented the anatomical situation of a very high basilar artery tip (blue arrow), lifting the floor of the third ventricle (1+ 1b) in a three ventricular hydrocephalus, causing, that the caudal position of the ventricle floor is impossible. There is an incomplete aqueduct stenosis with the typical form of the aqueduct and flow. Additionally, a strong anterior communicating artery (yellow arrow) fixing the chiasm was striking as well as an empty sellae (orange arrow). Anyway, there was a sufficient gap for the endoscopy (green arrow). However, the LASER (red line; 1b, 4) had to cut along the basilar artery(1b) which is possible with Tu-Yag-LASER as the penetration depth is only 0.5 mm. During endoscopy, at the floor of third ventricle and between the mammillary bodies, the basilar artery tip could be seen protruding through the neural tissue (2) (blue arrow). Two third of the way to be perforated the floor (4) was in contact with the wall of basilar artery, but the LASER enabled to selectively spit the neural tissue and the arachnoid membrane. When penetrating with the endoscope into the prepontine cistern a transgressing AICA through the abducens nerve became visible on the left side (5). At the end of the endoscopy journey, beneath the ponto-medullary sulcus and the vertebro-basilar conjunction, the view goes into the area of foramen magnum (6) with a long way of medulla oblongata and medulla spinalis with the fibers of the C1- and C2- roots left and the spinalis anterior artery system. At the C1 root the entrance of the left vertebral artery can be hardly seen. The inferior hypoglossal fibers are visible between vertebral artery and the brainstem. Normal arachnoid membranes are well presented, and no deep obstructive membranes are diagnosed visually. This endoscopic visual evaluation is absolutely high-end and not recommended for not very experienced endoscopic neurosurgeons! Finally, this Lady improved, mainly her walking and incontinence, but also slowly her memory and cognitive abilities. The mental changes in such patients are most striking and do finally decide the amount of improvement. However, for this group of patients each improvement is a big step towards personal freedom, making care of them much easier and cheaper. Therefore, one should always give them the chance and in such difficult anatomical circumstances the LASER will be of great impact to solve the problem safely and elegantly. Moreover, the shunt-systems do rarely improve the mental problems enough, and often cause the well-known complications.

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1.4.1.2 Case 2: High Basilar Tip (Graph 1.8)

Graph 1.8  Very high basilar artery ETV

1 Laser

1.4 Illustrative Cases

15

This 78-year old man was admitted with nausea, headache and dizziness combined with high blood pressure and anticoagulation with ASS. For 24 h before surgery, he developed vomiting and progressive dizziness. Imaging showed on CT (7) an extreme high basilar artery head and a calcificated lesion in the fourth ventricle (7 O). On MR (1/2) the extraordinary anatomical situation was confirmed as well as an aqueduct-stenosis (2 →). The floor of third ventricle was lifted by the basilar tip (2 ↑) so high, that it obstructed the approach width (2 / 3⇔) and the LASER (1/2/4/5/) was the only tool to fit through this narrow passage (2 / 3 ⇔ 0), aiming to the cinereum in a disadvantage angle (2 ⇔). The compression of the midbrain roof (2 ⇓⇓⇓) is often the only sign in sagittal view for the elevated liquor pulsation, if the floor is lifted and cannot be pressed down. This detailed imaging information is an indispensable analysis for a precise MIN planning. It is important to understand the difference between information for diagnosis and that for MIN planning. The planning according to the planning data predicted the need of LASER, as the usual trans-endoscopic instruments would not fit through the narrowed approach pathway (2/3). But also, the analysis suggests that for safety reasons it was too dangerous to use a mechanical technique for ETV. The close proximity of the neural tissue of the third ventricle floor with the possibility of adhesions to an aneurysmatic basilar artery head, and only 24 h stop of ASS, made the LASER necessary as the only tool to solve this problem. In summary the planning was the condition to apply this MIN procedure. During endoscopy (3–6), it was first visible how the lifted right mammillary body narrowed the right foramen Monroi formed by thalamus (3a), choreoid plexus (3b) and fornix (3c), obstructing the approach (3⇔ 0). Once the LASER (4/) reached the cinereum (4b) the ETV was started while the endoscope could not be pushed over the mammillary body 4(a). Step by step, the floor of the third ventricle (5 b) was ab vaporized (5 c) pre-mammillary (5 a). Finally, over the right mammillary body (6 a) through the ETV, the wall of the basilar artery (6 c) with some remnant fibers of the subarachnoid membrane (Liliequist) was visible dorsal to the red spot of the infundibular recess (6 d). The endoscope could pass the perforation and the interpeduncular cistern with the left oculomotor nerve was seen. There was a good flow of the rinsing and minor bleedings stopped fast. A control of deeper regions was not necessary and not recommended. The patient was free of symptoms postop within hours. He refused any further therapy regarding the process in the fourth ventricle. CTA control was planned, no shunt was necessary. ETV to avoid a shunt and to solve the liquor-dynamic problem was only possible with the aid of LASER, serving as a MIN-Key technique. Moreover, with MIN techniques and strategies surgery under ASS is possible safely. But this is not a standard procedure and should be done only by experienced MIN surgeons well trained in all 5 MIN Key techniques. (s. Vol. I).

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1.4.1.3 Case 3: Multi-LASER Cystic Complex Hydrocephalus (Graph 1.9) Multiple stomies to make a complex ventricular system into a simple one!

1

3

2

6

5

4

III

Cystostomy Stomy of a chuge temporal lobe cyst to the right frontal horn.

ETV Complex ETV into a scary Interpeduncular cistern

Graph 1.9  Complex LASER application in cystic hydrocephalus

Aqueductoplasty LASER enlargement of the Scary entrance of aqueduct

1.4 Illustrative Cases

17

This case belongs to a group of patients, which is neglected so far, as it is still the standard to shunt them in a standard way. But they have very complex and each one unique condition calling for an individual approach. We see a twin which experienced a peri-natal sever ICH due to immature brain and with consecutive complex hydrocephalus. During the first view months 4 isolated compartments have been developed and were managed during the resorption of the clots, by placing reservoirs ultrasound navigated, serving for liquor puncture. These procedures were done according to minimal-invasive strategies. After connecting the compartments endoscopically, a single shunt was inserted. Anyway, 1 year later the boy developed a cystic enlargement in the ventricular system on the right side (1) and the shunt function became worse. The child became symptomatic with ICP rising very slowly. An endoscopic revision with testing the shunt was indicated. The pre-op MRT enabled the planning of three stomies to normalize the liquor dynamics. Red ROI, to connect the cyst with the ventricle (1), blue ROI to open the aqueduct (2) and yellow ROI to perform an ETV for connection to the basal cisterns (3). During endoscopy (4, 5, 6) a former stomy developed a reclosure (4) and could easily be opened by laser (Graph 1.10).

Graph 1.10  After opening of the reclosed membrane, the ventricular system and both frontal horns became their typical shape in the intra-operative ultrasound back and presented the appearance of a mono-ventricle. The post-op MR confirmed this finding (3). The pre-op suspected cyst was an isolated huge temporal horn (1) compressing the frontal horn and obstructing the ventricle catheter. However, as the child was now more than 1  year old, an opening of the membranous aqueduct and an ETV was indicated to optimize the liquor dynamics and making the child more independent from the shunt. However, the shunt could be left in place, but the liquor dynamic opened the chance for less shunt complications

18

1 Laser

The ETV (5) came out to be difficult and only possible by LASER due to scarfs, and it was the oculomotor nerve (5) which could be recognized and used as a guideline and anatomic landmark. The opening of the aqueduct (6), in contrast, turned out to be easy by LASER. Postoperatively, the replaced shunt, just by insertion of the ventricular catheter again, presented now after flow regulation a normal function and the child recovered quickly and could be taken home again. Postoperative MRT (3) confirmed a typical mono-ventricle system in place without shifting or compressions. Behavior and developing became better after all compartment were drained by a single shunt system and regulation of the liquor dynamics was optimized by the LASER-assisted endoscopic procedures. Such difficult and complex cases need a minimal-invasive strategy. The problem is principally simple just to communicate the compartments, but the realization is very difficult, especially in the premature period. Here we have extremely small spaces and very vulnerable tissues. Many procedures may be stepwise necessary, and the overall trauma must be kept small to be successful. The use of the LASER as a minimal or non-tough technique is the ideal tool to fulfill these conditions. In combination with endoscopy and ultrasound, such challenging tasks can be accomplished. These cases are a perfect field to prove the capabilities of the MIN Key concept of the optimal combination strategy of minimal invasive tools with high precision and precise planning. Moreover, this group of cases show, that rare and unusual cases should not be treated with standard concepts and techniques. In addition, the underlying pathophysiology and timing plays also a crucial role.

1.4.1.4 Case 4A (Graph 1.11)

case of poor patient group Pre 56y, congenital hydrocephalus no treatment! came due to trauma to our dept. worsening during time and staying in bed for many years! Post • Recovering from apathia • Mobilisation shortly after Endo-neurosurgery • No risk of shunt complications (30%-50%!) • No shunt-desease! • Chance for some rehabilitation and life-quality

Graph 1.11  Complex application in multicystic hydrocephalus

1.4 Illustrative Cases

19

This case of a 56-year old macrocephalic woman belongs also to the group of neglected patients with a typical fate. She was admitted as a trauma case after a weal-chair drop. For few years, she decompensated slowly showing aggression attacks, strong stress reactions, and endocrinological deficits with visible virilization. Moreover, she had vertical ophthalmic paralysis, parkinsonian tremor, anxiety and autistic automatisms. Finally, she ended in bed, and rarely passive mobilization in the weal-chair. The ICP monitoring presented B-waves with a pathological form, as seen in elevated ICP situations. Imaging presented an extreme, complex and chronic “burn-out” -NPH with a history of 56 years of non-treatment after neuro-toxoplasmosis. An aqueduct-­stenosis and an isolated fourth ventricle was visible in a mega ventricular system and multiple cystic enlargements.

1.4.1.5 Case 4B (Graph 1.12) 3. ventricle-floor/ mono-ventricle 2

1

ETV

4

5

3

Basilar head

6

Aqueducto plasty 7 7/8

8 9/10/11

f. magnum 9 medulla

VI f. magnum

9/10/11 Jugular f.

Graph 1.12  Close-ups: multiple LASER stomies

20

1 Laser

During endoscopy (3b), the view was given into the three supra-tentorial ventricles from the entrance in a wide perspective, showing no single normal detail. The ependyma of the mega ventricle showed atrophic parenchyma with pale color and many remnants of crossing and stretched vessels (LASER cutting) and fiber-tracts (1/2). Foramen Monroi (2) was extremely enlarged, giving view into the complete third ventricle from mamillary bodies to the aqueduct. Only remnants of choroid plexus were existing, and septum pellucidum was only a network of tissue remnants, allowing view into the opposite ventricle. View was also possible into the temporal horn with the typical form of hippocampus. The pineal recess was enlarged and transparent, giving sight on the pineal gland. The third ventricle was so broad that the inter-­thalamic adhesion was stretched to a band. Many remnant tissue fibers and vessels crossed the third ventricle, one was coagulated (1) to prevent bleeding by rupture. The aqueduct (3) presented a membrane that had two perforations. Posterior commissure was hardly recognizable. With the LASER, an aqueductoplasty was performed, giving broad pathway into the mega fourth ventricle (6). The view into fourth ventricle presented only a remnant of the cerebellum and cisterna magna with opaque arachnoid walls. The pre-mammillary membrane (cinereum) was atrophic and showed changes by past inflammation (4). Mammillary bodies were displaced laterally and atrophic, leaving transversal fibers of the midbrain visible (4). Orientation for ETV and the right perforation place was impossible, and due to post-inflammatory scarfing adhesions with the vessel of interpeduncular cistern were suspected. With the LASER, this changed tissue and membrane could be stepwise ablated until a visual control into the cistern was given (5) and finally the last thin arachnoid membrane was opened giving broad view on the complete basilar head system (5). Then the endoscope was moved under visual control into the basal cistern space with an unusual wide and deep perspective, from the CPA left with CN 7/8 to the jugular foramen with CN 9/10/11 (7). Moving towards the midline, the view goes along the pons and the CN 6, and further into the depth to the left vertebral artery and even into the foramen magnum (8). A final move to the midsagittal plane gives sight on the right vertebral artery and the brainstem until medulla spinalis level C2. There were no additional membranes obstructing CSF flow present, as sometimes is given in post-­inflammatory cases (9). The journey back proves the free broad pathway for the CSF and free communication with all ventricular compartments. Postop the woman could be mobilized and after some years in bed preop she started to walk again with help in a few days (3a). The post MR showed the flow signal in the coronary images (3b red arrow).

1.4 Illustrative Cases

21

The clinical course showed stabilization of walking with help and beginning communication. However, these kinds of “burn-out” hydrocephalus” over a long period, will mostly recover only in little steps and incomplete, but, these small neurological and especially neuropsychological recovery steps mean a big step in life quality and easier care and handling. To use shunt strategy can easily end in fatal outcome, because the cranial outflow of CSF is very dangerous for getting bleedings. These impaired brains do not tolerate the slightest incommodities due to a non-perfect fitting shunt-adaptation to this individual brain, and these patients do not tolerate many operations due to shunt complications. LASER plays a key role in such cases.

1.4.1.6 Case 5: Multi-septated CSH (Graph 1.13) Symptomatic Multiseptal CSH

MIN: Avoiding craniotomy; fast recovery, short hospital stay, minimal risc of compl.

post Cutting of membranes to get one SDH compartment to drain

Graph 1.13  Application in cystic subdural hematoma

prä

Multi-cystic CSH, Hp right and aphasia. Normal neurologically: 1h postop!

22

1 Laser

This patient was admitted with hemiparesis right and difficulties to speak. He could only speak very slowly and was unable to speaking fluently, he spoke only stepwise and seeking for words. He was unable to walk safely and was in danger to drop to the right side. The right arm was actively not used, and his behavior was very slow (Graph 1.14).

Graph 1.14  The planning of approach and strategy was to come through a 1 €-craniotomy from the frontal border of the chronic hematoma capsule and to transgress intra-capsular cutting all septum by LASER, and epi-arachnoidal rout cutting the visceral membrane of the capsule to connect all compartments. By this MIN- technique and -strategy a usual craniotomy could be avoided. Without the LASER this was not possible Lateral view on the radiology image from another case shows the area that can be reached in a big SDH endoscopically through a small approach under visual control. Additionally, this enables a radical evacuation without drainage if this advantage is necessary in specially cases (bad coagulation, high age…)

1.4 Illustrative Cases

23

During endoscopy, from a left frontal MIN-approach (1), it was possible to enter the capsule of the chronic SDH (2/4) and saw the capsule from the visceral side (4a) and looking on the surface of the brain (4b). Under continuously rinsing, with the LASER (5a) the visceral membrane of the capsule (5b) was cut and coagulated. Through the openings the old blood flew out over the surface of the brain (5c) and was washed out by rinsing and flow-out. All septum (2) were opened and coagulated and contents washed out. Finally, a Jackson Pratt drain was placed epi-arachnoidal and a liquor drain (7b) placed intra-capsular (7a, d) through all septum, seen from epi-arachnoidal (7c). After communicating all compartments by LASER (5a), the strong irrigation washed out most of the blood. In the postop CT next day (3) the diminishing of the SDH was already visible, as well as the tip of the Jackson Pratt drain epi-arachnoidal. The complete drainages of all connected volumes let the SDH capsule collapse and giving best chance to connect the capsule membranes to a single one, that cannot fill with blood again, and that does not compress and irritate the cortex again. The patient was awake directly after surgery (6), spoke fluently, and presented no paresis 1 h later. Drains were displaced at the second postop day and the patient went home without complications after 6 day. This case could not be done minimally-invasive without LASER, which in such cases fulfills the meaning of a MIN Key technique. Such type of chronic SDH, when operated classically, not rarely, have a bad outcome, even fatal. The endoscopy, additionally, allows to control the procedure visually and do a quite radical washing out of blood. In easy cases, no drainage is needed, therefore.

1.4.1.7 Case 6 (Graph 1.15)

Graph 1.15  Laser Fenestration and ETV in cystic Craniopharyngioma

24

1 Laser

Large cystic craniopharyngiomas are challenging in ophthalmology as well as in neurosurgery. Even the best series in literature report 15% overall mortality. A supra-sellar located tumor injures the visual pathway at its´ most vulnerable site functionally: compression of the chiasm, less than a half of cm3, causes blindness! There is a narrow window of time for acting to save vision. Intense interdisciplinary interaction and application of minimally invasive concepts and techniques preserved vision and visual field in each of the 4 phases of therapy in this case. In this case of a 53 years old female acute decrease of vision and visual field was diagnosed by ophthalmologist followed by emergency MRI and immediate sending to neurosurgery. Visual acuity and perimetry as well as MRI and endocrinological laboratory pre- and postop were analyzed retrospectively in all 4 phases of therapy. Neurosurgical micro- and endo-surgical operations assisted by neuro-sonography and LASER were applied according to minimal invasive concept. Due to tumor distribution on the floor of the third ventricle, endoscopy was applied from the left side, and first view was into the frontal horn (A1) and its’ typical features, foramen Monroi and the choroid plexus, which is always on the opposite side, where you are coming from. The thalamo-striate vein is overlaid by tissue of stria terminalis of lateral ventricle (A1). After the first perforation (A2 0) of the cyst membrane, the cyst collapsed and the big enlarged space of third ventricle took allot light away making the viewdark. Entering the cyst, the typical appearance of the craniopharyngioma was recognized. The ETV was done by LASER (A4 /) to avoid injury of adherent basilar artery, and through the perforation (A4 0), surrounded by tumor (4A a), the wall (A4 c) of basilar-trunk adherent to the cystic floor of third ventricle (A4b) became visible. Pre- and postop imaging (A5) confirmed the decompression of the third ventricle and tumor. A flow void signal indicated the patency of the ETV. Without LASER, perforation of basilar artery, or rupture of a perforator vessel by mechanical force was possible. The lady recovered within hours (C). During the next 3 operations (A6), the LASER was not needed. (see Vol. 1, Chap. 6) (Graph 1.16).

1.4 Illustrative Cases Pre

25 Post

Graph 1.16  Follow-up of visual field

Recovery of visual function after each surgical intervention and finally complete resection of tumor were documented. Return to normal vigilance without disturbance of liquor dynamics and minor hydro-cortisol substitution postop for some month, could be accomplished (C). It was convincing to use the unusual strategy of stepwise solving the problem in such a cystic case. Solving the liquor dynamics problems and the compression effect on the third ventricle wall, by controlling the cysts endoscopically, and restoring the free flow pathway by cyst-fenestration and ETV, gave the extremely vulnerable tissue the chance to recover functionally, before the next steps of tumor resection is necessary. This MIN concept in difficult cystic cases by endoscopy and LASER should be considered and elaborated in future. The MIN key techniques, like LASER, however, need to be mastered, therefore. The overall trauma of the 4 MIN operations seems to be less than one large operation without recovery of the function, as seen very often in such cases by usual strategy. Visual function was the best and most sensitive parameter to detect the need of decompression. It may occur, that decompression is needed as an emergency procedure, and cooperation between neurosurgery and ophthalmology must be very close (Graph 1.17).

26

1 Laser

SUMMARY stepwise strategy by MIN: 2 endoscopic LASER-assisted operations to control the cysts 1 microsurg, operation with 90% resection of solid tumor, 1micro-endo operation with resection of last cyst and rest of tumor

RESULT of • •

vigilance: complete recovery (risk: hypothalamic/thalamic coma vigile!) vis. ac.: R 0,4 0,25*0,6 0,1*0,6 0,5 0,25 0,3*0,3 0,4 0,3*0,25

• • • •

L 0,4 0,5*0,8 0,4*0,6 0,5 0,4 0,3*0,4 0,6 0,5*0,4 0,6 11.2013 3.2014 5.2014 8.2014 4.2015 Visus-Amplitude OD 0,1→0,4 OS 0,3-->0,6 during the 4 Phases satisfactory visual acuity for the life quality of the patient perimetry recovery: MD(dB) OD 24,3-->5,1 OS 14,4-->5,6 end0crinological intact without substitution tumor status: complete resection without recurrency status of hydrocephalus: no shunt necessary

Graph 1.17  Postop results in summary

0,4

1.4 Illustrative Cases

27

1.4.1.8 Case 7 (Graph 1.18) Volume 1: 1500ml Volume 2: 300-500 ml ! Premature tissue!

Päd MIN-Key-Concept For premature babies

Fibers 10 000 Diameter 3.4 cm Length. 18.5cm W-Canal 1.82mm LASER 0.70mm Angle 0° View 70°

Graph 1.18  Sono-assisted LASER application in post-bleeding hydrocephalic preterm babies

28

1 Laser

This group of patients is neglected if seen with standard concepts. The premature babies with complex hydrocephalus and bleedings need an interdisciplinary and MIN strategy with the full use of the MIN key-techniques. The first reason is the size of the head, going down to 300  ml brain volume (1–2) leaving only few tools, like LASER and ultrasound (3/4), and in cystic cases, mini-­endoscopes may be used (5). However, everything is much smaller than usual, even for MIN experienced surgeons. But moreover, the premature tissue, which is extremely fragile and vulnerable, need a very extraordinary strategy and art of working. These two conditions alone can never be solved by standard concepts and mono-technique of shunting. Timing and avoiding of trauma became the major issue for success. The challenge was to deal with a principally simple problems which is often most difficult to be solved because of the mentioned challenges. Preliminaries are a perfect interdisciplinary team with good info- and work- flow. Surgeries will often have to take place inside the incubator (2), as each transportation and translocation is risky. Another preliminary is a high-end ultrasound equipment with small probes (3), like burr-hole probe or small-part probes, and a high quality and resolution imaging (4). With ultrasound and LASER only, in such cases might be able if endoscopy is too traumatic, however, these techniques is very difficult, because guiding with ultrasound in one hand and another tool (like a LASER fiber 4 /) in the other, is very difficult. The safer standard is the trans-endoscopic LASER use, were you can control the LASER fiber mechanically and visually. Usually the laser will come into use in these patients, when opening of post-­hemorrhage cysts is needed, or to communicate compartments of complex hydrocephalus. Tri-planar control of the LASER fiber per se is very difficult, however, in parallel with guiding the LASER fiber within the ultrasound-plane is a real mental and manual acrobatic. All this, in a very small volume of vulnerable tissue, and with the risk of a fatal bleeding or injury. This can be done only with regular training. However, the result is the only chance for these babies, and it can be accomplished only with MIN- key techniques like LASER and endoscopy and ultrasound (Graph 1.19).

1.4 Illustrative Cases

a

29

b

c

Graph 1.19  The LASER- fiber produces an artifact (a–c) on the ultrasound- image, moving the LASER can be seen in real-time. The main challenge is to catch the tip of the LASER (or catheter or instrument) in the ultrasound plane, it can be only controlled visual when appearing in the ultrasound plane!

30

1 Laser

Endo-Sono-LASER Navigation and Coordination (Graph 1.20). Coordination Navigation A LASER-Endoscopy

Navigation B LASER-Ultrasound

Trans-Fontanelle Sono

Graph 1.20  Navigation: Endo-assisted LASER (A) and Sono-assisted LASER (B)

1.4 Illustrative Cases

31

The extra-endoscopic ultrasound navigation of a tool can hardly be done intuitively. Therefor all actions must be done very slowly, and with feed-back control of two tools and two images! (but see trans-endoscopic ultrasound vol. 1, Chap. 5) The sono can be applied trans-fontanelle (e) (axial a, sagittal b, coronal c), but also transcranial with a TCD probe, which in children will enable always a good imaging quality for navigation. Draping the head must consider the positions of the ultrasound probe. The LASER (/) through the burr-hole (d) will be imaged intracranially by all sono positions (axial a, sagittal b, coronal c). Before the final shunting, after resorption of all blood, all compartments were connected by LASER fenestration. For the prognosis, the simplification of a complex hydrocephalus is essential. It can be done and will be tolerated by MIN key techniques. These procedures need only very small approaches avoiding unnecessary trauma. In principle, the LASER can also be applied without endoscopy but ultrasound navigation in very small preterm cases. The working of the LASER will cause artifacts in the ultrasound image by bubbles. MIN strategies and techniques will enable to avoid bleedings. Even the bleeding of the skin-incision is not tolerated in pre-terms, but the smaller the incision, the less bleeding will be caused (Fig. 1.7). Fig. 1.7  This pre-term twin had a severe peri-natal ICH subependymal with IVH and developed a complex hydrocephalus. During the first year 13 MIN operations had to be performed until he went home with a single shunt, well tolerated. Timing and minimal trauma in each single procedure were the basis for the success at the end. Together with his brother he could be taken home by his parents. These cases cannot be solved by standard strategies but by MIN

32

1 Laser

In summary, we see few illustrative cases, which each one represents a different strategy and problem profile. Indication for LASER was chosen strictly by the criterion, that only with the aid of the LASER, the case could be managed. Moreover, only with this MIN key- technique the MIN key- concept could be realized, and seemingly impossible results can be enabled. The LASER belongs to the Key- Techniques of MIN and need to be trained intensively, as this tool may cause unexpected effects and injuries. Actually, the LASER did not make sense without endoscopy or ultrasound. It is absolutely specific for the MIN-Key Concept to combine several techniques, aiming at compensation of weakness of one tool and substitute abilities to one another. In contrast to malignant diseases, it is our obligation to solve simple biological problems, and we should not fail only because it is complex and difficult. MIN can reach undiscovered territories, and in some cases even off-label indications may be realized in experienced hands.

References Belykh E, Yagmurlu K, Martirosyan NL, Lei T, Izadyyazdanabadi M, Malik KM, Byvaltsev VA, Nakaji P, Preul MC. Laser application in neurosurgery. 2017;8:274.

Suggested Reading Akimoto J, Muragaki Y, Maruyama T, Ikuta S, Nitta M, Saito T, Iseki H. A phase two clinical study on photodynamic therapy (pdt) with second- generation photosensitizer talaporfin sodium and semiconductor laser in patients with malignant brain tumors. Belykh E, Cavallo C, Gandhi S, Zhao X, Veljanoski D, Izady Yazdanabadi M, Martirosyan NL, Byvaltsev VA, Eschbacher J, Preul MC, Nakaji P. Utilization of intraoperative confocal laser endomicroscopy in brain tumor surgery. J Neurosurg Sci. 2018;62(6):704–17. https://doi. org/10.23736/S0390-­5616.18.04553-­8. Epub 2018 Aug 28. Bilici T, Mutlu S, Kalaycioglu H, Kurt A, Sennaroglu A, Gulsoy M. Development of a thulium (Tm:YAP) laser system for brain tissue ablation. Lasers Med Sci. https://doi.org/10.1007/ s10103-­011-­0915-­0 Bouras T, Sgouros S.  Complications of endoscopic third ventriculostomy: a systematic review. American Society for Laser Medicine and Surgery: Abstracts Published online in Wiley Interscience, 2008. www.interscience.wiley.com. https://doi.org/10.1002/lsm.20321 Byvaltsev V, Panasenkov S, Tsyganov P, Belykh E, Sorokovikov V.  Nanostructural changes of intervertebral disc after laser ablation (experimental study). Calisto A, Dorfmüller G, Fohlen M, Bulteau C, Conti A, Delalande O. Endoscopic disconnection of hypothalamic hamartomas: safety and feasibility of robot-assisted, thulium laser–based procedures. Technical note. 2014. https://doi.org/10.3171/2014.8.PEDSI13586AANS. de Boorder T, Brouwers HB, Noordmans HJ, Woerdeman PA, Han KS, Verdaasdonk RM. Thulium laser-assisted endoscopic third ventriculostomy: determining safe laser settings using in vitro model and 2 year follow-up results in 106 patients. Downing EF, Ascher PW, Cerullo LJ, et al., editors. Laser in neurosurgery. New York: Springer Wien; 1989. Ebner FH, Nagel C, Tatagiba M, Schuhmann MU. Efficacy and versatility of the 2-micron continuous wave laser in neuroendoscopic procedures

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Einstein A. On the quantum theory of radiation. Physikalische Zeitschrift. 1917;18:121. Hutchens TC, Gonzalez DA, Hardy LA, McLanahan CS, Fried NM.  Thulium fiber laser recanalization of occluded ventricular catheters in an ex  vivo tissue model. J Biomed Opt. 2017;22(4):048001. https://doi.org/10.1117/1.JBO.22.4.048001. Ludwig HC. Shunt oder laserassistierte Neuroendoskopie? Ludwig HC, Kruschat T, Knobloch T, Teichmann HO, Rostasy K, Rohde V. First experiences with a 2.0-mum near infrared laser system for neuroendoscopy. Neurosurg Rev. 2007;30(3):195–201. [Epub ahead of print]. Ludwig HC, Kruschat T, Knobloch T, Teichmann HO, Rostasy K, Rohde V. First experiences with a 2.0 micron near infrared laser system for neuroendoscopy. Ludwig HC, Kruschat T, Knobloch T, Rostasy KM, Teichmann HO, Buchfelder M. Endoscopic cystoventriculostomy and ventriculo-cysternostomy using a 2.0 micron fiber guided CW laser in children with hydrocephalus. Ludwig HC, Bauer C, Fuhrberg P, Teichmann HH, Birbilis T, Markakis E. Optimized evaluation of a pulsed 2.09 microns holmium:YAG laser impact on the rat brain and 3 D-histomorphometry of the collateral damage. Ludwig HC, Kruschat T, Knobloch T, Teichmann HO, Rostasy K, Rohde V. First experiences with a 2.0-μm near infrared laser system for neuroendoscopy. Maimann TH. Report. Phys Rev Lett. 1960;4:564. Mastronardi L, Cacciotti G, Di Scipio E, Parziale G, Roperto R, Tonelli MP, Carpineta E. Safety and usefulness of flexible hand-held laser fibers in microsurgical removal of acoustic neuromas (vestibular schwannomas) Mohammadi AM, Hawasli AH, Rodriguez A, Schroeder JL, Laxton AW, Elson P, Tatter SB, Barnett GH, Leuthardt EC. The role of laser interstitial thermal therapy in enhancing progression-free survival of difficult-to-access high-grade gliomas: a multicenter study. Nakamura H, Fujinaka T, Yoshimine T. A novel monitoring system of cerebral blood flow on neurosurgical operation: clinical experiences of laser speckle flowmetry. Passacantilli E, Anichini G, Delfinis CP, Lenzi J, Santoro A. Use of 2-mm continuous-wave thulium laser for surgical removal of a tentorial meningioma: case report. Photomed Laser Surg. 2011;29(6):437–40. https://doi.org/10.1089/pho.2010.2809. Passacantilli E, Antonelli M, D’Amico A, Delfinis CP, Anichini G, Lenzi J, Santoro A. Neurosurgical applications of the 2-lm thulium laser: histological evaluation of meningiomas in comparison to bipolar forceps and an ultrasonic aspirator. Photomed Laser Surg. 2012;30(5):286–92. https://doi.org/10.1089/pho.2011.3137. Passacantilli E, Lapadula G, Caporlingua F, Anichini G, Giovannetti F, Santoro A, Lenzi J. Preparation of nasoseptal flap in trans-sphenoidal surgery using 2-l thullium laser: technical note. Photomed Laser Surg. 2015;33(4):220–3. Passacantilli E, Anichini G, Lapadula G, Salvati M, Lenzi J, Santoro A. Assessment of the utility of the 2-m thulium laser in surgical removal of intracranial meningiomas. Passacantilli E, Lapadula G, Caporlingua F, Anichini G, Giovannetti F, Santoro A, Lenzi J. Preparation of nasoseptal flap in trans-sphenoidal surgery using 2-l thullium laser: technical note. Posokhov M, Gorbunov O, Bondar B, Posokhov P, Markov O. Experimental-morphological study of the techniques of alcoholic, cryo- and laser destruction of nerve trunks. Potapov A, Goryaynov S, Gavrilov A, Golbin D, Okhlopkov V, Shurkhay V, Chumakova A, Savelieva T, Loschenov V, Kuzmin S. Intraoperative fluorescence diagnostics and laser spectroscopy in brain tumor surgery. Resch KDM. Endo-, sono and LASER-assisted neurosurgery. Resch M, Ulrich P. Endoscopy-, ultrasound- und laser - assistance in Min Klaus Dieter. Schawlow AL, Townes CH. Infrared and optical masers. Phys Rev. 1958;112:1940. Schuhmann Martin U, Cahit K, Lisanne L, Ebner Florian H, Christoph B, Hans-Christoph L. 2-micron continuous wave laser assisted neuroendoscopy: clinical experience of two institutions in 524 procedures

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Stupak V, Shabanov S, Okladnikov G. Analysis of the Nd-yag laser efficacy in surgical treatment of primary extramedullary tumors. Tunc B, Gulsoy M. Tm:Fiber laser ablation with real-time temperature monitoring for minimizing collateral thermal damage: ex vivo dosimetry for ovine brain Virgili G, Menchini F.  Laser photocoagulation for choroidal neovascularisation in pathologic myopia. Cochrane Database Syst Rev 2005;(4):CD004765. https://doi.org/10.1002/14651858. CD004765.pub2. www.cochranelibrary.com. Zelenkov P, Konovalov N, Nazarov V, Kisaryev S, Loschenov V, Grachev P, Rotin D, Saveljeva T, Potapov A, Shevelev I. Ala guidance and laser spectroscopy in spinal cord surgery: interim results of a phase II study.

2

Sealing/Tachosil

TachoSil® (Human Thrombin, Human Fibrinogen absorbable collagen fibrin sealant patch) is a ready-to-use degradable surgical patch. TachoSil® consists of a whitish, closed cell (honeycomb) equine Collagen Sponge coated on one side with the active © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_2

35

36

2 Sealing/Tachosil

ingredients Human Fibrinogen (human sealer protein) and Human Thrombin. Riboflavin is included in the coating mixture as a yellow colorant to signify the active side. Each cm2 contains 5.5  mg of Human Fibrinogen, 2.0  units (IU) of Human Thrombin and 2.1 mg Collagen Sponge. Each fibrin sealant patch is packaged in an appropriately sized blister pack of PET-GAG formed foil and HDPE foil and overwrapped with an aluminium laminate foil pack with a desiccant bag. The manufacturing procedure of TachoSil® and its active substances includes processing steps designed to reduce the risk of viral transmission. In particular, pasteurization, precipitation and adsorption steps are included in the manufacturing of fibrinogen and thrombin and pH treatment in the manufacturing of the collagen sponge. Validation studies for fibrinogen, thrombin and collagen sponge manufacturing steps were conducted for their capacity to inactivate and/or remove viruses. TachoSil® is sterilized by gamma irradiation after completion of inner and outer packaging, resulting in a sterile product in a sterile inner package. A validation study was conducted evaluating the capacity of gamma irradiation to inactivate viruses.

2.1

Recommended Dose

The number of TachoSil® patches to be applied should always be oriented towards the underlying clinical need for the patient. The number of TachoSil® patches to be applied is governed by the size of the wound area. The TachoSil® patch should be applied so that it extends 1–2  cm beyond the margins of the wound. If more than one patch is used the patch should overlap by at least 1 cm. The patch can be cut to the correct size and shaped if too large. Open, unused TachoSil® should be discarded as it cannot be re-sterilized. Application of TachoSil® must be individualized by the treating surgeon. In clinical trials, the individual dosages have typically ranged from 1–3 patches (9.5 cm × 4.8 cm); application of up to 7 patches has been reported. For smaller wounds, e.g. in minimal invasive surgery the smaller size patches (4.8 cm × 4.8 cm or 3.0 cm × 2.5 cm) are recommended (Table 2.1).

Table 2.1 Specification TachoSil® patch size 3.0 cm × 2.5 cm 4.8 cm × 4.8 cm 9.5 cm × 4.8 cm a

Amount of human fibrinogen/total patch size (mg)a 41.3 126.5 250.8

Amount of human thrombin/total patch size (IU)a 15.0 46.0 91.2

Each cm2 contains: 5.5 mg Human Fibrinogen and 2.0 IU Human Thrombin

2.2 Administration

2.2

Administration

Fig. 2.1  Application size for MIN

37

38

2 Sealing/Tachosil

TachoSil® is used under sterile conditions. Prior to application the wound area should be cleansed, e.g. from blood, disinfectants and other fluids. The fibrinogen and thrombin proteins can be denatured by alcohol, iodine or heavy metal ions. If any of these substances have been used to clean the wound area, thoroughly irrigate the area before the application of TachoSil®. It is important to note that failure to adequately clean adjacent tissues may cause adhesions. After removal of TachoSil® from the sterile package the patch should be pre-­ moistened in sterile saline solution. Once moistened TachoSil® should be applied immediately. The yellow, active side of the patch is applied to the bleeding surface and held against it with a gentle pressure for 3–5 min. This procedure enables an easy adhesion of TachoSil® to the wound surface. Alternatively, e.g. in case of stronger bleeding or wet wound area. TachoSil® may be applied without pre-moistening, while also pressing gently to the wound for 3–5 min. It is recommended that a moist surgical tissue or pad is used for applying pressure if TachoSil® is applied dry. Pressure should be applied with moistened gloves or a moist pad. After pressing TachoSil® to the wound, the glove or the pad must be removed carefully. To avoid the patch from being pulled loose it may be held in place at one end, e.g. with a pair of forceps. Leave TachoSil® in place once it adheres to organ tissue. Remove unattached TachoSil® patches (or part of) and replace with new patches. It is strongly recommended that every time TachoSil® is administered to a patient, the name and batch number of the product are recorded in order to maintain a link between the patient and batch of the product.

2.3

Mechanism of Action

TachoSil® is a ready to use degradable surgical patch consisting of a Collagen Sponge of equine origin, coated with Human Fibrinogen and Human Thrombin (Fig. 2.1a). In contact with physiological fluids, e.g. blood, lymph or physiological saline solution the components of the coating dissolve and partly diffuse into the wound surface. This is followed by the fibrinogen-thrombin reaction which initiates the last phase of physiological blood coagulation (i.e. coagulation cascade). Fibrinogen is converted into fibrin monomers which spontaneously polymerize to a fibrin clot, which holds the Collagen Sponge tightly to the wound surface. The fibrin is then cross linked by endogenous factor XIII, creating a firm, mechanically stable network with strong adhesive properties (Fig.  2.1b). The active components of TachoSil® cause the wound surface and the patch to be adhered together. TachoSil® exhibits flexibility to accommodate for the physiological movements of tissues and organs.

2.6 Tachosil Product Characteristics

2.4

39

Pharmacokinetics

Fibrin sealants/hemostatics are metabolized in the same way as endogenous fibrin by fibrinolysis and phagocytosis. After administration to a wound surface, TachoSil® progressively degrades. In animal studies, TachoSil® progressively degrades with only few remnants left after 13 weeks. Complete degradation of TachoSil® was seen in some animals 12 months after its administration to a liver wound, whereas small remnants were still observed in others. The degradation was associated with infiltration of granulocytes and formation of resorptive granulation tissue encapsulating the progressively degraded remnants of TachoSil®. No evidence of local intolerability has been observed in animal studies. From the experience in humans there have been isolated cases where remnants were observed as coincidental findings with no signs of functional impairment.

2.5

Storage and Stability

TachoSil® should be stored at 2–30 °C. TachoSil® does not require refrigeration. Do not freeze.

2.6

Tachosil Product Characteristics

Human Fibrinogen and Human Thrombin are obtained from pooled human plasma obtained from US licensed plasma collection centers. The Collagen Sponge is of equine origin.

2.6.1 Fibrinogen Fibrinogen is manufactured by treatment of cryoprecipitate for purification of fibrinogen. The preparation is treated by pasteurization, following which it is precipitated, and concentrated. After concentration the product is formulated, 0.2 μm filtered, aseptically filled and lyophilized.

2.6.2 Thrombin Thrombin is manufactured by chromatographic purification of pro-thrombin from cryo-poor plasma. The preparation is pasteurized and precipitated. The pro-­thrombin is converted to thrombin, and the preparation is concentrated, 0.2 μm filtered, aseptically filled and lyophilized.

40

2 Sealing/Tachosil

2.6.3 Collagen Sponge Collagen Sponge is a whitish, sponge-like material cut into the form of strips. Collagen Sponge is intended for use as a carrier for further manufacture of TachoSil.

2.6.4 TachoSil TachoSil consists of a whitish equine Collagen Sponge coated with the active ingredients Human Fibrinogen and Human Thrombin, and riboflavin as yellow colorant.

2.7

Neurosurgical Application (Graph 2.1)

a

b

c

d

Graph 2.1  Sandwich technique

2.7 Neurosurgical Application

41

Tachosil should be taken out and opened only just before application. It can be used dry and wet, the dry use is better if one needs to avoid sticking, like in per-nasal use. However, in the application of burr-hole or MIN approaches, the wet application gives a better consistency to modulate the piece on the surfaces of dura and bone border. If ever possible, at least one adaptation suture (B, b) should be placed to have a better chance to press the Tachosil piece firm enough against the dura. Principally in burr-hole closure, to underlay fibrin sponge, will give satisfactory stability to adapt and press the small Tachosil pieces on the dura also. The safest technique to get CSF sealing is the sandwich technique (D). The first piece of Tachosil is placed subdural with the yellow side visible and underlaying to the dura-­ boarder of the opening. Then, the dura is adapted and pressed gently on this yellow surface (if possible, with an adaptation suture), and the second layer is placed with the yellow surface to the dura (epidural) and the bone borders. The adaptation of the Tachosil must be done patiently and precisely. To invest this time is not wasted but makes the Tachosil work safely. The pressure should be done with a wet gaze or brain-patty and needs 3  minutes, which seems a long time. Once the sealing is working, the Tachosil starts to pulsate with the CSF. The epidural layer should stay now dry. A final fibrin sponge into the burr-hole or MIN approach will continue the pressure and stabilize the closure during suturing the skin and further on (Graph 2.2).

A. Bone B. Bone Tachosil C. Spongiosa Tachosil D. Dura Tachosil E. Dura

B A

B C

C D E

10 mm.

Graph 2.2  Burr-hole sealing

A

42

2 Sealing/Tachosil

Superficial sealing of a burr-hole epidural (E + D), of spongiosa (C) and on the scull surface (B) gives a safe and dry closure of the dura (E) and hemostasis of the spongiosa (C). The Tachosil (B + C + D) may be in one piece and is best adapted in a wet condition with a moist patty (Fig. 2.2). Fig. 2.2  In MIN, the burr-hole O is a full competent approach and must be dealt as such one. The last layer of Tachosil (a) is pressed carefully by the aid of a moist gaze (b) and the bipolar forceps. The sealing of the paradigmatic MIN approached is finished

2.8 Illustrative Cases

43

As only Tachosil enables such safe closure in MIN approaches, even if suturing is impossible, it must be seen as a MIN Key Technique within the MIN Key Concept. It is indispensable to use this strategy and philosophy safely and routinely.

2.8

Illustrative Cases

2.8.1 C  ase 1. ICH Left Par-Occ with HP, Aphasia, Hemi-Anopsia, Pre-coma, and Limbic Syndrome (Graph 2.3)

Graph 2.3  MIN-approach sealing

44

2 Sealing/Tachosil

This 42-year old man came with suddenly head- ache, aphasia and hemi-anopsia right, decreasing vigilance and a limbic syndrome followed. First diagnosis was cerebral insult, and he was admitted to the stroke unit. The emergency-CT presented a left parieto-occipital ICH with peri-focal edema. Due to deterioration with incontinence he came to the ICU and finally needed intubation. His relatives reported, that he started not to see well on the right side and could not concentrate on his doing. He was soon impossible to recognize reality and behaves progressively confused and agitative. The neurosurgeon in duty was called and indication for evacuation of the ICH was given. During surgery, which was done through a burr-hole only, the brain was edematous and reddish by blood, the bleeding had a firm consistency and many pathological vessels had to be coagulated. However, an angiopathy could not be seen in histological examination. At the bottom of the bleeding cavity, many very tiny vessels need to be coagulated (1). Finally, the rinsing became clear and the turgor of the parent brain tissue kept the cavity open with normal pulsation and staying below the dura (2). In this case, suturing of the strong dura was possible. The wet Tachosil was adapted to the dura and spongiosa in the burr-hole with moist gaze by meticulously modelling with the bipolar (4). Postop CT showed complete evacuation, and he recovered fast within 1 day. His wife reported, that next day he looked as nothing would have happened. Visual field was normal at ophthalmological examination few days postop, but slight remnants of the limbic syndrome could be described by the patient himself. Wound healing was uneventful, and MIN did not disable the patient in any way (5). He went back to work and got his driving license again, blood pressure control and follow-up by neurological department was indicated, because the intra-­operative appearance of the tissue looked like angiopathy, though histological finding was negative. MIN approaches, like here a burr-hole, may be useful in evacuation ICH even in angiopathy cases and weak coagulation. With and also without suture, Tachosil will safely seal the dura and hemostasis will be working to prevent complication from CSF leakage and bleeding. This is a typical and regularly finding, enabling MIN strategy by MIN Key Techniques. Safe dura closure and sealing with Tachosil is therefore on of the MIN Key Techniques and must be part of training programs in MIN education.

2.8 Illustrative Cases

45

2.8.2 C  ase 2. ICH Left Par-Occ after Stroke with HP and Limbic Syndrome This woman came to the neurological department, impaired by a sudden hemiparesis right side and an increasingly limbic syndrome and aphasia. She was transferred to the stroke unit and a conservative therapy was started. The emergency CT showed a big ICH parietal left-sided with a perifocal edema. The lateral ventricle was compressed and a beginning herniation into the posterior tentorial incisura. Intra-venous anticoagulation and anti-edema therapy was started. At the third day of onset the patient deteriorated and became pre-comatose. As the patient was in a good general condition and independent, the relatives wished an operation, and she was transferred to the neurosurgical department. The change of departments was through the OR because she got worse and was intubated (Fig. 2.3).

Fig. 2.3  IH par-occ

46

2 Sealing/Tachosil

The indication was difficult as she was dehydrated and anticoagulated during the stroke-therapy. However, the experience with MIN Key Techniques gave the possibility to operate under anticoagulation with sealing combined with hemostasis by Tachosil. MIN techniques, moreover, allow a fast evacuation within 1 h (Fig. 2.4).

Fig. 2.4  MIN operations allow a fast positioning of the patient without Mayfield within 15 min. The correct positioning reduces bleeding, edema and enables ergonomic working conditions (see Vol. 1, Chaps. 2 and 3)

Graph 2.4  Sandwich-technique for sealing

2.8 Illustrative Cases

47

The safe closure and sealing of a 1€-approach (15 × 15 mm) are best done by sandwich technique (Graphs 2.4 and 2.5). A wet fibrin sponge (1) may safe the cortex and prevent bleeding from corticotomy. A Tachosil piece upside with the yellow side to the dura (2 + 3) will seal from subdural side. An adaptive suture (4) if possible, will stabilize to enable the adaptation pressure for the second epidural piece of Tachosil (5). A final dry fibrin sponge can save the package from dislocation and presses the Tachosil further on during the stabilization of the wound healing (6) (Fig. 2.5).

48

a

2 Sealing/Tachosil

b

c

Fig. 2.5 (a–c) This MIN approach technique needs a closure and sealing that depends not on suturing, if not possible in case. This concept, however, recommends strictly a high disciplined, and a very precise and clean working. Such allows to work in small shaved skin area, which is a microbiological advantage around the incision. But this works only if the field and especially the hair are kept free of blood (1). Tachosil does support this working as it assists a very fast closure and sealing and at the same time a fast hemostasis even in cases of weak coagulation, like in stroke therapy cases. This does not work only, in cases of hemorrhagic virus infections. But in such cases operation should not be indicated. The psycho-neuro-immunological advances of MIN are obviously (2)

2.8 Illustrative Cases

49

This concept can convince only, if the perfect closure is enabled reliably. The small size of approaches according to a thorough planning and adaptation individually in each case will lead to a fast opening, fast closure, short operation time and decrease of complication. However, the failure tolerance is very low and recommends for a precise ad disciplined work- flow. Without Tachosil, this would not work in a way, which makes a MIN technique to a MIN Key-Technique.

2.8.3 C  ase 3. ICH Left Central, Double Anticoagulation, Functional Hemiplegia, Dura Closure without Suture, Indication: Preservation of Function This patient was suffering from an arteriosclerosis of basal cerebral vessels. Due to the mega-dolicho vertebro-basilaris he was using ASS- and due to cardial reasons Falithrom- medication. Prior CT showed sever sclerosis of the vertebro-basilar system (red arrow, Graph 2.5).

Graph 1.5  ICH central subcortical left

50

2 Sealing/Tachosil

The patient came by taxi to the primary hospital with hemiparesis, RR of 199syst., and INR > 6! After CT he was sent to the stroke unit in our hospital. Then he was admitted from the stroke unit to the neurosurgical department because of an ICH, seen in the CT, left sided central region with perifocal edema, and functionally complete paresis of the right side. The change to surgical therapy was a functional indication, addressing the direct compression of the central region. On the other side the patient was double anticoagulated because of sever pathologies. However, following a MIN strategy, operation under compromised anticoagulation within a peri-operative substitution-window, a functional indication was drawn (Fig. 2.6). a

b

c

Fig. 2.6 (a–c) The burr-hole is a complete approach in MIN strategy and need a different handling compared with usual microsurgical approaches, regarding geometry conditions and pathophysiology of wound healing. The anatomical condition regarding size, often do not allow to suture the dura. However, safe closure is indispensable to avoid sever complications, and to make the method a safe and successful procedure. Therefore, the sandwich-method of Tachosil is necessary to get a firm and safe closure and sealing, and in addition a strong hemostasis in the wound field. The complete concept enables procedures which otherwise would not be able and can safe function or life in near fatal or difficult conditions. The decision is to be made individually in each case, as such cases are complex and rare, and not suitable for large clinical trials

2.8 Illustrative Cases

51

“Burr-hole surgery” within MIN are a paradigmatic model in MIN strategy and have shown to depend strongly on the use of Tachosil for sealing and closure even without suturing, if not possible. This model presents a challenge and a guide-line for the 5 MIN Key Techniques within MIN. Therefore, it can also be seen as an ideal standard model for training in courses in the laboratory setting.

2.8.4 C  ase 4. Bullet Injury and ICH, Evacuation Via Exit-Hole and Sealing Pernasal

1

4 3

Bleeding by bullet 2

Hemiplegia Aphasia Coma

1 d post ICH evacuation and debriement 5

6 2 MIN Ops: 1.)ICH evac. and 2.)Pernasal Endoscopic Sealing

Graph 2.6  ICH by bullet injury transoral-transnasal transcranial

3. M post

52

2 Sealing/Tachosil

This 41-year old man came intubated into the emergency room, respirated and relaxed, isochoric miotic pupils, with stabile vegetative conditions. Relatives reported a shooting through the mouth with exit of the 7.5 mm-bullet, after a family quarrel. He was at once comatose, and bleeding from mouth, nose and exit- wound were present. Nobody of the primary team would have given him a chance, but the precise analysis of the bullet canal (1) (Graph 2.6), the size of the bullet of 7.5 mm and the limited ICH and edema, with regard of MIN-Techniques and strategies, let to a precise result, that there was a reliable chance for recovery. The bullet went through the hard palate, producing a hole. Then went through the left nasal cavity, destroying nasal conchae partially, and then running through the ethmoid bone and the skull base. Now it passes the left optic nerve and left carotid artery with few mm distance, taking the way through he left frontal lobe additionally entering and leaving the frontal horn of left lateral ventricle, but with distance to the basal ganglia. It exits laterally to the superior sagittal sinus without hurting a major bridging-vein, transgressing the skull and causing a mushroom-like protrusion of lamina externa, and finally leaving the head in the post-coronary para-­ median region with a small exit wound of the skin (4). The transgression-canal was filled with blood and necrotic brain tissue, and the left lateral ventricle was filled with blood also. The energy-wave parallel to the bullet-canal caused a peri-focal edema of about 20  mm in diameter, which got broader close to the skull as an echo-effect of the energy-wave at the skull. It is essential to imaging exactly this route of primary brain injury and the following functional consequences. Moreover, it is important to imaging the pathophysiology of secondary injury caused by resorption of blood, brain damage and liquor dynamic impairments. The option to minimal invasively evacuate the damage and blood to avoid secondary injury and in addition, avoiding liquor dynamic problems, was the key for the decision. Finally, a clearance of the wound to avoid infections, but also the major question for the possibility of a safe closure on both sides of the bullet canal, had to be respected. This is possible with the MIN Key Technique of Tachosil. So, the decision was in favor for MIN surgery. The post-op control (2) showed a complete evacuation of the bleeding and a clean bullet-canal, no increase of the perifocal edema, perfect position of the drainage and no bone fragments in the wound anymore (2 + 3). This result was a good condition for recovery of the tissue and functions. Closure by safe sealing assured avoidance of CSF leakage and infection complications (3) (Fig. 2.7).

2.8 Illustrative Cases

53

a

c

b

d

e

Fig. 2.7 (a–e) Sealing at the bullet-exit O epidural and entrance endo-nasal 0 is essential for avoiding complications and success, and was accomplished in separate sessions, first epidural and 1  week later per-nasal. The interdisciplinary cooperation is important, and in both operations Tachosil enabled a MIN procedure and a safe sealing. Timing of the per-nasal approach is important: waiting for the primary brain recovery, but before CSF leakage. Big sub-frontal approaches are contra-indicated in such precise small lesions of the skull base. MIN gives the chance for recovery in cases, when in the first impression it seems impossible. Anyway, the further course of clinical history will be difficult representing the message, that the MIN concept and strategy is not a technical one but an overall concept. (see Vol. 1 Chap. 3). MIN enables to come earlier as usual into this phase of rehabilitation, and Tachosil will prevent to get drawbacks by complications. The patient recovered completely and went back to work as a driver 6  month after injury. Beside incomplete anosmia, he had now neurological or neuropsychological deficits. Another year later, when the patient visited me, I could experience, that he is back in a meaningful and happy life, without any anger about the dramatic fate. So, he teaches us: never give up! MIN gives us the techniques, concepts and hopes

54

2 Sealing/Tachosil

In summary, the MIN concept and the MIN Key-Techniques can be learned (see Vol. 1 Preface). Tachosil is one of the MIN Key-Techniques and in this case, it could be shown in very difficult conditions, the preventing of a fatal decision at the admission, and avoiding frequent complications like CSF leakage and infection. Sealing at the skull base is difficult for many reasons, and in the past was usually combined with tremendous and traumatic approaches, causing many additional symptoms and morbidity not present before surgery. Until today, it is frequently possible to hear the believe of approaching CSF leakage: the bigger, the safer. The techniques of sealing have changed this. Tachosil moreover allows to closure and seal without suturing in MIN approaches due to its strong adhesive capacity and in addition strong coagulation qualities.

2.8.5 Case 5 (Graph 2.7)

1

2

Pernasal - Endoscopic Pituitary Surgery

3

Graph 2.7  Per-nasal endoscopic pituitary surgery

4

In this case of a hard tumor binostril technique was used

5

The tumor could be taken in one piece

2.8 Illustrative Cases

55

This 67-year old man was operated 1 year before actual surgery. At the first operation it came out a hard and bloody tumor that could only be operated by taking a biopsy. The tumor was intra- and supra-sellar and rather big and showed growing in the imaging (2 + 3). There was no visual deficit but a partial hormonal dysfunction. With substitution of L-Thyroxin he was in a good overall condition (Graph 2.8; Figs. 2.8 and 2.9, Fig. 2.10).

Positioning is most important to get ergonomic condition and to allow a patiently sealing at the skull base per-nasal endoscopically. Video-Tower

Patient

Surgeon

Graph 2.8  Possitioning for pernasal endoscopic approach

56 Fig. 2.8  Sealing of the skull is difficult, as there, peri-sellar, is only thin bone and a thin dura, very adherent to that bone. There is not much soft tissue for healing. The Tachosil pieces must be adapted very carefully with a broad contact to the bone around the dura. It must be pressed firmly and for 3 min

Fig. 2.9  The sphenoid sinus can be filled with autologous fat graft and the sinus sealed sandwich like. Through the narrow cavity of the nose it is not easy to prepare the Tachosil piece correctly, and one should take the time to perfectly do this if it should safely work. However, it is the most reliable way to close and seal there, by MIN

Fig. 2.10  The tumor was taken out with a bi-nostril technique bimanual (4), and mainly in one piece to avoid too much bleeding and operation time (5). The Tachosil layers were placed peri-sellar inside the sphenoid sinus and one layer outside the sinus and epi-mucosal to seal the mucosa

2 Sealing/Tachosil

2.8 Illustrative Cases

57

There were no complications of CSF and no hormonal- or electrolyte- changes nor symptoms. Histology showed an adenoma and no remnant was seen in the control imaging.

2.8.6 Case 6. Per-cutan-transorbital Perforation with CSF Leakage See Figs. 2.11, 2.12, 2.13, 2.14 and Graph 2.9.

a

b

c

Fig. 2.11 (a) This 2-year young boy was injured with a screwdriver by his brother. He was primarily awake and could not open his left eye, which was swollen and showed a CSF leakage through a small wound. He needed immediate medication due to strong pain. (b) After intubation and CT, as well as clinical examination, it became clear, that his left eye bulb surprisingly was not injured. The screwdriver perforated the medial superior eye- lid, perforated the intra-orbital fat and transgressed a few milli-meters through the orbital roof into the brain fronto- basal brain near to the rectus gyrus. There was no bleeding visible and no foreign body or edema. (c) The coronal CT reconstruction showed a very small defect of the orbital roof and a minimal laminal bone-fragment could be diagnosed

58

a

2 Sealing/Tachosil

b

Fig. 2.12 (a, b) A 1.5 cm- incision supra-orbital medial to the supra-orbital incisura was quite enough to approach this minimal lesion. The only need was, to seal the CSF lesion, and to look for damaged tissue. It is still standard to do large craniotomies for skull- base lesions with CSF leakage. This is a classical condition to experience the superiority of MIN strategies. In this case the MIN approach of 15 mm incision was perfect to find the lesion and to judge the tissue condition there. Only one simple layer of Tachosil sealant was enough to perfectly close the leakage within 30 min from skin to skin. This layer is thin, and it does not compress the orbital content. In CT and MRT it causes a typical artifact (red arrow)

Fig. 2.13  At the next morning the boy was quite patent and in a good mood. There was a slight remnant of swelling and a little pupil difference. However, he had a good fixation and conjugated motility of eyes. Demission occurred at the fourth day already, follow-up took place outside the hospital, so we lost him for further examinations. No complications were reported anyway

2.8 Illustrative Cases

59

Fig. 2.14  The difference between MIN incision supra-orbital and standard incision coronal is obvious, but the traumatological, pathophysiological and psychological difference are more significant

Graph 2.9 Sealing enables new concepts and approaches. These properties make Sealing a Key-Technique of MIN

Skin incision

60

2.9

2 Sealing/Tachosil

Other Techniques for MIN as Probable MIN-Key Option

2.9.1 Sono-thrombolysis There are some candidates which seem to have functions as a MIN Key Technique, like sono-thrombolysis. The author has no experience with this technique, but it is worth to keep it in mind, and to urge young colleagues to examine this tool (Graph 2.10). Graph 2.10 Fokussed Sono-Thrombolysis

2.9 Other Techniques for MIN as Probable MIN-Key Option

61

However, it is also of great importance to keep focus on the time course of the lysis and avoidance of resorption through the surrounding brain tissue to preventing secondary injury. The time plays a critical role in pathophysiology of these events in the brain tissue. Mostly the evacuation is not fast enough to prevent adverse effects by the blood clot. This therapy has been used since few years and reported in the literature. However, there is not enough experience to understand side effects and benefit. We hope to see progress in the near future.

2.9.2 Focused Ultrasound FUS/HIFU 2010 2011–2013 2013–2014 2014 2016 2016

Phase I clinical trial for noninvasive tumor ablation; to prevent heating of the skull, a water cooling, circulating, and degassing was used (McDannold et al.58) Use of tcMRgHIFU for ET (Elias et al.22 and Lipsman et al.53) In vitro and in vivo studies for sonothrombolysis of ICH (Monteith et al.64 and Harnof et al.38) Report on the first experience with tcMRgHIFU for PD (Magara et al.55) Randomized controlled trial of tcMRgFUS thalamotomy for ET (Elias et al.23) Preliminary report on randomized controlled trial of MRgFUS thalamotomy for PD (Bond et al.)4

Focused ultrasound is used in a variety of indications and examined in clinical trials. The ultrasound technique is used to apply high energy dose to the brain tissue. This is enabled in a per-cutan technique and mainly controlled by MRT (MRgFUS). However, this application needs an expensive and space consuming equipment that bear some conflicts with ergonomics principles like simplification and low costs. (s. Vol. 1) (Graph 2.11).

62

2 Sealing/Tachosil

Graph 2.11  Focussed ultrasound

2.9.3 Integration of Multiple Min Key-Techniques The description of the 5 MIN Key Techniques, used by the author, should not end without remembering the concept of combining MIN techniques. The best way is the development of combined equipment in a single rack system. The key of success is the concept of simplification. The concept is to evolve all effectors into a chain of micro-system-technique, where the architecture of all components is composed with reference to the function of the complete system, and with a smooth workflow and ergonomics (Graph 2.12).

2.9 Other Techniques for MIN as Probable MIN-Key Option

Chain of Micro-Technique

Chain of Micro-System-Technique

CT/MR Mikro Instrumente

63

Sono Imaging

Bohrioch Mikro Instrumente HMD System

Monitoring Energie Support

Koaxiales Licht Ergonomic Trauma

Energie Support

NEW

Endoskop Licht

Endoskop System Kette: Mikro Technik

Mikroskop

Neuro Navigation

System Kette: Mikro System Technik >>PICO

Sono Navigation

Graph 2.12  Ergonomics evolution of technique-chain

The combination of ultrasound and endoscopy in one instrument equipment is one of the urgent evolutions to be done. The ENS-equipment (s. Vol. 1, Chap. 5) is not major and not a true single rack instrument as the combination is enabled by mechanical insertion of the sono-catheter into the working-canal of the endoscope must be done each time manually by the surgeon. In addition to the radial sonography, a longitudinal sonograph is needed in such a new instrument. Of course, the instrument must be combined with a computer aided surface for interpretation and navigation (Graphs 2.13, 2.14, and 2.15).

64

2 Sealing/Tachosil

Graph 2.13  A single instrument sono-guided endoscope is still not developed for MIN, as this is the case since decades in other fields of medicine. This is a major lack, as endoscopy will not advance without sono-­ graphy and a two equipment solution is very difficult if possible

Graph 2.14 Radial sono-elements in the shaft of the endoscope. The sono-imaging can be displayed as a multi-level online representation or, and in addition, as a 3D modelling to navigate the endoscope in real-time. Reliable navigation is only safe by real-time technique, however, the few real-time techniques need to be combined in single tool strategies to use them intuitively and easily. The MIN surgeon needs conditions to concentrate to the surgery and not to struggle with the Immature technical tools

multi-level sonography

navigated endoscopy

2.9 Other Techniques for MIN as Probable MIN-Key Option

65

Endo-Sono-Exo-Sono 3D Navigation-system

3D anatomyassisted sonographynavigated endoscopy

gistration

Anatomic-Optical Re System

Graph 2.15  The main disadvantage of usual neuronavigation is the lack of real-time imaging. This leads to several server problems that have soon become clear and were the target to develop compensation techniques. Moreover, usual systems of computer-navigation are very expensive an do not follow the needs of ergonomics, even they use to disturb the workflow and are in contradiction to the principles of MIN. (Vol. 1. Chap. 3). Therefor a novel concept should be considered

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This new concept is based on anatomy and ultrasound. The ultrasound technique is an original real-time application with the lack of easy primarily intuitive recognition. A 4D ultrasound technique, well known from prenatal diagnostics, should be combined with an anatomical interpretation surface to support interpretation of the imaging during following and controlling a procedure. This should navigate a balanced robotic holding device of an endo-exoscope system to be used for endo-­ exoscope assisted microneurosurgery. This concept, that was primarily used in the “PICO-Project” (Vol. 1, Chap. 4) is a typical example, that combined systems are the way of future for MIN. The most important guidelines of evolution are ergonomics and real-time, modularity and low -cost strategy. There must be a clear priority of the clinical goals versus the technical overkill. MIN surgeons must be integrated into the team of such interdisciplinary and translational projects.

2.9.3.1 MIN and Design of Combined MIN-Key-Systems>> Simplification (Graph 2.16)

MIN

Graph 2.16  Model: Single-rack system of multimodal modular effector-system

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According to the mental ergonomics, the center of developing new MIN-Key-­ Systems is the surgeon himself. The complete environment and especially combined systems must support the intuitive usability and oriented to solution of the clinical task. One reason, to avoid combined techniques is the lack of such functionality. One of the main guidelines of MIN is: Simplification. Our question to the developer and the industry is: can you make my work more simply? And the question to us is: what makes my work more simply? If it is no problem to you, that you have expensive mono-machines that you don’t use in combination because it is too complex and difficult and that your approaches look like that before world war II, ore you have the most expensive equipment but the whole procedure becomes more and more complex and time consuming, something is questionable. MIN always rises this fundamental question, because the status quo is not made for MIN. Combined techniques in well-designed single rack tools will be the next generation of MIN-Key-Techniques: the MIN-Key-Systems.

Suggested Readings Fischer L, Seiler CM, Broelsch CE, de Hemptinne B, Klempnauer J, Mischinger HJ, Gassel H-J, Rokkjaer M, Schauer R, Larsen PN, Tetens V, Buechler MW. Hemostatic efficacy of TachoSil in liver resection compared with argon beam coagulator treatment: an open, randomized, prospective, multicenter, parallel-group trial. Surgery. 2011;149(1):48–55. Frilling A, Stavrou G, Mischinger HJ, de Hemptinne B, Rokkjaer M, Klempnauer J, Thorne A, Gloor B, Beckebaum S, Ghaffar MF, Broelsch CE. Effectiveness of a new carrier-bound fibrin sealant versus argon beamer as hemostatic agent during liver resection: a randomized prospective trial. Langenbecks Arch Surg. 2005;390(2):114–20. George B, Matula C, Kihlström L, Ferrer E, Tetens V. Safety and efficacy of TachoSil (absorbable fibrin sealant patch) compared with current practice for the prevention of cerebrospinal fluid leaks in patients undergoing skull base surgery: a randomized controlled trial. Neurosurgery. 2017;80(6):847–53. https://doi.org/10.1093/neuros/nyx024. Johnsen EJ, Tada T. European Commission approves surgical patch TachoSil® (humanthrombin/ human fibrogen) for use in neurological surgery. 2016. Maisano F, Kjærgård HK, Bauernschmitt R, Pavie A, Rábago G, Laskar M, Marstein JP, Falk V.  TachoSil surgical patch versus conventional haemostatic fleece material for control of bleeding in cardiovascular surgery: a randomised controlled trial. Eur J Cardiothorac Surg. 2009;36:708–14. Otani N, Toyooka T, Fujii K, Kumagai K, Takeuchi S, Tomiyama A, Nakao Y, Yamamoto T, Wada K, Mori K. “Birdlime” technique using TachoSil tissue sealing sheet soaked with fibrin glue for sutureless vessel transposition in microvascular decompression: operative technique and nuances. J Neurosurg. 2018;128(5):1522–9. https://doi.org/10.3171/2017.1.JNS161243. Sagalowsky AI. Editorial comment on: efficacy and safety of TachoSil as haemostatic treatment versus standard suturing in kidney tumour resection: a randomised prospective study. Eur Urol. 2007;52(4):1162–3. Siemer S, Lahme S, Altziebler S, Machtens S, Strohmaier W, Wechsel H-W, Goebell P, Schmeller N, Oberneder R, Stolzenburg J-U, Becker H, Lüftenegger W, Tetens V, Van Poppel H. Efficacy and safety of TachoSil® as haemostatic treatment vs standard suturing in kidney tumour resection: a randomised prospective study. Eur Urol. 2007;52:1156–63. Van Poppel H, Siemer S, Lahme S, Altziebler S, Machtens S, Strohmaier W, Wechsel HW, Goebell P, Schmeller N, Oberneder R, Stolzenburg JU, Becker H, Lüftenegger W, Tetens V, Joniau

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S. Kidney tumour resection with use of TachoSil as haemostatic treatment. Eur Urol Suppl. 2006;5(2):180. Augmented reality navigation system for endoscopic surgery based on three-dimensional ultrasound and computed tomography: application to 20 clinical cases. International Congress Series 2005;1281:537–542. https://doi.org/10.1016/j.ics.2005.03.234. Bhatia K, Hepburn M, Ziu E, Siddiq F, Qureshi AI. Modern approaches to evacuating intracerebral hemorrhage. Curr Cardiol Rep. 2018;20(12):132. https://doi.org/10.1007/s11886-­018-­1078-­4. PMID: 30311010. Review. Bonsanto MM, Staubert A, Wirtz CR, Tronnier V, Kunze S. Initial experience with an ultrasound-­ integrated single-rack neuronavigation system. Acta Neurochir (Wien). 2001;143:1127–32. https://doi.org/10.1007/s0070101000031:STN:280:DC%2BD3MnosVelsQ%3D%3D. Bretsztajn L, Gedroyc W. Review article: brain-focussed ultrasound: what’s the “FUS” all about? A review of current and emerging neurological applications. Br J Radiol. 2018;91(1087):20170481. https://doi.org/10.1259/bjr.20170481. Bruno F, Catalucci A, Arrigoni F, Sucapane P, Cerone D, Cerrone P, Ricci A, Marini C, Masciocchi C. An experience-based review of HIFU in functional interventional neuroradiology: transcranial MRgFUS thalamotomy for treatment of tremor. Radiol Med. 2020;125(9):877–86. https:// doi.org/10.1007/s11547-­020-­01186-­y. Epub ahead of print. PMID: 32266693. Review. Enchev Y. Neuronavigation: geneology, reality, and prospects. Neurosurg Focus. 2009;27(3):E11. https://doi.org/10.3171/2009.6.FOCUS09109. Focused ultrasound: current and future applications. Neurosurg Focus. 2018;44(2). Gallay MN, Moser D, Jeanmonod D. MR-guided focused ultrasound cerebellothalamic tractotomy for chronic therapy-resistant essential tremor: anatomical target reappraisal and clinical results. J Neurosurg. 2020;7:1–10. https://doi.org/10.3171/2019.12.JNS192219. Epub ahead of print. PMID: 32032945. Gronningsaeter A, Kleven A, Ommedal S, Aarseth TE, Lie T, Lindseth F, Langø T, Unsgård G. SonoWand, an ultrasound-based neuronavigation system, n.d. Harary M, Harary SM. Focused ultrasound in neurosurgery: a historical perspective. Neurosurg Focus. 2018;44(2):E2. https://doi.org/10.3171/2017.11.FOCUS17586. Jackson DA, Patel AV, Darracott RM, Hanel RA, Freeman WD, Hanley DF. Safety of intraventricular hemorrhage (IVH) thrombolysis based on CT localization of external ventricular drain (EVD) fenestrations and analysis of EVD tract hemorrhage. Neurocrit Care. 2013;19(1):103–10. https://doi.org/10.1007/s12028-­012-­9713-­1. PMID: 22544476. Jung NY, Park CK, Chang WS, Jung HH, Chang JW. Effects on cognition and quality of life with unilateral magnetic resonance-guided focused ultrasound thalamotomy for essential tremor. Neurosurg Focus. 2018;44(2):E8. https://doi.org/10.3171/2017.11.FOCUS17625. PMID: 29385928. Konishi K, Hashizume M, Nakamoto M, Yoshihiro K. Kobe University; Japan, n.d. Le Roux P, Pollack CV Jr, Milan M, Schaefer A. Race against the clock: overcoming challenges in the management of anticoagulant-associated intracerebral hemorrhage. J Neurosurg. 2014;121(Suppl):1–20. https://doi.org/10.3171/2014.8.paradigm. PMID: 25081496. Review. Magnetic resonance-guided focused ultrasound neurosurgery for essential tremor: a health technology assessment. Health Quality Ontario. Ont Health Technol Assess Ser. 2018;18(4):1–141. eCollection 2018. PMID: 29805721. Review. Mould WA, Carhuapoma JR, Muschelli J, Lane K, Morgan TC, McBee NA, Bistran-Hall AJ, Ullman NL, Vespa P, Martin NA, Awad I, Zuccarello M, Hanley DF, MISTIE Investigators. Minimally invasive surgery plus recombinant tissue-type plasminogen activator for intracerebral hemorrhage evacuation decreases perihematomal edema. Stroke. 2013;44(3):627–34. https://doi.org/10.1161/STROKEAHA.111.000411. Epub 2013 Feb 7. PMID: 23391763. NDI electromagnetic tracking systems. 2014. http://www.ndigital.com/products/. Neuroendoscopy Market by Product (Rigid (Videoscope, Fiberscope), Flexible endoscope), Usability (Reuse and Disposable), Application (Transnasal, Intraventricular, and Transcranial), Region (North America, Europe, Asia)—Global Forecast to 2022 © 2018 Market Research

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Future® (Part of WantStats Research and Media Pvt. Ltd.) https://www.marketresearchfuture. com/reports/neuroendoscopy-­market-­5836 Newell DW, Shah MM, Wilcox R, Hansmann DR, Melnychuk E, Muschelli J, Hanley DF. Minimally invasive evacuation of spontaneous intracerebral hemorrhage using sonothrombolysis. J Neurosurg. 2011a;115(3):592–601. https://doi.org/10.3171/2011.5.JNS10505. Epub 2011 Jun 10. Newell DW, Shah MM, Wilcox R, Hansmann DR, Melnychuk E, Muschelli J, Hanley DF. Minimally invasive evacuation of spontaneous intracerebral hemorrhage using sonothrombolysis. J Neurosurg. 2011b;115(3):592–601. Resch KDM. Transendoscopic ultrasound for neurosurgery. Springer; 2005. Slawsky K, McInnis M, Goss TF, Lee DW. The clinical economics of ultrasound-guided procedures. Sorger H, Hofstad EF, Amundsen T, Lango T, Leira HO. A novel platform for electromagnetic navigated ultrasound bronchoscopy (EBUS). Int J Comput Assist Radiol Surg. 2016;11(8):1431–43. https://doi.org/10.1007/s11548-­015-­1326-­7. Teo C, Sughrue ME. Principles and practice of Keyhole brain surgery, n.d. Unsgård G, Solheim O, Selbekk T. Intraoperative ultrasound in neurosurgery. In: Jolesz FA (Ed.) Intraoperative imaging and image-guided therapy, n.d. Vougioukas VI, Hubbe U, Hochmuth A, Gellrich NC, van Velthoven V. Perspectives and limitations of image-guided neurosurgery in pediatric patients. 2003. Zaaroor M, Sinai A, Goldsher D, Eran A, Nassar M, Schlesinger I. Magnetic resonance-guided focused ultrasound thalamotomy for tremor: a report of 30 Parkinson’s disease and essential tremor cases. J Neurosurg. 2018;128(1):202–10. https://doi.org/10.3171/2016.10.JNS16758. Epub 2017 Feb 24. PMID: 28298022. Ziai WC, Muschelli J, Thompson CB, Keyl PM, Lane K, Shao S, Hanley DF. Factors affecting clot lysis rates in patients with spontaneous intraventricular hemorrhage. Stroke. 2012;43(5):1234–9. https://doi.org/10.1161/STROKEAHA.111.641050. Epub 2012 Mar 1. PMID: 22382155.

Experiences with TachoSil® in Microneurosurgery Kivelev J, Göhre F, Niemelä M, Hernesniemi J. Acta Neurochir. 2015;157(8):1353–7; discussion 1357. Epub 2015 Jul 3. https://doi.org/10.1007/s00701-­015-­2473-­x.

3

Evolution of Anatomy to a Key of MIN

3.1

Anatomy/Topographic Anatomy/Surgical (Gestalt) Anatomy

3.1.1 Approach-Analysis and Approach-Design The speedy technical evolution of visualization and imaging and surgery recommends a second loop to the anatomical laboratory. Training within surgical simulation environment is necessary during years. In history, all great Master of Surgery did so (see Fig.  3.1). However, it was a completely different kind of anatomy necessary to have the needed training effect for MIN. Fig. 3.1  M. G. Yasargil and C. Drake, studying the subtemporal approach of Drake. (Microsurgical Course in Chicago 1988)

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_3

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The usual experience for neurosurgeons at the beginning of their career, but also in times of changing imaging- and visualization-techniques, is the difficulty to translate topographical anatomy into surgical anatomy, to understand what they see during surgery. Moreover, space orientation intracranial remains a main topic in the daily work. Navigation tools did poorly change this problem, even many didbelieve the industry advertising and promises, that they would master now this problem easily. Today everybody can know, that this promise is not solved, due to the lack of real-time imaging. The strategy of technical overkill even did not resolve the problem! Moreover, a new one was produced: them is leading of naive colleagues, who misunderstood technique as a religion, experienceing surprises, and the result was a mental stop of innovation towards MIN. The enthusiasticrecommendation of Yasargil during the upcoming era of micro-­ neurosurgery, to draw the attention not only to the technique, but primarily to the new kind of anatomy, especially the anatomy of the cerebral cisterns and subarachnoid space, was not welcome (pers.com. 1984). “The subarachnoid cisterns are the road-maps of micro-neurosurgeons.” (Graph 3.1). Yasargil concept Mouth tracking New approach design

Subarachnoid approach

Contraves microscope system

New instrumentals

Mental fibertracking

New anatomical concept

Graph 3.1  Some Major Concepts of Yasargil

Change of Arnold/Benninghoffs’ lobe-concept

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But it was Yasargil again, who changed many anatomical concepts (see Microneurosurgery Vol. I and Vol. IV A). He evolved Arnold/Beninghoffs’ 4-lobe concept from 1938 to a 7-lobe model in the 1980th and developed a mental fiber-tracking. The main new step was to establishthe cerebral cisterns as “road-maps of microneuro-surgeons”. The reason why all these problemsdo happen is a lack of anatomical education, but moreover, the usual kind of anatomical training. A very early and surprising experience of the author was the observation, how often neurosurgeons lost orientation in the pre-CT era, and, disappointingly: that this did hardly change in the next decades with modern imaging. No surprise was, however, that under such conditions MIN did not evolve easily, and that anatomical concepts, like the primarily key-holeconcept, did not meet an anatomical prepared community. Many misunderstandings occurred and evolutions of the concepts were necessary (see Vol. 1, Chaps. 2 and 3). In general, it was not recognized and accepted, that the kind of surgical anatomy needs to be changed for each new technical era. Rhoton started a tremendous and well-known project of anatomy for microneurosurgery. However, in contrast to ethical recommendations, surgery was always ahead to anatomy at that time (Graph 3.2).

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3  Evolution of Anatomy to a Key of MIN 6 Strategy in t repanation Locations supratentorial Dorsally CT Measurements

Measurements level 5 : topogram 1:1

level 5 : topogram 1:1

2 1

1 Compte r pr og 2 ram

5 cm

oint of the t um al p or ntr Ce

Window!

Window!

Transfer With compasses or computer 2 topogram 6 cm 5.5

5

3

Bregma 8

vel 5

5.5 c m

3

4

CT le 5 cm

7

10

Parion 5 cm

Projection of central point Mapping before op.

5 cm

9

1 to 10 Seduence of procedures

Graph 3.2  Surgical Localisation-System of W. Seeger

W.  Seeger presented a large series of volumes with very complex anatomical sketches of microneurosurgical procedures (adaptation of anatomy to microsurgery), and in Vol. 7: “Planning Strategies in Microneurosurgery”, he introduced a sophisticated and simple anatomical orientation concept, based on anthropological

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landmarks, to neurosurgery. By that, he solved the mayor problem of transposing imaging data to the surgical field, one of the most difficult topics during training in neurosurgery, using visible and touchable landmarks with measures of distances and angles. The accuracy of this method to target regions of interests (ROI) is 5 mm, not far away from surgical accuracy of navigation systems, and precise enough to control their results, ruling-out mayor failures. The anthropological landmarks are visible in the imaging and touchable at the skull, providing real anatomical coordinates for orientation and targeting of approaches during the planning, immediate before surgery (Fig. 3.2).

Obelion Bregma

Obelion (x-ray+op)

For parietale - may be unilateral or permagnum-

1

11-1 2c m

3

cm

Persistant of sutura frontalis. -rarely constant anat+ op finding-

Lambda

Os (Ossal interperiet) Os Incae. Common anat Linea nuch +op finding suprema ~ M trapez.

7-7.5 cm

Nasion Ingin

Stephanion

m 5c 53.

Pterion

Opisthion (x-ray-op)

Parion Landmarks (visible/palpable) - in roentgenogram and topogram for CT - on patients head (before operation e.g.) - in operation on skull surface

Fig. 3.2  Antropologic Landmarks (W. Seeger)

Linea nuch sup. ~ M semispin capitis

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Anatomical precision andplanning became a major step in microsurgery and indispensable in MIN. The result of this precision and planning is a significant minimizing of the trauma, getting smaller approaches and smart corridors. But, the smaller theapproach, the more precision and decisions are necessary, and the more possibilities of failures are given. This is still the failure tolerance-gap in MIN (Graph 3.3). Graph 3.3 Approach classification Macro/ Micro/Eno

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These anatomical planning and decision makings, according to technical evolution, however, recommends for a new vision of anatomy training setting. Due to neuro-psychological reasons, and ergonomics conditions (s. Vol. 1, Chaps. 2 and 3), it makes no sufficient training effect, to train only macro-anatomy for micro-­ neurosurgery or endo-neurosurgery. This step, of changing and adaptation ofthe paradigm, is the very core of the anatomical MIN concept, making anatomy to a Key of MIN. There are three factors to determine what makes anatomy working for MIN: 1. The visualization technique, surgery is using, like microscopy, endoscopy, exoscopy, virtual imaging, etc. 2. The kind of anatomical method, like systematic, topographic, clinical-surgical, Gestalt-anatomy 3. The correlation to a surgical approach and the change of approach-geometry: Approach-analysis and Approach-design Visualization of the anatomical training-setting must be adapted to the surgical visualization for which the training is needed. The visualization used, will change everything, whether you realize it or not: mainly ergonomics and the Gestalt-effect will change and impact the training. (s. Vol. 1 Chaps. 3, 4 and 6). Training means not to follow a schedule, rather than forming the brain of the trainee. Anatomical training for surgery can only be acquired by a surgical simulation setting concept with regarding ergonomics and Gestalt effect (Graph 3.4).

Graph 3.4  Evolution of Visualization Technique

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Anatomy evolution for MIN (Graph 3.5) started with systematic anatomy (1–3), leading to topographic (2–3) anatomy and then to surgical anatomy (4). The needed training effect, however, will only work, if the training-setting offers the experience of the Gestalt-function within the surgical correlated ergonomics. Endoscopic anatomy (5) and endoscopy-assisted anatomy (video-anatomy) will be the next step. It has no training effect to look on an open brain or through a macroscopic approach with the endoscope. This can be observed in surgery frequently but does not make since and has no benefit for the patient. It might be called fun-viewing. A completely different field is virtual visualization (6) and virtual training-­settings. Due to the laws of ergonomics and Gestalt-phenomena, this will not work. It might give the surgeon the illusion of competence, but this is as danger as non-­real-­time “navigation” tools. But it all starts with the anatomical training-­environment, that is used. In summary, it must be a “surgical-simulation environment” to become a key for MIN. Coming back to Yasargil and Seeger, who always recommended, that microneurosurgery needs a new kind of anatomy. This is true for all new visualization generations and for all changes of surgical approach techniques. A major reason of bad trained surgeons is the lack of this concept and following training methods.

Graph 3.5  Types of Anatomy

3.2 Gestalt: Theory for MIN

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79

Gestalt: Theory for MIN

The neuro-psychological aspect of training and recognition is best described and explained by the “Gestalt”—Theory. The history starts with Aristoteles: “The whole is more than the sum of its’ elements”. The quality of the whole is the basic of Gestalt-philosophy by Chr. Ehrenfels, “In Gestalt qualities” 1880 and 1932, he claimed, in addition to Aristoteles, that the whole is not only more than the sum (Σ) of the elements (e), but has also a different quality (Ψ) of the elements of that whole:Σe  +  XΨ.Max Wertheimer in 1923 developed the results of his teacher to the final Gestalt-theory: (Σe + X)Ψ (formalism by the author). Finally, W.  Köhler and K.  Koffkaestablished the Gestalt-psychology (Berlin school, 1910–1940) transposing the philosophical terms and ideas into neuro-­ psychology (neuro-physiology). Today, the term Gestalt is mainly found in the context of Gestalt-psychology and Gestalt-therapy, indicating the context of neuro-psychology. The term Gestalt means a cognitive process based on an awareness for afferent actions like hearing or vision.The theoretical background is very complex and not necessaryin detail here for our application in anatomy. (see: Doerr/ Schipperges): The most distributed application today is: “Gestalt-psychology, school of psychology founded in the twentieth century that provided the foundation for the modern study of perception. Gestalt theory emphasizes that the whole of anything is greater than its parts. That is, the attributes of the whole are not deducible from analysis of the parts in isolation. The word Gestalt is used in modern German to mean the way a thing has been “placed,” or “put together.” There is no exact equivalent in English. “Form” and “shape” are the usual translations; in psychology the word is often interpreted as “pattern” or “configuration.” (Encyclopaedia Britannica). The exceptionell scientific meaning of the Gestalt-theory is the re-introduction of the category “quality” into science as a fundamental entity. When Kant expressed, that there is only as much science in a subject as there is mathematics in it, he was misunderstood, at least. However, one should remember, that mathematic started with geometry, which means, that the core of mathematics at the beginningisabstracting by morphological relations. Thisis the theoretical Gestalt, by which we are mirroring the world and reality around us and our selves: Gestalt effects, by recognition of meaning and sense of a structure or event.

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3.2.1 Examples Below (Graph 3.6) we see two famous figures, highlighting the effect of Gestalt. A famous image (a), showing two different persons: an old woman and a young lady. It depends from the Gestalt-effect, namely the context recognition of the “whole”, which one of the persons will be recognized. It can switch from one meaning to the other meaning, depending of the Gestalt effect in relation of interpretation of the elements leading to two possibilities in this image. But also, in geometrical graphics like a cube (b), the being optical mistaken, will not induce the recognition of the cube, it is caused by the Gestalt-effect, which makes the cube comprehensive for the spectator, giving the optical mistake the meaning of a cube. We remember here also the concept of idea by Platon, without Gestalt cannot be understood. Theusual loss of the category “quality” in science, causes a lack of a significant intellectual tool for science. The Gestalt-theory is a convincing example,for bringing back the category of quality into science again.It cannot be substituted by category“quantity”. This problem still remains a fundamental blind spot of science.

3.2 Gestalt: Theory for MIN

a

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b

c

Graph 3.6  Gestalt Examples: Picture, Geometry, Cat-Shadow

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There are two Gestalts of one cat (c). They can be correlated mathematically, and they are in a physical correlation: one is the shadow of the other by sun-light. But only one is the shadow and one is the cat, and both have different meanings. The visible effect of the meaning is the Gestalt: “cat” and “shadow”. The correlation of both, the cat and her shadow can be seen also as one Gestalt, because the meaning is also visible at once. The context of the configuration, forms and has a meaning. Gestalt always presents a comprehensive meaning. Meaning works as understanding, so Gestalt is a neuropsychological process. Understanding works by meaning, so Gestalt is a visible structure that produces understanding by its unique construction in a context. It works not by explaining or deriving, but only by direct afference to the brain. Another example is the sound-Gestalt, explained in a very famous theme from a worldwide known composer. However, the representation of his famous sequence as a sound wave (A) and as a computerized instrumentation plan (B) will not be recognized by most people. The representation as a professional notation (C) of music will be recognized by most music professional only, and a verbal representation (F) of the typical rhythm of the sentence might be recognized by gifted people outside of music profession. However, the real music (D) will be recognized by the most people in the world, because it represents the Gestalt of this sentence, which gives this music its unique characteristic and the meaning: it is the Gestalt of this sound (Graph 3.7). a

b

c

d e

Graph 3.7  Sound Gestalt

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3.2.1.1 Scenario-Gestalt A complete scenario can have the effect of a Gestalt. The right side shows components, each one having a different and clear meaning and being understandable. On the left side the components are constructed to an environment with a meaning containing a message. This message within the environment is a Gestalt effect, in this case very complex.It contains also the dimension of space and time, and it provokes cognitive processes by the question about the correlations of the components. The surgeon is in a cosmos with 1025 stars, but the Gaia-system (global biotope) around the surgeon contains 1033 viruses. This comparison elicits following messages within the actual mental environment of this surgeon, and for the spectator. This process of understanding by awareness and recognition is effected by the Gestalt phenomena. This Gestalt comprises the dimensions: space, time, scenario and mental processing. The mental processing is open and might even developed the idea, that a physical-system and a bio-system with so many particles in such a wide space during such a long time, must be very successful and system-relevant for nature. This should be kept in mind when dealing with such systems. Gestalt theory explains the orders behind such structures and processes (Graph 3.8).

Graph 3.8  Scenario Gestalt

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Another application was given in pathology by my pathology teacher at university of Heidelberg, Prof. Dr. Dr. h.c. mult. W. Doerr: Gestalt Theory and Morbid Anatomy Abstract Contact with medical students as a university teacher has shown that there are different types of aptitude: 5/9 of German medical students possess a visual faculty, 3/9 are kinesthetic and only about 1/9 have the gift of the auditive faculty. Apart from this, there is a general quality which may be termed gestalt perception or gestalt blindness. The fact that for decades the attempt was made to relate qualitative differences in the characteristics of medical observations and pathological and anatomical findings to quantitative changes was the reason for the development of the concept of Relationspathologie. Intellectual pre-occupation with the perception of “gestalt qualities” has resulted in pathology in general being seen as the expression of the biophysics of open systems and making an organismic evaluation of its phenomena. The aim of allnatural-science is the recognition of order. Theoretical biology seeks an order free from hypotheses. Theoretical pathology involves the application of gestalt philosophy to the detection and evaluation of all potentially dangerous disturbances. Theoretical pathology has nothing to do with “natural philosophy”, the “natural history viewpoint”, the “ vitalism “ of the turn of the century or the “holism” of the 1930s. Gestalt qualities can be characterized by means of the “Ehrenfels criteria”. In most cases this means distinguishing between “space gestalt”, “time gestalt”, “tone gestalt”, and “sentence gestalt”. As defined by gestalt theory, mental and physical processes correspond. Gestalt can always be defined and understood in concrete terms. In the gestalt the conceptual contradiction between “external” and “internal” is overcome. External phenomena are the manifestations of internal nature. In the fields of pathological anatomy, gestalt theory has direct methodological relevance with regard to the following: (a) the concept of homology (b) the conceptual idea of what is known as “specific inflammation” (c) the theory of stages in minor organ diseases (d) the characterization of the various forms of pathomorphosis (e) patho-anatomical diagnostics according to the laws of mathematical logic. The relationship between individual sciences and philosophy has always been critical. The individual science and philosophy are mutually obscured from one another. Research into facts and research into essence come together, as in a “gestalt circle”, to form a single process of understanding. All lawfulness and orderoriginate from a principle of the mind. The visible manifestation of this principle is the innermost nature of the gestalts. (Virchows Arch Pathol Anat Histopathol. 1984;403(2):103–15. https://doi.org/10.1007/BF00695227.)

3.2.1.2 Gestalt-Anatomy In 1986, the author introduced the Gestalt-theory into clinical anatomy of the headduring a lecture at neurosurgical department of Vienna University, after using this concept since 1980 in the anatomical laboratory. It was described in the methodology section of his theses, because it became necessary to explain the scientific

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basics of this new kind of “surgical simulation anatomy” and the paradigm shift, which it means. Indeed, the Gestalt-phenomena is a recognition process regarding structures within a context and the meaning of this structure indicated by the context. In cases of anatomical approaches, the meaning of a single structure and the complete construction of the anatomical situation is induced by the unique figure, shape and appearance of this construction, effecting the recognition process in the observer. This effect will not be able by the single anatomical parts of the construction. The author experienced this effect during studying anatomy, which did not produce understanding the meaning of the structures for surgical context, even topographical anatomy did not produce this. Moreover, the surgical situation and the surgical approaches were so far away from anatomy, that the geometrical understanding was very difficult, if possible. This was the case even more, as the surgical procedure cannot focus on this problem of recognition, resulting in a too slow learning process. The reason of all this, and the explanation for all this is best given by Gestalt-theory. This theory delivers also the criterions, how anatomy must be practiced, to generate the Gestalt-process and to generate understanding. Therefore, the author has applied this theory for clinical anatomy of head and brain, to create a new concept of surgical anatomy, that can realize the Gestalt-effect. It was named “Gestalt-­ Anatomy”. Today the term of “Surgical Simulation Concept” might be used, however, this is only true, if the Gestalt-effect is realized and aimed for. In this simulation environment, the understanding process can also comprise all neighborregions that the surgery is not allowed to reach, resulting in a deep understanding of all the surrounding of an approach additionally. Anatomical concept: The anatomical preparations were not done according to classical anatomical dogma. A change in paradigms was necessary for anatomical presentation to represent structural and spatial conditions for effective use of minimally invasive techniques. This new paradigm was developed according to Gestalt theory (see above). This concept recommends microneurosurgical and endoneurosurgical approaches for preparation in nonfixed specimens. In particular, the subarachnoidal cisterns can be well demonstrated with this method, in contrast to common techniques, in endoscopy, we get new insight in cistern variations and details. Compared with more well-known methods, it allows us, so to speak, to enter the subarachnoidal cisterns, and visualize and experience them as if travelling through them. (Theses/author: 1990, Heidelberg). In the application, in clinical and surgical anatomy, the Gestalt-effect can be shown, and is the main reason, why all great surgeons took repeating anaddition loop into the anatomical laboratory, simulating surgery there. It can be easily recognized in surgery, who has gained this state of experience and has experienced the Gestalt-effect for each approach. It may be compared by the change from bird-perspectivetostreet-view (Graph 3.9).

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Graph 3.9  Map- and Bird-View

Gestalt-anatomy ispresent in the street-view of anatomy. The author used the term “pants pocket-anatomy” because the surgeon needs to be familiar with the approach environment like with the content of his pant pockets, safely moving inside and blindly finding everything there. It represents real the perspective in a given situation, during surgery. (surgical simulation anatomy) (Graph 3.10).

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Street-View

Graph 3.10  Street View

The author has observed, during the last 40 years, independent from the surgeon and his experience, that this level of anatomical awareness is the pre-requisite of each precise and problem-related surgical strategy. If this level is not reached, fear will be his strategy.

3.2.2 The Perneczky Pyramid A master-piece of Gestalt application was the introduction of the Pyramid of the supra-sellar anatomy by Perneczky. To make this complex area more comprehensive for planning, Perneczky reduced the Gestalt of supra-sellar anatomy to a Pyramid. The Gestalt of this Pyramid is much easier for use in the planning, especially for planning of approach-angles and corridors through the structures, to reach a hidden target without the need of compression on any structure by spatula (Graph 3.11).

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Graph 3.11  Perneczky Pyramid

It is necessary to know some rules, to discover the Gestalt-effect later in anatomical structures: Very typical anatomical structures and landmarks may appearincomprehensive after changing the angle or the approach. It is impossible to mentally transpose the appearance of an anatomical space from one perspective into another one, if you have never experienced the Gestalt -aspect of both approaches. You need a library of images or video-clips in your mind of the anatomy appearance of all approaches, before you can imagine it. You need a lot of training to imagine a surgical aspect, derived from radiological imaging. In summary, only if you have experienced the Gestalt of approaches, you are able to Imaginate them. It is impossible to derive this fromtopographical anatomy aspects. That means in the above model, you cannot derive mentally a street-view from a map-view or a bird-view. (s. empirism of David Hume) (Graph 3.12).

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Graph 3.12  Change of Gestalt

We see the target structure “basilar head” through four different approaches and perspectives, which changes the Gestalt. It is impossible to transduce mentally these four Gestalt from one into the others, their Gestalt can only be experienced by direct viewing. The Gestalt are that different, that it even might be difficult to recognize, that it is the same target of basilar head in some cases, especially true for the endoscopic approach. For planning, the Perneczky Pyramid may support the comprehension by reduction of the complexity to a geometrical model. However, this works only, if the Gestalt of the target through all approaches, had been experienced. By topographic anatomy alone, this cannot be acquired. Today, learning anatomy starts with systematic anatomy, acquiring all the mayor details, but not leading to any imagination of the human body. Next, topographic anatomy may lead to some understanding of correlations and relations of details composed together to regions of interest, to areas, where diseases will occur. This will, however, not lead to understand directly surgical anatomy. The gap in-between is too large and needs to be bridged. Pathological anatomy will not be helpful in this context, because the pathological changes will be an additional challenge. The famous anatomist Julius Tandler, chair of anatomical institute, university of Vienna, wrote in the preface in the fourth volume 1929, and keeping the problem of clinical anatomy in mind: “Precision in science is important. He, who is counting the sand particles is doing precision, but does he promote science? It is much more meaningful to describe an anatomical region, being able to guide a surgeon safely.” He knew the Gestalt-phenomena, starting in this book the 3D drawings, by his scientific artist, of the endoparenchymatous nuclei and fibers of the brain, today well known from Nieuwenhuys et al., Springer. Starting neurosurgery with this gap of surgical anatomy knowledge will be very hard and the prize will be paid by the patients.

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3.2.2.1 Cases: Different Appearance of Optic Chiasm and Basilar Head Through Different Approaches, Changing the Gestalt of the Targets (Graph 3.13) Graph 3.13  Chiasm- and Basilar Head-Gestalt

3.2 Gestalt: Theory for MIN

• This is, what the neurosurgeon will not have and see during surgery, but anatomical education is still going on with such aspects of the brain. Even in courses, the fact, that the brain is intracranial is simply ignored. • The quality of anatomical structures is neglected and displaced by quantifications, measuring meaningless scales for surgery. • In this case here, the Liliequist membrane is preserved quite well and contrasted by a SAH. Nearly neglected, the openings of the cisterns for the cranial nerves (s. CN III) and the vessels, which can be always observed during intra-cisternal endosccopy. • Red and green ROI are used for modelling of Gestalt phenomena by the Perneczky pyramide for the target basilar head (green) and optic chiasm (red).

Figs. 3.3, 3.4, 3.5, 3.6, 3.7, and 3.8. Fig. 3.3 Bifronto-basal approach: optic chiasm is seen from semi-superior and symmetrically along the median plane. Transforming the aspect of the suprasellar region from the overview above to this one is mentally difficult, if it was never seen before. This is the case even in this easy symmetrical median view case, which mean only a rotation of about 90° in the median-sagittal plane. The cisterns are all opened, giving sight on the stalk and parts of the anterior circle of Willis

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92 Fig. 3.4 Pterional interfascial approach (Yasargil): The optic chiasm and supra-sellar structures now seen in an angeled, to all orthogonal planes, presentation, allowing to see the the anterior circle of Wllis and the stalk. Anterior wall of chismatic cistern is preserved inbetween the optic nerves, and inferior with contact to the stalk. Ipsilateral anterior Sylvian cistern is open, opposit one is not Fig. 3.5 Fronto-temporal approach: The optic chiasm and supra-sellar structures are now seen in less basal angle to pterional, hiding the stalk by the chiasm and right optic nerve. Both Sylian cistern are opened giving sight to the complete anterior circle of Willis. The median wall of the opposit carotid arery is visible between the optic neves and accessable through this window Fig. 3.6 Fronto-orbital approach: The projection of a doupple anterior com. artery (inferior one clipped) is on the left boarder of the optic chiasm by this lateral view of supra-sellar structures through a fronto-orbital approach

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Fig. 3.7 30°-Endoscopic supra-orbital approach: The lateral endoscopic 30°-view shows the supra-sellar rgion and the optic chiasm in a complete uncommon way. In this case, the right optic nerve and chiasm is lifted by a coiled aneurysm of the carotid artery. A white thrombus at the rupture site can be seen. (It can be visibly understood, why symptoms may not release after coiling in such a case)

Fig. 3.8 Pernasal trans-sphenoidal approach: this rare view of the supra-sellar region shows the optic chiasm from anterior -inferior after opening the chiasmatic cistern in the midline. The typical redish stalk is clearly visible, laying on the roof of the interpeduncular cistern, which is the Liliequist membrane. Above the optic chiasm we see, after opening the midline cisterns the anterior com. artery complex. Between optic chiasm and the arteries, the gap leads us to the lamina terminalis, the anterior wall of the third ventricle. The view is microscopic

The basilar head is an all side hidden structure with a significant Gestalt and many variations. It is a masters’ region and many approaches must be evaluated to get there safely and being able to solve a problem through a small canal (Figs. 3.9, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15, 3.16, and 3.17).

94 Fig. 3.9  This basilar head within the interpeduncular cistern and sitting on the floor of the hypothalamus and hiding mammillary bodies in this case, is approached through a midline Le-Fort I approach. Occulomotor nerve is visible on both sides. The blueish band marks the third ventricle floor, perforator arteries from com. post. arteries enter from lateral. The dark area behind the basilar head contain its perforator arteries to the interpeduncular fossa Fig. 3.10 Classical pterional approach (Yasargil) to a high basilar head through the window lateral of ICA: After opening of all cisterns, in this case, the complete bifurcations are visible and both P1 have contact with the mammillary bodies. The figure of the head is rotated in all tree planes. Very few changes decide, if to see targets or not. The Gestalt effect of all supra-sellar structures is essential Fig. 3.11  The fronto-­ orbital approach through the posterior cavernous sinus brings us quite close to the basilar head from a more fronto-basal angle. Both oculomotor nerves are visiblr also after opening of all cisterns. Petrosal apex and dorsum of sellae are drilled

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3.2 Gestalt: Theory for MIN Fig. 3.12  A fronto-orbio-­ cygomatic approache enables in this extremely high basilar head to enter the very hidden structures. The complete upper third of the basilar artery is visible after opening of interpeduncular and prepontine cisterns. Condition of rotation and angeling decide if one can see and reach the targets of surgery

Fig. 3.13  Through a medial–subtemporal approach (Drake), the basilar head can be seen and reached from lateral, and all branches are recognized quite different. The right SUCA is duple, and we come very close to the ipsilateral oculomotor nerve. The high and low positions of the basilar head are accessable, and there is more space than in fronto-temporal approaches, if the temporal lobe can be relaxed enough and the angle is not too fare anterior

95

96 Fig. 3.14 Endoscopic view through a midline approach (Le Fort I) gives a briad sight into a very small region with all branches of basilar head, but also both oculomotor nerves and also the interpeduncular perforator arteries. Endoscopic visualization gives suprisinly appearenc of structures not known by microscopic aspects. Target can be visible but not accessable due to angled view

Fig. 3.15  This is a pernasal trans-sphenoidal 30°-endoscopic approach to the basilar head, much more difficult to recognize. In this unique case, also an opposit side aneurysm of the com. post. artery contacting oculomotor nerve right is visible. The basilar trunc can be followed along the pons, after clival fenestration (very difficult preparation!)

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3.2 Gestalt: Theory for MIN Fig. 3.16  The classical appearance of the basilar head through an 0°-endoscopic third ventriculo-cisternostomy. (s. Vol. 1, Chap. 5) The position of the head can vary a lot, also the appearance in realtion to the trajectory of the endoscope

Fig. 3.17  The supra-orbital approach leads directly to this beautiful baslar head within the interpeduncular cistern. In this early postmortal endoscopy, the conditions are very close to surgery. Especially the preservation of the subarachnoid membranes is of great impact for better understanding their architecture. Here the roof of the interpeduncular cistern, Liliequist membrane and its typical construction and position is well understandable. The variations of the Gestalt of basilar head is far higher than in microscopic view and approaches. (if the possibilities of endoscopy are rally practiced)

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3.2.2.2 Conditions for Anatomical Analysis and Simulation-Training Preparation training and questions to be analyzed need special conditions which are far away from classical anatomical research and methods, as described above, and according to Gestalt-theory. The working place setting has many conditions comparableto a surgical setting. Aims of analyzing are reaching into pathological anatomy, description of approach design and target regions, mostly in terms of quality and spatial relations according to Gestalt-phenomena. The training and anatomical simulation of surgery need all the repertoire of micro-and endo-surgical instruments. Usual anatomical equipment is complete insufficient. Visualization techniques, like microscope, endoscope, monitors and head-mounted-display are ad hand, and ultrasound, trans-endoscopic ultrasound and LASER are available if needed. If possible, sealing material can be added for training reasons. Finally, ergonomics rules are applied always, which is not easy in every case and locations. (s. Vol. 1, Chaps. 4–6) (Graph 3.14).

Graph 3.14  Surgical Simulation Setup

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3.2.3 Preparation Concept The example of a step by step approach-analysis and approach-design takes place by a precise preparation of each tissue layer. The standard is not sufficient, because MIN uses individual approaches according to a planning procedure. The approach-­ design occurs not only according to imaging information, but also according to physiological parameters and many parameters important within the planning. The MIN surgeon must,therefore, know the history and findingsof the patient, but also, if possible, know the relatives. (s. Vol. 3). All clinical data and knowledge, finally, must be translated and transposed into a surgical-anatomical preparation concept, otherwise it cannot have impact on the benefit for the patient by surgery. This concept can be trained in the surgical simulation setting in anatomy, in absence of surgical risks for the patient, and the surgeon will pay the prize. Later, in the OR, the patient will pay the prize! (Graph 3.15).

Graph 3.15  Pterional Interfascial Approach

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Introduction of endoscopy into neurosurgery needed a new understanding and recognition of anatomy, not just application of a new technique or a new tool. Especially with a conceptual perspective, the endoscopy changed all, like the microscope did before. Moreover, within the MIN, the endoscopy is by no way just a tool, but a new paradigm, if one wants to evolve it to substitute it for the microscope, leading finally to endoscopy assisted micro-neurosurgery. Ergonomics and Gestalt effects will change markedly, which can be trained in surgical simulation setting in anatomy. Pay the prize for your patients! (Fig. 3.18).

1990 Fig. 3.18  Trans-endoscopic Ultrasound Surgical Simulation Setup

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Comparison between a microsurgical visualization through a Le Fort I-approach and an endoscopic visualization through a supra-orbital burr-hole explain easily the visual differences, but not all the additional changes involved. It is a completely different world of working, using endoscopy, not just a tool! (Graph 3.16).

Graph 3.16  Micro- and Endo-View

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Case Application According to Gestalt-Anatomy

3.3.1 Approach-Analysis and Approach-Design 3.3.1.1 The Transoral-Trans Pharyngeal Approach to the Ventral Brain Stem In this chapter we see the approach-analysis and approach-design according to Gestalt-Anatomy criterions, making anatomy to a Key concept of MIN: In 30 cases, an analysis of the transoral trans pharyngeal approach to the ventral brain stem was made. All preparations were performed as surgical simulation using microscopic and endoscopic methods. Modern imaging techniques and computer-­assisted approach planning are also applied and discussed. To show the subarachnoidal cisterns in a realistic impression of the tissue, the preparations were performed in 26 non-fixed specimens. To use currently available equipment safely, it is important to take all anatomical levels of the approach canal into account, when determining precisely the size and type of the clivus window. Preparation of the preclival tissue is the most difficult step. It requires a clear approach plan to ensure safe closure. This selective approach gives the best access to the lower ventral brainstem, without any of the problems associated with other approaches to the same region. The transoral trans pharyngeal approach is described here within the context of minimally invasive techniques, in particular endoscopy, modern imaging methods, and computer-assisted approach planning. The transoral trans pharyngeal approach to the brain has seldom been used. The results have mostly been poor, the main problems caused by meningitis owing to CSF leakage (Bonkowski et al. 1990; Chono et al. 1985; Crockard and Bradford 1985; Drake 1968, 1973; Erbengi et al. 1991; Friedrich et al. 1990; Hadley et al. 1988; Hashi et al. 1976; Haselden and Brice 1978; Hayakawa et al. 1981b, 1989; Hitchcock and Cowie 1983; Laine and Jomin 1977; Litvak et al. 1981; Mackhmudov et  al. 1998; Matricali and van Dulken 1981; Miller and Crockard 1987; Mullan 1981; Pia 1979; Saito et al. 1980; Sano 1973; Verbiest 1977; Yamashita et al. 1989; Yamaura et  al. 1979; Yasargil 1969, 1984; Yasargil et  al. 1980) (see (Segal and Sundaresan 1998), p 216)]. Few anatomical studies have been performed to analyze and design a transoral trans pharyngeal pathway to the intradural structures (Grote and Römer 1972; Kollmann and Kuhn 1982; de Olivera et al. 1985; Pasztor 1985; Renella et al. 1986; Resch 1990; Yamaura et al. 1979). It is interesting to note that anatomical understanding of the transoral approach historically lagged behind surgical practice and that anatomical methods that have been used so far are insufficient to describe the anatomical problems encountered with this particular surgical approach. Such problems of anatomical methods were already mentioned in general by Seeger (Seeger 1978; Seeger n.d.). In selected cases, this is the approach of choice, because it fills a gap in the selection of possible approaches to the same region.

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In all 30 specimens, anatomical preparations were made using microsurgical and endoscopic techniques. Four specimens were fixed with formalin (in three of them, the vessels were injected with colored polymer solution) and preserved by the new technique of “Plastination” (see Chap. 5) (von Hagens 1985–1986; von Hagens et al. 1987), by which perishable tissue is impregnated with plastic solution and hardened, after the solution has substituted the fat and water contents. Three-­dimensional, plastinated “phantoms” result, which can then be used for further studies (Resch 1989, 1990; Resch and Perneczky 1990). With these phantom specimens, 3D spiral CT views were compared with microscopic and endoscopic views to rule out the limitations and possibilities of computerized imaging technique (Resch et al. 1996a, 1997a, b) (see Figs. 3.37, 3.38, 3.39, 3.40, 3.41, 3.42, 3.43, and 3.44). The other 26 specimens were prepared without fixation (“fresh preparation”). All micro- and endoscopically, in a surgical simulation setting. This method has been named: “Gestalt anatomy” (Doerr 1983, 1984; Resch 1989, 1990; Resch and Perneczky 1990). Since 1990, the microscope was replaced by the endoscope, and only para-­endoscopic preparations through keyholes were used (Graph 3.17). Training Environment and Evolution of Equipment (anatomical and patho-anatomical cases) Evolution of Anatomical Preparation Technique

cases

1 - 11

12+13

Microscopy 40

14 - 74

Patho-Anatomy

Endoscopy 110

Anatomy

Substitution of the Microscope by the Endoscope

1988

1990

Graph 3.17  Evolution of Setup

2000

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The photographs were taken using a Minolta 500 (Osaka 541, Japan), a 220 mm adapter, a Zeiss OP-MI 6 microscope (Zeiss, Oberkochen, Germany), and 50 ASA color slide film. Lens endoscopes with a diameter of 3–4 mm and angles of 0°, 30°, and 70° respectively (Wolf, Knittlingen and Aesculap, Tuttlingen, Germany) were used. The instrumentation was that of an operating theater. Special attention was paid to the ergonomics of working conditions. Three types of imaging and consecutive ergonomic conditions could be differentiated: Microscopic Preparation Since 1982, micro technique came to the dissection table in non-fixed specimens with preparations through neurosurgical approaches. This was done in 40 cases, with different approaches (Graphs 3.17 and 3.18). The procedure was anatomical simulation of microsurgery.

a

b

Graph 3.18  Microsurgical Setup (1980). Microscopic preparation. Since 1982, micro technique was brought to the dissection table in nonfixed specimens with preparations through neuro-­surgical approach. The method used was microsurgery. (a) microscope, (b) micro instruments

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Endo-Video Preparation After 1991, microscopy was replaced by endoscopy, and the technique of video surgery has been used. The preparation had been para-endoscopic for all minimally invasive approaches. This was done in 110 cases (Graphs 3.17, 3.19, and 3.20).

Graph 3.19  Micro-Endo Revolution

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Endovideo preparation. Since 1991, microscopy was replaced by the endoscope and the method became video surgery. Preparation technique was para-endoscopic in all minimally invasive approaches in neurosurgery.

Graph 3.20  Endo-Monitor Set-up 1990

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Endo-Head-Mounted-Display Preparation In 1997, in three cases, the first use of the new head-mounted liquid display was made (SofamorDanek, Cologne, Germany) (Graph 3.21). This technique is well-­ suited to the needs of the surgeon and therefore has great potential for the future. It was soon clear, that this technical setting had the best ergonomics, especially incases of combined techniques with multiple imaging. The main disadvantage was the limited optical resolution at that time, reducing the quality of the endoscopic images.

Graph 3.21  Endo-HMD Setup (1997). Endo-head-display preparation. After 1997, the first few experiences with the new head mounted liquid display equipment was had in three cases. This technique allows one to minimize enormously the size of the equipment. (a) Head-mounted LCD display, (b) endoscope, (c) holding device with integrated light source and camera, and (d) control monitor

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3.3.2 Dissection Steps (Graph 3.22) Angles of approach in a sagittal schema: (a) Approach to the ventral brainstem; (b) approach to the upper spine; (c) approach angle; (d) foramen magnum angle; e) reclination angle. The correct reclination angle is of great impact to get to the target-region in an ergonomics working condition

A

B

C C e e

b

a

d

Graph 3.22  Transoral Route: Planning-Geometry

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The transoral trans pharyngeal approach reaches from C2/3 to the inferior and middle position of the clivus. The route to the brain stem runs through the clivus and presents a markedly different anatomy compared to the route to the upper cervical spine (Fig. 4). These differences are the reason why this approach is much more difficult than that one to the ventral cervical spine. Its anatomy tells us all we need to approach and to leave adequately. Soft tissue The oral and pharyngeal cavity: The first structures anterior to the brain stem in a transoral view are the soft palate and the nasopharynx. The uvula projects to C2 and the soft palate can be lifted up to the position of the cranial border of the atlantic arch (Fig. 3.19). To see and reach the nasopharyngeal cavity, the soft palate has to be split, in this midline route revealing the raphe palate. The velum palate has three layers: the oral mucosa, the muscles layer (m. tensor and m. levator of the velum palate, m. palatopharyngeus and palatoglossus, and m. uvulala), and the nasal mucosa. The nasopharyngeal cavity (Fig. 3.19) is a narrow space. The caudal border is marked by the most important mid-line structure: the tubercle of the anterior arch of atlas (Fig. 23a–d). Viewed under microscope, the form of this cavity is like a dish—the depth of the floor is somewhat lower. Fig. 3.19  The soft palate (d) is split along the midline and spread with sutures. Thereafter, the view is free to the deep nasopharynx (a), whose caudal border is formed by the main midline structure called the anterior tubercle of the atlas (c), together with the longus capitis muscle (b), border of the open mouth (e)

110 Fig. 3.20  After splitting the soft palate (d) and the pharyngeal wall (a), the insertion of the paravertebral muscles at the anterior tubercle of atlas (b) can be seen. To reach the clivus (e), the atlanto-occipital membrane (c) is split

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3.3 Case Application According to Gestalt-Anatomy Fig. 3.21  Soft palate (g), pharyngeal wall (a), and the atlantooccipital membrane (e) are split so that the clivus (f) can be seen. The longus capitis muscle (d) is pushed laterally, so that the atlantic arch (c) and the longus colli muscle (b) come into view

111

112 Fig. 3.22  For a wide view of the clivus (f), the longus capitis muscle (d) is incised (g) and the atlanto-occipital membrane (e) cut from the atlantic arch (c). For atraumatic spreading of the pharyngeal wall (a), it is opened down to the level of the longus colli muscle (b)

3  Evolution of Anatomy to a Key of MIN

3.3 Case Application According to Gestalt-Anatomy Fig. 3.23  The last step allows atraumatic spreading of preclival tissue (a), provides a wide view of the caudal clivus (d), with both midline landmarks: anterior tubercle of atlas (c) and paryngeal tubercle of clivus (f). Laterally, the condyle (e) and, caudally, the beginning of the longus collimuscle (b) is reached er than the atlantic arch. The mucosal layer of this nasal cavity floor is very thin and fragile. It has no muscle layer and is separated from the clivus only by the thin pharyngobasilar fascia. There is much lymphatic tissue—the pharyngeal tonsils, which have deep valleys reaching as far as the pharyngobasilar fascia. This fascia is very strongly attached to the clivus

Fig. 3.24  The oral side is open to the nasal cavity by the coans. The lateral sides end as a cleft, and there the eustachian tubes enter the nasopharyngeal cavity. Since only the soft palate had been split along the midline, these parts of the nasopharynx cannot be seen transorally under the microscope. But with the help of endoscopy, all of this space is visible

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3.3.2.1 The Retropharyngeal Space and Atlanto-Occipital Connective Tissue Several different kinds of layers can be found behind the pharyngeal mucosa, depending on the level of approach: (Figs. 3.19, 3.20, 3.21, 3.22, 3.23, and 3.24). 1. Craniallyofthepharyngealtubercleoftheclivus, there is only the pharyngobasilar fascia, which is strongly attached to the clivus. 2. Between the pharyngeal tubercleand the foramen magnum there are different layers: The pharyngeal wall has three layers (mucosa, m. constrictor pharyngeus sup., fascia pharyngea). Between the pharyngeal fascia and the deep cervical fascia, there is the retro-pharyngeal space, which is just a gap formed by soft, moist connective tissue. This gap continues laterally into the parapharyngeal space with the neurovascular bundle, and caudally it continues into the mediastinum. Next, dorsal to the deep cervical fascia, between the anterior atlantic arch and the pharyngeal tubercle position of clivus (pars basilaris), there is the anterior atlanto-occipital membrane. 3. Between the foramen magnum and anterior arch of atlas, the anterior atlanto-­ occipital membrane continues, reaching the arch of atlas. Dorsally of this strong ligament, the peridural space begins, which consists of fat tissue, the apical ligament of dens, the longitudinal fibers of cruciform ligament, the tectorial membrane, and the external vertebral venous plexus, which continues from the basilar plexus.

3.3.2.2 The Craniocervical Muscles Even with the anterior arch of atlas and dorsal to the deep cervical fascia, the longus colli muscle enters at the anterior atlantic tubercle. Laterally to the tubercle, the capitis longus muscle runs between the deep cervical fascia and the anterior atlantic arch, which it uses as an arch of atlas, and enters at the pars basilaris of lower clivus just cranial to the atlanto-occipital joints. In retroflexion of the head, the pharyngeal wall and the capitis longus muscle (hypermochlion) are curved over the arch of atlas and therefore not laterally mobile. In a midline preparation, the anterior rectus capitis muscle is not visible. 3.3.2.3 Bone and Dura The anterior arch of atlas and foramen magnum. If the capitis longus muscle is cut transversally at the height of the atlas, the whole anterior atlantic arch is visible. Dividing the anterior atlanto-occipital ligament at the atlantic arch, the foramen magnum comes into view. The atlas, foramen magnum, and lower clivus. The preparation displaying the whole atlantic archis easy. But to make the lower clivus visible, the anterior atlanto-­ occipital membrane has to be separated from the clivus, where it is strongly attached. This opens the view to the anterior border of foramen magnum and the atlanto-­ occipital joints. Above the pharyngeal tubercle, only the fragile mucosa and pharyngobasilar fascia, which is also very adherent, must be separated to reach the clivus at this position.

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The lower cranial base. The inferior border is formed by the foramen magnum between the occipital condyles, through which runs the hypoglossal canal. Laterally to the condyles, the jugular foramen is the caudal end of the petroclival border. Laterally and parallel to this border lies the carotid canal beginning with the external aperture of the canal cranially to the jugular foramen, ending in the foramen lacerum. The important midline structure of the lower clivus is the pharyngeal tubercle. The cranial clivus is hidden by the hard palate. The clivus window. Indeed, the skull base sets no anatomical limits on the form of the clivus window (Figs. 11 and 12), but it is possible to describe: 1. The infracondylar window (Figs. 11h, i, 11a–l, and 12a) is about 20 mm in diameter and located between the anterior- or ends of the occipital condyles (Fig. 11b). If it reaches over the pharyngeal tubercle (Figs. 9f and 10a), the vertebro-basilar junction usually projects into this window (reference below). 2. The supracondylar window (Figs.  11a, i, l, and 12b) reaches cranially to the condylar position of the hypoglossal canal (Fig.  11c), the jugular foramen (Fig. 11d), and the petroclival border (Fig. 11j). 3. The petroclival window (Figs.  11a–i, 11e–k, and 12c) has the carotid canal (Fig. 11k) as its lateral border. Its caudal diameter is about 50 mm. The clivus—its architecture and the median basilar channel. From the foramen magnum to the vomer, in the sagittal plane, the clivus becomes thicker in diameter and, in the frontal plane, smaller. In the axial plane, the radius of the internal lamina is smaller than that of the external lamina, so there is a clivus hollow on the intracranial side. Therefore, the caudal clivus is thinnest in the midline area (Fig. 3.25, Graphs 3.23 and 3.24). Fig. 3.25  The caudal clivus viewed transorally. The upper clivus is hidden by the hard palate. The important midline landmark is the pharyngeal tubercle. The foramen magnum is laterally limited by the condyles, which are transverse from the hypoglossal canal. The petroclival border begins at the jugular foramen and runs along the carotid canal

116 Graph 3.23  Three types of clivus windows can be described: the infracondylar (b, b) window (a, h, l, i), the supracondylar window (a, j, l) and the petroclival window ending at hypoglossal canal (c), jugular foramen (d), and the carotid artery (k), which runs in the petrosal apex (f), in its canal (e, g)

Graph 3.24  Types of clivus windows compared to instrument size show that the clivus window most often described in the literature (type a: infracondylar) is rather small for manipulation at the dura, even with today’s instruments. a Infracondylar clivus window; b supracondylar clivus window; c petroclival clivus window. 1, Perneczky clip and applier; 2, Yasargil clip and applier; 3, Zeppelin needle holder

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Graph 3.25  The insertion of the pharyngeal wall (red line) in correlation to the clivus-windows (1: pharyngeal tubercle/small window, 7: medium window, yellow: big window)

6 5

8

4 1

7

1

In a rare variation, the median basilar channel (Fig. 3.26a), a venous sinus, may lie within the clivus at this position. The lateral part of the clivus, where the compact laminae curve from the frontal plane to the sagittal plane, is rather thick. The median basilar channel can be seen on a CT with contrast medium as a contrast spot between both lamina of the clivus (Figs. 3.26c and 3.27).

118

a

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b

Fig. 3.26 (a) The specimen shown below underwent a CT before preparation. The median basilar canal (a) can be seen as a white spot between the compact lamina of the clivus through a midline split of the soft palate (b). Teeth (d). (b) View through a midline split of the soft palate, after the dura has been opened. The vertebro-basilar conjunction and the origin of the PICA are in direct view Fig. 3.27  CT scan of the same specimen with a contrast-spot (a)

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Fig. 3.28 Vertebro-basilar Conjunction

The vertebrobasilar conjunction. If the soft palate (Fig. 3.28) is split along the midline as far as the hard palate, and the clivus window is at least as wide as the distance between the occipital condyles and extends as far as the pharyngeal tubercle (infracondylar type), after the dura is opened, the vertebro-basilar conjunction will be well-centered in all windows. Normally, it lies near the midline on the pontomedullary sulcus. Medullary medial vein and latera vein of the medulla are present. Right PICA is visible. The subarachnoidal cisterns. Six cisterns are visible: the premedullary cistern (Fig.  3.29) between the vertebral arteries (d), the two lateral cerebellomedullary cisterns (h), with the eleventh, tenth and ninth cranial nerves, and the PICA, the two pontocerebellary cisterns (g) with the abducens nerve, and the caudal apex of the prepontine cistern (e) with the basilar artery. This compartmentation of the subarachnoidal space can usually be found, along with more subtle subcompartmentation by various membranes. With the help of endoscopy, more cisterns can be made visible (). Model of transorally reached cisterns. From the typical cisternal anatomy of the lower brainstem, a geometrical model of the microarchitecture can be derived (Graph 3.25), making understanding of approach planning easier. The subarachnoidal vessels near the vertebrobasilar junction and the abducens nerve. To obtain this view, it is necessary to enlarge the infracondylar clivus window and to make a lateral cut in the soft palate along its border to the hard palate. With respect to the blood vessels, the medullo-pontine area is the site of the vertebrobasilar junction (c). Dislocation of the junction allows us to better see the perforating arteries (e) of the vertebral (d) and basilar arteries (e) (Graph 3.26).

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Fig. 3.29  Through the midline split of the soft palate (a), after the dura (b) is open, there are six cisterns visible around the vertebro- (d) basilar (e) conjunction (c): the premedullar cistern (f), two lateral cerebellomedullar cisterns (g), two pontocerebellar cisterns (h), and one prepontine cistern (e)

c. präpontis clivus-Fenster c. pontocerebellaris (sup)

a b 8

b

7

c

c

10 11 12

c

c. cerebellomedullaris lateralis dura-Fenster

c.pramedullaris

a b

b

c

c d

Graph 3.26  A model of the trans-oral transpharyngeal approach through (a) prepontine, (b) pontocerebellar, (c) lateral cerebellomedullar, and (d) premedullar subarachnoidal cisterns

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This dislocation (Fig. 3.30) causes the vertebral artery to cross the midline, while the PICA lies too deeply to be visible but could appear along the entirely visible vertebrobasilar line (a–c). The anterior spinal artery complex (Figs. 3.30, 3.31, and 3.32) typically lies between the vertebral arteries (Figs. 3.30/Fig. 3.31) and has two main branches. The median pontine vein (Fig. 3.30J) and the median medullary vein (Fig. 3.30M) in the basilar sulcus, are visible dorsally to the arteries (in contrast to the brain cortex). The lateral medullary vein (Fig.  3.30L) runs over the hypoglossal nerve (Fig. 3.31g), the olive, and the pyramid (Figs. 3.30n, 3.31k, and 3.32c). The intracisternal part of abducens nerve (Figs. 3.30R and 3.32d) begins at the pontomedullary sulcus, and almost reaches the midline and the basilar artery (Figs. 3.30F and 3.32a), but there is no structure that limits the design of the clivus window. Fig. 3.30  Through a large window, limited in this photograph by the dura (g), soft palate (f), and alveolar process of maxilla (h), a displaced caudal vertebro(b) basilar (a) system shows many perforators: pontine perforators (j, e) which cross over the median pontine vein (i), and the anterior spinal artery system (c) crossing over the median medullary vein. The abducens nerve (d) and cranial part of the hypoglossal nerve (k) is also seen

122 Fig. 3.31  A close-up of Fig. 18 shows the anterior spinal artery system (b), between the vertebral arteries (a) and crossing over the median medullary and the lateral medullary vein (e), the pyramids (d), and medulla. The caudal pons (c) and cranial part of the hypo-glossal nerve (g) are just in view

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Fig. 3.32  A close up of Fig. 18 through a large window reveals a displaced vertebrobasilar conjunction (a–c) giving an unobstructed view of many pontine perforators (e, g) crossing over the median basilar vein (f). The abducens nerve (d), inferior nasal concha (h), soft palate (j), hard palate (k), and alveolar process of the maxilla (l) are seen

Overview in the median sagittal plane. This “sagittalization” of the head was performed after a transoral preparation to the vertebrobasilar junction (Fig. 3.33). With correct positioning and projecting, the layers and their windows.

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Fig. 3.33  The transoral pharyngeal approach canal (b–c, e–g, j–n, m–k) is shown in the median sagittal plane: between the tongue (c) and the hard palate (b), through the split soft palate (g), above the atlantic arch (n) and the dens of C 2 (i), and then the vertebro-basilar conjunction (m) is reached through the clivus (k–j). The vomer (e) leads to the floor of the sphenoid sinus (f) and the epiglottis projects to C 3. Also seen are the nasal cavity (a), pharyngeal wall (h), medulla oblongata (l), and eustachian tube (d)

This approach is through the oral cavity, with the tongue (Fig. 3.33c), the hard palate (b), and the split soft palate (g). Then it follows the vomer (e), which separates the coans, to the nasopharyngeal cavity (d) and above the anterior arch of atlas (n) through the pharyngeal wall (h). It then passes through the clivus window (j–k), between the floor of sphenoid sinus (f) and the foramen magnum (k). The last two soft windows are formed by the dura and the arachnoidea to reach precisely the vertebrobasilar junction (m).

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Schema 4 Kulissenmodell Des Light-undo Manipulationskanal

a

M.longus captis ligmenta

125

Axis

Dura

Atlas

A. vertebralis

4-5 cm 3 cm 2 cm

Abasilaris Clivus Pharynx 0.5-1 cm

Palatum mole 0.5-1 cm f=300mm Mikros kop

OS

1-2 cm 7-8 cm

caudal

m

c -12

10

dorsal

li

Präparator Abstände

re Reklination Rotation Deklination

oral

cranal

b

Model of preparation layers and approach - canal

A

vertebro basilar - conjunktion

dura

B

clivus + C1 + C2 pharynx soft palatum

Graph 3.27 (a) Original Model of the Transoral Approach (Doctoral Thesis 1990). (b) Model of the Transoral Approach (1999). The model of the approach canal shows all preparation layers and their windows (b/B). If the windows are correctly positioned, the target area of the vertebrobasilar conjunction will project through all windows (b/A), which are to form the approach canal, are easily visible in this plane (Fig. 3.34).

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Model of approach canal. Openings of all layers form the typical approach canal, or keyhole (Graph 3.26 a + b) and demonstrate an approach design which enables correct projection of the lower brain stem within all layers (Fig. 3.34). Fig. 3.34  This upsidedown (surgical) position (C), transoral to the target (vertebro-basilar conjunction), shows perfect projection of all windows (s. b/A), and correct design of the windows, forming a usefull surgical MIN-canal

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Endoscopic view. An endoscope (3 mm lens) gives a better overview of the vertebrobasilar junction area than we are used to with microscopes. The basilar artery (Fig. 3.35a), the vertebral artery (Fig. 3.35b), medulla oblongata (Fig. 3.35c), and pons (Fig. 3.35e) with pontomedullary sulcus (Fig. 3.35b, f) become visible in a panorama view within the dura (Fig. 3.35d). For temporary and permanent clipping, the approach design should allow easy handling of clips para-endoscopically. One basilar temporary clip (Fig. 3.36a), two vertebral temporary clips (Fig. 3.36b), and a final clip on the vertebrobasilar conjunction (Fig. 3.36c) are easily placed. We see very closely the pons (Fig. 3.36d), medulla oblongata (Fig.  3.36e), PICA (Fig.  3.36f), and the hypoglossal nerve (Fig. 3.36g) within the dura (Fig. 3.36h). Fig. 3.35  With the help of an endoscope (3 mm lens), we have a better overview of the vertebrobasilar conjunction area than we are accustomed to by microscope. In view are the basilar artery (a), vertebral artery (b), medulla oblongata (c), dura (d), pons (e), PICA (f), and pontomedullary sulcus (g)

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Fig. 3.36  The approach design allows comfortable paraendoscopic maneuvering of clips in both temporary and final clipping. Seen here are the basilar temp. clip (a), vertebral temp. clip (b), vertebro-basilar conjunction final clip (c), pons (d), medulla oblongata (e), PICA (f), hypoglossal nerve (g), and dura (h)

30° lens makes it possible to see around corners and visualize areas that cannot be seen through a microscope. The caudal view through this transoral transpharyngeal approach shows a view into the upper cervical spine. We see the medulla cervicalis C1/2 (Fig. 3.37A), the vertebral artery entrance on both sides (Fig. 3.37Ab), root C1 (Fig. 3.37Ac) and root C2 (Fig. 3.37d), and even some subarachnoidal trabeculae (Fig. 3.37e) under the closed dura (Fig. 3.37f). Dura closure. With an approach designed according to anatomy, it is possible to suture the dura (Fig. 3.37Bb), even though it is much deeper than the atlantic arch (Fig. 3.37Ba). This suturing was done using para-endoscopic technique and allows firm packing and safe sealing.

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3.3.3 A  natomy and Modern Imaging: 3D CT, Microscopy, and Endoscopy The fast evolution of modern imaging techniques, i.e., 3D and “virtual reality” (VR), has nurtured interest in evaluating the possibilities and limitations of standard techniques. For clinical use, such evaluations mean greater safety for the patient and, moreover, are useful for giving industry a profile of professionals’ needs. Generally, this usually entails electronic data processing methods, but the results arrived at in this way can be misleading. To evaluate data of the new imaging techniques is quite simple: it requires only direct comparison of anatomical pictures. Therefore, a 3D CT in an “Allegro” version of the primary 2D CT data of a plastinated specimen was made. To get an idea of the usefulness of this computer view, it was necessary to compare it with the real anatomical view. We used plastinated crania for this because of their brilliant presentation of the smallest structures and the ability to perform repeated examinations. We also used specimens with exact microsurgical approaches, because the computer was not able to simulate them accurately. The computer-derived view (Fig.  3.37C) shows the surface, the transoral approach, and the vertebrobasilar conjunction (Fig. 3.37Ca, b). The real, anatomical view (Fig. 3.37D) shows what the computer does not “see”: all the smaller arteries (Fig. 3.37Df) and cranial nerves (Fig. 3.37Dd). The closeup of the real anatomy demonstrates dramatically what computer closeups do not show such as the vertebral (Fig.  3.37Db) and basilar (Fig.  3.3Da) arteries, the pontine arteries (Fig. 3.37Df), the abducens nerve (Fig. 3.37Dd), the median pontine vein (Fig. 3.37De), the pontomedullary sulcus (Fig. 3.37Dc), parts of the anterior spinal artery system (Fig. 3.37Dg), and even the subarachnoidal trabecula. All these structures are part of micro- and endo-neurosurgery’s daily fare.

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a

c

b

d

Fig. 3.37 (a) With the help of an 30° scope lens, it is possible to see around corners and visualize areas that cannot be seen through the microscope. The caudal view through this transoral transpharyngeal approach extends to the upper cervical spine, showing the medulla cervicalis C1/2 (a), vertebral artery entrance (b), root C1 (c), root C2 (d), subarachnoidal trabecula (e), and dura (f). (b) The correct approach design adequately allows para-endoscopic suturing for safe packing and sealing. Anterior atlantic arch (a); dura (b). (c) 3D CT reconstruction of transoral approach imaging shows the vertebrobasilar conjunction (a) through a transoral transpharyngeal transclival window. Vertebral artery (b); brain (c). (d) Close-up of real anatomy shows details which the computer cannot see. Besides the border structures of the approach, soft palate (h), hard palate (i), an inferior nasal concha and alveolar process, and laterally the basilar artery (a), vertebrobasilar conjunction, and vertebral artery (b), we see the abducens nerve with its vessels (d), numerous pontine branches with the part of the subarachnoidal trabecular system, median pontine vein (e), the medulla oblongata (c), and the anterior spinal artery system (g). All these structures are at the microneurosurgical level. Close-ups of computer views could not present more detail than Fig. 27

3.3 Case Application According to Gestalt-Anatomy Fig. 3.38  This endoscopic view (0° lens) presents an enormous overview transorally in this enlarged approach. Basilar artery (a); vertebral artery (b); pons (c); abducens nerve (d); medulla oblongata (e); pontine arterial branches (f); anterior spinal artery (g); hypoglossal nerve (h); atlantoo-occipital joint (i); PICA (j); jugular bundle (k); acoustic meatus (l); 7/8 bundle (m); petrousus bone (n); trigeminal nerve (o)

Fig. 3.39  3D CT reconstruction of the brain is a virtual aspect, as an actual brain is indeed still intracranial. We see here an overview of the brain base which real anatomy does not show, presenting the basilar artery (a), middle cerebral artery (f), optic chiasm (e) with pituitary gland beneath (d); pons (c); vertebral artery (b)

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Fig. 3.40  With the 30° endoscope, we can see the complete ventral brainstem and vertebro-basilar sytem, after a radical median clivectomy. The region of trans-nasal and of trans-oral approach are visible by the endoscope

The endoscopic view (Fig.  3.37) shows more dramatically the differences between standard computer imaging and optical techniques: we see more of the basilarand vertebral arteries with the pontine arteries in a crossing over position by dislocation of the vertebrobasilar conjunction. The anterior spinal artery system is visible along with several cranial nerves: the abducens, trigeminal, 7/8 bundle, jugular bundle, and both fiber groups of hypoglossal nerve. Furthermore, we see a fish-eyeview of the medulla (Fig. 3.38e) with the midline arteries (Fig. 3.38a, b, f), the lateral side with all the cranial nerves (Fig. 3.38d, h, k, m, o), the meatus (Fig. 3.38l), the petrosal bone (Fig. 3.38n), and the atlantooccipital joint (Fig. 3.38i). Additionally, we experience a parallaxis effect that gives a 3D impression. Depending on the distance, the view becomes very brilliant and bright, with great depth of field. In all these properties, the endoscope is superior to the microscope.

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Fig. 3.41  This 3D reconstruction shows a virtual geometric scull window with an overview of the brain stem: basilar artery (a); vertebral artery (b); pons (c); basilar tip (e); 7/8 bundle (f); trigeminal nerve (g); optic chiasm (h); oculomotor nerve (i)

The computer view of the ventral brain stem through a virtual geometric approach (Fig. 3.41) gives a virtual overview, which the anatomical specimen does not allow. It is a purely virtual aspect but not purely computer-generated: the computer shows the basilar artery, the vertebral arteries, the basilar head, the optic chiasm, the oculomotor nerve, the trigeminal nerve, and the 7/8 and jugular bundles in fusion, all on the yellow brain stem.

134 Fig. 3.42  This 3D window shows a cavernoma (c) without skull, its position in the brain stem (g), relation to the vertebral arteries (b), and the hyperglossal nerve (e) and jugular bundle (f). The semiautomatic approach canal is determined using the lines (x y z). Basilar artery (a); 7/8 bundle (d); cerebellum (h); carotid artery (k)

Fig. 3.43  This 3D view with skull shows the cavernoma (c) and related structures through a clivus window. In the window we see the basilar artery (a), vertebral arteries (b), hypoglossal nerve (e), 7/8 bundle (d), and jugular bundle (f). The yellow lines (x y z) represent the view was chosen through a large clivus window to present an overview of the relationship of the cavernoma to surrounding structures

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Fig. 3.44  The 3D window (3.44/1) shows a small clivus window, through which the cavernoma (c) can be adequately approached. The yellow lines show the angle of view of the virtual endoscopy image (Fig. 3.44/2), which is of a 30° angle, looking laterocranially from the right side of the patient. Therefore, we see a little along the gap between clivus (d) and brain stem (e), so that the basilar artery (a) becomes visible, as well as the vertebral arteries (b) and the cavernoma (c) with its connections to the right vertebral artery (b) and the right jugular bundle (j). Planning imaging axial (3.44/3) and sagittal (3.44/4) with the trans-oral rote

The computer picture of the brain base (Fig.  3.39), after calculating away all cranial tissue, presents an overview of the main basal arteries (in red). The basilar, vertebral, and medial cerebral arteries, and the optic chiasm and pituitary gland (both in yellow). This aspect is also a virtual one; in reality the brain is still in the cranium and cannot be seen in this total overview. Comparing this aspect with the real anatomy view through the transoral approach (Fig. 3.38 and 3.40) we miss many of the details which the computer again has not “seen”.

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3.3.3.1 Computer-Assisted Approach Planning In one clinical case with a cavernoma in the medulla oblongata, computer-assisted approach planning was used (Figs.  3.37, 3.38, 3.39, 3.40, 3.41, 3.42, 3.43, and 3.44). The alternatives seen in the virtual microscopic view (Figs. 3.32, 3.33, 3.34, 3.35, 3.36, 3.37, 3.38, 3.39, 3.40, 3.41, 3.42, 3.43, and 3.44) as well as the virtual endoscopic view (Fig.  3.44/2) show that this cavernoma should best be operated transorally. The operation finally was done in that way, with successful excision and results. (Perneczky). The virtual 3D CT views were rather undefined, showing only the cavernoma in three 2D-windows (Fig. 3.44/3, Fig. 3.44/4) and in one 3D window (Fig. 3.44/2, Fig. 3.44/3), giving an idea of the condition around the lesion. However, this impression could be greatly expanded by a display with an unlimited variety of angles and showing all approaches. The new software program “NeurOPS” from the University of Mainz allows creating semiautomatic approach channels very quickly. In the hands of an experienced neurosurgeon, together with a neuroradiologist and a computer specialist, it was possible to use the system to go through the different spatial conditions of the various approaches. The results, of course, had to be interpreted by a group of specialists. In the transoral approach, the type of clivus window necessary, and its exact position, could be readily determined, but further details such as neural nuclei or fiber relationships, could not be discerned. The 3D-window (Figs. 3.42 and 3.43) showed the cavernoma without the scull, its position in the brain stem, the position relative to the vertebral arteries and to the hyperglossal nerve, and the jugular bundle. The semiautomatic approach canal is determined by using the lines x, y, and z. The 3D view with scull (Figs.  3.42 and 3.43) shows the cavernoma with the above-described relative positions, viewed through a clivus window. We see the basilar artery, the vertebral arteries, the hypoglossal nerve, and the jugular bundle. The yellow lines (x, y, z) represent the camera angle presenting an overview of the relationship of the cavernoma to surrounding structure. The 3D window (Fig. 3.44/1) shows a small clivus window, through which the cavernoma (Fig. 3.44/1c) can be approached satisfactorily. The yellow line shows the view angle of the virtual endoscopy (Fig.  3.44/2), which is a 30° angle of view looking laterocranially from the patient’s right side. Therefore, we also see a little way along the gap between clivus (Fig. 3.44/2d) and brain stem (Fig. 3.44/2e); so, the basilar artery (Fig. 3.44/2a) becomes visible, as well as the vertebral arteries (Fig. 3.44/2b) and the cavernoma (Fig. 3.44/2c) with its relations to the right vertebral artery (Fig.  3.44/2b) and the right jugular bundle (Fig. 3.44/2j). The course of the operation showed that this approach planning was sufficient. It became especially clear, while displaying the situation, that this was one of those lesions for which a transoral approach is preferable.

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3.3.4 Discussion The transoral transpharyngeal approach is usually discussed together with the transoral approach to the upper spine, for historical reasons and because of their anatomical proximity. Sometimes in discussion it is not easy to differentiate these two approaches, although they are completely different regarding anatomy, tissue characteristics, physiology, operative technique, and difficulties (Apuzzo et  al. 1978; Apuzzo n.d.) (M.  L. J.  Apuzzo et  al., personal communication). There are clear reasons why the transoral approach to the spine is standardized, in contrast to that discussed here. Therefore, it is necessary to continue research and find a safe method for this approach (De los Reyes et al. 1992; Sano 1973, 1979; Sano et al. 1966; Tuita et al. 1996).

3.3.4.1 History Since S. Mullan reached the intradural space and K. Sano the vertebrobasilar junction (Mullan et al. 1966; Sano et al. 1966; Sano 1973), both transorally, discussion on this approach has been continuous (Beals and Joganic 1998; Bonkowski et al. 1990; Crockard 1995; Chono et  al. 1985; Crockard and Bradford 1985; De los Reyes et al. 1992; Drake 1968, 1973; Hadley et al. 1988; Hashi et al. 1976; Haselden and Brice 1978; Hayakawa et  al. 1981a, b, 1989; Hitchcock and Cowie 1983; Kondoh et al. 1990; Laine and Jomin 1977; Litvak et al. 1981; Miller and Crockard 1987; Mullan 1981; Ogilvy et al. 1996; Pia 1979; Pia and Lorenz 1980; Resch 1990; Resch and Perneczky 1995, 1996; Saito et al. 1980; Sano 1973, 1979; Sano et al. 1966; Seifert and Laszig 1991; Tuita et  al. 1996; Uttley 1997; Verbiest 1977; Yamashita et al. 1989; Yamaura et al. 1979; Yasargil 1969, 1984; Yasargil et al. 1980). The history of the transoral approach to the brain now exists for about 60 years, but its roots go farther back (Table 3.1): 3.3.4.2 Difficulties From an anatomical point of view, the problems involved in the transoral approach to the brain lie between the teeth and the dura. Each window in each of the layers of the approach require its own design to ensure an overall correct approach (Graph 3.27a, b). The approach design is principally not limited by the anatomical structures, but by anatomical knowledge and technical problems. Finding a balance between the ideal anatomical approach design and the technical possibilities appears important. This becomes clear when one compares the dimension of clivus windows described in the literature (Graph 3.28) with technical possibilities: the dimensions of the clivus windows are still too small for the instruments used.

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Table 3.1  History of the trans-oral route 1894 1918 1930 1944 1950 1958 1962 1964 1966 1968 1990 1991 1992 1995 2001

A. Chipault described the transoral approach to the vertebral column (Chipault 1895) LeFort described the extraction of a projectile near the dens axis (Drommer 1986; Grote and Römer 1972) W. J. Germann used the transoral approach to the vertebral column in dogs (Pasztor 1985) W. Southwick and R. Robinson operated an osteoma at the C1/2 level (Southwick and Robinson 1957) W. B. Scoville mentioned the idea that neurosurgeons should use this approach to the vertebral column (Scoville 1951) H. Fang and G. Ong used the approach to C1 and C2 fractures (Fang and Ong 1958) R. J. White und M. S. Albin used the approach in monkeys to reach the basilar artery (Stevenson et al. 1966) S. Mullan reached a retro-clival neurofibrosarcoma with this approach (Mullan et al. 1966) K. Sano risked using this approach to reach a vertebrobasilar aneurysm transorally (Sano et al. 1966) C. G. Drake (Drake 1968) and M. G. Yasargil carried on with this approach (Yasargil 1969) R. A. De los Reyes et al. performed angioplasty transorally at the basilar artery in baboons (De los Reyes et al. 1990) H. A. Crockard presented seven transoral intradural cases (Crockard 1991) R. A. De los Reyes et al. clipped one giant basilar aneurysm (De los Reyes et al. 1992) K. D. M. Resch and A. Perneczky presented a case with transorally operated angioma of the brain stem in two steps (Resch and Perneczky 1995) R. Reisch, M. Bettag, A. Perneczky published a cavernoma case operated transorally

In (Graphs 3.23, 3.24, and 3.25), some possible dimensions of clivus windows are shown. The usual window described in the literature is that of the infracondylar type. To be able to make a satisfactory clivus window allowing safe use of instruments at and within the dura, a sufficient preparation of the layers in front of the clivus is necessary. The soft palate has been split in many ways (Delgado 1981; Drake 1973; Hayakawa et al. 1981a, 1989; Hitchcock and Cowie 1983; Litvak et al. 1981; Louis 1983a, b; Pasztor 1985; Pasztor et al. 1984; Sano et al. 1966; Sano 1979; Schmelzle and Harms 1988; Wood et al. 1980), but splitting along the midline is the easiest and in most cases adequate for reaching the vertebrobasilar junction (for individual anatomy, refer to the neuroradiological findings in each case). The nasopharyngeal wall is perhaps the most difficult structure to be prepared in this approach, and many methods and strategies have been used (Delgado 1981; Drake 1973; Hayakawa et al. 1981a, 1989; Hitchcock and Cowie 1983; Litvak et al. 1981; Louis 1983a, b; Pasztor 1985; Pasztor et  al. 1984; Sano et  al. 1966; Sano 1979; Schmelzle and Harms 1988; Wood et al. 1980). As described in Figs. 5–9, three important facts have to be taken into account:

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1. The tubercle of the anterior arch of atlas is the main midline point. 2. The nasopharyngeal cavity has a dish form, so at the bottom it is much deeper and narrower than the space at the atlas level. 3. The mucosa at the bottom of this dish is very fragile, having no muscle layer but abundant lymphatic tissue. The only solid submucosal tissue is the thin pharyngobasilar fascia, which is very strongly connected to the clivus. For a successful approach, the preparation of the nasopharyngeal mucosa is the most difficult and, with respect to the closure, most important step. In the approach of Schmelzle and Harms (Schmelzle and Harms 1988; Wood et al. 1980), which was designed by Koenig in 1900 and first used by Stewart in 1909 (Lanz et  al. 1979), preparation of the pharyngobasilar fascia was easier: it was split laterally along the coans and mobilized craniocaudally. However, in most cases such an enlargement is not necessary in order to reach the vertebrobasilar junction (Mullan 1981). There is no doubt that better technical equipment, such as new instruments, lasers, and closing methods, endoscopy, and ultrasound will make preparation and manipulation of this approach easier in the future (Crockard et  al. 1991; Hadley et al. 1988; Resch and Perneczky 1997, 1998; Resch and Reisch 1997; Resch et al. 1996b, 1997c, d).

1 Aneurysm 1966 K. Sano

2 Aneurysms 1968 C. G. Drake

2 Aneurysms 1969 M. G. Yasargil

2,5 cm

2 x 1,5 cm

1 x 1,5 cm

2 x 2,5 cm

2 Aneurysms 1974 K. Salto

1 Aneurysm 1979 A. Yamaura

2 Aneurysms 1979 T. Hayakawa

4 Tumors, 1 Cyst, 1 Aneurysm 1991 H. A. Crockard

2 x 1,5 cm

2 cm

2 x 2-3 cm

Neurofibrosarkom 1964 S. Mullan

1 x 2 cm

Graph 3.28  Clivus windows used since 1964, their designers

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The craniocervical connective tissue and muscles are the next layers to be dealt with: after splitting of the fascia pharyngeal, and deep cervical fascia along the midline and cranially to the pharyngeal tubercle of clivus, the strong anterior atlanto-occipital membrane is reached. Like the pharyngobasilar fascia cranially to the pharyngeal tubercle, this membrane is very solidly attached to the clivus and difficult to prepare. It seems easier to cut it at the arch of atlas and then mobilize it laterally. There is, however, one danger: it is easy to slip too deeply into the gap between clivus and atlas and injure the epidural venous plexus, the dura, or even intracranial structures (Figs. 3.23 and 3.24). To prepare the atlas and clivus laterally to the condyles, it is helpful to mobilize the capitis longus muscle; and it might be necessary to cut it transversally at the level of the atlas, where it uses the arch of atlas as a hypermochlion (the muscle slides against the bone). Then a broad approach to the atlas and clivus is possible. The clivus shows the second midline landmark of this approach: the pharyngeal tubercle (Fig. 3.25). Statistical analysis of four cases of classical anatomical dimensions did not change this fact (Renella et al. 1987). The intracranial cavity of the clivus (Lang 1981; Lanz et al. 1979, 1985) and the declination of the compact lamina, laterally from the frontal to sagittal plane, must be considered. A sophisticated, high speed diamond drill is required to fully exploit the anatomical possibilities (Graph 3.23). In rare cases, a venous sinus, the median basilar canal, is found in the bone (Fig. 3.26) (Lang 1981; Bergerhoff 1964; Resch 1990; Resch and Perneczky 1996). This might cause major bleeding intraoperatively (Resch and Perneczky 1996). Understanding this extradural anatomical relationship and its direct bearing on preparation is the key to successful use of this approach (Resch 1990; Resch and Perneczky 1995).

3.3.4.3 Anatomy and Comparison with Other Approaches The vertebrobasilar conjunction is anatomically hidden—Drake called it “no man’s land” (Drake 1968). The pons and jugular tubercles hide it from above, and dorsally and dorso-laterally, the medulla or cranial nerves VI–XII, and blood vessels are in front of it (Seeger 1980b, 1983). This remains so even after drilling away the jugular tubercle (Knosp et al. 1993; Seeger 1978, 1990). Craniolaterally, the temporal lobe is in danger of injury, and the superior petrousus sinus and cavernous sinus lie unfavorably in the way. All temporal bone structures, including the jugular bulbus and carotid artery, hide it (Denecke 1966, 1968, 1989; Sakaki et  al. 1987; Sen and Sekhar 1990). The only direction from which to approach that allows a broad overview without endangering adjoining parent vessels and neural structures is the anterior route (De los Reyes et al. 1992; Sano 1973, 1979; Sano et al. 1966). Approaches to the vertebrobasilar junction can be made from many directions, including pterional and subtemporal (Yamaura et al. 1979; Yasargil 1984), extreme variants of laterobasalapproaches (Fujitsu and Kuwabara 1985; Sen and Sekhar 1990), lateral suboccipital (Perneczky 1986; Seeger 1978; Seeger n.d.), infratemporal (Denecke 1968; Sakaki et al. 1987), laterocraniospinal (Knosp et al. 1990;

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Sen and Sekhar 1990), transcervical (Stevenson et al. 1966), transfrontal transbasal (Derome and Guiot 1979), facial translocation (Arriaga and Janecka 1991), translabio mandibuloglossal (Wood et  al. 1980), and transmaxillar Le Fort I (Archer et al. 1987; Drommer 1986). Compared to all these, the transoral transpharyngeal approach is a relatively small and direct one (Sano et al. 1966; Resch 1990). A new upcoming route is the pernasal endoscopy assisted one.

3.3.4.4 Anatomical Concept The anatomical preparations were not done according to classical anatomical dogma (Kritz 1995; Lang 1981; Lanz et al. 1979, 1985). A change in paradigms was necessary for anatomical presentation to represent structural and spatial conditions for effective use of minimally invasive techniques (Kuhn 1988). This new paradigm was developed according to Gestalt theory (Doerr 1983, 1984; Resch 1990). This concept recommends microneurosurgical and endo-neurosurgical approaches for preparation in nonfixed specimens (Resch 1990; Resch et al. 1997a). In particular, the subarachnoidal cisterns can be well demonstrated with this method, in contrast to common techniques (Lang 1981; Lanz et al. 1979, 1985; de Olivera et al. 1985; Ono et al. 1984a, b; Rhoton Jr 1979; Rhoton Jr 1981; Rhoton Jr et al. 1979). In endoscopy, we get new insight in cistern variations and details. Compared with more well-known methods (Key and Retzius 1875; Liliequist 1956, 1959; Yasargil et al. 1976b; Yasargil 1984), it allows us, so to speak, to enter the subarachnoidal cisterns, and visualize and experience them as if travelling through them (Perneczky et al. 1993; Resch and Perneczky 1993, 1994, 1995; Resch et al. 1994). 3.3.4.5 Modern Imaging Technique and Anatomy The example presented don’t need to be discussed extensively, as their message follows the principle: “to see is to understand” (L. da Vinci). The goal of this investigation is to give a “feeling” to the reader for the limits and real advantages of 3D CT presentation. The critical mind shall not forget: diagnosis and the planning process can never rely entirely on 3D CT presentation. This is still true for the much more sensitive 2D CT presentation, as the CT cannot acquire enough data to present detail equivalent to that of operative microscopy or endoscopy (Resch et  al. 1996a, 1997a, b). Postprocessing procedures induce a significant operator-dependent variability and errors presented in the 3D images. In practical application, the accuracy of the images depends dramatically on the team-work of experienced neurosurgeons and experienced neuroradiologists very familiar with anatomy (Resch et  al. 1996a, 1997a). There is nevertheless real, additional information to be obtained with 3D CT. It can answer spatial questions concerning the direction and design of approach, or in case even contralateral approach, for reaching target areas without danger to overlying structures. The question, how the vertebrobasilar conjunction fits into which approach canal, can easily be answered by 3D CT. However, so far, in general the consequences of an approach and which important structures can be involved in

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surgery with regard to the strategy of an operation, cannot be completely answered by use of 3D-views, and not as effectively asby using direct optical views (Resch et al. 1996a, 1997a). For determining the feasibility of an approach, offline programming, namely “multimedia anatomy,” “interactive anatomy,” and “voxel man” are all part of an unrealistic scenarioproposed by many groups. At the present time, no computer exists that can adequately simulate neurosurgery or neurosurgical approaches. With the abovementioned offline-programming, it is indeed possible to put data of a useful approach into a computer; and this might be helpful for intelligent, computer-­ assisted approach planning. The goal of this examination method is to work with analogous approaches and not with virtual approach fantasies. The used software, NeurOPS, does have some tools that come closer to simulating approaches, but it requires too much time and effort in use (Jendrysiak and Resch 1999; Resch et al. 1996a, 1997a). And, take care: it has no alarm function for impossible or dangerous steps. “Virtual reality” has possibilities and limitations. The step from a computer view of an approachto an overview of the brain stem is indeed a virtual one, as the latter does not exist in reality. Post processing the 3D CT on a work-station can produce such results. Clearly, it is very difficult to derive any planning data by such “virtual” pictures. It may seem an effective procedure, but intraoperatively it can be proven to be a dangerous video game. The computer can produce any nonsenseandcannotreliablyreflectreality.Mostuserswill not have any training with such new techniques. The sensor control here must be the brain of an experienced practitioner trained to use his own judgment. At the moment, each virtual step should be evaluated with more reliable methods, such as anatomical preparations, for developing more adequate techniques in the future (Krüger 1993; Schröder 1993; Warnecke and Bullinger 1993; Wenzel and Claßen 1993). Comparison of the virtual computer view with the endoscopic view shows, that what has been said above, even more so to neuroendoscopic planning, because the possibility of error is even more probable. However, our anatomical (Resch and Perneczky 1993, 1994; Resch et al. 1994) and clinical (Resch and Perneczky 1993; Grunert et al. 1995; Jendrysiak and Resch 1999) experience has taught us how helpful 3D CT planning tools can be, if used correctly, having the anatomical reality in mind. Finally, the example quoted shows, how experience can be helpful in daily work and that the brain of a well-trained user is the best virtual reality apparatus (Yasargil 1994a, b). The rule for anatomy in the future is to acquire primary data, watch and evaluate modern technical developments in computer-assisted imaging, and give new technologies a controlled chance. We must retain clear heads and good judgment with these new techniques, as has always been applied in balancing mental and technical science. Discussions about modern techniques vary from Disneyland fantasies (Savata 1994) to precise approaches (Warnecke and Bullinger 1993). The most important difference between modern imaging techniques in non-scientific fields and those of

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medicine is that the latter requires very exact and reliable projection, meaning exact and reliable image-reality-correlations. The imaging must be defined correctly and exactly. Reliability is the rule of effectivity in scientific imaging, especially in medicine, which sometimes stands in opposition to the wish to present data more as an experience. There are two basic questions to answer when dealing with new techniques: • Does the new technique provide a solution to an unsolved problem? • What are the side-effects and pitfalls of using it (Resch et al. 1997a)? When using modern, computer-supported imaging techniques, it is important to know their limitations. It is important to keep in mind a balance between technical and intellectual equipment, to avoid danger. Anatomy belongs to intellectual equipment. Because 3D and virtual reality techniques allow the compression of important information into a few, multidimensional images, more effort is needed to develop it and gain experience, so as to define its clinical usefulness. Clinical Cases and Computer-Assisted Approach Planning One case has already been reported (Resch and Perneczky 1995) (Table 3.2). The patient was a man born in 1936, with tetraparesis since 1985. He was admitted with a diagnosis of pilocytic astrocytoma. Histology was obtained with a dorsal biopsy. The first operation for hemangioma of the ventral medulla C 1/0 in 1992 presented surprisingly an angioma, and only few feeders could be coagulated. In 1994 the patient was readmitted with neurological deterioration, angiography showing an angioma from C1 to the pontomedullary sulcus. Embolization was refused by two neuroradiological departments, and a second operation through a 2 × 4 cm transoral transpharyngeal approach was performed, in which the angioma was completely removed (Resch and Perneczky 1995). The patient recovered slightly and died about 2 years later from a pneumonia. Table 3.2  Clivus window sizes mentioned in the literature compared with clip size (Fig. 35) Year 1964 1966

Designer Mullan S. Sano K.

Lesion Neurofibrosarcoma 1 Aneurysm

Window size 2.5 cm 2 × 1.5 cm

1968 1969

Drake C. D. Yasargil M. G. Saito K. Yamaura A.

2 Aneurysms 2 Aneurysms

1 × 1.5 cm 2 × 2.5 cm

2 Aneurysms 1 Aneurysm

1 × 2 cm 2 × 1.5 cm

Hayakawa T. Koos W. T. H.

3 Aneurysms

2 cm

1 Epidermoid

2 × 1 cm (after photos)

1974 1979 1979 1985

Instruments Clip: 0.6–2.2 cm Head of clip applicator: 0.8 × 0.3 × 1.0 cm Dura needles: 0.3–1.0 cm

Head of needle applicator: 0.5 × 0.3 × 1.0 cm

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Strong arguments are needed if the brain is to be entered trans-viscerocranially. The imaging for diagnosis and planning will have a great impact on the decision-­ making. The problems of accuracy of imaging data for the decision were discussed in the above case. This applies, of course, to all computer-assisted approach planning with such imaging techniques. That the second case with the cavernoma should be best approached transorally, according to computer-assisted planning, was not known to the surgeon (A. P.), who chose the transoral approach intuitively and operated, with excellent results. In this case, NeurOPS came to the same conclusion in approach-planning as a famous neurosurgeon did. This was possible because the NeurOPS user respected the limits of the software and imaging technique, not overemphasizing it, but just understanding it as an aid to his own, overall experience. However, it is generally possible to answer questions about spatial problems using this system. The type of clivus window can be well determined (Jendrysiak et al. 1993a, b; Jendrysiak 1994; Jendrysiak et al. 1995a, b; Jendrysiak et al. 1997a, b; Jendrysiak and Resch 1999). Virtual endoscopyis a very interesting technique for diagnostic and approach planning, but it is very difficult to decide, which images can be used for realization from those that cannot (Darabi et al. 1997; Jendrysiak and Resch 1999).

3.3.4.6 Minimally Invasive Concept The concept of minimal invasiveness has always been in the focus of neurosurgery at all stages of development (Thorwald 1986; Yasargil 1994b). But this concept and its realization underwent significant evolution (Buess 1990; Perneczky 1992; Perneczky and Fries 1998). Up to now it has not been generally accepted and was not always understood (Gilsbach and Raimondi 1997). The basic concept was developed from anatomical investigations (Perneczky et  al. 1993; Resch 1990; Resch and Perneczky 1993, 1994; Resch et al. 1992, 1994). Since 1991, in our anatomical laboratory we left the classical working concept of trans-endoscopic instrumentation. This became the basis for so-called “endoscopy assisted microsurgery”, in use since 1994 (Knosp et  al. 1993; Perneczky et  al. 1999). Furthermore, the microscope was displaced by the endoscope preparation done para-endoscopically (Resch and Perneczky 1993, 1994; Resch et al. 1992, 1994). Modern imaging technique enabled visualizing a patient’s anatomy using individual procedure to minimize trauma (Perneczky 1992; Perneczky and Fries 1998; Perneczky et al. 1999). Minimizing the approach is not the goal, but rather a result of planning, selective, and precision. The concept is fulfilled only when the therapeutic aim has been reached. Finally, new techniques (Hadley et al. 1988) and instrumentation such as new clip applicators (Crockard et al. 1991; Perneczky and Fries 1995) or catheter ultrasound (Resch and Perneczky 1997, 1998; Resch and Reisch 1997; Resch et  al. 1996b, 1997c, d) make or will make the practice easier. The main advantage of this concept is that it decreases the overall trauma, including the postoperative psychological course. Our experience shows clearly that patients with minimal trauma have fewer complications and shorter hospital stays. The main disadvantage of this concept is the minimal tolerance for errors. Approaching in this way seems

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astonishingly simple, but if there are problems, managing them may become more difficult than in standard approaches. Realizing a minimally invasive concept should not be just copied, it needs to be well-grounded in anatomy, neuroradiology, neuropathology, and neurophysiology (Key and Retzius 1875; Kritz 1995; Liliequist 1956, 1959; von Lindert et al. 1998; Matsuno et al. 1988; Matsushima et al. 1983; Nagata et al. 1988; de Olivera et al. 1985; Ono et al. 1984a, b; Pasztor 1980; Pasztor et al. 1986; Perneczky et al. 1993; Perneczky et al. 1999; Resch 1990; Rhoton Jr 1979; Rhoton Jr et al. 1979; Seeger 1980a, 1985, 1986, 1990; Tandler 1929; Yasargil and Fox 1975; Yasargil et al. 1975, 1976a, b; Yasargil 1994a). The strategy for the transoral transpharyngeal approach is selective and aimed precisely at lesions of the lower ventral brainstem. It needs special solutions depending on anatomical details (De los Reyes et  al. 1992; Resch 1990; Resch and Perneczky 1994; Sano et al. 1966). Minimally Invasive Techniques: Instrumentation, Endoscopy, Neuronavigation, ENS (See Vol. 1) Realization of the minimally invasive concept needs, additionally to the above-­ mentioned basic requirement, new instruments. A special transoral instrument set and other new instruments, such as a special clip applicator, have been designed by A.  H. Crockard (Codman) (Crockard et  al. 1991). A.  Perneczky (Zeppelin) also developed many useful instruments (Perneczky and Fries 1995). However, in our anatomical laboratory we found since 1991 that most microsurgical instruments are not suited for para-endoscopic working. Experience in endoscopy (Griffith 1986; Grunert et al. 1995; Heilmann and Cohen 1991; Hopf et al. 1999; Perneczky et al. 1993; Resch and Perneczky 1993, 1994; Resch et al. 1994) has taught that a well-­ known argument has to be changed: the wrong instrument can make a famous surgeon look like a fool. If, for example, a procedure that took 5 s in microsurgery, takes up to 1 h in endoscopic surgery, then something is wrong—and it might be the instruments. Endoscopy is the leading technique for neurosurgical minimal invasiveness, because of its visualization qualities. It allows paradigmatic execution of the keyhole concept. Surprisingly, it was very soon seen during anatomical work in 1991 that lens endoscopes are far superior to fiberscopes (Oppel et al. 1984; Perneczky et al. 1993; Resch and Perneczky 1993, 1994; Resch et al. 1992, 1994). It seems ridiculous that it was not possible until today to have a holding device in microsurgery as safe as the Contraves-system. Moreover, compared to microsurgery, endoscopy lags far behind in fulfilling safety needs (Resch and Reisch 1997; Resch et al. 1996b, d; Resch and Perneczky 1997, 1998). Microneurosurgery, by the way, had the same problem 60 years ago (Malis 1988; Penzholz and Piscol 1976; Yasargil 1969; Yasargil et al. 1987). Neuronavigation is still an incorrect term because it promises characteristics that are not held by all known systems. Navigation is a cybernetic principle and therefore the object being navigated must be online and receive real-time feedback information about course and target point. Today we have a group of neurological planning systems that require no online data (Kikinis et al. 1998; Maciunas 1994;

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Mehdorn et al. 1998; Nafe et al. 1992; Schlöndorf 1998; Wirtz and Kunze 1998). This also applies to intra-operative imaging, because it does not present real-time information. These problems are well-known, and time will tell whether these techniques will become too expensive or new ideas will come up. However, the best navigation system today is basic knowledge of anatomy and the surgeon’s intellect (Resch et al. 1997a, b; Yasargil 1994a, b). Ultrasound is at present the only tool that fulfills navigational requirements but has been overlooked for a long time in neurosurgery (Auer and van Velthoven 1990; Chadduck 1989; Kanazawa et  al. 1986; Koivukangas et  al. 1993; Masuzawa et  al. 1985; Mayfrank et  al. 1994; Moringlane and Voges 1995; Warnecke and Bullinger 1993; Tsutsumi et  al. 1989). Transendoscopic ultrasound (endo-neuro-sonograph -ENS) will make endoscopy safer and can be developed into a navigational system (Frank et al. 1994a, b; Froelich et al. 1996; Köstering 1991; Resch and Perneczky 1997, 1998; Resch and Reisch 1997; Resch et al. 1996b, 1997c, d). It is small enough to be used in transoral surgery and does not have problems with optical depth of field, as the catheter can be brought directly to the target. Ergonomics of Minimally Invasive Methods: Instruments, Microsurgery, Endo-videosurgery, and Endo-head-display Surgery The instruments must be designed such that it is possible to work through deep key-­ holes, which means having a long, thin shaft, an extra-axial hand piece, and a form that ergonomically fits the surgeons’ hands. It does not make sense to deny this because of those who compensate for these problems with virtuosity. Ergonomics is the best-preserved secret for good results in modern neurosurgery. This became more and more obvious during evolution of neurosurgery. The more techniques available, the more they will influence the quality of our work. In minimally invasive surgery, we reached a point at which the sensible relationship between the surgeon and the patient’s head was more and more disturbed by poorly designed monster techniques. In para-endoscopic work, this is a dangerous game, which we studied for 8 years in our laboratory (Resch and Perneczky 1993, 1994; Resch et al. 1992, 1994). In the future, the overall ergonomics conditions will be decisive in the evolution of minimally invasive neurosurgical techniques. The three ergonomics work methods (microscopy, endo-video, and endo-HMD) that have been tested and compared are in continuous evolution. Today, the generally effective method of microsurgery is not standard in endoscopic video-surgery. The head display system could overcome some important shortcomings and therefore be the future method of choice.

3.3.4.7 Other Transoral Approaches The transoral approach to the spine is far easier than the one described above, for anatomical reasons and because one can stay outside of the dura. This fact and its more frequent indication make the spinal route a well-standardized and used approach (Apuzzo et al. 1978; Crockard 1985; Crockard 1995; Louis 1983a, b).

3.4 Conclusions

147

There are several transoral approaches frequently used extradurally, mostly by ENT and maxillofacial surgeons. These are easier in preparation, but some of them can not properly be called minimally invasive. They are not recommended for trans-­ viscerocranial neurosurgery (Kondoh et  al. 1990; Mullan 1981). Interesting transoral alternatives with various target areas and minimally invasive characteristics are: the Le Fort I approach (Archer et al. 1987; Drommer 1986; Uttley et al. 1989; Uttley 1997), the unilateral transmaxillar approach (Beals and Joganic 1998; Uttley 1997), the transoral transpalatal approach (Alonso et al. 1971; Schmelzle and Harms 1984; Schmelzle and Harms 1988; Seifert and Laszig 1991), all of which are well-­ documented and often used. All these variations on the transviscerocranial route to the brain have a great future, as they use natural pathways.

3.4

Conclusions

1. Analysis and design of approaches for the transoral route to the brain has been insufficient until now, owing to previously used anatomical methods which were not able to describe the key-hole anatomy. Therefore, surgical simulation setting in nonfixed specimens, using microscopic and endoscopic technique from a neurosurgical point of view, had to be developed. This concept was named “Gestalt anatomy”. Anatomy had to change to become a key Concept in MIN. 2. Proper dimensioning of the windows and correct positioning and projection of all the layers of preparation are the key to success with this approach. 3. The main preparation problems are presented by the layers of nasopharyngeal mucosa, the preclival connective tissue, and the clivus window. In particular, the dimensions of the clivus window should be defined with regard to the size of the operator’s instruments. There is no anatomical limit to a window, it may be as large as necessary for safe manipulation of instruments at and within the dura. 4. The transoral transpharyngeal approach to the brain closes a gap in the spectrum of approaches to the ventral brainstem. It represents a relatively atraumatic route to the ventral brain stem, requires no brain retraction, and also affords the best overview. Therefore, it provides the safest possible environment for manipulation. 5. With respect to the anatomical eventualities described above and the rapid development of new skills, it is sure to become asuitable route to the ventral brainstem (Sano 1973, 1979; Sano et al. 1966). 6. In the context of minimally invasive techniques, selective approaches will become more important as alternatives to standard approaches (Resch 1990). In summary, anatomy must be elaborated according to Gestalt theory to become a Key of MIN. Still anatomy is the house of medicine, giving a mental place to all knowledge and theories and biological functions. In this meaning of anatomy it is more connected than usual with pathology and physiology followed by surgery.

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References Alonso WA, Black P, Connor GH.  Transoral transpalatal approach for resection of clival chordoma. Laryngoscpe. 1971;81:1626–31. Apuzzo M, personal communication (letter); n.d. Apuzzo M, Weiss MH, Heiden JS. Transoral exposure of the atlantoaxial region. Neurosurgery. 1978;3(2):201–7.

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Stevenson GC, Stoney RJ, Perkins RK, Adams JE. A transcervical transclival approach to the ventral surface of the brain stem fot removal of a clivus chordoma. J Neurosurg. 1966;24:544–51. Tandler J. Lehrbuch der systematischen Anatomie, vol. 4. Leipzig: Vogel; 1929. Thorwald J. Im zerbrechlichen Haus der Seele. Munich: Droemer Knauer; 1986. Tsutsumi Y, Andoh Y, Sakaguchi J. A new ultrasound-guided brain biopsy technique through a burr hole. Acta Neurochir Wien. 1989;96(1–2):72–5. Tuita GF, Veres R, Crockard HA, Sell D. Pediatric transoral surgery: indications, complications, and long-term outcome. J Neurosurg. 1996;84(4):573–83. Uttley D.  Transfacial approach to the scull base. In: Cohandon F, et  al., editors. Advances and technical standards in neurosurgery, vol. 23; 1997. p. 145–88. von Hagens G. Heidelberg plastination folder. Heidelberg: Anatomisches Institut I, University of Heidelberg; 1985–1986. von Hagens G, Tiedemann K, Kriz W.  The current potential of plastination. Anat Embryol. 1987;175:411–21. von Lindert E, et al. The supraorbital keyhole approach to supratentorial aneurysms: concepts and technique. Surg Neurol. 1998;49:481–90. Uttley D, Moore A, Archer DJ. Surgical management of midline skull base tumors: a new approach. J Neurosurg. 1989;71(5):705–10. Verbiest H.  Indications et possibilités de la voietrans-bucco-pharyngée. Neurochirurgie. 1977;23:249–314. Warnecke HJ, Bullinger J, editors. Virtual reality 93. Berlin: Springer; 1993. Wenzel S, Claßen HJ. Die Anwendung von Virtual Reality bei Telerobotik. In: Virtual reality 93. Berlin: Springer; 1993. p. 259–69. Wirtz CR, Kunze S.  Neuronavigation: Computerassistierte Neurochirurgie. DtschArztebl. 1998;95:A-2384–90. Wood BG, Sadar ES, Levine HL, Dohn DF, Tucker HM. Surgical problems of the base of the skull. Arch Otolaryngol. 1980;106:1–5. Yamashita K, Abe H, Ikota T, Tashiro T, Kamiyama H.  Transoral transclival approach to vertebral posterior inferior cerebellar artery aneurysm. Case report. Neurol Med Chir (Tokyo). 1989;29(4):342–6. Yamaura A, Makino H, Isobe K, Takashima T, Nakamura T, Taekmyia S. Repair of cerebrospinal fluid fistula following transoral transclival approach to a basilar aneurysm. J Neurosurg. 1979;50:834–6. Yasargil MG. Microsurgery applied to neurosurgery. Stuttgart: Thieme; 1969. Yasargil MG. Microneurosurgery, vol. 1. Stuttgart: Thieme; 1984. Yasargil MG.  Microneurosurgery IV a. Neuroradiology conclusion. Stuttgart: Thieme; 1994a. p. 209. Yasargil MG. Microneurosurgery IVb, Open MRI system. Stuttgart: Thieme; 1994b. p. 67. Yasargil MG, Fox JL.  The microsurgical approach to intracranial aneurysms. Surg Neurol. 1975;3:7–14. Yasargil MG, Fox JL, Ray MW. The operative approach to aneurysms of the anterior communicating artery. In: Krayen-Bühl H, editor. Advances and technical standards in neurosurgery, vol. 2; 1975. p. 11–128. Yasargil MG, Antic J, Laciga L, Jain KK, Hodosh RM, Smith RD.  Microsurgical pterional approach to aneurysms of the basilar bifurcation. Surg Neurol. 1976a;6:83–91. Yasargil MG, Kasdaglis K, Jain KK, Weber HP.  Anatomical observations of the subarachnoid cisterns of the brain during surgery. J Neurosurg. 1976b;44:298–302. Yasargil MG, Mortara RW, Curcic M. Meningiomas of basal posterior cranial fossa, Advances and technical standards in neurosurgery, vol. 7. Berlin: Springer; 1980. p. 3–115. Yasargil MG, Reichmann MV, Kubik S.  Preservation of frontotemporal branch of facial nerve using the interfascial temporalis flap for pterional craniotomy. Neurosurgery. 1987;67:463–6.

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Suggested Reading Fasel J, Morscher E. A contribution to the anatomic basis of the transoral approach to the atlas and axis. Surg Radiol Anat. 1988;10:15–20. Landolt AM, Strebel P. Technique of transsphenoidal operation for pituitary adenomas. Adv Tech Stand Neurosurg. 1984;7:119–58. Sala L.  Virtual reality: uncreating reality rather than recreating. In: Virtual reality 93. Berlin: Springer; 1993. p. 223–5. Sutcliffe JC.  The value of intraoperative ultrasound in neurosurgery. Br J Neurosurg. 1991;5(2):169–78. Urban V, Hasenbrink F. Der Arzt als Gast im Körper des Patienten. Virtual reality imOperationssaal der Zukunft. In: Medicine goes electronic. Medien: Burda; 1995. p. 88.

4

Laboratory: Surgical Simulation and Training for MIN Post-mortal Training Setting and Setup of Endoscopic-­ Assisted Dissection Technique for MIN (PMI)

In this chapter we draw the line from Gestalt-Anatomy to a surgical simulation application in pathological anatomy of aneurysm cases. We can see a training-­ setup dealing with all morphological and manual aspects of MIN, applied in aneurysm cases (Graph 4.1):

Graph 4.1  New training setting for MIN

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_4

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4  Laboratory: Surgical Simulation and Training for MIN

Introduction

In 63 patients with 74 aneurysms, and in five other lesions, postmortem microsurgical and endoscopic-assisted inspections and dissections were done. This work not only allowed for safe patho-anatomic findings, but moreover, showed characteristics of a training method, developed to a training setting with clear standards. This concept and setup give training in: 1. Understanding of patho-anatomic topography and Gestalt-patho-anatomy 2. Analysis of imaging findings 3. Analysis and design of approaches (approach planning) 4. Para-endoscopic methods (video surgery) 5. Clipping-training 6. Analyzing the ergonomics of the setting and instrumentation 7. Challenging surgical simulation training in patho-anatomy setting (Graph 4.2)

Clin. Anatomy Pterional Approach right

PMI

SAH° 4-5 ICA-Aneurysm r. no DSA

Graph 4.2  Macroscopic Gestalt-Anatomy and -Patho-Anatomy

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159

However, the very first experience, changing from anatomy to patho-anatomy in SAH specimen is the different appearance and behavior of the parenchyma. This is one of the most important abilities to learn for MIN, to understand the behavior of the parenchyma. Color, pulsation, turgor and shifting are the language of the brain during surgery and need to be understood immediately to react before disasters follow! (s. Vol. 3) Targeting of an aneurysm in a specimen after SAH is, perhaps, the best and most challenging training model for MIN. Working within a minimal space canal to leave the edematous brain in peace is an art, once you master, you can start MIN in patients. You do but, not have the assistance of pharmacology, ventilation and physiology to improve the situation. You have to count on positioning the specimen and sophisticated approaching, using the smallest remnant of gaining space to the target. Drilling, angling of the head, endoscopy or alternative approach, all together strategies, valuable in the surgical situation later on (Graph 4.3).

Pterional Approach right SAH° 2b CT/DSA

PMI

Anatomy

r. ICA+M1Aneurysms

Graph 4.3  Microscopic Gestalt-Anatomy and -Patho-Anatomy

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Recognition of all structures in pathological conditions may be difficult and the imagination and mental videotheque will be necessary and can be learned in this unique surgical simulation setting. The abilities you can train, makes this training method superior to all other approaches, even to surgery itself at the beginning of MIN education. During surgery, MIN cannot be imitated, this leads directly to disasters. During training you can learn all these things and later you can concentrate on the pure manual part of surgery, the art of surgery. The in-effectivity to dissect aneurysms trans-endoscopically led to the new paradigm of para-endoscopic dissection: the microscope was just displaced for the endoscope leading to endoscopy assisted microdissection (Graph 4.4).

Graph 4.4  Para-Endoscopic Preparation-Technique

4.1 Introduction

161

In the series presented, aneurysms were the focus of attention. Post-mortal inspections trains most manual and cognitive abilities necessary for operative management of such difficult lesion. The acceptance and applicability of this method for resident training must be encountered in future.

4.1.1 Recalling Some Problems Why do even the most attractive virtual training methods not provide surgical abilities in the end result? How can the most precise anatomical drawings not contain the information necessary for safe intracranial working? How can we train a neurosurgeon’s brain according to micro-/endo-surgical needs before surgery finally takes place? Such questions have already been raised in the past (Seeger 1978; Weinberg 1992; Yasargil 1994). Will there be acceptance for training microneurosurgery using nonfixed specimens? (Schaller and Zentner 1998; Schaller et al. 2002). Will we lose microneurosurgery to image-guided concepts (Abound et al. 2002; Apuzzo 1992; Kuhn 1988; Lang 1981; Paleologos et  al. 2000; Roth 1999; Weizäcker 1950) (Graph 4.5)? Graph 4.5 Mona-Leon

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Learning from History

The first anatomist in modern history was not a physician but an artist: Leonardo da Vinci. His precept was: “To see is to understand” (Tulleken 1999). But this concept was preparational because it meant to make un-visible things visible (s. Vol. 1 Preface). This was important because most things in anatomy are hidden from view. Modern neuropsychological and systems-analysis knowledge (Gestalt-theory) present much more complex insights into the problem of making complex structures and spatial relations comprehensible (Müller and Hatfield 1996; Mueller 1994; Reulen and Steiger 1997). Moreover, it was a major problem to document the gained knowledge in a visible technique and to preserve it for the future. And last but not least, it was important to assure high precision in representation of the natural reality. In all these fields Leonardo was a unique master (s. Vol. 1, Preface).But the fundamental new step was to create science through experience and observations. Contemporary we are in danger to get lost of this concept and ability. It was not long ago that surgeons went to anatomy or pathology departments to prepare operations for the next day (Türe et al. 2000). Today there is a tendency to use virtual techniques for training and guidance (Liu and Apuzzo 2003; Liu et al. 2003). In 24 male and 39 female patients, post-mortalendoscopy-assisted preparations were done. Their ages varied from 1 day to 87 years (mean 57 years). Of these 63 patients, 58 cases were for aneurysm and five had different diagnoses. Microsurgical technique was used in 14 cases, pure endoscopic techniques in 13, and para-­ endoscopic methods in 47. In 51 cases, the work was video-surgical, and in 28 cases clipping training was done. Developing PMI, para-endoscopic practice became the most important preparation technique, as it was impossible to prepare complex lesions trans-endoscopically. An endoscope, 4-mm in diameter, was substituting the microscope. Traveling into the anatomy, leaving enough working space in the minimally invasive approach, which could only be through a single burr hole, became the usual method. Micro-instrumentation, microsurgical dissection methods, and modern clip sets were ad hand. Different microsurgical and endoscopic approaches were chosen to dissect intracranial aneurysms. Neuroradiological imaging such as CT, MRI, CTA, 3D CT, and DSA was used whenever available.

4.3

 lassification of Post-mortal Inspection/Training (PMI) C Settings

In the course of the work, it soon became obvious that there are typical, recurrent clinical constellations which can be classified (Table 4.1).

4.4 Understanding of Patho-anatomic Gestalt Phenomena

163

Table 4.1  Classification of training-stting PMI 1. Preangiographic 32%

CT +

Angiography −

OP −

Section −

2. Postangiographic

+

+

−

−

63% 3. Postoperative 24%

+

+

+

−

+ + +

− + +

− − +

+ + +

4. Presection 14%

4.4

Technique Transnasal/oral Burr hole The only visualization Selective approach planning Visualization Alternative approach? Clip-analysis Surgical problems 2× imaging 3× imaging 4× imaging

Understanding of Patho-anatomic Gestalt Phenomena

The first and very effective item of learning and training in pathological conditions after SAH is to get a feeling for the spatial correlations of structures within a given approach. This can be also seen in normal clinical anatomy, but in case of sub-­arachnoidal hemorrhage (SAH), a much more difficult situation exists for preparation and for understanding by viewing. Clinical anatomy allows better clarification of spatial understanding, and pathological conditions are more analogous to surgery (Graphs 4.30, 4.31, and 4.34). In this fresh preparation, one recognizes both optic nerves as well as the frontal brain spatula. A multiple clipping training is performed on the anterior circle of Willis. Gestalt phenomena for clipping is shown. In patho-anatomical training setup the same situation shows immediately the much more difficult situation after SAH. Again, after analyzing the clipping of the aneurysm (ICA right), the opportunity for clip application on the anterior CW is taken and posterior communicating artery on the right, anterior communicating artery, internal carotid artery on the left, and middle cerebral artery on the left are targets of clipping. The Gestalt phenomena under pathological conditions can be experienced. A feeling for the space and the possibilities of manual action, especially the contralateral approaching and visualization can be learned. This cannot be simulated digital (Graph 4.6).

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4  Laboratory: Surgical Simulation and Training for MIN

Pterional Approach right SAH° 3b Clipping - Training

PMI

Anatomy

right ICA Aneurysms

Graph 4.6  Clipping Training-Anatomy and -Patho-Anatomy

Anatomy: In this fresh preparation one recognizes both optical nerves (1) and the frontal brain spatula (2). The following clip positions were performed: internal carotid artery on the right (3), posterior communicating artery on the right (4), anterior cerebral artery on the right (5), communicating branch on the right (6), anterior cerebral artery on the left (7), internal carotid artery on the left (8), middle artery on the left (9), and the bifurcation of the middle cerebral artery on the left (10) Patho-Anatomy: This post mortal inspection presents a view after subarachnoid bleeding of distinct swollen optic nerves (1) and the aneurysm which caused the bleeding (2). The following clip positions were performed: posterior communicating artery on the right (3), anterior communicating artery (4), internal carotid artery on the left (5), and middle cerebral artery on the left (6). Three characteristics in nonfixed specimens are commonly not recognized and make preparation quite difficult: 1. Brain edema results in highly fragile tissue and narrows the space of an approaching SAH, even more than in surgery. 2. Nonfixed specimens can bleed from veins and sinus-es, which can lead to very difficult preparation conditions, because there is no hemostasis at all. 3. If PMI starts very early post-mortal (within 12 h, to my experience) a transgression of serum and liquid occurs. Liquor in the basal cistern will be clear in nonbleeding cases, whereas it will be opaque in the ventricles. The sub-

4.5 Training Topics

165

arachnoid space and basal cisterns, however, will be visible and accessible by endoscopy even if they do not present anymore in CT. These characteristics increase the training effect because they make preparation difficult, of course they still differ from problems of surgery.

4.5

Training Topics

4.5.1 Analysis of Imaging In particular, post-angiographic training (see Table 4.1) may serve to train analysis of imaging. In this series, scans on CT, CTA, MRI, angiography, and in two cases a computer-assisted planning had to be analyzed and compared by visualization during PMI. This gives a feeling for the limitations and applicability of different imaging techniques: “Did I understand the anatomical situation correctly according to the imaging?” “What did the imaging see incorrectly?” “Were patho-anatomic details important to operative strategy visible at imaging?” In 62 cases, this method could be trained during simulation. This training effect is similar to that in surgery, but at patho-anatomical MIN training it is possible to experience this much more extensively, clarifying all questions that could not be followed during surgery. Of special importance to training is the analysis of imaging data, not only for diagnosis but also for planning the approach and operative strategy—“Did I reach the target as expected according to imaging?” The case shown in (Graph 4.7) concerns a condition proven by angiography after subarachnoid bleeding, with three aneurysms of the anterior communicating branch, the M1 length of the left side middle cerebral artery, and the bifurcation of the middle cerebral artery of the left side. In a computer, reconstruction of these three aneurysms could have been well reproduced and well-presented concerning the different surgical approaches, in this case particularly with regard to the supraorbital approach on both sides. The question here is: from which approach is it possible to supply all aneurysms? The PMI was performed through a supraorbital approach from the right side, which is a contralateral approach. Having received permission to do a dissection, all aneurysms could be presented and left in situ. The dissection preparation (Graph 4.7) shows the precision of computer-­ supported screening; especially it demonstrates the limits. We also see bleeding of the anterior communicating aneurysm. Both media aneurysms are equally well comprehended in their positions. The left side presents the internal carotid artery, the anterior cerebral artery, and the middle cerebral artery with the aneurysms. The right side presents the internal carotid artery, the anterior cerebral artery, the middle cerebral artery, and the aneurysm of the anterior communicating complex. Such analysis of 3D imaging and imaging of planning systems is very important training (Graph 4.7):

166

a

4  Laboratory: Surgical Simulation and Training for MIN CT/CTA

Computer assisted PMI

b NeurOPs Prototype OR Planning System 1997

Approach Related Analysis

Vessel Related Analysis

Graph 4.7 (a, b) 3D Planning-System

4.5 Training Topics

167

Angiography showing aneurysms of the anterior communicating branch (1), the M1 length of the left side middle cerebral artery (2), and of the bifurcation (3) of the middle cerebral artery of the left. In a computer reconstruction, all of these three aneurysms could have been well reproduced and well presented with regard to the different surgical approaches, and in this case with regard to the supraorbital approach on both sides (5). The question here is: from which approach is it possible to reach all the aneurysms? This left-side dissection preparation shows the precision of computer-supported screening. In particular it demonstrates its borders. The bleeding of the anterior communicating aneurysm can also be seen. The positions of both media aneurysms are equally well discerned. Visible are the internal carotid artery (4), the anterior cerebral artery (5), and the middle cerebral artery (6) with the aneurysms. Right-side view of the dissection preparation shown in Fig.  4. Visible are the internal carotid artery (7), the anterior cerebral artery (8), the middle cerebral artery (9), and the aneurysm of the anterior communicating complex (10).

4.5.2 Approach-Analysis and Approach-Design In 44 cases (70%), approaches of clinical relevance were used. Pre-angiographic training (see Table 4.1) were usually not preferable. Therefore, the other three types (Table  4.1) were perfect training for dealing with approach planning: post-­ angiographic situation made precise planning to the target possible and selection of an approach or different approaches were done. In post-operative situation (Table 4.1) cases, one approach was already given, and in these 14 cases (25%), the opportunity to evaluate an alternative approach was possible. Pre-sectional cases (Table 4.1) was used for enlarged approaches and multiple approaches in comparison. In 22 cases (35%), a burr-hole approach was chosen. Evaluation, selection, and analysis of approaches for MIN training allowed the comparison of approach planning closer to approach reality. Dissection of the different approaches allowed training in approach design and the according preparation: in 22 cases (35%), a burr-hole approach was used, leading to preparation through a true key-hole. In 17 cases (27%) a single burr-hole was used, and in four (6%) the burr-hole was combined with a microsurgical approach. This burr-hole approach could be viewed as a hyper-selective and accurately placed approach, or in case, using the burr-hole which already existed from CSF drainage (Table 4.2). In ten cases (16%), several approaches to the same lesion were examined, which allowed comparison and presented the aneurysm from different directions, assisting in the understanding of spatial relations and problems. In the 63 cases with 74 aneurysms, altogether 75 approaches were explored and trained (Table 4.3).

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Table 4.2 Approaches Approach analysis of microsurgical approaches In 44 cases (70%), 52 microsurgical approaches were done: 1. Ten frontolaterobasal (16%) 10 multiple approaches (16%) In the 16 BA-aneurysms (25%) and 7 giant aneurysms(11%) 2. 13 supraorbital (21%) mult. approaches were used whenever possible 3. Two subtemporal (3%) 4. 14 transnasal (22%) 5. 12 transoral (19%) 6. One far lateral suboccipital (2%) Table 4.3 Approach-analysis Approach-analysis Groups of surg. approaches: microsurgical approach burr-hole approach combined approach Clinical relevant approaches 38 (67%) Alternative approaches 14 (25%) Multiple approaches 10 (16%) Burr-hole approach 19 (33%) Imaging of approach correlated problems 23 (40%) In 68 preparations, approach-analysis exceeded the surgical indication Future possibilities? Collateral problems? New design of approach?

4.5 Training Topics

169

4.5.3 Para-endoscopic Dissection Concept (Graph 4.8) Evolution of PMI Technique

cases

1 - 11

12+13

Microscopy

14 - 63

Endoscopy

Substitution of the Microscope by the Endoscope

Graph 4.8  Substitution of the Microscope by Endoscope

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4  Laboratory: Surgical Simulation and Training for MIN

In the 47 cases (75%) in which para-endoscopic dissection was used, the preparation was done as a video dissection. The target area was not seen but only visualized through the endoscopy and video chain. The instruments were introduced para-­ endoscopically and only their tips were under visual control. This kind of endoscopy-­ assisted microsurgical dissection technique caused new manual and visual abilities to be trained (Table 4.4): Table 4.4  Training-parameters in para-endoscopic dissection Training-parameters in para-endoscopic dissection 1.  New eye-hand coordination quite different from that in microsurgery 2. Strict coaxial manipulation technique within the keyhole approach 3. Free-hand endoscopy, resulting in navigation according to a mobile view as the scope is used together with the microinstruments 4. Spatial concurrence of the scope with the instruments within the keyhole 5. Paraendoscopic introduction of instruments into the keyhole without visual control 6. The fisheye effect and virtual 3D effect because of the deep focus range creating a different optical sensation than with a microscope. Sizes and distances can hardly be estimated and the use of all these optical characteristics must be trained 7. Viewing only one small piece of an anatomical mosaic makes the surgeon’s mental navigation necessary

4.5 Training Topics

171

This list of conditions will be applied and trained and will lead to shorter preparation time while doing more complex preparations in future. It may be further evolved to burr-hole preparation and clipping training. Moreover, ergonomics working conditions will be explored and experienced. This kind of working differs a lot from microsurgical or trans-endoscopic preparation, and the currently used endoscopes and instruments were not sufficient for safe and routine use in general.

4.5.4 Clipping (Tables 4.5 and 4.6) Table 4.5 Training-parameters Clipping-training in PMI 28 cases (44%) 22 cases (38%) through a Single Burr-Hole 1. Limitations of different clip appliers 2. Possibilities of different clip shapes in relation to anatomical location 3. The feeling of manipulating different clip systems 4. Possibilities of controlling the clipping result 5. Placement, replacement, and correction of the clip 6. Advantages and difficulties of contralateral clipping

Table 4.6  Clipping training Effectivity of visualization of the leason: Excellent Good Fair Cases of the only visualization Only visualization without DSA Diagnosis and cause of the bleeding! Posterior circulation aneurysm cases Para-endoscopic taken pathol. specimen Clip analysis clarified in 13 cases of 16 analyzed cases Clipping performance in 33 non operative cases: Clipping-Training:

98.3% 77% 19% 4% 25 (44%) 18 (32%) 21 (31.3%) 22 (35%) (81%) 17 (52%) 28 (49%)

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4  Laboratory: Surgical Simulation and Training for MIN

Besides the analysis of clip position in the post-operative cases, it was possible to evaluate possibilities of clipping in the non-operative cases, and clipping training was done in 28 cases (49%). This training was done microsurgical and para-­ endoscopically through the surgical approaches, which were just burr-holes in 22 cases (38%). A variety of techniques and abilities could be trained: In 23 cases (37%), clipping was shown in the aneurysms found at preparation and analysis, in eight cases of which the Perneczky clip set (Zeppelin) was used. It was seen that optical control is easier with the Perneczky clip, especially in small windows and in the para-endoscopic application through a burr-hole. But haptic of application was more difficult than with Sugita or Yasargil clips. Replacement was easier with the Perneczky clip than with the other two. The pre-sectional cases (see Table 4.1) showed that this kind of clipping analysis and clipping training were not possible in the open skull or the brain only. The examples showed, that manipulation training in para-endoscopic dissection and clipping was so complex that an alternative technique of training was not considered anymore. Additional manipulation techniques that could be trained in PMI were: 1. 7 third ventriculo-cisterno-stomies (ETVs) (12%) 2. 12 ventricular hematoma evacuations (IVHs) (19%) 3. 6 cavernous sinus preparations (10%)

4.5.5 A  nalyzing Ergonomics of the Setup and Instruments (s. Vol. 1, Chaps. 2 and 3) It became obvious in preparation and training that harmony of all equipment components and the surgeon himself is essential to get useful results, or any result at all. This operative harmony is directly related to the ergonomics of the setting. Ergonomic overall conditions will result in a working model characterized by safety, efficacy, and failure tolerance. The mental ergonomics is provided by the similarity of this training concept to surgery (simulation concept) and similarly the lack of a therapeutic challenge and related stress (mental concept). The para-endoscopic work was quite different from well-known microsurgical work. The co-axial dissection technique required different movements and hand-­ coordination. The video preparation technique was a different visual and manual experience than the microsurgical one. In the case of burr-hole approaches, para-­ endoscopic manipulation such as dissection, clipping, or taking specimens (as with a basilar tip aneurysm with parent vessels) became mainly a question of the harmony of all components. Especially, the instruments were a major problem, as most microsurgical instruments were not burr-hole compatible. Such experiences led to a profile of problems and further evolution of the instruments. The training of manual abilities and recognition of working characteristics of the instruments or endoscopes were two fields of evaluation with a reciprocal effect: the

4.5 Training Topics

173

more the problems with instruments were compensated for by manual training and surgical acrobatics, the fewer recommendations were found for evolving the technique. Such experience led to the need of a minimum of applicability to be expected from the instrumentation. If this was not present, another instrument was selected. In the 1970s, the introduction of micro-techniques to neurosurgery led to the founding of training laboratories for microsurgery. The first multicenter study evaluating intra- and extracranial bypass did not prove an advantage of surgical treatment over pharmacological therapy. This had the negative side effect that such laboratories nearly disappeared (Eser et al. 1989; Yasargil 1996). But in the microsurgical laboratories, not only bypass was trained but microsurgical technique in general. Training programs are a frequent theme in journals and conferences (Cappabianca et al. 1998; Hoff 1955; Jendrysiak and Resch 1999; Jho and Carrau 1997; Kriz 1995; Nievas and Höllerhage 2000; Perneczky and Fries 1995). The literature about training presents a lot of formal and organizational data but does not answer what essentially makes a training method work (Seeger 1978). Indeed, training today happens in outside courses with high costs, but regular laboratory training of microsurgical or endoscopic preparation is rare (Yasargil 1996). In future, needs for training will rise as planning gets more precise and manipulation more difficult (Resch 1999; Resch et al. 1997a). Post-mortal inspection and preparation showed the characteristics of a training model. Moreover, it was open to new questions and techniques. It depends on some prerequisites when working with nonfixed specimens, which leads to the necessity of an anatomical or pathological institution nearby and also presents ethical questions in this field. However, this training concept leads to reflection about death and human specimens, which still seem to be taboo (Bonelli 1995; Dujovny et al. 1997; Frank and Horgan 1999). In a time of decreasing autopsies and the deteriorating reputation of macroscopic anatomy, it is a question of social consent whether medical education and surgical training will return to the human body (Lurija 1973). This series seems rather small, with 63 cases, 74 aneurysms, and five other lesions. However, training effectiveness, minimal costs, and flexibility for swift further development and adaptability to new questions makes it attractive. Indeed, this idea is a very old concept, but it is combined with modern techniques dealing with all the routine imaging, instruments, and techniques of modern neurosurgery (Türe et al. 2000). Some prerequisites for future: 1. The optical solution of the video chain and endoscope must be that of a subarachnoid trabecula 2. A zoom capability of the endoscope is recommended 3. A burr-hole compatible group of instruments is necessary 4. A safe and mobile holding device is indispensable To understand patho-anatomical topography (Graph 3.5), according to Gestalt theory, this concept does not work in terms of classical anatomy or pathology, but gets its validity from regarding the context, which is in our case the lesion within its

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4  Laboratory: Surgical Simulation and Training for MIN

surroundings through a surgical approach (EC/IC Bypass Study Group 1985; Schaller et al. 2002). We are not looking for measurements and counting structures and analyzing them statistically. Instead, this concept of Gestalt aims for data of the overall spatial configuration and how this affects a surgeon’s understanding regarding manipulation possibilities. Therefore, the preparation is analogous to neurosurgery. The sum of the single structures does not represent the whole (Doerr 1984b; EC/IC Bypass Study Group 1985; Yasargil 1969). The surgical simulation concept analyzes just that information, classical anatomy or pathology would neglect, which is but most important to neurosurgery. The recognition of Gestalt characteristics in the anatomy is the first training effect and has direct consequences for the operator’s manipulative abilities according to neuropsychology (Goertz and Müller 1995; Oka et al. 1999; Tandler 1929). This training cannot be simulated by virtual means which do not induce the process of understanding but make us believe it nonetheless (Cristante 2000; Hopf et  al. 1999; Jho et  al. 1996; Resch 2003; Shekhar n.d.; Wallach 1987).

4.5.6 Analyzing Imaging Findings and Navigation Neuroradiological images speak a different optical language, being a result of mathematical operations as compared to natural images as a result of evolution and experience (Feldenkrais 1968; Taniguchi et al. 1999). To get a training effect, the artificial neuroradiological image must be directly compared with the original anatomy. Especially the post-angiographic situation gives us the chance to do what the surgeon does when he analyzes the images pre-operatively: “Did I visualize the anatomy correctly according to the neuroradiological findings and how detailed is the imaging?” The illustrative case (Figs. 3.37 and 3.42) shows the two cases in which simulation was planned with a 3D computer planning system (NeurOPS, Convis, Mainz, Germany) (Kikinis et al. 1996), and the specimens taken of aneurysms and vessels at preparation represent approximately the imaging of the computer imaging. Still, such systems are very dependent on user experience (Schaller and Zentner 1998). There is a difference between visualization by optical means and imaging by digital technique. Victor von Weizäcker already described the visual process in his book “Gestaltkreis:” “The optical apparatus and the CNS do not have a mathematical image of the space. Indeed, they form the reality of space online”. Digital media separate descriptions of tasks and their hardware, but the brain does it all together; there is a context of evolution (Resch et al. 1997b). If one tries to get a computer to see, it will be re-organized that viewing is a complex process of information postprocessing management (Cristante 2000; Hopf et  al. 1999; Resch 2003; Shekhar n.d.). From a neurobiological point of view, visualization is a learning process of recognition (Feldenkrais 1968). Digital imaging is the result of mathematical processing and results in a pixel and voxel world. In an operation or at surgical simulation concept, visualization is an ongoing process using biological coordinates:

4.5 Training Topics

• • • • • • • • •

175

3D-system of the vessel tree Sulco-gyral system Cisternal space system Ventricular cavity system Dural cover system Endoscopic landmarks (fingerprint-system) Color-code system (gray and white matter, tumor changes, etc.) Loco-motion registration (pulsation, shifting, CSF flow) Haptic feed-back (mechanical behavior of tissue) (Graph 4.9)

Biological Coordinates inside the Navigator

Biological Interactive Coordinates Within the Navigatior

Mobile Navigator

Mobile Target

Graph 4.9  Biological Coordinates

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Navigation according to biological coordinates have two problems: 1. Educational (functions only in reality like an operation or Simulation) 2. Socio-ethical (slow availability, specimens for training?) Digital navigation systems have the following problems: 1. Real time problem 2. Optical solution problem 3. Amount of data problem 4. Pixel/voxel value problem (all pixels appear equal in meaning) 5. Ergonomics problems 6. Target-navigator problem (where is the coordination system?) (Graph 4.10)

Mathematical Coordinates inside the Navigator Coordinates are converged and synchronisizedin the joy-stick

Radar

Target

Cockpit

Radar Targeting

Joy-Stick

Target

Intuitive Navigation

Navigator Pilot

Graph 4.10  Mathematical Coordinates

4.5 Training Topics

177

Surgical simulation concept is a decision in favor of visualization rather than imaging and asks for an anatomical culture at clinics as long as there is no better paradigm available that is proven (Lurija 1973; Maciunas 2000; McDonald 1992).

4.5.7 Analyzing Approaches In the simulation environment it is possible to compare approach planning with approach reality, which was done in 66% of cases, representing that approach analysis is one of the focuses with reference to each lesion. In standard approaches, it can be seen regularly that, at the end of the operation, only part of the opened approach was necessary. Planning at the time of computer-­ assisted imaging should analyze the actual part of a standard approach which will be really necessary (Resch et al. 1997a). This can be trained in the simulation concept. Moreover, optimization and alternative approaches can be examined in relation to a lesion. The trans-nasal approach became the standard for pre-angiographic cases when only CT is present. The trans-nasal simulation is an anatomic precursor of the actual field of endoscopic per-nasal cranial base surgery (Cappabianca et  al. 1999; Chandler 2000; Knoll 1994; Kockro et al. 2000). In future we will see a tendency from standard to selective approaches. Analyzing the patient’s individual anatomy (Riede 1995) pretraining will be more important, therefore (Kriz 1995) (Graph 4.11).

Graph 4.11  Para-Endoscopic Working within the Simulation Concept

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Para-endoscopic procedure is a change in the working concept in endoscopy that departs from trans-endoscopic instrumentation to combine the microsurgical competence with the advantage of the endoscope’s better visualization. This concept led to the clinical application under the term “endoscopy-assisted microneurosurgery” (Kelly 2000; Resch et al. 1993). This new concept was used for the first time in case 43 (January 1991), in which trans-endoscopic dissection of an aneurysm was impossible. This technique of dissecting and the related ergonomics conditions have some important differences from the well-known microsurgical technique, why para-endoscopic working must be trained. This should be done in fresh specimens (Riede 1995), or at simulation in patho-anatomical cases, which is more difficult.

4.5.7.1 Approach-Simulation Concept and Clipping Training Not only analysis of the clip position was done in post-operative cases (Poggio 1987) but also examination of clipping possibilities from different approaches and with different types of clipping sets. Finally, this step ends in clipping training, which was done in 45% of cases. Clipping of multiple aneurysms according to one approach was an interesting subject covered in training (Yasargil n.d.). Morphological findings of this series showed that difficult cases were examined, in which one can expect clipping difficulties. Endoscopy-assisted clipping has already reached clinical application (Resch et al. 1992; Yasargil 1985). A future type of clipping will be para-endoscopic clipping through a burr-hole. Another future type of clipping will be per-nasal clipping of anterior communicating artery and basilar tip aneurysms. Every vascular neurosurgeon knows situations that brought him close to panic. Surgical simulation as training is a reliable fundament to be prepared mentally and manually by multimodal neuropsychological abilities. Finally, testing of new clip systems can also be done, so the Perneczky clip system (Zeppelin, Pullach, Germany) was examined in 47% of clip analysis cases (Edelmann 1992; Resch et al. 1992).

4.5.8 A  nalyzing the Ergonomics of the Setting and Instrumentation The technical developments around the operation table seem poorly coordinated and many instruments and different kinds of apparatus do not work together smoothly. Actually, it is not clear whether the technical solutions to one problem result in several new problems. Today, the sensitive relation between the neurosurgeon and the patient’s head is impaired, and the surgical art seems to be handicapped thereby. The reason for this is the neglect of ergonomics. This fact is recognized by experienced neurosurgeons (Cooper and Shepard 1987; Kübler-Ross 1984; Perneczky 1992; Witt et al. 1999) but commonly is not easily accepted (Resch 1991). However, techniques like neuronavigation or intra-operative CT and MRI have a high reputation (Lang 1981; Paleologos et al. 2000) and it seems necessary

4.5 Training Topics

179

to introduce the term “ergonomics trauma” that occurs to the patient and to the surgeon (Schaller et  al. 2002)! New kinds of instruments are now being developed (Doerr 1984a). The ergonomics of this series of cases differs markedly from well-known and standard microsurgical technique. This is also the case with video neurosurgery, para-endoscopic neurosurgery, and head-mounted display neurosurgery. Many components of these systems are not mature and need developing. This can be more extensively examined at simulation concept than at operation and must be recommended by neurosurgeons. At simulation training, the same experience about ergonomic problems of neuroendoscopy, that were seen at operations, could be studied. Small instruments are needed in the future (Doerr 1984a; Haase 1999), and cleverly designed apparatuses like endo-neuro-sonography, (Perneczky and Fries 1998; Sacks 1989; Sampath et al. 2000; Schmidt 1999), endoscopic microdoppler (Ulrich et al. 1997), transendoscopic CUSA (Regan et al. 1987), multilaser systems (Ascher 1989; Auth 1990), and other sensor/effector systems (Linke 1999; Perneczky et al. 1999) make neurosurgery safer and more atraumatic. All these components must be integrated smoothly, and the micro-technique must evolve to a microsystem-technique to guarantee ergonomics conditions. D. Linke, for example, proposed, that “using data from cognitive neuroscience for the theory and practice of neuronavigation is promising for the optimization of technical and didactic aspects of operating room techniques” (Müller and Hatfield 1996) (Table 4.7). There is also an ergonomics concept for the brain of the patient derived from anatomy and physiology. It is the concept of the subarachnoid approach to lesions of the brain by Yasargil. Image-guided neurosurgery actually seems to replace this concept (Black et al. 1997; Kübler-Ross 1984; Lang 1981; Paleologos et al. 2000). The surgical simulation results confirm the subarachnoid keyhole concept (Resch et al. 1997a). The usefulness of transoral and trans-nasal approaches in a situation of severe brain edema supports the key-hole concept, when the subarachnoid space is very limited. The simulation training shows the important correlation between the key-hole concept and approach analysis.

Table 4.7  Key-hole concept and simulation concept PMI through the burr-hole The burr-hole approach is used as a full competent approach in PMI for diagnosis as well as for training 21 (33%) Burr-hole 17 (27%) Single burr-hole 4 (6%) Combined with other appr. 7 (11%) ETV-route as approach

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4.5.9 Training Programs and Education (Table 4.8) The surgical simulation concept in nonfixed specimen should be able to close a painful gap in the training of residents. Until now, it was only practiced by the author and some guests after watching this method. The effectiveness and practicability for a big number of residents must be considered in the future. The main problem will probably be the ethical consent to train on specimens (Frank and Horgan 1999; Lurija 1973; Türe et al. 2000). As it takes place with the art and precision of neurosurgery, using even burr-holes as fully valid approaches and leaving the brain in place, in the author’s experience, relatives’ acceptance is very high. Moreover, it seems to be an important part of education to teach residents an ethical attitude at the dissection table as well as at the bedside (Bonelli 1995; Frank and Horgan 1999; Kaufmann et al. 1987; Maciunas 1994; Seeger 1986). When commenting on his teacher, Yasargil remembers Cushing’s attitude: “Whatever his specialty may happen to be, it is only when a surgeon is shouldered with the responsibility of acting largely on his own diagnoses that he will be impelled seriously to study his own cases before they come to the operating table and will be inclined to follow the results of his procedures to the end to see how his mistakes can be rectified on subsequent occasions” (Table 4.9).

Table 4.8  Case-related indication for training Indication of PMI 1. The only way to visualize the lesion (no DSA, no operation, no obduction) 2. Lesions with high operative difficulty (Ba-aneurysm, giant aneurysm) 3. Clip-Analysis (cause of postop. complications?) 4. Cause of death, diagnosis (cause of SAH?, …) 5. Training in Minimally Invasive Neurosurgery (approach analysis, imaging control, new techniques …) Table 4.9  Indication of Post-Mortal Inspection (surgical training setting) Conclusion PMI is able to: – Prove, safe and visualize lesions if obduction is not accepted – Achieve obduction through a burr hole – Present findings in their topographical relationship in place – Visualize the lesion through neurosurgical approaches – Analyze lesions through several approaches in comparison – Make analysis of clip-position – Complete spectrum of imaging to neuroradiology and neurosurgery PMI is an Excellent Training-Method for MIN

46% 33% 21% 70% 100%

4.6 Cases

4.6

181

Cases

Illustrative cases show the training capabilities of surgical simulation concept for MIN. Analysis of the cases shall give an overall-impression of the material and variety, but also typical structures and orders of the concept and techniques. These cases of the four main conditions (Table 4.1) may show the complete spectrum of problems, and solution-training for MIN.

4.6.1 Case-Analysis In 63 patients, postmortal inspection (PMI) was done and 74 aneurysms were explored. In 5 cases there were other lesions. All main types, sizes and origins of aneurysms are in this series, but clearly the difficult cases are overrepresented. In 49 (78%) cases visualization was excellent, in 12 (19%) cases it was good, in 2 (3%) cases it was sufficient. In 30 cases (48%) surgical simulation training led to the only visualization of the lesion. The ratio of supra-/infratentorial cases was 69%/31%. From the SAH cases,41 patients presented bad clinical conditions grade 5 and 4 at admission, good conditions grade 3–1 were present in only 16 patients. In the setups, modern neurosurgical technique like micro-techniques and endoscopy are brought to the dissection table. In theory, it can be described as working analogous to neurosurgery. The main working technique is para-endoscopic microsurgical dissection (Graphs 4.8 and 4.12). Distribution of SAH Grading Cases 25

20 SAH ° 15

03:

16 cases

4/5:

36 cases

10

5

0 0

1

2

Graph 4.12  Distributions of Grading

3

4

5

SAH °

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Expectably, the sever cases are over-represented compared with clinical reality as they will have more fatal outcomes, giving the obligation to examine the reasons. (“… to follow each case to the end …”, as Cushing recommended.) These conditions rise the value and training effect, because the difficult cases and condition need most a strong preparation. All cases and clinical histories were known to the author, taking the clinical problems to the laboratory directly. This needs the motivation and being on standby to strictly follow this goal, which was mostly only able during night. However, the training effect of this surgical simulation concept realized much more than just the manual haptic training. It is, moreover, an education, remembering more to an emergency situation as to usual laboratory work. But the learning curve is convincing, and all the efforts cause a strong basis for clinical work. (Many young trainees complained not having the chance to operate more. I answered, they should use this time in the simulation lab to be prepared for the tremendous responsibility coming to them. At bedside it will be too late for preparation.) (Graphs 4.13, and 4.14; Tables 4.10 and 4.11). Graph 4.13 Anatomical Distribution of Aneurysms of this Series

Distribution of aneurysms at PMI

1

1

25

9

13 3 16

1

2

3

4.6 Cases Graph 4.14 Anatomical size and shape in this series

Table 4.10  Size and location of aneurysm cases

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Table 4.11  Direction and origin of aneurysms in this series

4.6.2 Preparation Concept Efficacy is not only due to technical equipment, but also due to a new concept of preparation and anatomy. This concept is derived from Gestalt-theory and results in the following characteristics of working: 1. Synthesis of patho-anatomical and neurosurgical techniques • micro-technique • endoscopic technique • using operatively done approaches • using an alternative approach to the actually operative one • using a burr hole (from CSF drainage) • using biportal approach in selected cases • using a surgical not used approach 2. Obduction with respect to neurosurgery • lesions are approached with a neurosurgical point of view • additional result to that of usual obduction technique • results, which are important for minimally invasiveness 3. Visualization must respect physiology of vision and recognition • The syntopy of anatomy is preserved, and a result itself

4.6 Cases

• • • • •

185

Spacial relations must be made visible directly Resection must not disturb visual recognition Perspectives have to be similar to neurosurgical ones Limits of surgical manipulation must be respected Enlargement of preparation should not be surgical unrealistic

4.6.3 Cases of all 4 Classifications (Table 4.12) 4.6.3.1 Case 1 (Graph 4.15) This case1of SAH ° 5, of unclear origin, was brought in the emergency CT. Only a burr-hole for ventricular drainage was done, but finally the patient died. There was only a permission to do an inspection endoscopically through the existing burr-hole. The goal in this “No-DSA Case” was to find the origin of the SAH through a single burr-hole frontal right, given after an emergency liquor drainage. This is an excellent training challenge! Usually many lessons are teaching, that in a Post-CT Case (No-DSA-Case) the per-nasal route is the best one to probably find the origin of the SAH (see the following cases). But in this case the relatives did not want any new approach, however, they gave permission only for an approach through the given burr-hole. After reaching the frontal horn of the right lateral ventricle, along the EVD, the enlarged foramen of Monroi was easily found and the third ventricle approached. After creating an EVD the endoscopic view was able far into the depth prepontine. Disappointingly, there was no aneurysm found at all usual sites at circle of Willis. So, the search went on, along the basilar trunk, until the vertebrobasilar conjunction came into sight. Only after meticulously locking for, close to the entrance of the right vertebral artery, a very thin walled small aneurysm was found finally. The

Table 4.12  Pre-angiographic cases

PMI

CT

Angiography

OP

Section

1. Preangiographic

+

–

–

–

2. Postangiographic

+

+

–

–

63% 3. Postoperative

+

+

+

–

+ + +

– + +

– – +

+ + +

32%

24% 4. Presection 14%

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a

b

Graph 4.15 (a, b) Trans-ventricular (Burr-Hole) Vertebral Aneurysm. (b) Anatomy and Endoscopy of Aneurysm Site

4.6 Cases

187

Since 1980 Anatomical preparations: •Approach-Analysis •Approach-Design •PMI •Para-Endoscopic OP-Simulations

Transnasal Approach:

First Model for a MIN Key-hole Standart Approach for PMI in no DSA Cases

Graph 4.16  Concept of Trans-nasal Route

attempt to take out the aneurysm failed, as its’ wall was too thin, however, taking specimens of basilar artery and CoA-complex, was successful. This Trans-EVD-PMI resulted in the diagnosis, on site, the only visualization of the lesion, and a para-endoscopically resected specimen of a basilar artery and a CoA-complex. For MIN, not the neuro-endoscopic pathology is in the focus, but the Gestalt-­ effect of patho-anatomical site (see above), and most, the training environment and challenge. This surgical simulation concept cannot be copied by digital means. Many clinical abilities and competences can be trained within this concept, applied in real cases with a clear target of high difficulty. In summary, this anatomical simulation environment is a key of MIN training. (see Vol. 1; Chap. 3) The Micro- and Endoscopic Per-nasal Cases In contrast to intrasellar surgery, endoscopic peri-sellar surgery needs the bimanual technique (Graph 4.17). Instrumentation and setups have still many handicaps left until today, which leads to rare application by a small pioneering group world-wide.

188

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Graph 4.17  For the post-CT cases (no DAS), the per-nasal approach became a kind of standard in the surgical simulation concept. The trans-nasal route was applied in all visualization setups (Graph 4.16). This approach allows to approach most aneurysm sites of circle of Willis (CW), giving the new extended ways peri-sellar free for exploration and training. This leads to new field of per-nasal endoscopic scull-base surgery

4.6 Cases

189

a

b

Transfrontaltransbasal

Trans-viscerocranial Approaches to the brain

Transnasal Transoral

Suboccipital Translabio mandibular

Transcervical

Graph 4.18 (a, b) Trans-nasal Route Cases. (b) Original fromDoctoral Thesis 1990

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Graph 4.19  Trans-nasal Route to Basilar Tip Aneurysm

The trans-viscerocranial routes (Graph 4.18)give access to the ventral brain base and brain-stem. However, they contain serveral major problems: • • • • • • •

The way to the dura is rather long and forms an approach canal They cause a sever post-op morbidity especially in case of complications They trans-gress a microbiological biotop causing high risc of infection Dura closure is nearly impossible and sealing techniques are needed They are by nature MIN cases with high surgical difficulties Ergonomics must be perfect:zero tolerance for failours A laboratory training periode is indipensable

When training trans-nasal approaches, above listed problems must be kept in mind. In MIN, all problems are adressed primarily by surgical techniques and concepts. This must and can only be trained in a surgical simulation way, because it is close to surgical reality. The trans-nasal routes are perse natural MIN approaches and recomment all techniques and concepts of MIN. Decades of experience show, that the swift step from trans-nasal endosellar to trans-nasal peri-sellar surgery will hardly work without laboratory training. The prize will be paid by the patients.

4.6 Cases

191

Starting the trans-nasal surgery without sufficient training will result in avoidable tumor remnants, regularly empty nose syndromes, extended surgery times and many avoidable re-operations. The first experience and impression, when starting with training, will be, this is impossible! When talking about the step from intra-sellar to peri-sellar, the training environment should be the surgical simulation concept. Other methods will push difficult parts of the training to the OR, the pation will becom the training object. Aneurysms, as a target for simulation setups are an excellent task to come close to surgical reality. The simulation siuation of emergency, necessary in working with non-fixed (fresh) speciments will have the best training effects and bleeding cases are much more difficult and valuable compared with non bleeding cases. One should start with a non-bleeding case and with microsurgical simulation setup. (s. case 2 (Graph 4.19) below):

4.6.3.2 Case 2 In case 2 (Graph 4.19) a pterional approach right side, to clip a bleeding basilar tip aneurysm, was used. Post-op the patient developed thalamic infarctions and infarction of other ganglia. Finally, the patient died. The an obduction was not accepted, but an endoscopic approach to examine the situation and future possibilities, invisible at the surface. The simulation setup, in one of the first cases of the series, was microsurgical trans-nasal as an alternatively approach training. But also, trans-nasal, because from pterional side, the clip-analysis was impossible. Three clips blocked the view to the basilar region completely. A blind clip taking could have destroyed the vascular structures and the situation, preventing clipping-analysis. In the first trans-nasal case of the series, this approach seemed the best direction to analyze the situation and to approach the basilar tip trans-nasally, visualizing the aneurysm neck. This could be enabled without toughing the brain, which presented a sever edema, compressing the basilar trunk ventrally and showing no Subarachnoidal space anymore. Under the microscope, the approach was well possible to the retro-sellar region, and finally the aneurysm neck clearly shown. However, the aneurysm itself and the clips were not visible. Under this the direct visible control of the aneurysm neck, the clips were taken from pterional direction. Thereafter the aneurysm could be moved easily into the trans-nasal view without any tearing. Finally, a trans-nasal clipping training was possible. As the aneurysm neck was visible without the tips of the clips, it can be concluded, that the neck was not completely within the clips. The traces of the clips showed, that the three clips were placed longitudinal over the aneurysm sack. A safe finding, if a clip compressed a perforator, was not ruled out undoubtedly. The complete preparation was carried out without a disturbance of the aspect of the patient avoiding any additional scarfs and traces. This is an excellent education.

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However, this first trans-nasal surgical simulation through the trans-nasal route and to the basilar tip aneurysm, was a very strong experience and exploration, as has been done for years in the Gestalt-anatomy setting (Chap. 3; Vol. 2 Chap. 5). It became clear, that a preparation of a basilar aneurysm neck and a clipping should be further examined and analyzed. However, it became also clear, as mentioned above, that the techniques and the equipment was not mature for MIN. But also, it was a result, that only with the concept and techniques of MIN, such goals might be realized in the future. During this type of surgical simulation training for MIN, goals could be enabled, that were not imagined before. And finally, it could be experienced expectably, that such research and results cannot be reached by indolent routine trails. This case already gave an early impression in this series, that this kind of experiences and trainings needs to establish a training and simulation environment in many neurosurgical departments, making clinical training and surgical training in parallel. Each resident should use the time, when surgery is not the priority, at the beginning, and one should get the opportunity and obligation to have this chance during these first years of education.

4.6 Cases

193

a

b

Graph 4.20 (a, b) Para-Endoscopic Pernasal CoA-Aneurysm  +  Basilar Tip. (b) 5 Peri-Sellar Windows Concept

4.6.3.3 Case 3 Case 3 represents a sever SAH°5, with ventricular involvement and cisternography by blood. Site of origin of SAH was not clear after CT, however, the patient deteriorated and finally died.

194

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Relatives did not allow an obduction but accepted an endoscopic post-mortal inspection (PMI). During the preparation, first bone of the sellae was resected. Then tuberculum and planum sellae were resected, which is usually not too difficult if the bone is thin, because dura is rather tuff and smooth. Finally, the clivus bone is resected, which is more difficult, ending at a complex dura with the basilar venous plexus and inter-cavernous sinus. There are 4 peri-sellar windows (Graph 4.20b), planum-, clivus-, and bilateral cavernous-window. Each window leads to different intra-cranial or intra-cavernous structures, and all window present typical dura patterns with specific difficulties. The easy one is the planum window, leading to A.-com.-complex. The clivus-window leads to the basilar head and interpeduncular cistern and prepontine cistern. The cavernous windows lead into the cavernous sinus and the syphon of ICA with intra-cavernous branches. More laterally, the cavernous branches of cranial nerves IV-VI may be approached. The sellae window is the usual window of this route to reach pituitary gland region. It is dangerous to tear out dorsum of sellae and only necessary in a high position of the basilar tip. In this case it was not too difficult, resulting in a better view on the caudal placed basilar head. Opening of dura is difficult also and shows the blood clot of the sever SAH. The complete route with all 5 windows is MIN approaches and high difficulty level. Sucking away the blood carefully rostral to the dura of sellae, trans-sphenoidal windows gave the view to the arteria-communicans-anterior complex and the bleeding cause of a fusiform aneurysm. Preparation to this region is comparable to the anterior superior wall of sellae, but the space of approach becomes narrower the more advancing anteriorly. The target of an aneurysms there, was already mentioned by Yasargil in 1969. However, neuroradiological finding mast be analyzed extremely perfect to understand the planning keys of this route regarding difficulties and dangers. Proximal control is challenging if possible, and direction of aneurysm dome plays critical role. Main advantage is the direct approach to the neck with minimal toughing of the brain, especially in edema circumstances.

4.6 Cases

195

4.6.3.4 Case 4 (Graph 4.21)

Graph 4.21  Trans-nasal Pcom-Aneurysm

Case 4 is another post-CT (No DSA) case and the post-mortal approach was enlarged laterally, and the origin of a Pcom-aneurysm could be made visible. The dissection of the pituitary gland from the cavernous sinus was necessary to reach this area, even with the 30° endoscope. However, this gave an image, not possible with any other means. The complete basilar artery with all branches of the head, and a unique presentation of the topography of ICA, Pcom and oculomotor nerve with the aneurysm. The neck and origin and correlation to ICA and Pcom can most clearly and comprehensive visualized. All the morphology causing the surgical difficulties of this location are present with one view, causing the phenomena of Gestalt effect: to understand directly 1 s: “heureka!” In the case of no DSA, this brought the diagnosis and the only visualization of the lesion. Moreover, a specimen could be taken for further examinations. But, of course, we see a unique training environment for surgical simulation in MIN (Table 4.13).

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Table 4.13  Post-angiographic cases

CT

Angiography

OP

Section

+

–

–

–

2. Postangiographic

+

+

–

–

63% 3. Postoperative

+

+

+

–

+ + +

– + +

– – +

+ + +

PMI 1. Preangiographic 32%

24% 4. Presection 14%

4.6.3.5 Case 5 (Graph 4.22)

Graph 4.22  Supra-Orbital Coiled medial ICA-Aneurysm

4.6 Cases

197

Case 5, a sever SAH 4°, was coiled due to angiographic and clinical findings, belongs to the post-angiographic type, which means, that the aneurysm site is exactly known. In such a situation there is a perfect setting for training the pre-op planning and preparing of the procedure. So, the first learning step will be to analyze the imaging. After diagnosis of a SAH is proven by CT, we need to study the angiography, which means today DSA, and this means a massive reduction of optical resolution. We have to keep in mind, that we will not see the most perforators close to the aneurysm, due to the lack of visual resolution of modern imaging. This must be compensated by surgical experience, and a big library of cases we have seen. This is the desaster of pure CTA diagnostics, and even experienced neurosurgeons might be busy for hours of uncertainty during surgery, to getting sight on the perforators in the fog of subarachnoid blood. The lack of indipensable information leads to a loss of strategy. You then have to fly without radar! For MIN this is the end, resulting in a non-MIN procedure regarding all ergonomics fields: spatial, procedural and mental. Our actual imaging technique enables to see and understand an individual anatomy and pathology of my actual patient. Ony this leads to an individual planning procedure and individual approach. To this information pool belongs all information regarding the planning of the procedure, not only the diagnostic data. This additional planning information must be asked for from the (neuro-) radiologist very precisely. This information must be converged and synchronizied with the library of operation-clips and knowledge in the brain of the surgeon in an ongoing process,creating a narrative and intuitive concept of the needed operation. In the surgical simulation concept for MIN, these processes and procedures can be learned within a calm and stress-free setting and environment, without a therapeutic mission. Our “neuro-navigation systems” do not navigate, but are an expensive tool for cognitive (not mental) monitor planning, which is, however, not a training procedure, but a first step to it (better than nothing). DSA showed close proximity to the cranial base, which indeed is better viewed in CTA (not shown), a distance of the aneurysm neck from ophthalmic artery, and a protrution of the aneurysm dom caudally and medially. My library tells me immedially, that the optic nerve must be comressed. The aneurysm neck is well estaplished but short and not very narrow. It could be expected that clipping was not easy, on the other hand, coiling would not release the pressure on the optic nerve. The critical overall condition was in favour for coiling. However, the patient died and an obduction was not allowed, but an endoscopic inspection, leaving the brain in place, was accepted. The condition at this night gave only time for one approach. The decision options for which sidewould be better to approach could not be proven by looking through approaches on both sides. Anyway, the supra-orbital approach with a 3 cm eybrow incision (douple burr-hole) enabled an endoscopy assisted surgical simulation training to the aneurysm. The amount and severity of the compression and lifting of the right optic nerve was surprising and the visibility of the coils through the aneurysm wallimpressive, remembering that this wall could easily rupture.It is not visible from the ipsilateral sinde if an contralateral approach could be the better approach for clipping. However, because the aneurysm has already lifted the optic nerve and opened a window, clipping from the ipsilateral side.

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Today virtual techniques of simulation give the possibility to simulate the opposite view, however, such simulation bear a incalculable possibility of error. The surgical simulation concept and environment is much closer to reality than vitual techniques enable. Finally, a specimen could be taken endoscopy-assisted through the douple burr-­ hole to do further examinations. Diagnosis, visualization and pathology of the bleeding disease as well as all the planning and preparing measurements could be learned and trained within this concept. If the clipping by MIN will be atraumatic and with less complications than in non-MIN procedures, a decompression of the optic nerve would have been possible. Only MIN strategies will compete interventionel neuroradiological interventions. It means to keep the door open in cases, radiological intervention is not possible. But we need to be prepared and trained therefore.

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4.6.3.6 Case 6 a

b

Colour coded Vessel Analysis in 3D Reconstructed CTA by NeurOPs-Prtotyp System 1997

Graph 4.23 (a, b) Computer-assisted Planning PMI. (b) Colour Coded Analysis

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Like in Case 6, As mentioned above, in particular, post-angiographic training (see Table 4.1) may serve to train analysis of imaging. In this case, angiography, and in two cases a computer-assisted planning had to be analyzed and compared by visualization during surgical simulation preparation. This gives a feeling for the limitations and applicability of different imaging techniques: “Did I understand the anatomical situation correctly according to the imaging?” “What did the imaging see incorrectly?” “Were patho-anatomic details important to operative strategy visible at imaging?” The case shown in (Graph 4.23) concerns a condition proven by angiography after subarachnoid bleeding, with three aneurysms of the anterior communicating branch, the M1 length of the left side middle cerebral artery, and the bifurcation of the middle cerebral artery of the left side. In a computer, reconstruction of these three aneurysms could have been well reproduced and well-presented concerning the different surgical approaches, in this case, particularly with regard to the supraorbital approach on both sides. The question here is: from which approach is it possible to clip all aneurysms? The PMI was performed through a supraorbital approach from the right side, which is a contralateral approach. Having received permission to do an obduction, all aneurysms could be presented and left in situ. The dissection preparation (Graph 4.23a, b) shows the precision of computer-­ supported screening; but it demonstrates also the limits. We see bleeding of the anterior communicating aneurysm. Both media aneurysms are equally well comprehensive in their positions. The left side presents the internal carotid artery, the anterior cerebral artery, and the middle cerebral artery with the aneurysms. The right side presents the internal carotid artery, the anterior cerebral artery, the middle cerebral artery, and the aneurysm of the anterior communicating complex. Post-mortal simulation training through supra-orbital approaches gave the chance to take specimens for pathological examinations. Comparing the specimens with their CTA reconstruction by NeurOPs visualized directly the vast difference in optical resolution, which is reduced factor 1000, which means: all the not-­ represented details of the real anatomy of the aneurysms and parent vessels, parenchyma and arachnoid space is blinded. However, surgical skills in neuro-microsurgery of a well-trained surgeon takes place at the resolution level of an erythrocyte! (4–5 μ). Actual planning systems within neuronavigation-systems are rarely used routinely, but still do not represent perforators close to aneurysm neck. It is one of the main training-effects, to visually recognize these differences and to learn dealing with this and taking into account, what the computer systems do not see and never know. This causes, still today, lives of patient, due to this lack of experience, and un-believable, due to blind believing in navigation-systems and the non-real-­ time hidden incompleteness of information. (see also Chap. 3; Fig. 3.37) (Table 4.14)

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Table 4.14  Post-operative cases

CT

Angiography

OP

Section

+

–

–

–

2. Postangiographic

+

+

–

–

63% 3. Postoperative

+

+

+

–

+ + +

– + +

– – +

+ + +

PMI 1. Preangiographic 32%

24% 4. Presection 14%

The post-operative cases offer, additional to the former types: surgical clipping analysis, clarification if the surgical clipping caused the infarction or rebleeding, examination and training of alternative approaches to the chosen surgical one. Alltogether an excellent research-and training-opportunity, an obligation we are, ethically, not allowed to miss. Surgical simulation concept for MIN creates a training culture at the places of, and for neurosurgery in general.

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a

Trans-palatal Approach PMI

b

Graph 4.24 (a, b) Trans-sphenoidal Basilar Head-Aneurysm. (b) Trans-palatal Approach

4.6.3.7 Case 7 Case 7 presents a SAH 3b(Yasargil-Grading) from a basilar-tip aneurysm, that was clipped from a right pterional approach. Postop several infarctions appeared visible on CT with the pattern of basilar-tip and right(!) P1 malperfusion. An obduction was refused by the relatives but endoscopic inspection was allowed. The training approach was in this case a trans-palatal approach, providing access to all the midline cranial base (Graph 4.24b). The very strong gingiva plate

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is a quite safe basis for perfect closure. Inbetween both mucosal cannels of nasal cavity, after resection of nasal septum, there is a direct access to peri-sellar targets. After opening of retro-sellar dura, the basilar head and two big clips become visible. Analyzing clip-position, it is obvious that P1 of the left side is within the clips. However, there is a strong Pcom on that side and no P1 pattern of infarctions on the left side in the CT.  However, clip-possition indicate the cliping of thalamo-­ perforators, explaining the thalamus infarction on both sides. The unusual perspective shows the way and direction the clips are coming from. Cavernousus sinuses on both sides are opened. The optic nerves, chiasm and -tracts are visible in place. The sellae with dural cover is in normal possition and fixed with the typical ligaments owith the dural walls of the cavernous sinuses. Pre-chiasmatic the two A1 are hardly visinble.The overview of the basilar artery head and surroundin is impressive and enables a unique perspective on the aneurysm. It is impressive,that in cases of refused obduction, the endoscopic inspection is allowed because the brain is left in place, and there are no visible marks post-­ inspection. Under this hard conditions, a vast amount of informations, diagnoses and training-effects are provided. The post-mortal surgical simulation used the chance for clipping analysis through an alterative approach, providing excellent approach angle and examine the conditions and difficulties of this alternative approach. These conditions offer an environment of high significans even in times of coiling and flow-divertor. “Themost difficult cases, neuroradiological interventions cannot solve, will be left to neurosurgery”, was the answer of A. Valavanis to the question of a neurosurgical resident. Surgical solutions of such cases will only compete if MIN strategies and techniques are used. This must be trained intensively, proving the surgeon in the OR with a strong basis of knowledge and self-security, enabling smart strategies, aiming fast to the target and shorten the procedure.

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4.6.3.8 Case 8 a

b

Graph 4.25 (a, b) Trans-sphenoidal P1-SUCA-Aneurysm. (b) Subtemporal and Trans-sphenoidal Approaches

Case 8 presents a surgical simulation with a clearifyng clipping analysis, and additionally two alternative appoaches to the surgical one. The patient had a sever SAH from a basilar head aneurysm between P1 and SUCA right. Finally, the patient had malignat vasospasm with multiple infarktions. Obduction was accepted later but in-time. So there was not major limitations for surgical simulations, but with a cosmetic acceptable result.

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Therefore, a trans-palatal trans-spheoidal approach was choosen giving extended access to the peri-sellar midline region with sellar-, pre- and retro-sellar winows. In adddtion to case 8, the content of sellae was dissected from the left cavernous sinus to better visualize the aneurysm site. In (Graph 4.25b) the two alternative approaches were presented together with also an anatomical preparation to better recognize and understand the surgical simulation. In addition the angiography in the same orientation is added for comparision angiographic, anatomical and surgical simulation aspects. The pathological preparation of the basal vessels with the aneurysm precisely and impressively show the differences to the surgical simulation aspects and the different amount and quality of information which can be analyzed. Extremly different aspects are comprehensive and comparable between the trans-sphenoidal and the subtemporall approach. Afer opening the dura-windows and dissecting the Sella-content from the cavenous sinus left, the clip-possition can be clearly seen. It becomes visible, that there is a remnant of the aneurysm left (Graph 4.25a). Also it can be understood, that the clipping angle from the oopposit side (pterional right) was not optimal. However, there was no clipping of perforators found. Pre-chiasmal the a. com. -system (CoA) is visible, but also para-chiasmal, the a1 on the right side. The sever edema post-mortal was no problem in approaching the aneurysm site trans-­ sphenoidal from the direct anterior route. It was also prooven, that the subtemporal approach as well as the trans-­sphenoidal provided a much better angle to completely clip the aneurysm. This approach provided a clipping training trans-sphenoidal and subtemporal. Surgical simulation concept provides in such a complex and difficult case many valuable learning opportunities regarding clipping analysisand training, approach design of alternatives to the surgical one, and to study the anatomy in the context of MIN by the Gestalt-effect. There is no other concept and technique which can offer all these possibilities with such a training power.

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4.6.3.9 Case 9 (Graph 4.26)

Graph 4.26  Para-EndoscopicTrans-Ventricular Basilar-Tip Aneurysm

In Case 9 a basilar tip aneurysm caused a SAH°4 and a ventricular tamponade which was treated by bi-ventricular EVD. Typically in ventricular clot situation, this did not work well.Through a 2 cm in diameter craniotomy, medio-pupillary, precoronar transfrontal ventricle clot evacuation was performed, and trans-­foraminal (Monroi) evacuation of clot from the third ventricle also, suddenly the aneurysm came into sight. This was a new route created by the bleeding, however, well known to endo-neurosurgeons from ETV, but never used in an aneurysm case. The chance to clip the aneurysm and stopp the risk of rebleeding was taken. But the clipping was challenging, as the approach did not well present the aneurysm neck. Stepwise, the aneurysm sack was compressed by 3 clips, while their tips reconstructed the normal line of parent vessels.However, maybe the evacuation was too late, teaching us that early and fast evacuation of ventricular or intracerebral clot is essential to give the patient a chance for recovery. Under bad clinical SAH conditions, the evacuation needs to be done by MIN and as early a possible. However, in this case it was indispensable to do it with clipping prepareness.But also the sever SAH and primarily bad clinical condition may have led to a fatal outcome finally. The post-op perfusion CT showed a sever general perfusion deficite, correlated with a general vasospasm. Surgical simulation concept was applied through 3 approaches: first through the surgical right sided MIN craniotomy frontal trans-ventricular (1), second through the second left-sided burr-hole trans-ventricular (2), and finally through a supra-­ orbital burr-hole sub-frontal right side (3). Clipping analysis showed, that the reconstruction of parent vessel (P1-bifurcation) was perfectly reconstructed and the broad complex aneurysm neck was clipped.

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Perforators were left in peace and the aneurysm sack collapsed. Pathological examination could confirm this finding by autopsy, in this case. Approach analysis showed, that supra-orbital route (3) enabled a better perspective on the aneurysm neck and the tips of the three clips. However, using the evacuation route (1) enabled a MIN strategy regarding saving time and minimizing trauma, but in this case, difficulty of clipping became maximum. A vast amount of experience and training is needed to safely do this kind of procedure. This can be trained with the surgical simulation concept and -setup, digital methods will not end in any relevant training effect.

The multi-portal analysis gives a possibility to compare the approaches and perspectives. However, in MIN a bi-portal approach is necessary very rarely, and it was surgically never used by the author. One reason is, that endoscopes enable to see nearly everything from one approach only. Moreover, the MIN concept recommends a precise selected optimal approach, instead of a standard approach. This selection can be learned during approach analysis within the surgical simulation concept.

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4.6.3.10 Case 10 (Graph 4.27)

Graph 4.27 ICA-/Pcom-Aneurysm Ventricular PMI

right

Supra-Orbital/Clip-Analysis/Burr-Hole

Trans-­

Case 10 was an ICA-Pcom-aneurysm right sided, the patient was operated through a supra-orbital approach, 14  days post SAH, after the patient has recovered. Obduction decision was not clear at the start of PMI, so the surgical simulation training was only possible though the existing burr-hole of the EVD on the right side. Angiography has shown the typical finding and challenge of this aneurysm site, the supply from three directions, one of them, the Pcom, hidden by the tentorium and proximity to the cranial base. If the aneurysm neck involves additional to ICA, the Pcom, the blood-supply comes from ICA, from opposite side via CoA, and from the posterior circulation via Pcom. There might be no space for proximal control of ICA, and Pcom can be hidden for temporary clipping. For a MIN strategy, all these factors and many others need to influence the planning. Post-op DSA shows that the aneurysm was clipped perfectly, but also the general vasospasm. The trans-ventricular route for surgical simulation concept offered a superb environment for training, however clip-analysis was difficult and final clarification best documented by the para-endoscopic taken specimen through the burr-hole of EVD. See the clips and the traces with reconstruction (red dots) of the parent vessels. Without this simulation training, such masterpieces will not become gold standard (Table 4.15).

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Table 4.15 Pre-autopsy

CT

Angiography

OP

Section

+

–

–

–

2. Postangiographic

+

+

–

–

63% 3. Postoperative

+

+

+

–

+ + +

– + +

– – +

+ + +

PMI 1. Preangiographic 32%

24% 4. Presection 14%

Cases 11, 12 and 13 are such difficult and extraordinary and rare cases, that surgical simulation concept byimaging analysis, approach analysis, approach design, clip analysis, comparing multiple approaches, specimen taking, para-­ endoscopic training should allways be reached, and valuable information and experiences be taken. In fatal cases also usual obduction should stay at the end to evaluate from a classical perspective the complete pathology. This is even true in times of interventional techniques. Case 11, for example surprised with the finding of arising perforators directly from the aneurysmen, which was documented and published for the first time. We need to take advantage to learn from such cases as much as possible and not miss any effort to apply recent techniques to study each case. All three cases were not operated, case 11 underwent interventionel procedureof that time. Because of the better approaching, the ventral types of approaches (trans-viscero cranial) were prefered in the surgical simulation concept. Surgical future strategies were illuminated and compared also with standard approaches. All cases were followed clinically and scientifically, giving the fatal outcome an additionalmeaning by learning for future cases, and by the knowledge we were allowed to collect. Such cases represent an ethical imperative to follow-up andreview the course to the end.

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4.6.3.11 Case 11 (Graph 4.28)

a

b

Graph 4.28 (a–e) Giant VB-Aneurysm. (b) Trans-oral Trans-pharyngeal Analysis. (c) Vertebro-­ Basilar Perforators and Spinalis anterior System (Chap. 3, above)

4.6 Cases

211

This patient came with the diagnosis of a CPA tumor according to CT findings and CPA + VI CN Symptoms left. Hearing loss, facial pulsy and nearly impossible towalk, with strong head-ache and decreased allertness. The first view on the CT showed that this was not a tumor ( ). However, MR presented a giant VB-aneurysm, an unbelivable aneurysm size in the region of “no man’s land”. A flow void signal was present, compression on the brainstem with a large perifokal edema. DSA showed a breath-taking finding with a true giant vertebro-basilar aneurysm placed in the left CPA and compressing the brain stem. Typically the DSA does not present the perforators, remembering that the optical resolution of DSA decreased about 2000% compared with the classical angiography. As discussed already above, this has enormous consequences for the outcom in vascular surgery, but also for strategy in tumor surgery. This lack of information is intolerable in MIN. It can be compensated by neuro-sonography, giving this key technique of MIN a special role (s. Vol. 1, Chap. 5).

c

Graph. 4.28 (continued)

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The neuroradiological concept was to reduce flow by balloon placement in both vertebral arteries, provided with a testing strategy (see below). However, the perforators from the basilar artery and from the anterior spinal artery system were not regarded to exist if they were not present in the pre- and post-op control DSA: Bio-­ electronic systematic failure. The existance of perforators and their variations are well described, however, the limits of digital imaging are mostly not well known. It makes no sense to digitalize medical processes if the quality is not kept in mind. Quality cannot be substituted by quantity (see above Chap. 3). The patient developed a locked in syndrome, and MR showed a terrible large infarction of the brain stem. This failure might be directly a consquence of the missing informations of DSA, the perforators are not detected, and even more, neuro-­ family lost the knowledge of finger prints and patterns of the small vessels. This costs lives every day. The pathological aspect of obduction on the brain base is impressive, but does not contain sufficient information we need for MIN. However, we get, at least, the impression of the transoral approach at the skull-base from inside, which was performed for the surgical simulation analysis and training. The open pathological presentation has to destroy the context of the findings seen through the approach, once detroyed it can hardly be reconstructed. Only in the surgical simulation concept this information is preserved and can be analyzed and documented. During the PMI setup we get a complete different and informativ aspect, useful for future surgery and for training exsperiences: The setup for surgical simulation training looksmore like an OR-setup than that of an obduction or anatomical preparation. Microscope, endoscope and micro-­ instrumentation are indispensable and symbolize the new concept to bring recent technique to the dissection table. This enables that anatomy can close up to the development of surgery, and that learning and training becomes up to date for clinical practise. A tran-soral trans-pharyngeal approach with cranial enlargement to the vomer and lateral to the left CPA was performed. The dura was opened in a triangle shape and the complete aneurysm became visible. The first striking aspect was the balloon of the right vertebral artery, shining through the subarachnoid membranes of pre-­pontine cistern. Due to the dislocation of the vertebro-basilar conjunction to the left CPA, the subarachnoidal membranes were teared laterally giving them some tension. Pushing the medulla minimal medially, the balloon in the left vertebral artery became also visible. But the most surprising finding, after opening all cisterns and subarachnoid membranes, were three strong perforators, originating directly from the aneurysm sack (see below: Forsting et  al. 1991; AJNR 12: 1063–1066). Clipping training showed the possibility to exclude the aneurysm and to close both vertebral arteries, without compromising PICA or the spinalis anterior system. The neuro-obduction by taking out the brain only, was performed by the author, and this brain was preserved for further studies by plastination (see next Chap. 5). Today such a case would be treated by flow-diverter placement and life-long anticoagulation medication. However, here we have the basic knowledge for several

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surgical strategies and the training environment, which cannot be substituted by digital means actually, and if, in future, development needs to be controlled by analog techniques until the progress is safe and working with sufficient quality controls. Balloon Occlusion of a Giant Lower Basilar Aneurysm: Death Due to Thrombosis of the Aneurysm Michael Forsting, Klaus M. Resch, Rudiger von Kummer, Klaus Sartor Endovascular balloon embolization therapy tor neurovascular lesions was first described by Serbinenko in 1974 [1]. With improved technology, including detachable balloons, minicatheters, permanently solidifying agents, and real-time digital subtraction angiography, it is now possible to treat intracranial arterial aneurysms from an endovascular approach in selected cases [2, 3]. In the case reported here, the patient had a giant aneurysm without a definable neck at the junction of both vertebral arteries; he was treated by bilateral endovascular occlusion of the vertebral arteries distal to the origin of the posterior interior cerebellar arteries. Upon thrombosis of the aneurysm, the patient developed signs of severe brainstem ischemia and ultimately died. At autopsy, occlusion of perforating arteries that arose from the aneurysm sac was found to be the reason for the fatal outcome of endovascular therapy in this patient. Case Report

This 29-year-old man had a 6-month history of slowly progressive sixth nerve palsy and recent onset of rapidly progressive hearing loss on the left. CT showed a nearly spherical enhancing mass lesion measuring 2.5 × 2.7 cm in the left cerebellopontine angle. Cerebral angiography revealed the presence of a giant basilar aneurysm at the junction of the vertebral arteries (VA). The aneurysm opacified on injection of either VA, and had no definable neck (Fig. 1a). Super-selective digital angiography (DSA) with a Tracker microcatheter (Target Therapeutics, San Jose, CA) placed into the aneurysm did not show any perforating arteries arising from the aneurysm sac (Fig. 18). A team of neurosurgeons and neuroradiologists determined that the aneurysm was un-clippable. The hearing loss that had occurred during the preceding 3 weeks suggested growth of the aneurysm. It was thus decided to treat the aneurysm, if feasible, by bilateral VA occlusion via an endovascular approach. First, a test occlusion was done of both VAs distal to the origin of the posterior inferior cerebellar artery (PICA) while the patient was monitored continuously. Under local anesthesia, 9-French vascular sheaths (Terumo Corp., Tokyo) were placed in both femoral arteries. Following this, 5000 units of heparin was administered intravenously for systemic anticoagulation to prevent thrombus formation within the coaxial catheter system. After selective placement of an 8.0-French catheter into the proximal right VA, a 2.2-French microcatheter with a nondetachable silicone balloon (NDSB; lnterventional Therapeutics Corp., San Francisco) at its tip was advanced into the intracranial portion of the right VA distal to the PICA origin. Upon inflation of this balloon, contrast injection into the left VA via a second selectively placed 5-French catheter (Terumo Corp., Tokyo) revealed

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unchanged filling of the aneurysm. A second nondetachable balloon was then introduced into the left VA, again distal to the PICA origin. Test occlusion of the right VA for 45 min and then of both VAs for another 15 min was tolerated well by the patient; neurophysiologic monitoring did not reveal any changes indicative of subclinical ischemia of the brainstem. One week later, both VAs were permanently occluded under general anesthesia, while the patient was monitored continuously. Again, via a bifemoral approach, a detachable balloon (DSB; lnterventional Therapeutics Corp., San Francisco) was placed into the right VA distal to the PICA origin and the test occlusion was repeated by inflating the silicone balloon with nonionic contrast material (Omnipaque, Schering AG, Germany). During the ensuing 30 min all monitored neurophysiologic parameters remained unchanged. The balloon was then deflated, re-expanded with HEMA (3-hydroxyethyl methylacrylate; lnterventional Therapeutics Corp., San Francisco), and detached 60  min later. Up to this time no neurologic changes had occurred. A similar procedure was then performed on the left side. During this second test occlusion, a 5-French catheter was placed into the left internal carotid artery. Carotid angiography revealed good retrograde filling of the basilar artery. Because of this excellent collateral flow and unchanged evoked potentials, occlusion of the left VA was considered to be safe and the second balloon was detached 60 min after it was filled with HEMA. A final angiogram showed both vertebral arteries occluded, with excellent retrograde filling of the basilar artery (Fig. 1c). No protamin sulfate was given to reverse the action of heparin. The patient left the angiography suite in a stable condition. Eight hours later he suddenly became tetraplegic and was only able to make vertical eye movements. MR imaging on the first and third days (Fig. 1d and e) after the intervention revealed thrombosis of the aneurysm as well as ischemic infarction of the pons and medulla oblongata. Five days later, the patient died of sudden cardiac arrest. An autopsy with detailed anatomic examination of the vertebrobasilar system revealed complete thrombosis of the aneurysm. Neither balloon had changed position, and the basilar artery was patent. The left anterior interior cerebellar artery (AICA) and three pontine branches arose from the aneurysm sac and were completely thrombosed (Fig. 1f and g)

4.6 Cases

a

d

f

Graph. 4.28 (continued)

215 c

b

e

g

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4  Laboratory: Surgical Simulation and Training for MIN

Even in retrospect, we were unable to detect these arteries on the angiogram. Discussion

The accepted method of treating cerebral aneurysms is surgical clipping of the aneurysm neck. The direct surgical approach to giant aneurysms of the vertebrobasilar system is one of the most difficult operations to perform. Dandy’s experience of “the fastest death I have ever seen” [4] has additionally deterred many surgeons from treating giant vertebro-basilar aneurysms. Morbidity and mortality rates from 25% to over 50% have been reported in the literature [5, 6]. Endovascular techniques such as balloon occlusion may be a therapeutic alternative to surgery [3, 7–9]. Bilateral vertebral occlusion to initiate thrombosis within an aneurysm by eliminating the direct blood inflow and thereby changing the pressure and turbulence within the lumen was first recommended by Drake [5]. Pelz et al. [10] pointed out that before performing vertebral occlusion, it is necessary to show collateral blood flow to the brainstem via the posterior communicating arteries (PComA). These authors found strong trends indicating that patients with at least one large PComA do better than those with two small ones. Fox et al. [11] recommended a total test occlusion time of 15 min. In their study, eight of 67 patients did not tolerate the test occlusion, and signs of cerebral ischemia appeared between 30 s and 7 min after the occlusion. In our patient, progressive hearing loss was thought to indicate ongoing enlargement of the aneurysm, and the decision to apply endovascular techniques was made jointly by the neurosurgeons and the neuroradiologists. As recommended in the literature, we performed test occlusions demonstrating excellent retrograde filling of the basilar artery. In addition to clinical monitoring we were able to perform continuous neurophysiologic monitoring [12]. All parameters including somatosensory and acoustic evoked potentials remained unchanged during test occlusion. Despite this, the patient died from brainstem ischemia. Delayed death due to thrombosis of a giant aneurysm has been described before [2, 5], but as far as we know, the cause of such an event has never been explained. It has been speculated that the delayed ischemic complications are due to peripheral embolization from the aneurysm [2]. In our patient, autopsy revealed perforating arteries arising from the aneurysm-branches that subsequently thrombosed, leading to fatal brainstem ischemia. This observation provides important insights: super-­ selective DSA, even with the catheter tip inside the lesion, is not capable of demonstrating perforating arteries arising from the aneurysm sac; the microcatheter is probably not large enough to deliver an adequate volume of contrast material into a giant aneurysm. Even conventional cut-film magnification angiography never was totally reliable in showing the tiny perforating branches of the basilar artery. Thus, there is no radiologic technique capable of ruling out perforating arteries that arise from the aneurysm sac. Endo-vascular test occlusion or manual vascular compression to evaluate collateral blood flow (Allcock test) is only a diagnostic tool to determine hemodynamic tolerance of vessel occlusion. After changing the pressure within the aneurysm by endo-vascular techniques it may be useful to heparinize these patients to keep important arteries that arise from the aneurysm sac temporarily patent. This way, collateral channels have more time to establish themselves. In giant aneurysms in which it is unclear whether or not

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perforating arteries arise from the aneurysm sac, the first aim of the endovascular procedure should not be to achieve rapid thrombosis of the aneurysm but to reduce the jet stream pressure on the wall. On the other hand, it may be dangerous to change the jet stream by doing a staged occlusion-first one VA and later on the second-thereby raising the pressure on one point of the wall. One should also keep the patient anticoagulated tor a while, hoping to avoid delayed ischemic complications due to permanent endovascular occlusion. In our case, it probably would have been better if the VAs had been occluded below the PICA origin, allowing two good-sized vessels to maintain flow down the basilar artery. Thrombosis of the aneurysm would probably not have been as rapid nor as complete. Our rationale for occluding above the PICA origin was to protect the cerebellum from ischemia in case of extended thrombosis of the aneurysm. In conclusion, the clinical outcome of patients with giant aneurysms of the type described is unpredictable, regardless of the mode of treatment. If an endovascular approach is used even sophisticated monitoring techniques and tolerance tests cannot simulate all hemodynamic situations. A major problem is that such anatomic details as minute perforating arteries arising from the aneurysm itself are invisible on angio-grams. A first-look operation may help optimize the endovascular procedure in such cases.

d

e

Graph. 4.28 (continued)

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Perforators are best prognosed, analyzed and localized by intra-operative high-­ end ultrasound with a burr-hole probe and e-flow program (ALOKA/Hitachi), and a correct preset by the ultrasound-machine company. The clinical primate and priority of anatomical knowledge must be preserved to imaging, as this case finally shows. Whether perforators may exist originating from aneurysms or not, the origin of the left anterior spinal artery was obliterated by the vertebral balloon. The message, however, is to study and to memorize the perforator areas and their main branches. In the surgical simulation concept and in the MIN concept, such detail level is mandatory and must be reached during learning and training. The methodological basics limit any method and is limiting its´ validity and sensitivity. This must become a prerequisite before applying each imaging technique, and before deriving decisions from their results. Beside methods (standard in each paper), methodology must be aware always to be able doing correct decision-­ making (Resch 1990, doctoral thesis).

4.6 Cases

4.6.3.12 Case 12 a

b

Graph 4.29 (a–c) P1 Giant Aneurysm via Le-Fort I. (c) Median Perforators of Basilar Head

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This 55 year patient was admitted with a great SAH°3b to the ICU, and he had within 8 h, and after angiography (DSA) a sever rebleeding causing clinical signs of brain death. Angiography had shown a giant P1-aneurysm on the right side. MRI presented a very high possitioned aneurysm impressed into the interpeduncular cistern, compressing the mid-brain and causing a perifocal edema. Relatives refused organ donation as well as general obduction, but accepte to find out as much as possible about the brain. A neuro-cranial obduction finally was done (by the author), not limiting the examinations cranial during surgical simulation analysis. During this surgical simulation analysis and training, a Le-Fort I – approach was chosen, because all standard approaches like sub-temporal or pterional seemed not promizing to get meaningful results. A comprehensive overview, or even just a reaching of the neck, in this specific location was not belived to be successful. This is the point to remember, that the surgical simulation concept is not an usual laboratory work with an open end perspective, rather than being a tight schedule of time and ressources to get the analyzis and the training. It can be compared with an emergency situation which gives it an unique additional training characteristic. After sellar and retro-sellar resection of bone and dissection of pituitary gland within its dural cover from the cavernous sinus right sided, subarachnoidal blood-­ clot of the interpeduncular cistern was found first. With rinsing and suction the blood was evacuated and the whole basilar head became visible, while the aneurysm was nearly hidden in the depth. Ongoing blunt dissection discovered the broad aneurysm origin from the right P1 segment. The most important target was now visible and a clipping analysis followed. The surgical simulation analysis showed that this aneurysm was clipable through a Le-Fort I-approach and that it can be trained by this stup. Proximal control was easy given, as all major parent vessels were well presented. However, the perforators need to be known and respected, even in temporary clipping, and they must be aware and imagined always, as best shown in Yasargil Vol. 1, p. 147. Clipping is difficult and complex because a strong perforator originated close to the neck but from the aneurysmitself. Reconstruction by clip had to keep this vessel open. Only from the left, proximal side near basilar head, a clipp could be placed. But the dorsal branch of the clip had to be guided behind the neck and unvisibel. Clip control by mobilisation of the basilar artery made the median perforators visible in typical location, whatever DSA does see or not see (Graph 4.29c). The dorsal branch of the clip spared all perforators. Historically, aneurysm surgery became a success story when neurosurgeon understood how to preserve the perforators. However, this were times when angiography was abel to present the perforators. Today it is becoming sexy to operate on CTA information, and risking to fall in time consuming pitfalls. MIN absolutely needs all informations for planning and performing the one optimal procedure according to both, knowledge and imaging.

4.6 Cases

221

c

Graph. 4.29 (continued)

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4.6.3.13 Case 13 (Graph 4.30)

a

b

Graph 4.30 (a, b) Basilar Head Giant Aneurysm Trans-Palatal. (b) Clipping-Analysis and -Training

4.6 Cases

223

Case 13 was a 26 year man, admitted with a SAH°2b at ICU, very slightly slow mentally, with head-ache, meningism and nausea. MR presented a giant basilar-­ head aneurysm very high towards lateral ganglia and compressing the right peduncle of mid-brain, without perifocal edema. DSA showed that SUCA right originated from the aneurysm, and P1 right was bent over the aneurysm sack and pushed to the opposite side. The basilar trunk close to the aneurysm showed vasospasms. In this case a trans-palatal approachwas prefered, because of the very high lokation of the aneurysm and being less traumatic, leaving the maxilla in place. The gingiva of palatum is very thick and tuff, providing a strong material for safe closure. Moreover, the mucosal tubes of the nasal cavities are mor relaxt than in the Le-Fort approach an can be better spread to gain broad path-way to the spenoidal skull. So a palatal bone flap was created providing access to the septum which was resected. After bone resection of sellar window and retro-sellar window, and enlargement to the cavernous sinus window right, the dura was opened with deviding sella content from the cavernous sinus right. This gives view steep upwards towards the high basilar head which was blown-up to a thin walled chugh balloon. There was no neck recognizable, and reconstruction of a less blown-up basilar head was very challenging. The blood was only arround dome of the aneurysm in the depth of hypothalamus and interpeduncular cistern. Swelling of the brain-stem was, like always in trans-viscero-cranial approache, not a major problem. The proximal control was given by temporary clipping of the basila trunk lose to the origin of the both SUCA. The family of the young man refused a general obduction but accepted cranial obduction, invisible thereafter. So the brain was taken out (by the author) showing the majority of blood clot in the posterior fossa. The size and position of the approach could bestudied, however, the information and training-experience was only possible by surgical simulation concept. Again, as in the case 11 and 12, the brain was plastinated for future studies (see next Chap. 5).

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Summary and Conclusions (Graph 4.31) Training Spectrum of Imaging and Information Benefit for Nighbouring Disciplines

Neuroradiology Training Technique

Surgery

Surgical Simulation

Imaging

Visualization

Multipl.Visualization and Training

Obduction Technique

Pathology

Open aspect

Graph 4.31  Correlation of Neuro-Discipline with PMI

The surgical simulation concept interferes with other disciplines of the neuro-­ family, like neurosurgery/MIN, neuro-radiology and neuro-pathology. For surgery, it provides a unique trainings environment in surgical ergonomics, approach-analysis and approach-design, but also comparison to multiple approaches to the same site. It allows for haptic and manual learning, and visualization training and comparison in microscopy and endoscopy. Aspects, perspectives and viewing-­ angles are experienced in a very short and concentrated schedule. Use of all kinds of instruments and clip-systems as well as setup behavior and workflow can be examined and experienced. The problem of ergonomics for MIN becomes comprehensive. But also limits of techniques, instruments and approaches come into focus. Imaging used during surgery can be compared with results of PMI, and clip-­analysis as well as clipping-related complications can be recognized within the surgical context. Aspects and perspectives of alternative approaches, to the surgical one, can be studied, and future approaches and variants may be analyzed and compared. What did surgery not see related to imaging and approaching?

4.6 Cases

225

For neuro-radiology, CT-imaging will be confronted with visualization in pre-­ DSA cases and prediction of aneurysm site by SAH distribution studied. In post-­ DSA cases visualization and analysis can be compared to imaging. Did imaging reflect reality, and did lack of information impair surgery and cause bad outcomes? Did imaging recommend an alternative approach according to PMI analysis? Do new approaches need different imaging additional to that used at surgery? How is the correlation of imaging and reality in the present case? Was the optical resolution sufficient to decide the procedure? Did imaging represent the limits of information and contain the all information to plan and perform the procedure? Was the diagnostic information supplied by sufficient planning data? Surgery and neuro-radiological aspects and problems are a major issue of the surgical simulation concept and training. This will complete the mental library of imagin-analysis-clips and surgical procedures –clips to planning and perform the future cases more safely and being able to create plan b and c intra-operatively, if necessary. For neuro-pathology, PMI provides, in times of decreasing obductions, aminimally invasive technique, which is characterized with a high acceptance by relatives of the patient. Moreover, the findings will be shown additionally within the context of surgical problems, providing new aspects and perspectives to clarify the cases and their outcomes. Clarification of outcome and cause of death can be enabled with regard to surgical problems and context. Endoscopic obduction is a promising future pathway for pathology to stay update to the clinical needs and being of impact in the clinical communication flow. With the surgical simulation concept, pathological findings will be presented which will be not recognized by the classical technique and which will provide an explanation for the cause of death. For the involved neuro-disciplines, surgical simulation concept will promote and activate the interaction and cooperation, working out the findings and the knowledge to the level of understanding and meaning. This guaranties the availability and applicability of such knowledge for the future patients, which is the goal and meaning of all these efforts (Graph 4.32).

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Graph 4.32  Simulation Concept and Communication on Consent

Training-concept and training-environment is one of the keys for a future generation of MIN-surgeons. The surgical simulation concept provides for training and education the most effective setup and setting, and to reach all abilities and skillsin all key-techniques for MIN. The main problem will be to accept and understand this concept and to run laboratories in all big clinics for regular options, and to estaplish a new culture of real clinical anatomy. Moreover, the concept to training in non-fixed specimen, and to take over the field of endoscopic neuro-pathology is a matter of informed consent. Several members of the neuro-family should have aninteress to vitalize the cooperation and networking, and to form an interdisciplinary and interactiv generation of trainees. Communication and wide multilevel perspective will be the secret of success. This would enable to come again to a overview and orientation of former times without loosing high level of specialtry. We have toperform our own brains before we approache those of our patients (Graph 4.33).

4.6 Cases

227

Graph 4.33  Interactive Fields of Ergonomics Paradigms

In the surgical simulation concept, the intensive interaction between the ergonomics paradigms of surgical environment, work-flow and procedural chaos-­ principles and mental conditions of neuro-psychological functions can be experienced and studied. It can be directly and in-avoidable, if not painful, comprehended, that this system of conditions is the guid-line of training and development. The function within one paradigm influences that of the other two. OR environment parameters influences the procedural parameters like work-flow, and both interfer the mental and neuro-psychological parameters of the surgeon. These inter-relations of the three ergonomics fields define finally what is functioning and how. Prepairness and preparation and reddyness of all components in this chaotic system have a major impact on the outcom of the surgery. For MIN, these conditions must be understood and managed, to make MIN working, because MIN is mostly and best awarded by optimal results, if these parameters are known and implemented in training and education of futur MIN surgeons. The surgical simulation concept should promote setups that come as close as possible to these condition (Graph 4.34).

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Convergence and Synchronisation 8 y z

y z

x HMD

x

Endoscop

y z

ENS

Anatomy Patient

x

z

y z

Hand Coordinati

x Instrument Foot-Coordination Bipolar etc.

MIN Surgeon

Intuitive Interactive CoordinateSystem

Graph 4.34  Multiple interactive coordinate-systems

4.6 Cases

229

Training means to form the brain of the trainee, not just to follow a schedule. In the brain of the MIN surgeon, a synchronization and convergence of all virtual coordinate-systems is worked out and reliably confirmed to be applicable whenever necessary. The MIN surgeon can be compared with an artist, like a solo-musician (Graph 4.35). Graph 4.35 Endoscopyassisted technique with Zoom-Endoscope-Model

EndoscopyAssisted Microsurgery (Exoscopy)

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The main concept, regarding technique and equipment, is endoscopy-assisted microsurgery. 3D-endoscopy and zooming endoscopes as well as Olympus Exoscope were not introduced to neurosurgery as standards. Meanwhile the exoscope-­concept was followed by Med.-Industry (see Vol. 1, Chap. 4). These developments and evolutions must be integrated in future setups to have an updated training environment. It is not wise to equip the MIN training laboratory with bad or old technique. Prototypes use and cooperation with the industry is important and of benefit for all. One will discover, that the surgical simulation concept is an excellent and reliable testing environment for new equipment. (the author used this concept for 30 years to perform innovations)

4.7

Final Reflections on Training for MIN (Graph 4.36)

Graph 4.36  Evolution of training environment for MIN

4.7 Final Reflections on Training for MIN

231

The surgical simulation concept underwent an evolution during time of application to adapt to recent evolutions in surgery, or to be in front, testing new concepts or new equipment, and leading the developments in cooperation with the industry. Gestalt-anatomy, providing neurosurgery with approach-analysis and -design, followed by post-mortal analysis of aneurysm series, proceeding to endoscopy and endoscopic aneurysm project, then to endoscopy assisted (par-endoscopic) dissecting technique, and finally developed to surgical simulation concept with focus on ergonomics for MIN. For the future, the MIN environment with focus on simplification, miniaturization and modularize in single rack concepts was preferred, and became a priority. For the emergent ergonomics orbits (green, yellow, orange and red) in the Ergo-­ Suit the focus was directed toward the ergonomically most sensitive orbits orange and red to keep them free of disturbance by the concept of Wireless Support OR and placing equipment in the yellow and green orbit. To reach this goal, the key-­ hole concept had to change to the MIN Key Concept, asking for the keys of MIN (s. Vol. 1, Chaps. 3 and 4) (Graph 4.37). Graph 4.37  The ERGO SUIT (Heide Roesler 2010)

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New designs, equipment and techniques should be tested and trained in a near-­ reality environment before used in the OR and applied on the patients. The blue-­ print is the surgeon’s brain! Everything what happens in the patient’s brain during surgery before happens in the surgeon’s brain. Visions and controlling technique should occur in the surgeon’s brain, finally, before they become reality. Without visions and controlling the evolution of technique, one should not be eager to be involved in innovation. Usual standard-trials and standard-thinking will not add anything to innovation. Technical evolution must be adapted to the needs of the surgeon’s brain. Technique and logos are contradictions and the word-artifact “technology” is just a label but not true. The logos must control, not the technique. The narrative “technology” is a wrong framing to our mind. These field of meanings can be experienced in the surgical simulation concept, a key issue of MIN. The Hippocratic Imperative starts here! Strong concepts do survive without impairment of truth and science! (in contrast to Corona-Management)

References

233

References Abound E, Al-Mefty O, Yasargil MG. New laboratory model for neurosurgical training that simulates live surgery. J Neurosurg. 2002;97:1367–72. Apuzzo MLJ. Neurosurgery for the third millennium. AANS, USA; 1992. pp. 11–23. Ascher PW. Tumors on and in the pons and medulla oblongata. In: Downing EF, et al., editors. Laser in neurosurgery. Vienna: Springer; 1989. p. 69–93. Auth DC.  Fundamentals of lasers for endoscopy and laser tissue interactions. In: Jensen DM, Brunetaud J-M, editors. Medical laser endoscopy. Dordrecht: Kluwer; 1990. p. 1–16. Black P, Moriarty T, Alexander E III, Stieg P, Woodard EJ, Gleason L, Martin CH, Kikinis R, Schwarz RB, Jolesz FA.  Development and implementation of intraoperative magnetic resonance imaging and its neurosurgical application. Neurosurgery. 1997;41:831–45. Bonelli J. Der Status des Hirntoten. Vienna: Springer; 1995. p. IX. Cappabianca P, Alfieri A, de Divitiis E. Endoscopic endonasal transsphenoidal approach to the sella: towards functional endoscopic pituitary surgery. Minim Invasive Neurosurg. 1998;41:66–73. Cappabianca P, Alfieri A, Colao A, Ferone D, Lombardi G, de Divitis E. Endoscopic endonasal transsphenoidal approach: an additional reason in support of surgery in the management of pituitary lesions. Skull Base Surg. 1999;9:109–16. Chandler WF. Comment on: Paleologos TS, Wadley JP, Kitchen ND, Thomas GGT: clinical utility and cost-effectiveness of intracranial imageguided craniotomy: clinical comparison between conventional and image-guided meningeoma surgery. Neurosurgery. 2000;47:40–8. Cooper LA, Shepard RN. Rotation in der räumlichen Vorstellung. In: Ritter M, editor. Wahrnehmung und visuelles System. Heidelberg: Spektrum der Wissenschaft; 1987. p. 122–31. Cristante L. A set of coaxial microsurgical instruments. Neurosurgery. 2000;45:1492–4. Doerr W. Rechtliche Grundlagen der Obduction aus der Sicht des Pathologen. In: Doerr W, Jacob W, Laufs A, editors. Recht und Ethik in der Medizin. Wiesbaden: Steiner; 1984a. p. 126–39. Doerr W. Gestalt theory and morbid anatomy. Virchows Arch. 1984b;403:103–15. Dujovny M, Gundamraj NR, Misra M, Alp MS.  Aneurysm clips. Crit Rev Neurosurg. 1997;7:169–75. EC/IC Bypass Study Group. Failure of extra-intracranial arterial bypass to reduce the risk of ischemic stroke: result of an international randomized trial. N Engl J Med. 1985;313:1191–200. Edelmann GM.  Göttliche Luft, vernichtendes Feuer. Wie der Geist im Gehirn entsteht. Piper Munich; 1992. pp. 19–359. Eser A, von Lutterotti M, Sporken P.  Lexikon Medizin Ethik Recht. Freiburg: Herder; 1989. pp. 1011–1021, 1155–1159, 1173–1206. Feldenkrais M. Bewußtheit durch Bewegung. Frankfurt; Suhrkamp; 1968. pp. 19–83. Frank EH, Horgan M. An endoscopic aneurysma clip applicator: preliminary development. Minim Invasive Neurosurg. 1999;42:89–91. Goertz L, Müller A. First experiences with virtual reality-result of a group discussion with new users. In: Virtual Reality World 95:303–306, Fraunhofer Institute, Stuttgart; 1995. Haase J. Image-guided neurosurgery /neuronavigation/surgiscope-reflections on a theme. Minim Invasive Neurosurg. 1999;42:53–9. Hoff F.  Kritische Betrachtungen zu Grundproblemen der Krankheitslehre. In: Von ärztlichem Denken und Handeln. Stuttgart: Thieme; 1955. p. 5–36. Hopf NJ, Grunert P, Fries G, Resch KDM, Perneczky A.  Endoscopicthird ventriculoscopy. Neurosurgery. 1999;44:795–806. Jendrysiak U, Resch KDM. Ergebnisse der klinischen Erprobung der Operationszugangsplanung mit NeurOPS.  In: Bildverarbeitung für die Medizin. Algorithmen-Systeme-Anwender. Heidelberg: Springer; 1999. p. 187–91. Jho H-D, Carrau RL. Endoscopic endonasal transsphenoidal surgery: experience with 50 patients. J Neurosurg. 1997;87:44–51. Jho H-D, Carrau RL, Ko Y, Daly MA.  Endoscopic pituitary surgery: an early experience. Surg Neurol. 1996;47:213–23.

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Kaufmann HH, Wiegand RL, Tunick RH. Teaching surgeons to operate—principles of psychomotor skills training. Acta Neurochir. 1987;87:1–7. Kelly PJ. Comment on: Paleologos TS, Wadley JP, Kitchen ND, Thomas GGT: clinical utility and cost-effectiveness of intracranial image-guided craniotomy: clinical comparison between conventional and image-guided meningeoma surgery. Neurosurgery. 2000;47:40–8. Kikinis R, Gleason L, Moriarty TM, Moore MR, Alexanader E III, Stieg PE, Matsumae M, Lorensen WE, Cline HE, Black PM, Jolesz FA. Computer-assisted interactive three-­dimensional planning for neurosurgical procedures. Neurosurgery. 1996;38:640–51. Knoll M.  Microsensors. In: Wickham J (ed) Minimally invasive therapy 3. Medtech 1994;94[Suppl 1]:16. Kockro RA, Serra L, Tseng-Tsai Y, et al. Planning and simulation of neurosurgery in a virtual reality environment. Neurosurgery. 2000;46:118–37. Kriz W. Die Bedeutung der Anatomie in Forschung und Lehre. In: Bauer A, editor. Theorie der Medizin. Dialog zwischen Grundlagenfächern und Klinik. Heidelberg: Barth; 1995. p. 60–9. Kübler-Ross E. Über den Tod und das Leben danach. Güllesheim: Silberschnur; 1984. Kuhn TS.  Die Struktur wissenschaftlicher Revolutionen. Frankfurt am Main: Eighthedn. Surkamp; 1988. Lang J. Klinische Anatomie des Kopfes. Berlin: Springer; 1981. Linke DB. Das Gehirn. Munich: Beck; 1999. pp. 7–36. Liu CY, Apuzzo MLJ. The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part I: prehistory to 2003. Neurosurgery. 2003;52:3–19. Liu CY, Spicer M, Apuzzo MLJ.  The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part II: concepts for future development, 2003 and beyond. Neurosurgery. 2003;52:20–35. Lurija AR. Das Gehirn in Aktion, Einführung in die Neuropsychologie. Hamburg: Rowohlt; 1973. p. 230–58. Maciunas RJ. Interactive image-guided neurosurgery. AANS, USA; 1994. pp. 3–8. Maciunas RJ. Comment on: Paleologos TS, Wadley JP, Kitchen ND, Thomas GGT: clinical utility and cost-effectiveness of intracranial imageguided craniotomy: clinical comparison between conventional and image-guided meningeoma surgery. Neurosurgery. 2000;47:40–8. McDonald JM.  Mental Readyness and its links to perform excellence in surgery. Ottawa: Kinetek; 1992. Mueller G.  Microsensors. In: Wickham J (ed) Minimally invasive therapy 3. Medtech 1994;94[Suppl 1]. Müller A, Hatfield ARW.  Miniature endoscopic ultrasound. In: Lees WR, Lyons EA, editors. Invasive ultrasound. London: Dunitz; 1996. p. 235–42. Nievas MNC, Höllerhage HG. Risk of intraoperative aneurysm clip slippage: a new experience with titanium clips. J Neurosurg. 2000;92:478–80. Oka K, Go Y, Yamamoto M, Kumate S, Tomonaga M. Experience with an ultrasonic aspirator in neuroendoscopy. Minim Invasive Neurosurg. 1999;42:32–4. Paleologos TS, Wadley JP, Kitchen ND, Thomas GGT. Clinical utility and cost-effectiveness of intracranial image-guided craniotomy: clinical comparison between conventional and image-­ guided meningeoma surgery. Neurosurgery. 2000;47:40–8. Perneczky A.  Planning strategies for the suprasellar region-philosophy of approaches. Neurosurgeons. 1992;11:343–8. Perneczky A, Fries G. Use of a new aneurysm clip with an inverted-spring mechanism to facilitate visual control during clip application. J Neurosurgery. 1995;82:898–9. Perneczky A, Fries G. Endoscope-assisted brain surgery: evolution, basic concepts, and current technique. Neurosurgery. 1998;42:219–25. Perneczky A, Müller-Forell W, van Lindert E, et al. Keyhole concept in neurosurgery. Stuttgart: Thieme; 1999. Poggio T. Wie Computer und Menschen sehen. In: Ritter M, editor. Wahrnehmung und visuelles System. Heidelberg: Spektrum der Wissenschaft; 1987. p. 78–89.

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Regan D, Beverly K, Cynader M. Die Wahrnehmung von Bewegungen im Raum. In: Ritter M, editor. Wahrnehmung und visuelles System. Heidelberg: Spektrum der Wissenschaft; 1987. p. 90–103. Resch KDM. Beitrag zur Zugangsanalyse und zum Zugangsdesign des transoral-­transpharyngealen Weges zum Hirnstamm. Dissertation, University of Heidelberg; 1991. Resch KDM. MIN: transoral transpharyngeal approach to the brain. Neurosurg Rev. 1999;22:2–25. Resch KDM.  Endo-neuro-sonography: first clinical series (52 cases). Childs Nerv Syst. 2003;19(3):137–44. https://doi.org/10.1007/s00381-­003-­0717-­1. Resch KDM, Bohl J, Perneczky A.  Postmortal inspection, a new pathoanatomic method. Clin Neuropathol. 1992;11:191. Resch KDM, Bohl J, Perneczky A. Endoscopy to the basilar artery: anatomical and pathological aspects. Clin Neuropathol. 1993;12:263. Resch KDM, Perneczky A, Schwarz M, Voth D. Endo-neuro-sonography: principles and 3-D technique. Childs Nerv Syst. 1997a;13:616–21. Resch KDM, Atzor K, Perneczky A. Anatomical phantom CT-study of surgical approaches for 3-D and VR in neurosurgery. Min Invas Ther Allied Technol. 1997b;6:228–34. Reulen HJ, Steiger HJ. Training in neurosurgery. Acta Neurochir Suppl. 1997;69:58–82. Riede UN. Die Macht des Abnormen als Wurzel der Kultur. Stuttgart: Thieme; 1995. Roth G. Das Gehirn und seine Wirklichkeit. Frankfurt am Main: Suhrkamp; 1999. p. 258–311. Sacks O. Der Tag an dem mein Bein fortging. Reinbek bei Hamburg: Rowohlt; 1989. p. 205–22. Sampath P, Long DM, Brem H.  The Hunterian neurosurgical laboratory: the first 100 years of neurosurgical research. Neurosurgery. 2000;46:184–95. Schaller C, Zentner J. Vasospastic reactions in response to the transsylvian approach. Surg Neurol. 1998;49:170–5. Schaller C, Klemm E, Haun D, Schramm J, Meyer B. The transsylvian approach is “minimally invasive” but not “atraumatic”. Neurosurgery. 2002;51:971–6. Schmidt RH. Use of a microvascular Doppler probe to avoid basilar artery injury during endoscopic third ventriculostomy. J Neurosurg. 1999;90:156–9. Seeger W.  Atlas of topographical anatomy of the brain and surrounding structures. Vienna: Springer; 1978. Seeger W. Planning strategies of intracranial microsurgery. Vienna: Springer; 1986. Shekhar LN. Comment on: Paleologos TS, Wadley JP, Kitchen ND, Thomas GGT: Clinical utility and cost-effectiveness of intracranial image-guided craniotomy: clinical comparision between conventional and image-guided meningeoma surgery. Neurosurgery. n.d.;47:40–8. Tandler J. Lehrbuch der systematischen Anatomie, vol. Band 4. Leipzig: Vogel; 1929. Taniguchi M, Takimoto H, Yoshimine T, Shimada N, Miyao Y, Hirata M, Maruno M, Kato A, Kohmura E, Hayakawa T. Application of rigid endoscope to the microsurgical management of 54 cerebral aneurysms: results in 48 patients. J Neurosurg. 1999;91:231–7. Tulleken CAF.  The profile of a manually skilled vascular neurosurgeon. Eleventh European Congress of Neurological Surgery; 1999. p. 1. Türe U, Yasargil MG, Friedmann AH, Al-Mefty O. Fiber dissection technique: lateral aspect of the brain. Neurosurgery. 2000;47:417–27. Ulrich P, Perneczky A, Muacevic A.  Operative Strategie in Fällen von multiplenAneurysmen. Zentralbl Neurochir. 1997;58:163–70. Wallach H. Wahrgenommene Stabilität der Umgebung und Eigenbewegung. In: Ritter M, editor. Wahrnehmung und visuelles System. Heidelberg: Spektrum der Wissenschaft; 1987. p. 114–21. Weinberg R. Future direction in neurosurgery visualization. In: Apuzzo MLJ, editor. Neurosurgery for the third millennium. USA: AANS; 1992. p. 47–64. Weizäcker VV. Der Gestaltkreis. Stuttgart: Thieme; 1950. Witt H, Kozianka J, Waleczek H, et  al. Das Erlernen und Optimieren minimal-invasiver Operationsverfahren am menschlichen Leichnam. Chirurg. 1999;70:923–8. Yasargil MG. Microsurgery applied to neurosurgery. Stuttgart: Thieme; 1969. Yasargil MG. Hugo Krayenbühl. Acta Neurosurgica. 1985;76:1.

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Yasargil MG.  Microneurosurgery IV a CNS tumors: surgical anatomy, neuropathology, neuroradiology, neurophysiology, clinical considerations, operability, treatment options. Stuttgart: Thieme; 1994. Yasargil MG.  Microneurosurgery IV B, microneurosurgery of CNS tumors. Stuttgart: Thieme; 1996. p. 116–91. Yasargil MG. A legacy of microneurosurgery: memoirs, lessons, and axioms.

Suggested Reading Schröder R.  Virtual Reality im Unterricht: eine sozialwissenschaftliche Erörterung. In: Virtual reality, vol. 93. Berlin: Springer; 1993. p. 101–13.

5

The Role of Plastination for Research, Planning Strategies, Surgical Simulation and Training for MIN

5.1

History

The Story began for the author in 1979 at University of Heidelberg in the anatomy laboratory of Prof. Dr. Gunther v. Hagens (Fig. 5.1).

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_5

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a

Acryl-Embedding Head

b

Hemisphere

c

Sample of Acryl Embedding Specimen

Fig. 5.1 (a–c) Acryl-Embedding Head. (b) Hemisphere. (c) Sample of Acryl Embedding Specimen Since 1977 it was the author’s wish to have original anatomical models to intensively study real and precise anatomy. After watching and documenting over 1000 operations in all organs, providing a living anatomy, it was clear that this wonderful world of living anatomy would require an extremely effort to become comprehensible. Desperately seeking a way to preserve perishable materials in acryl glass, these results were beautiful but far away from sufficient to unfold the secrets of the morphological organization of the body and especially the brain. How to synthesize after analysis, and how to preserve the imagination after dissection? These questions were answered by getting to know Prof. Dr. Gunther von Hagens and his Science and Art of Plastination. My technique could only preserve the surface of the organ, with insufficient impregnation of the plastic in the depth of tissue. Only small specimens without color injected vessels, were utilized.

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239

The lack of anatomical educate for contemporary surgery, and the solution to this deficit, is described above in Chaps. 3 and 4. The preservation method of this knowledge, is an easy available, dry, precise and beautiful tool, which will be described in more detail in this chapter, the role of Plastination for MIN. Since ancient times and especially in old Egypt, it was the wish of mankind to preserve perishable matter. Psychologically and neuro-psychologically, the preservation of the body was identical with the preservation of eternal life. This also became a fundamental component of ancient religions. Philosophy changed this by creating the entity of the soul and mind, which was integrated in the mono-theistic religions. Actually, this discussion is pushed to the fields of bio-physics and quantum-­physics, where the difference between the material and the psychological does not exist. In medicine, however, still the body and anatomy form the house of medicine. But what is the role of Plastination in this context and for MIN? (Fig. 5.2). a

b

c

Fig. 5.2 (a–c) Plastination Laboratory University of Heidelberg 1979 For the author, it was a breakthrough-event in autumn 1979 to enter the Plastination-Laboratory and find the first organ-plastinations and slice-plastinations of the brain. It was the solution to the problem for preserving of whole organs but evolved tremendously in the following four decades.

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As much as possible during his medical education and training, and during the professional career, the author remained involved in Plastination as a user in its scientific application of clinical use. These multiple and enduring applications of Plastination have become a most valuable tool for MIN in planning surgery, research and education. a

c

b

d

Fig. 5.3  Prof. Dr. G.v. Hagens (a); 5. Plast.Conference/Heidelberg 1990 (b); 3. Plast. Conference/ San Antonio USA; 7. Plast. Conference/Graz Austria

5.1 History

241

A BRIEF CHRONOLOGY OF INTERNATIONAL HAPPENINGS IN PLASTINATION By Harmon Bickley, Ph.D. (1930–2001) Founder of the International Society for Plastination (Executive Director from 1986 to 1995) published in J. Int. Soc. Plastination, 9(1): 11–12, 1995 Many of us attending this meeting have been plastinating for some time now, so it might be interesting to briefly glance back and see how far we’ve come. Note that I am not dignifying this report by calling it a history. The history of international plastination is an important story that needs telling, but it will take far more effort and space than we are using here. Let’s begin with what we are calling (in retrospect) the “First International Conference on Plastination.” 1. The “First International Conference on Plastination” was actually entitled “Preservation of Biological Materials by Plastination.” It was convened in San Antonio, Texas, USA on Friday, April 16, 1982 and lasted only 1 day. Eighty people were registered, all from the United States. It wasn’t very formal, and it really wasn’t international. But we’re counting it anyway. 2. The “Second International Conference on Plastination” was held in San Francisco during April of 1984. It seems that it was hardly more formal than the first, since my files contain no examples of brochures or other mailings. As I remember, the attendance was close to 1 00 and even included some from outside the U.S.  The need for this kind of conference expressed by those in attendance encouraged us to do a better job on the next one. 3. The “Third International Conference on Plastination” was held in San Antonio, April 21–25, 1986. It was publicized widely in both North America and Europe; therefore, we anticipated a strong response. As a result, attendance was excellent, and the meeting finally began to take on an international character. With this conference, the current 5-day format was adopted: 2 days of lectures dealing with the principles of plastination, 1 day of informal gatherings, and 2 days of papers relating to advanced topics. It was at this meeting that the International Society for Plastination was founded and plans were made for publication of the journal. Volume 1, Number 1 of the Journal of the International Society for Plastination was released in January of 1987and contained many of the papers presented at this meeting Fig. 5.3b. 4. The “Fourth International Conference on Plastination” was held at Mercer University School of Medicine, Macon, Georgia, USA, March 21–25, 1988, again employing the current 5-day format. Judging from both attendance and comments, it was a resounding success.

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5. The “Fifth International Conference on Plastination” was one of the highlights of our brief history. It was particularly significant since it was held in Heidelberg, the “Birthplace of Plastination.” The dates were July 22–27, 1990, a change from the usual springtime interval. It was well publicized throughout the world and attendance was the best ever. 6. The “Sixth International Conference on Plastination” was held at Kingston, Ontario, Canada in 1992. Again, July dates were used since this seemed to accommodate those of us who had teaching duties. The meeting was thoroughly enjoyable and introduced many new people to plastination. 7. And here we are at Graz for the “Seventh International Conference on Plastination in 1994.” We couldn’t have chosen a nicer place to meet, so this is bound to be just another great meeting. Interim meetings (those held during the off-year intervening the International Conferences) popped up quite spontaneously. The initiative for holding them was provided by members who wanted an opportunity to serve as a host. They have been held at a number of interesting places such as Knoxville, Tennessee, Rancho Cucamonga, California, and Mobile, Alabama, all in the United States Fig. 5.3d. Although not advertised as international meetings, they have gradually become quite international in composition. They tend to emphasize the “hands-on” rather than the didactic approach.

Previous international conference 1982

First International Conference on Plastination—University of Texas Health Science Center, San Antonio, Texas, USA, April 1982

1984

Second International Conference on Plastination—University of Texas Health Science Center, San Antonio, Texas, USA, April 1984

1986

Third International Conference on Plastination—University of Texas Health Science Center, San Antonio, Texas, USA, April 1986

1988

Fourth International Conference on Plastination—Mercer University School of Medicine Macon, Georgia, USA, March 1988

5.1 History

243 1990

Fifth International Conference on Plastination—Faculty of Medicine University of Heidelberg, Heidelberg, Germany, July 1990

1992

Sixth International Conference on Plastination—Department of Pathology, Queen’s University, Kingston, Canada, July 1992

1994

Seventh International Conference on Plastination—Anatomisches Institute, Karl-­Franzens-­University, Graz, Austria, July 1994

1996

Eighth International Conference on Plastination—Division of Radiology, Master Misericordiae Hospital, University of Queensland, Brisbane, Australia, July 1996

1998

Ninth International Conference on Plastination—Departement du Chimie-biologie, Universite du Quebec, Trois-Rivieres, Quebec, Canada, July 1998

2000

Tenth International Conference on Plastination—Faculte de Medecine Jacques Lisfranc, Jean Monnet University, St. Etienne, France, July 2000

2002

Eleventh International Conference on Plastination—Medical Sciences, San Juan, Puerto Rico. July 2002

2004

Twelfth International Conference on Plastination—Departamento de Anatomia y Embryologia, Facultad de Veterinaria, Universidad de Murcia Spain, July 2004

2006

Thirteenth International Conference on Plastination—Anatomical Institute, Medical University of Vienna, Vienna, Austria, July 2006

2008

Fourteenth International Conference on Plastination—Heidelberg and Guben, Germany, July 2008

2010

Fifteenth International Conference on Plastination—Joint Meeting AACA—University of Hawaii, College of Medicine, Hawaii, USA, July 2010

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Sixteenth International Conference on Plastination—Beijing and Dalian, China, July 2012

2014

Seventeenth International Conference on Plastination—Saint Petersburg, Russia, July 2014

2016

Eighteen International Conference on Plastination—Toledo, Ohio, USA, June 2016

2018

Nineteen International Conference on Plastination—Dalian, China, July 2018

Fig. 5.4  Lecture with Plastinates at Dept. of Neurosurgery Univ. Vienna

After a presentation in the third International Conference on Plastination in San Antonio, Texas in the USA in 1986, the scientific and educational application started soon in Vienna 1986 and continued for a further 30 years. Participation at the fifth (1990) and seventh (1994) conferences in Heidelberg and Graz followed. From then, the application and supporting the field of MIN by plastinates, was my privilege, and are described below (Fig. 5.4).

5.2 Technique of Plastination

5.2

245

Technique of Plastination (Graphs 5.1, 5.2, 5.3, and 5.4)

Plastination is a process designed to preserve the body for educational and instructional purposes in a more detailed way than ever before. Plastinates are dry, odourless, durable and are particularly valuable educational tools not only for medical professionals but also for the broader public. The process itself is relatively simple:

5.2.1 Fixation & Anatomical Dissection The first step of Plastination is fixation. Formaldehyde or other preservation solutions are pumped through the arteries to kill all bacteria and to prevent the decomposition of the tissues. This process takes about 3–4 h. After that dissection starts. Skin, fatty and connective tissues are removed in order to prepare the individual anatomical structures and elements. According to the complexity of specimens, dissection can take between 500 and 1000 h of labour. During evolution of Plastination, this step became a paradigm change, because attractivity and beauty as well as scientific anatomical value, depend greatly on this step. Therefore, the art of plastination depends on the quality and design of preparation. This art was already recognized by Leonardo da Vinci, because most of the body is hidden and must be unfolded by a meaningful concept.

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Formalin Injection Pump

Graphs 5.1–5.4  Technique of Plastination

5.2.2 Removal of Body Fat and Water When the necessary dissection is completed, the actual process of Plastination begins. In the first step, the water and soluble fats are dissolved from the body in a bath of acetone. Under freezing conditions, the acetone draws out all the water and replaces it inside the cells.

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Aceton Bath

5.2.3 Forced Impregnation The third step is the central phase of the Plastination process, forced impregnation. Here the specimen is placed in a bath of liquid polymer, such as silicone rubber, polyester or epoxy resin. By creating a vacuum, the acetone boils at a low temperature. As the acetone vaporizes and leaves the cells, it draws in the liquid polymer in allowing the polymer to penetrate every last cell. This process lasts 2–5 weeks.

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vacuum chamber with liquid resin Vakuumpump

vacuum pump

Vakuum

Silicon impregnation Into tissue and cells Aceton is boiled out of tissue and cells by vacuum

5.2.4 Positioning After vacuum impregnation, the body is still flexible and can be positioned as desired. Every single anatomical structure is properly aligned and fixed with the aid of wires, needles, clamps, and foam blocks. Positioning requires a lot of anatomical knowledge and a defined sense of aesthetics. This step can take weeks or even months. Together with step one, positioning creates the most attractivity of the plastinate and this concept was first used in anatomy by Andreas Vesalius.

5.3 Concept of Plastination

249

5.2.5 Curing (Hardening) In the final step, the specimen is hardened. Depending on the polymer used, this is done with gas, light, or heat. Curing protects the plastinate against decomposition and decay. Dissection and Plastination of an entire body require about 1500 working hours and normally takes approximately 1 year to complete. This short description on the process of Plastination may provide a simplistic idea about the art of this technique to preserve biological specimens in an un-­ precedented quality, durability and beauty.

5.3

Concept of Plastination

The concepts of Plastination had a steep evolution over the three decades. The author had the privilege to use it for clinical anatomy and within MIN.

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The invention itself, and the results and quality of preservation of perishable matter, is a scientifically outstanding result for anatomy and a new level of performing anatomy. However, this could only become comprehensive, when the Plastinates began to “speak” and telling meaningful stories. This invention tells more about life than about death! Since the speaking Plastinates were presented in a communicative exhibition concept of great educational value and attraction, Plastination began to be fascinating and became the innovation of “BodyWorlds”. The most devasting experiences the author had in his clinical career was repeatedly encountering how little people and patients know about life and their own body. This is one of the striking origins of misusing the body and causing illness, to learn or to perish. The overwhelming creativity within the evolution of Plastination and presentation formats gives Plastination the proximity to art. Never in mankind’s history has the morphology of the body been preserved so closely to life and with such a convincing beauty. The art of nature itself seems to speak to us, recognizable within the first glance. However, starting to analyze each specimen, especially the whole-body compositions, it becomes clear, that this is science in its classical meaning: to make reality comprehensive. To see is to understand! (Leonardo da Vinci) (Fig. 5.5).

Fig. 5.5  Plastinate (G.v. Hagens)

5.4 Scientific Meaning of Plastination

5.4

251

Scientific Meaning of Plastination

Much has been written and said about Plastination, however, in the shadow of exhibition activities like “Body Worlds”, and their recognition world-wide, the scientific meaning of Plastination was not seen and communicated sufficiently. There are five scientific fields where Plastination delivered contributions of great impact: Plastinates are an Innovation-Tool! 1. Plastination is an evolution step in thanatology. The art and science of how to handle dead bodies is largely forgotten. It has come out of focus in society and is falling back to taboo. Forensic- and general pathology has decreased in recognition for decades and the anatomy culture in the clinical fields has decreased also. There is a tendency to believe, that this can be substituted by digital techniques, which is nonsense (see Chap. 3). The less is known of thanatology, the faster do irrational critics raise against Plastination. The scientific value in such a critical situation, loosing thanatology, at least for medical education, is extraordinarily high. But the recent “crisis of corona” is teaching, that without a professional management of the victims (dead bodies), irrationalism will steer the process. Meeting the dead body of our own patients is an indispensable culture of informative behavior and morality. Thanatology is a strict ethical guideline in medicine and should be open for an informed society also (Fig. 5.6). Fig. 5.6  The Death (Plastinate; G.V. Hagens)

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For the author it was most disappointing to see, that colleagues, getting the results of their operations analysed pathologically and in a surgical simulation setup (s. Chap. 4), did not make up them self to have an easy look on these results, in no single case! These are the alarming signs and the pitfalls that can be observed in the daily routine. The absolutely miracle of the human body is not solved. Plastination confronts and invites us to see and understand this miracle and represents the highest standard of morphological thanatology ever seen in history (Fig. 5.7).

Fig. 5.7  Plastinate Greizer Body Worlds 2020 (G.v. Hagens)

5.4 Scientific Meaning of Plastination

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2. Plastination permits the highest precision preservation of morphology that can be used even for light microscopy and for electron microscopy. Grondin et al. examined this in spleen- and pancreas-specimens and found subcellular structures patent (Biotechnic & Histochemistry, Vol. 69, 1994, Issue 4). The authors pointed out, that this would allow, even retrospectively to answer forensic questions. Von Hagens et al. reported already in 1987 of the possibility to use plastinated specimens for light microscopy. (Anatomy & Embryology 175, 411–421) (Fig. 5.8).

a

c

b

d

Fig. 5.8 (a–d) Histology: Inner Ear, Eye (K.  Tiedemann). Spinal Cord, Med.-sagittal Slice Cranial Base

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3. Plastination is an analogous storage medium of biological material. In times of digital storage, it is important to recognize such an analogous storage technique of an unprecedented quality. The storage of real biological matter is, in our times, of outstanding meaning to preserve information which is not coverable by digital means. This is true for all kind of qualitative information, which is in principle unable to be substituted by quantitative means. It is especially scientifically of high value, scientifically, to have a technique available of similar precision and durability as digital material but being able to preserve and save quality (s. below). During digitalization, it is of vital importance to have a tool to judge and control the quality and reality of digital procedures by analogous and real originals. This scientific counterbalance for digital procedures is vital, as we have learned from digital pitfalls and misuses. This problem can be observed in the daily work of medicine (Fig. 5.9). analog

Fig. 5.9  Analog and digital

digital

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255

4. Plastination is a medium that processes storage qualities, which is impossible to achieve with digital techniques. One of the struggles that exist in scientific theory today is the description of qualities by quantities, remains unsolved until today. As long as we have not solved this problem, it is of upmost importance to preserve quality assessment tools and to preserve qualitative scientific methods. There is currently a wide gap in this field, and Plastination is one of the few methods to bridge this lack of knowledge, forming a paradigmatic model for science theory of quality saving. One can store non-digital entities and knowledge. In Plastination it is mainly the qualities of anatomy and bodies. In the famous composition of the ancient Atlas mythos (Fig. 5.10), this strong symbol is expressed morphologically by a whole-body plastinate, representing the eternal burden, which is an expression of a quality. Fig. 5.10 Atlas-Plastinate (G. v. Hagens)

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5. Plastination can perpetuate Gestalt-characteristics. The scenario-Gestalt (Fig. 5.11) of the Poker Players, portrays not only the single whole body -specimen, but also the Gestalt of a group-interaction during a game. This is achieved through effective positioning to convey body-language and psychological expression. The information and effect of the whole group is more than the sum of the individual elements of the whole scenario. This is the Gestalt-phenomena, described by Gestalt-Theory (s. Chap. 3). Plastination is a medium, that can preserve and enhance Gestalt effects. Present day anatomy workings and presentation is about gathering knowledge through analysis. Nobody is looking for the synthesis, or the preservation in a comprehensive way of understanding and experiencing the quality of the whole of an object or a process. Real anatomy is living anatomy, which is presented and occurring always in reality as a whole and functioning as a whole. Analytical knowledge is not able to experience and understand a patient, if this analytical knowledge cannot be correlated with the appearance of the whole. Understanding analysis by experience the characteristic of the whole was named Gestalt-­phenomena by Gestalt -Philosophy and Gestalt-Theory (see Chap. 3), (s. application 4 below).

Fig. 5.11  Greizer Body-Worlds 2020 (G. v. Hagens)

5.5 Anatomical-Concepts: Topography, Gestalt-Anatomy and Surgical Anatomy

257

In summary Plastination has an uncharted meaning for science in modern anatomy and paradigmatically for science theory. Plastination contributes to the fields: thanatology, high precision preservation, analogous storage, quality storage, Gestalt storage. Therefore, the scientific impact is more important than the well-­ known and famous field of exhibitions and educations. The impacts of this scientifically role are numerous, and can be demonstrated by this spectrum of application: Plastinates can be used as innovation-tool.

5.5

Anatomical-Concepts: Topography, Gestalt-Anatomy and Surgical Anatomy

The variety of applications of the plastinates relay on the concepts which are realized in the preparation of the specimen before undergoing through the specific plastination procedure. The educational value and teaching competence depend on the quality and design, which permits an insight into the complex organization of such a compact structure (Fig. 5.12).

Fig. 5.12  Unfolding Concept; Greizer Body-Worlds (G. v. Hagens)

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Unfolding the complexity without making it in-comprehensive is the art of preparational design. This concept was already recognized by Leonardo da Vinci. When he started, the artist must paint the object as precisely as possible whilst simultaneously conveying the inner workings of this object/person. He knew, that the expression of the surface is in relation with the deep inside. Andreas Vesalius presented his graphic representations of anatomy within the context of life, affording them with such expressional demeanor, portrayed as though they were still living. This is what is done with the positioning in the plastination process, before the irreversible step of hardening is initiated. Together with these old concepts, the unfolding of the compact complexity to make as much visible as possible, defines the design of the plastinates. Another concept is the precisions in presenting each detail in situ, and finally the beauty in color and presentation. We see the concept of Plato, that people understand that they can love, and they love what they can feel as beautiful. Today we can image this neuropsychological pattern by f-MRT: what we love we learn and understand better and deeper. Once the limbic system is in action (love), the memory and learning systems will react more intensively. The attractivity of the plastinates has its origin in a very deep wisdom. It is not a show, and this is why we see that spectators are affected. This can only be induced by the original, rather than by only interesting sensations.

5.6

Applications of Plastinates During 33 Years in MIN

In 33 years, plastinated specimens were used in 12 different applications, each of which are demonstrated now. It can be typical, that the plastinated specimen is not substitutable for the task or goal of use; this will become clearer in the cases. The role of Plastination is becoming recognizable in promoting MIN practically and theoretically. The use of plastinated specimens brings the test conditions as close to real life as possible, for example, in testing tool quality, diagnostic and navigational equipment. Calculations and tests that used dummies as the subject did not come close to the sensitivity and specificity of plastinates, which provide more accuracy and precision due to its morphological similarities to a live specimen. For teaching and training, the plastinates always achieved the highest ranking by the participants and caused the strongest attraction within courses of different formats (s. Vol. 1, Chap. 1). There is no comparison to the plastinates, when it comes to planning or rehearsal of a surgical approach and the visualization of a surgical procedure. Especially in the comparison of alternative approaches, angles and depths, as well as limits and dimensions, the plastinates were absolutely convincing. No tool, neither analogue nor digital can surpass the utility of plastinates. When testing new devices, such as exoscopes, plastinates are superior even to surgery, as there is no stress or therapeutic goal limiting the examination.

5.6 Applications of Plastinates During 33 Years in MIN

259

5.6.1 T  opographic- and Surgical-Anatomy of Head-Plastinates (1982–1987) (Fig. 5.13) a

c

b

e

d

g

h

Fig. 5.13 (a–i) Head-Specimen (KDM Resch; G. v. Hagens)

f

i

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Four headplastinates, representing topographic anatomy design, classical microsurgical design, micro-/MIN design and lateral skull-base design, with many approaches according to the Gestalt principles, were prepared and then plastinated. They form a combination of preservation and surgical anatomical basis for MIN. In combination with Gestalt anatomy lab (Chap. 3) and surgical simulation lab (Chap. 4), an innovative training and research tool for many applications was created. The value of these plastinates was far superior to all photos and videos in preserving the results perfectly and very close to reality. Twelve applications were performed during the last 33 years in parallel with MIN and became an indispensable tool. This Plastinate (Fig. 5.14, 5.15, 5.16, and 5.17) has the design principle to show deep intracranial structures, the superficial facial, cervical and supraclavicular regions on the right side and vice-versa on the left (s. below). This enables the spectator to mirror the deleted structures by observing the opposite side. Through this, the imagination creates an experience of the topography, which produces the Gestalt-phenomenon (s. Chap. 3), to understand by seeing. The fourth specimen, was research on behalf of a famous skull-base surgeon, presented surgical approaches through the base of the lateral skull. This was because of the necessity to explain these approaches, which was never successful by classical means. Fig. 5.14 Head-­ Specimen: Lateral Topography

5.6 Applications of Plastinates During 33 Years in MIN

261

On the left side from antero-lateral, we see the intracranial surface and the deep facial and cervical regions. Fig. 5.15 Head-­ Specimen: Frontolateral Topography

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From latero-dorsal direction left, we see the para-pharyngeal nerve-vessel street and a resection of the occipital lobe with the complex wing-shape of the tentorium, which is marked by the transvers sinus. The deep cervical and suboccipital musculature from C2can also be seen. Fig. 5.16 Head-­ Specimen: Dorsolateral Topography

Fig. 5.17 Head-­ Specimen: Lateral Cranial-Base Topography

5.6 Applications of Plastinates During 33 Years in MIN

263

In contrast to anatomical models and drawings, we see the existence of a perfect reality. There is no drawing without a mistake, no artistic fabrications or variations, which was never created by nature. Below are two examples of anatomical key-­ points in surgery (Fig. 5.18a, b): a

b

Fig. 5.18 (a, b) In the famous Perneczky-pyramid, it seems that there is a trifurcation laying beneath the optic nerve, a variation that does not exist. In Mohsenipour et al., there is a variation which does not exist: the asterion is superior to the knee of sigmoid sinus (correct position by the author)

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The instructive design of dissection enables us to recognize the many correlations which are usually not visible: the proximity of hippocampal pes to Gasserian ganglion; the Kawase triangle between the trigeminal nerve ventrally and the labyrinth block dorsally; the proximity of pyramidal fibers close to the cell a media of the lateral ventricle wall; and the proximity of the spinosum foramen to the middle ear. Many correlations and MIN pathways, or planning parameters, can be explored precisely and accurately which are reliable for planning MIN approaches. All correlations, key points and landmarks are planning parameters in MIN and need to be seen in 3D to elect the necessary approach. Plastinates of good quality will present this reliability and visibility in a dry and easy to handle fashion. The spaces and gaps can be visited by endoscopy to analyze a surgical MIN pathway. The specimen is dry and odor-free, always available and can be taken to the OR for assistance and anatomical orientation. They can be used to correlate with the imaging material in 3D and moreover, with slice-plastinates. The planning with plastinates create a steep learning curve and growing imagination. The originality and the precision of plastinates aids in the prevention of mistakes in the planning. The mentioned failures in anatomical sketches occur daily in imaging material. Each radiological institute should have slice-plastinates to correlate unclear cases of imaging with slice plastinates, to control a virtual, voxel-world, with real anatomy (Figs. 5.19 and 5.20).

Fig. 5.19  Head-Slice-Specimen (G. v. Hagens)

5.6 Applications of Plastinates During 33 Years in MIN

265

Fig. 5.20 Head-­ Specimen: Superior Cranial-Base Topography

In contrast to the low optical resolution imaging, the original has no optical resolution limit. Moreover, the 3D precision and understandability of imaging on 2D screens is a critical matter. The Gestalt-phenomena cannot be induced by imaging. However, with plastinates this can be induced as often as needed, until the meaning is understood and memorized. Once you start to study a plastinate of good quality and with an instructive preparation design, you will always discover new correlations. In contrast to virtual programs, these are reliable. You see and understand the meaning of structures, possibilities and the limits of danger. Virtual tools only make you believe understanding, however, only very experienced surgeons with a large anatomical mental library, will recognize the limits of such tools. One might remove a lesion with ease virtually without realizing, that you have just killed the patient. This will not be the case with plastinates, as the preserver of original anatomy and preparational pathways. In this case, orbital, peri-ventricular relations and fronto-temporo-basal with trans-petrosal topical correlations can be made comprehensive. The plastinate can be studied under the microscope and even the endoscopic journey through the small corridors can be studied, enhancing your imagination (Fig. 5.21).

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Fig. 5.21 Head-­ Specimen: Axial Lateral Cranial-Base Topography

This close-up master perspective represents unique corridors to a very hidden target from quite unusual angles of view. The spacial conditions and proximity of the middle ear, labyrinth block, internal auditory canal and pre-sigmoid sinus are visible and explorable. Very complex approach analyses and designs are possible, and even “impossible” approach innovations for MIN can be discovered and trained outside the laboratory without any logistic efforts.

5.6.2 Organ Plastination and Preservation of Special Findings Important findings are usually documented digitally, losing a lot of information regarding 3D conditions and Gestalt-phenomena. Especially in very rare cases, like giant basilar aneurysms, for example, which can be preserved in its entirety using plastination. Moreover, difficult cases and important morphologies were preserved whenever possible by plastination, to maintain the subtility of morphological factors that can decide the fate of such cases. It is a morphological memory and archive, preserving information, otherwise lost, and which had been archived in former times by wet specimen collections or paraffin-samples (Fig. 5.22).

5.6 Applications of Plastinates During 33 Years in MIN

a

b

267

c

Fig. 5.22 (a–c) Brain-Specimen with Giant Basilar Aneurysms

Impressive cases you will always remember in your career. You will make promises never to forget, to preserve the memory and to learn the lesson for ever, but you will never keep this promise as precise and as durable as you can with a plastinate; keeping all the information you will forget, or which you have not yet realized. Dramatic and unique cases which you may want to share with the future and the young generation, one needs to plastinate, not only to write or video record them. The chance to take the specimen, dry and real in your hands, allows you to learn kinesthetically and truly understand by experience. One can examine the specimen with future techniques and new questions, preserving opportunities, which otherwise would be lost (Figs. 5.23 and 5.24, Graph 5.5).

268

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b

c

Fig. 5.23 (a–c) Giant Vertebro-Basilar Aneurysm This giant basilar artery aneurysm in the CPA belongs to a group of rare findings (Vol. II Yasargil MNS p. 272–4). Gross morphology of such cases is difficult to be imaginable and even 3D CTA reconstruction with animation does not change this but may elicit miss-imaginations. To study plastinates preserve much more relevant information for 3D correlations. The quality in this case was only medium, however, even the arachnoid membranes are partially preserved, especially the interpeduncular cistern with the basilar head inside (s. Chap. 4, Case 11).

5.6 Applications of Plastinates During 33 Years in MIN

a

269

b

Fig. 5.24 (a, b) Big CoA-Aneurysm

Graph 5.5 Video-Preparation Para-endoscopic surgical simulation setup for specimen-taking in non-obduction cases Specimens can be given to pathology or be preserved by Plastination for further studies and examinations, even for post-plastinated histology

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This is a specimen of CW with a big CoA-aneurysm taken during a surgical simulation procedure. This is the most difficult position of the aneurysm below all 6 parent vessels and impressed into the inter-hemispheric midline gap. The real size impression, 3D correlation and taking the finding with parent vessels through the MIN approach, should be preserved for memorizing and further studies (obduction was not permitted). Moreover, it is a model for micro/endoscopic obduction results (s. Chap. 4), preserving the main relevant finding without obduction. Slice-Plastination is currently of great impact due to new scanning and imaging techniques. In this opaque slice of a brainstem tumor case we see intracranial shifting (arrow), herniations and cervical stenosis (arrow). Such plastinations are the best references to manage imaging scan techniques like CT and MR. In this plastination each voxel is true, and the optical resolution is on the subcellular level. Imaging voxels might be artifacts or errors, and the resolution is about 1  mm. Information preservation of plastinates is 103–4 times higher than MR (Figs. 5.25 and 5.26).

Fig. 5.25  Slice Specimen Medio-sagittal; Mult. Herniations by Tumor

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Fig. 5.26 Slice-Specimen Medio-sagittal; Multiple Herniations by Tumor

This is a transparent slice plastinate in a brain stem tumor case. Grey and white matter can be discerned and vessels visible. The tumor (large circle) caused shifting (arrow) and herniation (small circle). Many details are visible in the parenchyma, and the resolution is again subcellular level in contrast to MR imaging 1 mm/voxel. Radiological institutions should have a high-quality head samples of slice plastinates in all planes to discuss critical findings and compare it with real anatomy. Controlling imaging requires a large mental library and is indispensable for MIN planning. This case became a long bloody night ending in disaster. Surgery was not planned sufficiently, rather than falling into it with an emergency indication, hours after SAH ° 3, and hydrocephalus. However, this was a very small (3 mm) aneurysm, current beliefs indicate no requirement for treatment. This case was preserved because it teaches, several statistical rules may turn out to be wrong with fatal results. Yes, these small aneurysms can bleed, but moreover, they are the very dangerous and if they arise very close to the cranial base, proximal control is difficult to achieve. Flattening the anterior clinoid process (green circle) is far away to be enough, closely to the ophthalmic artery (red arrow) and optic nerve (yellow circle), this increases the risk of surgery to maximal levels. This is a classical constellation for a contralateral approach (black arrow), which needs a detailed analysis of extended imaging, not convenient during night. Flow diverter and coiling did not exist at that time, even coiling was very dangerous in such a typical thin-walled small aneurysm. Such dramatic cases can be documented for future learning by

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plastination, preserving detailed information which would otherwise be lost, therefore making it indispensable for indication and strategy decision. These cases can rarely be handled without mouth tracking of the microscope. Large openings do not solve and not support successful managing. Experience and surgical simulation conceptions, however, give the best training to meet such cases (Figs. 5.27 and 5.28).

Fig. 5.27 ICA-Ophth. Mini-Aneurysm; Cranial-­ Base Topography

Fig. 5.28 Mastoidectomy; Petrosal Topography

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Plastination of complex bone preparations, like petrosum, should be plastinated to prevent the ongoing destruction of the bone-material. The petrosal drilling training, usual in ENT surgery, should be done by neurosurgeons also to become safe in skull-base surgery. The trans-petrosal route to the brain is of great value, however the routes and pathways are naturally small and of MIN type. To imagine these routes and the structures to be avoided, plastinated petrosal preparation can also preserve dura, nerves, vessels and all other soft tissues (Fig. 5.29).

Fig. 5.29  Axial Petrosal Cranial-Base Topography

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This close-up of the petrosum (s. Fig.  5.20), shows the inner and middle ear structures well preserved by plastination, especially the tensor tympani muscle, the malleolus and hammer of middle ear are beautifully visible. The concentrated structures within the hard, petrosal bone and not visible need a very fine drilling with an extremely precise and perfect technique and orientation to safely find the MIN pathways, trans-petrosal to the internal acoustic meatus and posterior fossa. Pre-sigmoid and post-labyrinth as well as Kawase-triangle or Trautman’s triangle are delicate routes to target selected lesions. Major and minor petrosal nerves and facial nerve in the Fallopian canal and also meningeal artery in the spinosal foramen can be studied and memorized for accomplishing missions within MIN. Such spacial anatomical knowledge allows one to follow very specific and exact strategies to maintain goals, largely believed to be impossible. Such goals can only be reached by special training and high quality plastinates with a MIN preparation concept can help profoundly to reach such level of imagination and performance (Fig. 5.30). a

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Fig. 5.30 (a) Pre-Sigmoid Medial Topography. (b) Petrosal Lateral Topography

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Trautman’s’ triangle (red) is visible from the inner-side of petrosal bone, pre-­ sigmoidal end retro-labyrinthine, a classical MIN route. The seldom visible endolymphatic duct is colored blueish, and the strong sigmoid sinus is preserved by plastination, without which, these structures would not be preserved. These spatial conditions cannot be comprehended in 2D and not by virtual means. However, models do not and cannot present original anatomy, giving details that can decide the outcome of surgical procedures in that region of the lateral skull base. This plastinate preserved the latero-posterior skull-base and the complex structures within the petrosal bone with the labyrinth, the middle ear and the facial nerve, drilled out of the petrosal bone. The sigmoid sinus, a strong jugular bulb and its position to the inner and middle ear as to the facial nerve are preserved by plastination. Such anatomy must be studied again and again with original anatomy, and easily available to train the imagination of this region. For MIN strategies this level of experience and haptic knowledge is mandatory to have the visions for planning other new approaches. MIN does not come from heaven, rather than from laboratory work and training, and plastination is a strong tool to preserve this anatomical knowledge in the most precise and realistic way (Fig. 5.31).

Fig. 5.31 Brain Specimen: Telo-­ Diencephalic Fissure

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This thick silicon brain slice plastinate presents one of the most difficult gross morphological regions to understand the ontogenesis of the brain, and to understand the 3D Gestalt of the telo-diencephal fissure (velum inter-positum). The rotational growing movement during ontogenesis and phylogenesis (Fig. 5.32) causes the overlay of the pallium over the thalamus-level. The roof of the lateral ventricle, together with the tela-choroid layer connect with that of the third ventricle. This arachnoid connective-tissue gap forms the telo-diencephal fissure. Once you have understood this ontogenetic movement, you will comprehend the gross-morphology of the brain. This is worthy of preservation by plastination.

Fig. 5.32 Acryl-­ Embedding Specimen Med-Sagittal

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The (blue) telo-diencephal fissure is caused by the (yellow) movement of pallium. It can be approached by endoscopy (arrow) (Fig. 5.44). The clinical case (Fig. 5.33) presents a subarachnoid cyst in the telo-diencephal fissure, usually misdiagnosed as a third ventricle cyst. Here the fissure is enlarged markedly (Resch 2005 Springer, ENS-book p.70–72). a

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Fig. 5.33 (a–c) Telo-Diencephalic Cyst

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Fig. 5.34 Acryl-­ Embedding Specimen: Bird Brain

Trans-endoscopic ultrasound (red) for intra-operative real-time navigation imaging (Fig. 5.34). During early phylogenesis, the pallium is not laying over the deeper parts of the brain, causing an open and well visible telo-diencephal fissure (blue). This is the brain of a bird (embedding-technique 1976), showing the incomplete rotation of the pallium (telencephalon), leaving the telo-diencephal fissure open. Ontogenesis and phylogenesis levels can be plastinated to better understand the evolution of complex organs. This understanding is a prerequisite to understanding MIN approach strategies and of course, many pathologies: heterochronia. The trans-cisternal strategy of approaching (Yasargil) is one of the fundaments of micro-neurosurgery and a pre-requisite for MIN. MIN approaches can use this natural path-ways and gaps, even if microneurosurgery would not be able to (endoscopy). However, the basis of understanding is the same: ontogenesis (Fig. 5.35).

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Fig. 5.35 Acryl-­ Embedding Brain Stem Specimen Medio-sagittal

This embedding specimen (1976) shows the extension of the telo-diencephal fissure, visible after dissection of the telencephalon, and showing the contact of choroid plexus of lateral ventricle and third ventricle with the tela-choroidal layer. This finding shows that the tela is carrying the choroid plexus, and that it has an extension laterally, becoming a virtual line only in the medio-sagittal plane (s. Fig. 5.32). In-between of the splenium of corpus callosum and pineal gland the telo-­ diencephalic fissure forms a natural pathway to the roof of the third ventricle and to thalamus lesions. But be aware of the Galenic vein and its five main branches, internal veins, basal veins and vein of superior vermis. By nature, this route is a MIN route, best started normally 1 cm para-median to avoid the peri-pineal vein system. This fissure approach concept (Yasargil) can be optimized by MIN strategies: planning, mental anatomical and surgical clips library, surgical simulation training concepts and plastinates for ongoing learning and mental preparation (Fig. 5.36).

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Fig. 5.36 Occipito-­ Frontal Endoscopy third Ventricle Via Telo-­ Diencephalic Fissure (s. Fig. 5.32 arrow)

Endoscopic entering the third ventricle from a posterior aspect can be done (s. Fig. 5.32 arrow) superior to the pineal gland and below the splenium of the corpus callosum (master class!). In between both thalami, the anterior region of the frontal third ventricle can be seen with its main structures: the anterior commissure, both columns of each fornix, forming a typical triangle. Laterally to both columns of the fornix, the foramen of Monroi (blue) is visible on both sides. The entering by this approach can be left with leaving a stent in place to have a ventriculo-cisternostomy if required. But clearly, this is a very elective approach for rare situations and of the greatest difficulty.

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5.6.3 R  esearch: CT Resolution and Imaging Evolution (1983) (Fig. 5.37) a

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Fig. 5.37  Canalis Basilaris Medianus (Venous Sinus in the Clivus). This is the rare variation of a Canalis Basilaris Medianus (a), approached and shown directly for the first and only time world-­ wide, and through the trans-oral approach. Only in such a trans-clival approach this irregular intra-­ bony sinus, could be origin of a sever unexpected bleeding. This is the correlate of contrast-spot (c) in the CT intra-clival. The trans-oral route is a very deep working canal (Fig. 5.38)

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Fig. 5.38  Vertebro-Basilar Conjunction (Pharyngeal-Clival). After correct opening of each layer (s. below) of the trans-oral approach, the view looks directly on the vertebro-basilar conjunction at the ponto-medullary sulcus of the brain stem. This is the contrast-spot intra-cranial. Each layer has its’ own difficulties in preparation and unique physiological conditions. (s. Chap. 3)

The head-plastinates with performed real MIN-approaches enable the testing of different generations of imaging techniques like CT-generations and ­imaging-post-­processing tools (Graph 5.6a, b).

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Graph 5.6 (a, b) Multiplanar and 3D-CT Reconstruction. (b) Digitalized Real MIN-Approaches by Off-line Programming New Planning Tool

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The comparison of CT resolution between 1983 and 2021 does not represent the real evolution of imaging. The pure resolution clearly is higher, up to 0.3 mm, however, but it is much more impressive: the multiplanar imaging and the 3D-reconstrictions. At the workstation the digital representation of the head-­ plastinate can be manipulated in4D, in many ways and in real-time. However, even with the most impressive evolution in resolution, speed and post-­ processing for 3D and 4D, the results are far behind the level of real anatomical complexity, and far behind of precision by surgical manipulation in MIN. Plastinates can make this visible directly as an experience, giving a feeling for the differences. This experience teaches one, un-forgettable, that imaging needs a translation into surgical environment by intensive training for many years. What can I use and believe for planning a surgery, and where are the limits? How can I get firm in mental creation of surgical clips, in-front of a planning work-station, providing 3D- and 4D-technique? Variety and spectrum of planning tools became so large, that the real anatomy library in the surgeons’ experience must be more extraordinary than ever. A head-plastinate with several real MIN-approach designs, preserved by the analog technique of Plastination, enables to off-line programming a virtual model with real MIN-approaches! This can, to date, not be done by any planning stations. The result is a tool, that cannot be simulated pure digitally. The scanner produces a learning-step into the work-station by the plastinate of unprecedented complexity and near-reality qualities. We create a digital analog on with near-­ reality training properties. With plastinates all coming generations of work-stations and future software can undergo a learning-step of real-approach designs, getting digital planning tools of unknown competence. By further optimation in off-line programed approach designs, new approach designs can be created and explored. Plastinates can be used as innovation-tools!

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5.6.4 P  lastinate Demonstrations at Congresses: “Neurological Surgery of the Ear and the Skull Base” 1988 ­Zürich/ Switzerland (U. Fisch; A. Valavanis; M. G. Yasargil) (Fig. 5.39) Fig. 5.39  Skull base approaches afer U. Fisch (Head-Plastinate)

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Demonstrating complex and sophisticated surgical approaches like the U.  Fisch-­ system (A, B, C, D), even for advanced community of colleagues, is impossible with virtual- and 2D-methods. In 1984, Prof. U. Fisch ordered a plastinate which can preserve and present in 3D precise anatomy of his approach-system Fisch ABC and other trans-petrosal approaches. It became obvious, that all his lectures and even life surgery lessons were not able to convey the real complexity of his approach-system in 3D and imaginable for his audience. He realized at once, during a visit in 1984 in Zürich, the value and meaning of plastinates, presented by the author during a stay at the neurosurgical department of M. Yasargil. The performed head-plastinate was demonstrated during the International Skull-Base Congress in 1988 in Zürich, a unique event to the first time seeing such complex approaches with original anatomy, dry and beautiful with highest precision (Graph 5.7).

Graph 5.7  Trans-Petrosal Preparation

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After formalin-fixation and vessel-injection with red and blue resin, the complex preparation of the approaches (here A + B), were performed. Petrosectomy retro-­ auricular on the right side (A 1–5) are shown in some steps, and approach type B left until intradural window (B 6 + 7) reaching pontine region with basilar artery, labyrinth block and abducens nerve. Type B approach will also contain drilling free carotid artery reaching the clivus and the sella-region, after transposing carotid artery ventrally. After opening the dura (not part of Fisch-approach), the complete ventral brain stem can be reached with cranial nerves 3–12. Type C approach goes further to the maxilla sinus and para-pharyngeal and naso-­ pharyngeal space. The preparation even can proceed to lateral cavernous sinus ipsilateral and medial cavernous sinus contralateral. After finishing this preparation, the specimen underwent the Plastination procedure (s. Graphs 1–4). Thereafter the plastinate can be used in many ways (s. example 1–12).

5.6.4.1 Lateral Skull-Base-Approach Fisch A-B-C Graph 5.8 Close-up skull-base approache after U. Fisch (Head-Plastinate)

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The approach-system to the lateral skull-base according to U.  Fisch (Graph 5.8) gives access to several regions and targets. Region 1 is the jugular bulb, sigmoid sinus, jugular foramen and the facial nerve within the Fallopian canal. Region 2 contains the middle ear and the inner ear, all within the very hard petrosal bone. Region 1 and 2 are the Fisch A-approach. The Fisch-system reaches further regions of skull-bas from lateral: region 3 is the path-way along the carotid-artery, if mobilized ventrally giving access to the clivus and to the ventral brainstem (s. below, endoscopy). This is a very hidden region and difficult to be reached (“no mans’ land”, C. Drake), and also difficult to understand regarding accessibility and imagination in 3-D (s. Graph 5.8). Region 4 contains the temporo-polar skull-base and the access to sphenoid sinus, cavernous sinuses, sellar region and maxillaris sinus. The carotid siphon within the cavernous sinus ipsilateral from lateral side and contralateral from medial side can be reached. Petrosal apex on both sides can be accessed. This route can access large malignant processes completely, otherwise not possible. Region 5 leads to the para-pharyngeal space and to the naso- and oro-pharynx, but also choana and supra-laryngeal space. Region 4 and 5 form the Fisch approach C. Through this approach it is able to manage big skull-base lesions otherwise in-­ accessible (Fig. 5.40). Fig. 5.40 Proceeding Video. At the annual meeting of the German Skull-Base Society in 2003, a video on the approaches A-B-C to the lateral skull-base by Ugo Fisch, was presented (by the author). It was published by Springer together with the proceeding 2003

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On this video the approaches A-B-C were described in detail macroscopic and microscopic. On this occasion Prof. U. Fisch was present, and he was honored by the society for his lifework.

Graph 5.9  Endoscopy: Fisch A-B-C Approach

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The access to the deep targets within the regions 3, 4 and 5 are best visualized by the endoscope. The quality of endoscopes, cameras and light machines in 1988 were not of todays’ quality, however an impression was possible. The complete ventral brainstem through the B approach with basilar artery and abducens nerve are visible (1). A latero-superior angled view shows additional trigeminal- and 7/8-nerves, looking along AICA (2). Part 4- and 5-region (type C approach) gives access to naso-pharyngeal space and even the medial side of carotid syphon contralateral can be recognize from a very un-usual perspective (3). Again region 3 (B type approach) gives view on the contralateral carotid syphon, the whole basilar artery and the pons (4). A more superior view shows pituitary gland (braun) in front of the contralateral syphon, coming from the contralateral petrosal apex, and the basilar trunk (5). In summary the Fisch approach system A-B-C gives access to most parts of the skull-base from lateral. Preservation and presentation of such complex approaches can only be understood by plastinates with 3-D original anatomy (Graph 5.9).

5.6.5 Endoscopy Courses During many different formats (Fig. 5.41a–d) of courses within 8 years, the author was part of the faculty and usual added some head-specimens to getting 2- and 3-D endoscopy experiences for the participants. At this time, the concept of “Körperwelten” (body-worlds) just came up and made an unbelievable evolution further-on. Tree head specimen (Fig. 5.13) mostly were used to give a training close to reality. This was at the endo of the different working places an interesting supplement to the basic steps to motivate and inspire the trainees (Graph 5.10).

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Graph 5.10 (a–d) Course Formats

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Fig. 5.41 A. Perneczky; Endoscopy-Assisted MIN Course

Prof. A. Perneczky always was at the front-line in all his courses to experience the problems the next generations have with the new techniques and concepts. He was eager to listen to the ambassadors of the future of MIN and let them take part in his experiences. Usual conditions in such courses, like wet specimens with bad odor and setups too far away from reality, are one reason to avoid such courses. A more attractive concept would be to establish such training opportunities in each major department with a sample of plastinates. The motivation effects of plastinates, fascinating by real anatomy and beauty, was convincing for the author in these courses, and it was not easy to end the work in-time at the end in this working place.

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5.6.6 2D Video/Monitor Endoscopy Training (Fig. 5.42)

Fig. 5.42 Micro-/Endo-Lab

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Micro- and Endoscopy-training with plastinates prepared with many surgical approaches, and with small groups had the most motivation- and training-effect. The setup was chosen as close as possible to surgical situation, but in a calm and relaxed chance to learn. In an easy logistic environment, compared to a wet laboratory, the training became attractive and very intensive. The beauty and reality of the plastinated specimens, presenting MIN- and common-approaches, produced a much higher respect for the artwork of the plastinates, presenting the art and realistic miracle of natural anatomy. The neuropsychological processes were incomparable to a wet laboratory, causing a much better teaching environment and results. There was never weakness in concentration and intensity, as the author saw in conventional training setups. With no exception, nobody had any aversions nor ethical problems under such conditions.

5.6.7 3D Endo HMD Training (Fig. 5.43)

Fig. 5.43  Laboratory for MIN training

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One of the most convincing training-reactions by each participant was to compare 3-D endoscopy with monitor and true 3-D endoscopy with HMD system in a plastinated specimen (Fig. 5.44). Fig. 5.44  The difference between monitor 3D and HMD 3D is, that the latter make a real 3-D experience to the spectator because each eye has an own image. This gives the imagination of a spacial visual environment, and the experience of moving through a real space. Depth and angles are more realistic to the feeling and haptic of the endoscopic handling in congruence of the image one is seeing. The training effect is much more natural giving higher safety in moving the endoscope properly

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5.6.8 Microscope-Navigation Training in Head-Plastinates (2006) (Fig. 5.45)

Fig. 5.45  Navigation training with Head-Plastinate

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Most of the neurosurgical community do rely on navigation systems. However is wassoon recognized, that the lack of real-time imaging caused sever problems, and that the surgical precision is far less than the technical. Usual test environment are neglecting complexity of anatomical and funcional reality. The awareness of these pitfalls in navigation systems can be clearly experienced and should be learned in plastinates before it comes to pitfalls in the OR. During the navigation training with navigation systems in plastinates the conflict of the two major concepts “image guided” and “trans-cisternal” becomes obious. In two examples, transoral- and pterional-approach this shall be shown: In the transoral route, the trajectory of the approach depends on the correct angle and on the correct design of the windows in all layers to form the path-way to the target. The window deign is outside the range of the navigation system, and the success of the approach depends on this reality. The factors defining the correct windows are not “known” by the naviation system (s. Chap. 3).

5.6.8.1 Navigation Test Transoral Approach (Graph 5.11 and Fig. 5.46) Graph 5.11 Transoral Approach navigation training in a Head-Plastinate

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Fig. 5.46  Approach canal tran-oral in a Head-Plastinate

For the navigation system the angeling of the approach vector can be well calculated, however, the design and shape of the windows of all levels cannot be described or simulated, because, manny tissue properties and biological condition of the different layers are not acquired by the navigation system. Despite the technical accuracy of the system, tested with phantoms or virtually, the surgical accuracy may differ remarkably. In this geometrical rather simple case, in contrast to biological factors, there is a surgical accuracy failour of about 2 mm. This can be seen directly (Fig. 5.47), as the pointer (black arrow) is in the microscopic view (reality) inbetween the vertebral arteries and in contact with the conjunction. In the virtual view, the tip of the pointer is lateral to the conjunction and to the right vertebral artery. The test-environment, offered by the plastinate, shows under direct visual control and real anatomy the failour of the navigation system within the surgical manuver and context.Moreover, this test environment by plastinates is a quite comprehencive training tool in navigation. The approaches in the plastinate are real and may be copied by the virtual planning system. Having these real approaches within the planning environment, there is no virtual failour possible, according to the approach, like in the pure virtual planning might occure. The training concept of neuronavigation with plastinates deminish the big ammount of fun-immaging during surgery, causing a time-trauma to the patient. Moreover, the training within real anatomy and with real approaches gives a feeling to the trainees for the limits of neuronavigation systems, not possible with technical training facilities alone.

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Fig. 5.47  BrainLab Surface Transoral Approach

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5.6.8.2 Navigation Test Pterional Approach (Graphs 5.12 and 5.13) Graph 5.12 Plastinate, pterional left

Graph 5.13 Non-fixed Brain, pterional left

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The navigation testing in apterional approach is much more complex, as the routes are not straight vectors but curved once. This cannot be easily demonstraded by plastinates, because the plastinated tissue becomes the consistancy of stiff silicon (Fig. 5.48). In futur more plyable materials might be used and are tested. According to Yasargils concept, the release of liquor and relaxation of the brain along gravitation, can be used if positioning of the head is correct. Therefore, the trajectories will be curved, wich cannot be simulated by the navigation systems (Fig. 5.49). The navigation test pterional left with the pointer (black arrow) showed a very good result in precision, which can be seen directly microscopically in real, and the virtual targeting virtually is in good concordance with reality. However, the navigation is only correctin one position, but mooving the head or direction of the pointer may not cause a reliable result compared to surgery.

Fig. 5.48  BrainLab Surface Pterional Approach left

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Fig. 5.49  Preparation Stepa Pterional Inter-Fascial left

The step by step development of the pterional approach represent the real conditions of getting access to the pterional target, discovering the factors making the accesses possible. These factors cannot be planned and simulated by navigation systems. If the pterional trajector is virtually planned wrong, being not realistic due to lack of releasing CSF and relaxing the brain as well as drilling the spenoid wing, more forceby brain spatula will be used. The correct work-out of approaches will result in a visual trajectory to the deep target without any spatula at all. The work-­ out trajectories, however, will not be straight, but curved allong the cisternal routes. Once the plastinate has fixed such a correct work-out and design of an approach, it can be used perfectly to train navigation and test navigation-systems. Then this will be the mostchallenging test environment of these system before surgery usage. After taking out the brain virtually from the head-plastinate 3D-reconstruction (Fig. 5.50), and comparing the result of the vertebro-basilar region with an endoscopic view(Fig. 5.51) in the plastinate, the difference in optical solution was even more striking compared to the case above (Figs. 5.52 and 5.53). These comparisons

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Fig. 5.50 3D-CT Reconstruction

Fig. 5.51 Endoscopy

were done with thetechnique of 1994, when the reconstruction and the postprocessing had to be done in a separate workstation.

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Fig. 5.52 3D-CT Reconstruction-Resolution Testing (1994)

Fig. 5.53 (a) The first comparison in 1994 between 3D CT reconstruction with visual optical resolution was most disappointing, because everybody was amazed at that time in the ability of virtual imaging in 3D. The plastinate gave a chance to compare the same area visualized by viewing and by 3D CT reconstruction. The painful difference was shocking, giving the true limits of the new technique and causing awareness on the remarkably resolution capacity of our visual system. Only with plastinates this could be experienced so convincingly. (b) Microsurgical Anatomy View

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Actually CT-imaging technique of 2021 shows serveral progresses compared with1983 and1994. The variation of tools, speed and 3D- and 4D-manuvers are now integrated in one machine. But the free choices of presets and manipulation options cause a big variety of changes in the imaging that can produce many artifacts, changes of appearance and even structures that do not exist. This causes many oportunities for misinterpretations and wrong diagnoses. The user dependance of the imaging is not well known in CT-imagingthough diminished by standards, however, it is in principle the same problem as in ultrasound imaging (Vol. 1, Chap. 4). We see in Graph 5.14, representations of pontine vessels, depending of the adaptation of contrast and tissue-window, which was not able in the postprocessing in 1994. However, even with great progresses, the result is far far away from the reality under the surgical microscope presentation. The imaging is non-invasive, but causing the price of a large distance to surgical reality, and this must be mastered by the professionals and cilnicians.

Graph 5.14  3D-CT of Head-Plastinate (2021)

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The actuall generation of (GE) CT-imaging and postprocessing realized, depending from corret parameter adjustment at postprocessing, to image some of the larger pontine vessels, however, the main advantage is the possibility to create many perspectives and image-characteristics by 3D- and 4D manuvers. But only in connection with aninterim analogous step, the off-line acquisition of real-MIN approach designs by plastinates, create a planning and training-tool with close to reality properties regarding surgical geometry. This surgical geometry analysis is one of the major planning steps in MIN. The morphological and anatomical steps are shown in this Vol. 2, but in Vol. 3 the patho-physiological parameters in general and for planning of MIN will be provided. In contrast to ultrasound imaging, scanning imaging is not provided by one hand, causing manny possibilities to get into pitfalls. The secrete of solution is: interdisciplinary personal communcation and cooperation! The world of radiologists and that of MIN surgeons is, only regarding morphology and anatomy, extremely different, and we need to communicate this and to invite one another to come and visit the other world. Therefore, Fig. 5.53 again in b-version: the anatomical MIN -World in comparison to Radiological -World. The morphological standard, in MIN -World is the subarachnoid trabecule and membranes. “The subarachnoid cisterns are the road-maps of microneurosurgeons” (Yasargil 1984). In the daly clinical use, the limitations of 3D reconstruction regarding optical solution and arti-facts are not well aware, causing wrong interpretations of imaging and all the consequences, finally in the patient. Even in the usual and well known scanning techniques, these missing focus on the limits causes failuors. Training in watching such differences by plastinates is an unfogettable experience. Surgeons have these experiences every daywhen they compare imaging with the surgical reality of the region of interest. With plastinates they can train the vision for it, before it comes to surgery. Moreover, it trains the surgeon to control imaging by knowledge, and to know the situation and the moment when this is necessary (s. Chap. 4, Case 11). Such testings should be done in each new generation of immaging machines. Plastinates are not conveniant for MRT, as they have no whater anymore in the tissue.

5.6 Applications of Plastinates During 33 Years in MIN

5.6.9 Endoscopy Roboter-Arm Prototype Testing (Graph 5.15)

Graph 5.15  PICO Project

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To get a significant progress in neuroendoscopy, after the MINOP I-project, the MINOP II (Perneczkyand 3 partners; Fig. 5.54)-project was started and supported by the German government. In parallel the PICO project (the author and 13 partners; Fig. 5.55) was started and supported by the European Commission. However, both projects did not bring the breakthrough, which perhaps will beovercome by the ongoing introduction of multiple Exoscope -systems (s. Vol. 1; Chap. 4).

Fig. 5.54  Paper of the MIN-OP project

5.6 Applications of Plastinates During 33 Years in MIN

Fig. 5.55  EU project document

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One major difference of the projects was the testing environment. The MINOP II was tested in a virtual environment, PICO used as test environment plastinates, which means real anatomy.Asmentioned in the above applications 1–9, real anatomy environment can show application problems better than phantoms or virtual tests do. The complexity of surgical environment in application cannot be simulated with phantoms or virtually. As has been learned with navigation systems, the brain shifting during surgery cannot be calculated, but analog systems like plastinates can simulate the situation by the preparation design of real approaches. Moreover, problems of the tested systems will be more comprehensive in plastinates than in virtual systems (Graph 5.16).

Graph 5.16  World of Technicians

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It turns out to be the most challenging factor in such a project, that technicians and ingineurs have no idea about the situation and extreme conditions of complexity difficuties and emergencies in MIN. This is, of course immanent, will become obiouse early in such a interdisciplinary project with the industry. It is indispensable to experience and to deal with, that the industry partners may have an incompatible mental system software compared with yours. To overcome this barrier it is necessary to let the partners into the medical-­ surgical world, and in many projects, the industry is invited even to visit the OR and to watch surgeries and see the application and conditions in this unique habitat. However, the rules in the OR does not allow to adapt the procedures to the needs of communication with the industry partners. This makes the difference to the learning and communication conditions with plastinates. The communication can be done as needed to bring the main messages to the other side, and to get the understanding of the industry partners for the extreme conditions and extraordinary abilities the technical solutions have to offer. Compromises will be paid by our patients. With plastinates one can workout an imagination about spacial conditions, the roboter arm has to function reliably and precisely (Graph 5.17).

Prototype Testing in a Multi-Approach Plastinate

Tracking by Instrument within MIN Approaches

Graph 5.17  Prototype Testing in a Head-Plastinate

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The plastinate, used in this testing, has a preparation design with many MIN approaches, like transnasa-, transoral-, subtemporal-, pterional-, infratemporal-, resigmoidal-, retrocondylar-, supratentorial-approaches, but also some burr-holes. The main problem of the prototype system were soon visible for the technicians: the safe and immobile holding of a possition, and the precise smoothly tracking of the endoscope with the tracking tool. It became on the screen comprehensive, that the system was too far away from fine-tuning, to allow working intracranially. This prototype could not compete with the Olympus prototype A3 in 2000, which was perfectly in this regard, but was not tracked, and only placed very softly and easy-going, by two fingers of the surgeon with swinging-free stops (s. Vol. 1, Chap. 4: first exoscope). This condition led to the solution of exoscopes, to avoid the intracranial problems of endoscopy in general. However, in 1999, during the annual japanese neurosurgical congress in Osaka, the Olympus prototype showed in a plastinate, that a combined endo-/exoscope solution was possible with good results in visualisation and handling. It was quite safe for endoscopy-assisted application and exoscop use also. Perneczky has used this combination already for several years (s. Vol. 1; Chap. 2). However, the safety and ergonomics of mouth-tracked high-zoomed MIN is not reached by this first endo-/exoscope and will have to be tested for all the actually exoscope gerarations. It was wise to start this in plastinates than in patients!(see below).

5.6.10 Light Depth-Range Testing of an Endo Tower (2018) Endoscope towers are combined systems which were optimized for the application field they are planned for. All components are design to get a common working system, to get a harmonic chain of techniques (Graph 5.18). If hospitals buy an endo-tower from one company and the same one for each specialty, most of the system will not be designed and adaptable to the majority of application fields. Technical testing of the components or even the complete tower, may not find out the component that does not fit to a certain application. With plastinates, it could be shown, why such a system did produce only dark images. Light absorptions and distances, as well as their relations were the parameters that cannot be calculated only technically but need simulation close to reality. The behavior of optics, light source and camera computer is difficult to be predicted and has to rely partially on experience.

5.6 Applications of Plastinates During 33 Years in MIN

Chain of Micro-Technique

Chain of Micro-System-Technique

CT/MR Mikro Instrumente

Energie Support

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Sono Imaging

Bohrioch Mikro Instrumente HMD System

Monitoring Koaxiales Licht Ergonomic Trauma

Energie Support

NEW

Endoskop Licht

Endoskop System Kette: Mikro Technik

Mikroskop

Neuro Navigation

System Kette: Mikro System Technik >>PICO

Sono Navigation

Graph 5.18  Evolution Micro-Technique to Micro-System Technique

This was a typical finding of a non-adaptable system for neurosurgery from a joint -endoscopy orthopedic unit. Even rather close to the basilar head, the light was too weak (Fig. 5.56). After changing the light machine, equipped with an adaptation tool within an expected range, the maximum of adaptation in that tower reached just a medium quality of light support.

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Fig. 5.56 Endoscopy Basilar Head not-Adjusted Tower

Even in an only medium-quality of light power, the illumination of the larger and deeper anatomic field became bright enough to see all structures better (Fig. 5.57). The dispersion of the light however is still not optimal, as the tested tower did not allow stronger light source.

5.6 Applications of Plastinates During 33 Years in MIN

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However, the plastinate testing environment gave the opportunity to analyze, which component was to be optimized, and which one the company of the tower could not predict. The simulation of condition regarding absorption and depth of anatomical regions was only able by the plastinates, and comprehensive for the surgeon by original anatomy conditions. Fig. 5.57 Endoscopy Basilar Head Adjusted Tower

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The testing environment was also able to show, that illumination of a small gap was possible by the camera computer, even if the surrounding field is reflecting a lot of light (Fig. 5.58). Origin of PICA and running through the two portions of CN XII into the depth to the jugular foramen laterally from the medulla oblongata from ventral view is possible. This can never be predicted technically alone, but need a perfect simulation condition, as given in plastinates. Very fine structure of dura around the hypoglossal foramina, or the surface of the brainstem can be offered in the original anatomy by plastinates, even in this preparation design from an unusual ventral perspective. The easier illuminated surface of medulla dorsally (Fig.  5.59) gives a nice appearance of the different surfaces of cerebellum and medulla regarding color and structure. In the para-medullary gap on both sides, the illumination was of good quality, even in the depth of these lateral gaps. However finally, one has to admit, for neurosurgery it is best to use a special neuro-endoscopic tower. For per-nasal use the light must be much stronger, and auto-correction needs a wide range. In plastinates one can proof this intensively. Function of the endo-tower is a requirement to enable any endoscopic surgery.

Fig. 5.58  Para-Medullar Trans-Oral

5.6 Applications of Plastinates During 33 Years in MIN

Fig. 5.59  Subocc. Median

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After adaptation of the light source, the illumination in the head-plastinate was much better. Basilar head area (1–3) and V-B conjunction area with cranial nerves IV-XII (4–6) could be visualized by 30° endoscope trans-nasal and trans-oral. Such complex test-environment for depth, focus-range and light-dispersion cannot be simulated virtually (Graph 5.19).

Graph 5.19  Endoscopy Trans-nasal; Trans-oral Basilar System in a Plastinate

5.6 Applications of Plastinates During 33 Years in MIN

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5.6.11 Exoscope: Kinevo 900 System (Zeiss) Testing (2019) Actually, the evolution of visualization for MIN is preferring the exoscope-way, which is represented by several systems on the market now (s. Vol. 1; Chap. 3). As these systems were developed rather silently and the prototypes of Olympus (Japan), MINOP II and PICO were not successful, the author was involved in the evolution of MIN mainly clinically. So, it was a good chance to organize a test-setup date during some conferences. Only with the application of plastinates this was possible easily outside of any laboratory environment. Nothing more than the exoscope system and a head-plastinate was necessary to have a quite effective test setup and experience. In all tested systems, the overall impression was, that the industry neglects any ergonomics rules (s. Vol 1. Chap. 3). However, new holding systems, high-resolution 4K cameras and large screens, enables to stay outside the cranium, avoiding all the safety-problems well known from endoscopy (Fig. 5.60).

wrong viewing angle

Fig. 5.60 View-Angle

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Each new visualization system must compete with mouth-tracked, high-zoomed surgical microscopy, the gold-standard of microneurosurgery. The seen, unusual microscopic approach trans-orally to the ventral brain stem, is not a very tuff task compared with a trans-burr-hole approach. Swift and easy change of focus and visual operative field, then is not indispensable, however, 3D effect and concentration on the necessary ROI with the chance for smaller approaches (MIN) is challenging (Fig. 5.61). No Fast Free-hand Tracking

Fig. 5.61  Manual Tracking

5.6 Applications of Plastinates During 33 Years in MIN

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The complete system is rather large, compared with others, but it is built on the Penthero-system, offering all the technical advances from there additionally. However, regarding the future rules of ergonomics (s. Vol. 1, Chap. 3), miniaturization and modularity will play a leading role. Visual ergonomics (s. Vol. 1, Chap. 3) is difficult, as the large screen does not allow to take the only necessary information 100% on the visual field of the surgeon. In this setup 90% of the information to the surgeon will be un-necessary and disturbing neuropsychologically (Fig. 5.62). The head-plastinate allow a test-environment to study such spacial- and visual-­ ergonomics conditions, which have a major impact on the work-flow and finally the results.Testing of new systems by the normal user takes place on conferences at the industry exhibitions insufficiently, or they were broght directly into the OR making patients a laboratory of testing. Both is not effective and not acceptable. One should start in the lab within a surgical simulation environment (Chap. 3), or much easier, at least with a plastinate.

4

3

5

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1

7 8

9

Fig. 5.62  Visual Ergonomics

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In comparison to Fig.  5.62, this is the gold standard in MIN (Graph 5.20), to focus by high-zoom on the important information of ROI. The brain of the surgeon is not disturbed by un-necessary information. This is an extremely fast and mobile concept of adaptation and focusing by mouth-tracking and zooming, which is not possible by automatic systems. In contrast, the exoscope-high-resolution screen concept is a rather static equipment, not taking advantages of the focusing concept (Graph 5.20).

Zooming up ROI Only important visual information to the visual field of retinal macula Near 100% needed visual information

97% not needed visual information!

Graph 5.20  Zooming (s. Vol. 1, Chap. 3)

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The main advantage of the exoscope concept is the ability to stay outside the cranium. Moreover, it avoids the use of mouth-tracking, which would need anyway an evolution to be convenient for a majority of users. But the testing with plastinates demonstrates, that actual exoscope standard seems not to reach the high MIN abilities of mouth-tracking high-zooming technique (Fig. 5.63).

Fig. 5.63  45° Free-Hand Endoscope Tool (QEVO)

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The KINEVO system (Zeiss) has an endoscopy-tool for intermittent use during exoscopic microsurgery. In general, this is aneloquent concept giving a variety of additional visualization. But, as one of the most active neuro-endoscopists (s. Vol. 1, Chap. 5), in the past 33 years, involved in all kind of neuro-endoscopy, I need to give a warning at this point: this tool has a 45° view-angle, which is, even for experienced endoscopists, challenging and dangerous. Finally, it is not necessary to use 45° angling, because 30° will do, as the broad perspective of modern endoscopes allow “to look around corners” anyway. The pitfall in this 45° tool is that it does not allow “mental navigation” (Graph 5.21) by the surgeon, as the visual-vector and the moving-vector of the endoscope are too far away from one-another. The danger is caused mainly, because the blind field of the 45° tool is just straight ahead in the moving direction of the endoscope (s. Graph 5.22). Such condition often did cause, that the endoscope is pushed ahead in this blind field, into the parenchyma, tearing nerves or vessels. The parallel visual control by the exoscope view is not safe enough to avoid this (Graph 5.23).

5.6 Applications of Plastinates During 33 Years in MIN

a

Exoscope View Trans-Nasal Approach Pituitary Gland Basilar Head

45°-Endoscope View Nasal Conchae Etmoid Base

b

Exoscope View Trans-Nasal Approach Endoscope

45°-Endoscope View Trans-Nasal Cranio-lateral CN III-XII

Graph 5.21 (a, b) 45° Endoscopy Trans-Nasal (a); Trans-Oral (b)

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Graph 5.22  Mental-Navigation in Neuro-Endoscopy Graph 5.23  Blind Field in the 45° Endoscope

The free-hand neuro-endoscope tool of the KINEVO system (Zeiss) presents a high-resolution visualization to support the exoscope in the field of “looking around the corner”. For this task the correlation of weight, dimension and mechanics with the visual quality is unique. However, as described above, 45° angling causes some challenges. Moreover, design and ergonomics is bound to the mentioned supporting task. Such abilities and limits can be best tested in head-plastinates. Also, a surgical simulation concept in non-fixed specimen can be a strict test-­ environment (s. Chap. 4), however, this is a lab-setup with high efforts. To go into the OR, holding this tool into a common approach-design, has nothing to do with MIN.

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Graph 5.24  Trans-nasal Endoscopy in a Head-Plastinate

During this test environment trans-nasal (Graph 5.24), trans-oral (Graph 5.25) and median suboccipital (Graph 5.25), in the head-plastinate, handling and resolution came out to be good, and illumination qualities were sufficient. Compared with the screen image of the exoscope, the endoscope tool is giving a strong close-up visualization and chance to looking into dark gaps, but rather dark in deep spaces. Light- and color-balance must be careful adjusted. But, again, think about the blind field just straight in front of the endoscope! The tool should not be taken, as recommended by the design, with one hand, as this promotes the disadvantage to hurt tissue in the blind field. The instrument is so light, that you can hold the shaft like a pencil, using all neuro-psychological experience since your school time. If you take the hand-piece in one hand you must control the shaft with the other one! The transoral visualization of the right vertebral artery, ventral to the typical double portion of the CN XII, shows in the close up a nice and strong sympathetic nerve (5). Medial a part of the spinalis anterior system is visible, running on the medulla. Vertebro-basilar conjunction in a dislocated case (1–3) in 45° cranial direction, and paraspinal region left (4) are well visualized. Median posterior fossa from dorsal route in an overview distance (6) show the illumination differences cerebellar and spinal. In summary, this tool is a pure assisting instrument, and cannot substitute a real neuro-endoscope. Keeping this in mind it has its’ specific place. The system has potential for evolution. Plastination can promote this.

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Graph 5.25  Endoscopy in a Head-Plastinate (Trans-oral 1–5; Subocc. Med. 6)

Endoscopes are weapons, to become a surgical instrument they must be adjusted in orientation, white-balance and focus! (s. Vol. 1, Chap. 5).

Suggested Reading Böker DK, Deinsberger W. Springer-Verlag. Currarino G.  Canalis basilaris medianus and related defects of the basiocciput. AJNR. 1988;9:208–11. Darabi K, Resch KDM, Weinert J, Jendrysiak U, Perneczky A. Real and simulated endoscopy of neurosurgical approaches in an anatomical model. In: CVRMed-MRCAS'97. Springer; 1997, pp 323–326. Fisch U. Infratemporal fossa approach for glomus tumors of the temporal bone; 1982. https://doi. org/10.1177/000348948209100502. Fisch U, Fagan P, Valavanis A.  The infratemporal fossa approach for the lateral skull base. Otolaryngol Clin North Am. 1984;17(3):513–52. PMID: 6091018. Fisch U, Valavanis A, Yasargil MG. Neurological surgery of the ear and the skull base. 6th ed. Berkeley: Kugler; 1988. Hagens GV. Impregnation of soft biological specimens with thermosetting resins and elastomers. Anat Rec. 1979;194:247–55. Hagens GV (1985/1986) Heidelberg plastination folder. Anatomisches Institut I, Universität Heidelberg. Hagens GV, Whalley A. Körpewelten (Katalog) 21. Auflage 2019 Arts & science, Verlagsgesellschaft mbH, Heidelberg; 2010. Hagens GV, Tiedemann K, Kriz W.  The current potential of plastination. Anat Embryol. 1987;175:411–21.

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Hagens GV, Whalley A, Maschke R, Kriz W. Schnittanatomie des menschlichen Gehirn. Darmstadt: Steinkopff; 1990. Hagens GV, Romrell LJ, Ross MH, Tiedemann K. The visible human body. Philadelphia: Lea and Febiger; 1990a. Hellwig D, Bauer BL. Springer Science & Business. Hopf NJ, Grunert P, Fries G, Resch KDM, Perneczky A. Endoscopic third ventriculostomy: analysis of 100 procedures. Neurosurgery. 43(3):684. Janecka IP, Klaus T. Skull base surgery: anatomy, biology and technology. Philadelphia: Lippincott-­ Raven Publishers; 1997. 422 pages. Jendrysiak U, Resch KDM. Ergebnisse der klinischen Erprobung der Operationszugangsplanung mit NeurOPS. Bildverarbeitung für die Medizin; 1999. p 187–191. Meditec CZ.  Lösungen für die Medizin made by Zeiss; 2017. https://www.zeiss.de/meditec/ produkte/neurochirurgie/operationsmikroskope/kinevo-­900.html. Accessed 14 Apr 2018. Resch KDM. Use of plastinated crania in neuroendoscopy. J Int Soc Plastination. 1989;3(1):29–33. Resch KDM. Plastinated specimens for demonstration of microsurgical approaches to the base of the cranium. J Int Soc Plastination. 1992;6:15–6. Resch KDM. Postmortem inspection for neurosurgery: a training model for endoscopic dissection technique. Neurosurg Rev. 2002;25(1–2):79–88. Resch KDM.  Necrosectomy by MIN techniques versus craniectomy in stroke. J Neurol Sci. 2013;333:e2262013. Resch KDM.  Minimally invasive techniques for neurosurgery: current status and future perspectives. Resch KDM.  Fisch ABC Approach (Abstract and Video). In:Schädelbasischirurgie: Robotik, Neuronavigation, vordere Schädelgrube. Resch KDM, Perneczky A. The use of plastinated specimen in planing microsurgical approaches to the scull- and brain base (fifth international conference on plastination, Heidelberg 1990). J Int Soc Plastination. 1990;3:29–33. Resch KDM, Perneczky A. Endoscopic approaches to the suprasellar region: anatomy and current clinical application. In: Cerebellar infarct. Midline tumors. Minimally invasive endoscopic neurosurgery (MIEN), 13; 1994a Resch KDM, Perneczky A.  Endoneurosurgery: the anatomical basics. In: Skull base surgery; 1994b, 78–80. Resch KDM, Perneczky A. Median basilar canal: anatomical variation of a venous sinus in the clivus surgery of the intracranial venous system. Tokyo: Springer; 1996. Resch KDM, Perneczky A.  Transendoscopic ultrasound in ventricular lesions. Surg Neurol. 2008;69(4):375–82. Resch KDM, Perneczky A. Beitrag zur Zugangsanalyse und zum Zugangsdesign des transoralen-­ pharyngealen Weges zum Hirnstamm. Resch KDM, Reisch R. Minimally invasive techniques in neurosurgery: the transoral transpharyngeal approach to the brain. Neurosurg Rev. 1999;22(1):2–25; discussion 26–7. Resch KDM, Schroeder HWS.  Endoneurosonography: technique and equipment, anatomy and imaging, and clinical application. Oper Neurosurg. 61(suppl_3):ONS-146–60. Resch KDM, Perneczky A, Schwarz M, Voth D. Endo-neuro-sonography: principles and 3-D technique. Child Nerv Syst. 2019;13(11–12):616–21. Resch KDM, Perneczky A, Tschabitscher M. Endoscopic anatomy of the ventricles. In: Minimally invasive neurosurgery II. pp 57–61. Resch KDM, Atzor KR, Perneczky A. Anatomical phantom CT study of surgical approaches for 3-D and VR in neurosurgery. Schebesch K, Brawanski A, Tamm ER, Kühnel TS, Höhne J. QEVO-A new digital endoscopic microinspection tool—A cadaveric study and first clinical experiences (case series). Surg Neurol Int. 2019;10:46. Tiedemann K, Hagens GV.  The technique of heart plastination. Anat Rec. 1982;204(3):295–9. https://doi.org/10.1002/ar.1092040315. Whalley A, Wetz F.  J. Der Grenzgänger: Begegnung mit Gunther von Hagens Arts & Science, Verlagsgesellschaft mbH, Heidelberg 201.

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Plastination Gallery 6.1

Body- Plastinates (I–IV)

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 K. D. M. Resch, Key Concepts in MIN - Intracerebral Hemorrhage Evacuation, https://doi.org/10.1007/978-3-030-90629-0_6

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6.1 Body- Plastinates (I–IV)

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Head- Plastinates (Figs. 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, and 6.7)

Fig. 6.1  Zygomatic Arch and M. temporalis detached

6.2 Head- Plastinates Fig. 6.2 Median Sagittalisation

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6.2 Head- Plastinates Fig. 6.4  Zygomatic Arch and M. temporalis detached

Fig. 6.5 Superficial Cranio-Cervical Nerves

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Fig. 6.7  Zygomatic Arch and M. temporalis detached

6.3

Cerebral Sheet- Plastinates

Scanning of anatomy causes geometrical artefacts, making difficulties in recognition of structures. Moreover, the digitalization causes a vast decrease of optical solution far below the level of MIN. The pixel- and voxel- world needs a strong interpretation capacity and a large experience. Clinical meaning of the structures relies on this mental ability leading to planning and decisions. The anatomical truth and level of acquired structural information is preserved most precisely in sheet plastinates and may be used as a reference and control for CT-scans and MR- scans. Miss-interpretations of pixels and voxels can be clarified with sheet- plastinates. All radiological institutions should have a sample of high-­ end sheet- plastinates in three planes (Fig. 6.8).

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Fig. 6.8  Series of Sheet-Plastinates of Cranium

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6.3 Cerebral Sheet- Plastinates

6.3.1 S  agittal Sheet- Plastinates (Figs. 6.9, 6.10, 6.11, 6.12, 6.13, 6.14, 6.15, 6.16, 6.17, 6.18, 6.19, 6.20, 6.21, and 6.22) Fig. 6.9  Near mediosagittal Sheet-Plastinate

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Fig. 6.11  Near mediosagittal Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.12  Near mediosagittal Sheet-Plastinate

Fig. 6.13 Injected Sheet- Plastinates

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Fig. 6.15 Multi-colored Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.16 Multi-colored Sheet-Plastinate

Fig. 6.17 Multi-colored Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.19 Transparent Sheet-Plastinate

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348 Fig. 6.20 Transparent Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.21 Transparent Seet-Plastinate

Fig. 6.22 Transparent Sheet-Plastinate

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6.3.2 C  oronal Sheet- Plastinates (Figs. 6.23, 6.24, 6.25, 6.26, 6.27, 6.28, 6.29, 6.30, and 6.31) Fig. 6.23 Multi-Color Sheet- Plastinates

Fig. 6.24 Coronar Sheet-Plastinae

6.3 Cerebral Sheet- Plastinates Fig. 6.25 Coronal Sheet-Plastinate

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352 Fig. 6.26 Coronal Sheet-Plastinate

Fig. 6.27 Coronal Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.28 Coronal Sheet-Plastinate

Fig. 6.29 Coronal Sheet-Plastinate

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354 Fig. 6.30 Coronal Sheet-Plastinate

Fig. 6.31 Coronal Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates

6.3.3 A  xial Sheet- Plastinates (Figs. 6.32, 6.33, 6.34, 6.35, 6.36, 6.37, 6.38, 6.39, 6.40, 6.41, 6.42, 6.43, 6.44, 6.45, 6.46, 6.47, and 6.48 Fig. 6.32 Axial Sheet-Plastinate

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Fig. 6.34 Axial Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.35 Axial Sheet-Plastinate

Fig. 6.36 Axial Sheet-Plastinate

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Fig. 6.38 Axial Sheet-Plastinate

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6.3 Cerebral Sheet- Plastinates Fig. 6.39 Axial Sheet-Plastinate

Fig. 6.40 Axial Sheet-Plastinate

359

360 Fig. 6.41 Axial Sheet-Plastinate

Fig. 6.42 Axial Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.43 Axial Sheet-Plastinate

Fig. 6.44 Axial Sheet-Plastinate

361

362 Fig. 6.45 Axial Sheet-Plastinate

Fig. 6.46 Axial Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.47 Axial Sheet-Plastinate

Fig. 6.48 Axial Sheet-Plastinate

363

364

a

6  Plastination Gallery

b

6.3 Cerebral Sheet- Plastinates

6.3.4 I njection Sheet- Plastinates (Figs. 6.49, 6.50, 6.51, 6.52, 6.53, 6.54, 6.55, 6.56, 6.57, 6.58, 6.59, and 6.60) Fig. 6.49  Injected coronal Sheet-Plastinate

365

366 Fig. 6.50  Injected coronal Sheet-Plastinate

Fig. 6.51  Injected coronal Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.52  Injected coronal Sheet-Plastinate

Fig. 6.53  Injected coronal Sheet-Plastinate

367

368 Fig. 6.54  Injected axial Sheet-Plastinate

Fig. 6.55  Injected axial Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.56  Injected axial Sheet-Plastinate

Fig. 6.57  Injected axial Sheet-Plastinate

369

370 Fig. 6.58  Injected axial Sheet-Plastinate

Fig. 6.59  Injected axial Sheet-Plastinate

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.60  Injected axial Sheet-Plastinate

371

372

6  Plastination Gallery

6.3.5 D  etail Sheet- Plastinates (Figs. 6.61, 6.62, 6.63, 6.64, 6.65, 6.66, 6.67, 6.68, 6.69, 6.70, 6.71, 6.72, 6.73, 6.74, 6.75, 6.76, 6.77, 6.78, 6.79, 6.80, 6.81, 6.82, 6.83, 6.84, and 6.85) Fig. 6.1 Vascularization of Muscles/Labyrinth Block (lat. right)

6.3 Cerebral Sheet- Plastinates Fig. 6.62  CN II, III, IV, V, VI; Gasserian Ganglion (lat. left)

373

374 Fig. 6.63 Pyramidal Pathway and Medial and Lateral Brain Ganglia

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.64  Deep Brain Ganglia, Middle Ear

375

376 Fig. 6.65  Optic Tract, CN III, CN V, Cavernous Sinus with Carotid Artery Syphon

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.66  Orbital Cavity and Nasal Sinuses (frontal)

Fig. 6.67  Orbital Cavity, Ethmoidal Cells; (axial)

377

378 Fig. 6.68  Basilar Head (coronal)

Fig. 6.69  CN II, III, V; Anterior Commissure, Fornix, Mandibular Joint (right)

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.70  CN V, VI, Petrosal Apex, Pons (axial)

Fig. 6.71  Medial Brain Ganglia (axial)

379

380 Fig. 6.72  Optic Chiasm, Circle of Willis, Midbrain (axial)

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.73  Optic Chiasm, Midbrain, Mammillary Bodies

381

382 Fig. 6.74  Optic Chiasm, Olfactory Tract, Midbrain

Fig. 6.75  Optic Chiasm, CN III, Orbital Cavity, Ethmoid Cells (axial)

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.76 Anterior Commissure, Fornix, CN II, III, V; Carotid Canal, (coronal)

383

384 Fig. 6.77  Pons, Clivus, Cavernous Sinus (axial)

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.78  CN II, III, V, Cranial Pons, Ethmoid Cells (axial)

Fig. 6.79  Sella, Pituitary Gland, CN III, Basilar Artery; Sphenoidal Sinus (axial)

385

386 Fig. 6.80  Peri- Sellae Region (axial)

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.81 Trigeminal Fibers entering Meckels’ Cavity (axial)

387

388 Fig. 6.82  Petrosal Bone, Posterior Fossa, CN VI, VII, VIII (axial)

Fig. 6.83  Petrosal Bone, CN VII, VIII; Middle Ear, Labyrinth Block, Carotid Canal

6  Plastination Gallery

6.3 Cerebral Sheet- Plastinates Fig. 6.84 Quadrigeminal Lamina, Pineal Gland, fourth Ventricle (coronal)

389

390

6  Plastination Gallery

Fig. 6.85 Splenium, Pineal Gland, Quadrigeminal Lamina; Cerebellum (coronal)

In summary: This Plastination-Gallery is intended to show the high-end quality of anatomy by Plastination, and to draw the attention of the reader to the difference of real anatomy and digital anatomy. One may work-out a feeling for the quality and precision of anatomical structures, patterns and appearances. After studying this gallery, analysis of CT-scans and MR-scans may be seen more critically, remembering that CTs and MRs are not images, but information carriers, which must be analyzed with both cerebral hemispheres, and this must be trained. Moreover, scientifically we see not quantities rather than qualities in a resolution which cannot be provided by CT or MR. (see: Janecka Ivo P. and Tiedemann Klaus, Skull Base Surgery; and: All Catalogues of Body-Worlds). Science is only based on reason, but reason not only on science. There is no vaccine to get reason!

6.3 Cerebral Sheet- Plastinates

391