Minimally Invasive (MI) Orthognathic Surgery: A Systematic Step-by-Step Approach 3031380118, 9783031380112

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Gwen R.J. Swennen Editor

Minimally Invasive (MI) Orthognathic Surgery

A Systematic Step-by-Step Approach

Minimally Invasive (MI) Orthognathic Surgery

Gwen R.J. Swennen Editor

Minimally Invasive (MI) Orthognathic Surgery A Systematic Step-by-Step Approach

Editor Gwen R.J. Swennen Department of Surgery Division of Maxillofacial Surgery and Facial Plastic Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium Bruges, Belgium

ISBN 978-3-031-38011-2    ISBN 978-3-031-38012-9 (eBook) https://doi.org/10.1007/978-3-031-38012-9 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed 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

I want to dedicate this book to my family and to my fellows Yves and Fernando who made this “impossible” project “possible” … Gwen R.J. Swennen

Foreword

A lot of books have been written about orthognathic surgery, but I think none as well illustrated and timely. The aim of this book is to introduce the concept of minimally invasive (MI) surgery for the standard orthognathic surgery procedures. Doing this safely, precisely, and efficiently involves a lot of prescriptions, starting with the planning but also during the perioperative phase and aftercare. This book describes in great detail all aspects that are essential for that facilitate MI orthognathic surgery. There is a lot of evidence in most surgical disciplines that MI surgery has brought about a lot of advantages: better outcomes, faster recovery for the patient, less comorbidities, shorter hospital stays, and better cost-efficiency. The laparoscopy has pushed the laparotomy into a very small corner with few indications. Endoscopic procedures have also been tried in Oral and Maxillofacial (OMF) Surgery in general as well as orthognathic surgery. But for now, at least there is no evidence that an endoscopic approach for the basic orthognathic techniques is viable. Until maybe the day that robotics, navigation, and artificial intelligence (AI) make a quantum leap of progress for these specific indications. Mind you, there are first anecdotal reports on robotic insertion of dental implants. So, the alternative to endoscopic orthognathic surgery consists then in minimizing the length of the incision, extend the tunnelling of the flaps and limiting the areas of degloving of the periosteum. And to do so in an optimal systematic way for all basic orthognathic procedures. Other criteria of course are protection of the tissues thus avoiding damage, creating adequate access and visibility of the target areas, and achieving the simulated results and length of the surgical procedure. More importantly, there is sound biological thinking behind the concept of MI orthognathic surgery. The rationale is very well explained and underpins the rationale for the following chapters. Making incisions shorter and safe degloving can be done by moving the incision further away from the mucogingival border. This will lead to less risk of gingival retractions and periodontal damage. Obviously, a short incision along the inside of the upper lip combined with atraumatic tunnelling toward the maxillary tuberosity leads to equally good exposure as a long incision just above the mucogingival border extending from one molar to the contralateral one. But the former will keep the non-randomized blood supply of the buccal flap intact and the degloved area can be limited vertically to the osteotomy level, without disturbing the periosteal attachment and blood supply to the alveolar process. Avoiding acute ischemia at the time of osteotomy and down-fracture as well as long-term chronically decreased intra-osseous oxygen tension are essential to avoid damage to teeth and periodontium. Some reports suggest significantly increased occurrence of dental pulp obliteration following “classical” approaches for Le Fort I osteotomies. And we do not want to create an ideal smile line, with exposure of the interdental papillae, while at the same time risking losing the fullness of these by chronic low-grade ischemia that could result in black interdental triangles. It is therefore important to keep this buccal flap as broad as possible and as well attached to the inferior portion of the maxilla as possible. This source of blood supply becomes even more critical in case of surgical damage to the major palatine artery and in some cleft cases where this blood supply is compromised.

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Similarly, minimal but safe degloving is advantageous for the sagittal split osteotomy (SSO). Maintaining blood supply to the condylar head and neck is important for the long-term stability of the condylar volume, which seems to be affected by these osteotomies. And there is no need for aggressive stripping of the masseteric mandibular insertion along the entire length of the mandibular angle, as this can lead to excessive and unpredictable resorption of the gonial angle, having devastating aesthetic consequences in some cases. Executing a surgically assisted maxillary expansion via a small endonasal incision and approach on both sides of the piriform rim illustrates best the principle of “minimally invasiveness,” combined with long tunnelling and safe handling of the cutting instruments. This approach indeed creates “closed boxes” where the distraction osteogenesis (DO) can occur undisturbed. Obviously, under the correct circumstances this approach will also lead to minimal bleeding, swelling, and discomfort for the patient with optimal postoperative fast recovery. Equally the MI orthognathic approach for the genioplasty results in minimal incision, safe and minimal degloving, and adequate fixation of the well-vascularized chin prominence. The author has convincingly demonstrated in this book that criteria of safety, efficiency, maximizing blood supply, and minimizing morbidity can be met. This requires a number of preconditions that all should be fulfilled. The first one was the development of new adapted instruments that allow for easy manipulation of the target areas via small incisions and long narrow tunnels. Instead of this being a risky leap of faith with unknown risk when trying this out, which we should not do, the author describes a standardized routine to proceed safely, swiftly, and precisely in a non-traumatic way. The core of the book consists of step-by-step description and illustration of the basic orthognathic procedures in a “Minimally Invasive (MI) Approach” with a “Minimally Invasive Mindset”: Le Fort I osteotomy, bilateral sagittal split osteotomy, genioplasty, surgically assisted maxillary expansion. Those illustrations have a consistent format consisting of graphically representing the correct use of surgical instruments using cadaveric specimen, synthetic skulls, clinical drawings, and highlighted text blocks. The quality of the photography and illustrations is superb, not to mention perfect. These illustrations accompany the step-by-step description of all relevant surgical actions during a specific procedure. These descriptions are detailed and self-explanatory. These chapters and their illustrations must have been a huge and time-consuming effort for all involved, not at least the photographer and the illustrator. Obviously, using new instruments alone will not lead to better or less invasive surgery. Professor Swennen has to be commended for describing in detail all other aspects that are key for a successful outcome. These deal with the preparation of the patient immediately prior to surgery, the anesthetic protocols, hypotension, local vasoconstriction, the positioning of the assistants and the nurse, the use of a specific extension of the OR-table, and all aspects of the aftercare. But actually, the MI orthognathic procedure starts much earlier. If we are going to make small incisions combined with long tunnels and minimal degloving, we must know exactly where the osteotomy cuts will be and where there will be interferences that need removing, so that we can stick to the MIS principles. That is where precise planning is essential. The authors describe in detail the clinical examination and documentation that are essential for the surgical planning as well as the 3D planning itself which should be done by the surgeon him/herself, so that they have detailed insight not only of the surgical movements they are planning but also all details relevant for MIS. As we all know, a good research paper should be written such that an experiment can be duplicated elsewhere in an identical way, leading to identical or similar results. It seems to me that this book allows exactly to achieve this as well. The solid structure of the book, the amount of details, and the illustrations should allow for that once the team is beyond the learning curve. As for the learning curve itself, this can be shortened significantly by following the step-­ by-­step instructions and illustrations in a simulated situation as illustrated in the book.

Foreword

Foreword

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I wish to congratulate Professor Gwen Swennen, the photographer Valerie Swennen-­ Boehlen, and all contributors with this detailed atlas of excellent quality. Professor Gwen Swennen cites in his book Theodore Lewitt: “Creativity is thinking up new things, innovation is doing new things.” I think that he has proven what innovation is. With a relentless passion and hard work over the past decades, he has developed an innovative way to perform minimally invasive (MI) orthognathic surgery based on precise 3D virtual planning and simulation, as well as creating modified instruments to facilitate MIS.  All of what is explained in this atlas, is backed by multiple peer-reviewed papers. His two previous books were innovating the area of 3D cephalometry (2005) and 3D virtual planning (2016). This new book eloquently squares the circle of innovation in orthognathic surgery. Piet Haers Oral and Maxillofacial Surgery, Guildford Nuffield Hospital Guildford, UK Dental Implant and Maxillofacial Centre Hong Kong

Foreword

Orthognathic surgery has witnessed a phenomenal paradigm change in the last two decades. This change has been driven by two specific factors, namely: 3D planning and improvement of surgical techniques. The advancement of 3D planning has allowed surgeons to design skeletal surgery in a predictable and accurate manner, yielding a significant improvement in surgical outcomes. Gwen Swennen, undoubtedly one of the top oral and maxillofacial surgeons in the world, has definitely contributed to this development and in cooperation with KLS Martin designed a comprehensive user-friendly platform for 3D planning. Minimally invasive surgical techniques have revolutionized the field in recent years. In this new book, Gwen and his coauthors provide a comprehensive overview of different orthognathic surgical techniques in an orderly and well-structured manner. Drawing on his years of experience, Dr. Swennen offers an in-depth and practical analysis of the latest techniques, used in orthognathic surgery. I am happy and honored to see that some of my original published techniques such as our minimally invasive Le Fort I, with a reduced approach using tunnelling techniques, as well as our technique for cross suturing of the nasal muscles to prevent nasal widening, have also been incorporated in the book. To give a practical twist, the authors again in partnership with KLS Martin have developed an extensive array of surgical instruments for each of the described surgical approaches. Precise indications for each of those instruments are presented in the book. Overall, this book is an essential resource for anyone interested in orthognathic surgery. It provides a comprehensive overview of the field and is filled with valuable insights and practical advice. Whether you are a novel or experienced surgeon, this book is must-read. Federico Hernández-Alfaro Full Professor and chairman, Department of Oral and Maxillofacial Surgery Universitat Internacional de Catalunya (UIC) Barcelona, Spain Director, Institute of Maxillofacial Surgery Teknon Medical Center Barcelona, Spain

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Preface

There’s a way to do it better – find it … Thomas. A. Edison 1957 Creativity is thinking up new things … Innovation is doing new things. Theodore Levitt 1986 Education is the path to Innovation . . . Peter Serdyukov 2017

For 25 years, I have been focusing on how to decrease patient morbidity and increase postoperative recovery and comfort after orthognathic/orthofacial surgery by continuous self-­ reflection, research, education, and innovation. The Color Atlas and Manual on Three-Dimensional Cephalometry (Springer, 2005) was an attempt to bridge conventional cephalometry with the 3D virtual approach by the introduction of 3D cephalometry. It is amazing that after more than 18 years the concept of this atlas remains more than actual for both orthodontists and surgeons. 3D Virtual Treatment Planning of Orthognathic Surgery: A Step-by-Step Approach for Orthodontists and Surgeons (Springer, 2017) represented a comprehensive, systematic, standardized but above individualized patient approach toward 3D virtual planning of orthognathic surgery in the daily clinical routine. Although I promised myself afterwards never to undertake a book project anymore, the intrinsic force toward teaching was just too big. The COVID-19 pandemic with three lockdowns in my country made me aware of how important education is to stimulate research toward innovation for better healthcare. This new atlas Minimally Invasive Orthognathic Surgery represents the third part of a “trilogy” based on a “personal 25 years Odyssey” dedicated to improving overall care of patients with maxillofacial deformity. I sincerely hope that this manual will be a guide for both young and experienced surgeons to increase both their own skills and the quality of life of their orthognathic patients. Bruges, Belgium April 2023

Gwen R.J. Swennen

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Acknowledgments

First, I need to thank my teachers and mentors Professor Jarg-Erich Hausamen (former chair, Department of OMF Surgery, Hannover Medical University, Hannover), Professor Henning Schliephake (chair, Department of OMF Surgery, Georg-August University, Göttingen), and Professor Chantal Malevez (former chair, Department of OMF Surgery, Queen Fabiola Children´s University Hospital, Brussels) who taught me not only the importance of working hard in order to become an excellent surgeon, clinician, teacher, and researcher but also the values of respect and loyalty. I am also very grateful to Professor Albert De Mey (former chair, Department of Plastic Surgery, University Hospital Brugmann and Queen Fabiola Children’s University Hospital, Brussels) and Peter Brachvogel (former staff-member, Department of OMF Surgery, Hannover Medical University, Hannover), both of whom unfortunately passed away too soon, for having trained me in all aspects of facial surgery. I want to thank all my associate colleagues (Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV and AZ St-Lucas, Bruges) for their continuous support and also all residents, international fellows, and course participants whom I was allowed to train over the years. I wish to thank all my referring orthodontists and colleagues for having been working together so nicely the last 18 years in Bruges and look forward to our further collaboration in the future. I am very grateful to SORG (Strasbourg Osteosynthesis Research Group), Oliver Scheunemann (SORG Secretary General), and his team and all my co-members of the orthognathic section for the excellent and stimulating collaboration over more than 20 years. In particular, I need to thank Professor Peter Kessler (chair, Department of OMF Surgery, Maastricht University, Maastricht) for our successful cadaver courses in Maastricht over more than 10 years and Professor Piet Haers (Oral and Maxillofacial Surgery, Guildford Nuffield Hospital, Guildford, UK; Dental Implant and Maxillofacial Centre, Hong Kong) for always having been pushing and motivating me. I also thank Piet for his nice and honest foreword to this atlas, which means a lot to me. I am also very thankful to Professor Octavio Cintra (SORG Latin America) and Professor Lydia Lim (SORG Oceania) for their help in the first MI Orthognathic cadaver courses in Florianópolis, Brazil and Melbourne, Australia. An important part of innovation is to be confident about sharing ideas. Especially, I want to thank Professor Federico Hernández-Alfaro not only because through him I had the opportunity to be the co-director of the first Spanish OMF European PhD thesis conducted by Raquel Guijarro Martinez on “Cone-beam computerized tomography evaluation of the upper airway in the context of orthognathic surgery” but also learnt directly through this most special connection, the potential of the pioneering work of Professor Federico Hernández-Alfaro on a minimally invasive approach to the Le Fort I osteotomy, on which the technique described in this atlas is primarily based. Fede, thank you also that you accepted my invitation to write your foreword which is a great honor to me. I also thank Raquel. Of course, I may not forget to thank Professor Mirco Raffaini (Department of OMF Surgery, University of Florence and Founder/Director, Face Surgery Center, Parma, Italy) for having written his foreword to my second book on 3D virtual planning of orthognathic surgery and having been always an inspiration to me.

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Toward this third book project, I need to thank so many people who were involved. Nasser AlAsseri (former 1-year fellow Bruges, Riyadh, Saudi Arabia) for his systematic review on minimally invasive orthognathic surgery. Professor Hugo De Clerck (private practice, Brussels, Belgium and adjunct Professor, Department of Orthodontics, University of North Carolina, Chapel Hill, USA) for the synthetic skull with braces and for his initial help already in 2016 in making pictures of the first demo MI orthognathic instruments with the help of Mauricio Demétrio (former 3-month fellow Bruges, São Luis, Brazil). I want to thank Abdulmalik Al-Yahya (former 1-year fellow Bruges, Riyadh, Saudi Arabia), Lies Pottel (Head, Clinical Trial Center, AZ Sint-Jan Brugge-Oostende AV, Bruges ), Paulo Bártholo (former 1-year fellow Bruges, Manaus, Brazil), and Matthias Dobbeleire (former resident, Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV and AZ St-Lucas, Bruges) for their tireless assistance during the photography sessions on the cadavers. A special thanks to Professor Arno Lataster (former Chair, Department of Anatomy and Embryology, University of Maastricht, the Netherlands) and this team for the possibility and assistance during the surgery on the cadaver specimen in Maastricht. I want to thank Rolando Carrasco (former 1-year fellow Bruges, Santiago, Chili) for his help in the MI orthognathic cadaver courses, and I especially thank Professor Sergio Miranda (Chair, Department of Facial Surgery, São Paulo, Brazil) for his support and personal advice. True innovation is only possible based on creativity in combination with continuous research, education and last but not least support of the industry to make it happen. I therefore need to thank KLS Martin with more than 150 years of experience in the development of surgical instruments. In particular, I wish to thank Christian Leibinger and Michael Martin for having pushed me to realize this project and for their continuous support. I also need to thank Thomas Samyn, Frank Reinauer, Sebastian Steppacher, Malvin Debono and especially Pascal Dilger, Volker Scheu, and Cederic Mühlmann for their tireless collaboration in the design and production of the MI orthognathic instruments. Moreover, I am very grateful to Tobias Held, Christoph Krüger, Bernard Tsang, Achim Riedle, Hannes Leibinger, Stefan Betzler, Ariane Kiehne, and Moritz Küssner for helping in setting up the educational courses. Of course, special thanks to Monica Hengstler and her team for their invaluable support during the online webinars and phantom web courses and Mayton Chacon and Candido Marques for setting up the cadaver courses. I want to thank Springer once again for their trust and collaboration in publishing this new project and especially Daniella Heller and Lee Klein for making this wonderful atlas feasible. Last but not least, I want to thank especially three wonderful persons without whom this project would never have been realized. My two contributors, Yves Weinberg and Fernando Andriola, and my lovely wife Valérie who made all the high-quality pictures shown in this atlas. Professor Gwen R.J. Swennen MD, DMD, PhD, MSc, FEBOMFS. Bruges, Belgium, April 2023 First of all, I would like to thank my wife Dorelle and my children Eyal, Aya, and Meshi for their support in this project and their countless sacrifices throughout the years. I am also grateful to my parents, Dr. Avraham Weinberg and Danielle Gourevitch, for being a strong pillar and role model and for their support and guidance. I would like to thank my teachers and mentors, Prof. Oded Nahlieli (Former Chairman, OMF Department, Barzilai Medical Center, Israel), pioneer in minimally invasive surgery and Dr. Amram Zagury (Deputy Chairman), for educating me to be a good clinician. I would also like to thank Prof. Shlomo Calderon (Former Chairman, OMF Department, Rabin Medical Center, Israel), a pioneer and leading orthognathic surgeon in Israel, for giving me the opportunity to learn from him and for his valuable advice. I am grateful to my teachers and colleagues over the years, Dr. Alex Abramson (Chairman, OMF Department, Barzilai Medical Center, Israel), Dr. Guy Weinberg, Dr. Dan Kopeliovich, Dr. Yaron Nazarian, Dr. Liat Hecht-Nakar, Dr. Noam Bruck, Dr. Sagi Sivan, Dr. Yuval Samuni, Dr. Izhar Shohat, Dr. Giovanni Audino, Dr. Rachel Berkun-Horwitz, Dr. Sigal Mazor, and Dr. Roi Keren for their teaching, friendship, and continuous support. A very special thank you also to all the staff members and residents of OMF and Facial Plastic Surgery

Acknowledgments

Acknowledgments

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Department at AZ Sint Jan hospital, for sharing their wide knowledge during my 1-year fellowship in Bruges, Belgium. Most of all, I want to thank the two people who shared this huge project with me. First to my talented colleague Dr. Fernando de Oliveira Andriola for sharing his clinical and scientific knowledge, for his hard work, for all the wise pieces of advice during the writing process, and for his friendship. Finally, I especially want to thank the editor and lead author of this atlas, Prof. Gwen R.J. Swennen, for being an inspiring teacher and mentor to me, for giving me the opportunity to learn from his tremendous knowledge in 3D treatment planning, from his outstanding surgical skills and innovative minimally invasive techniques, and also for all the amazing tips and advices, for teaching me what standardization and efficiency is, and for giving me the enormous honor of being part of this beautiful project. Yves Weinberg MD, DMD. Tel Aviv, Israel, March 2023 Great achievements are only possible if we are surrounded and supported by kind, special, and inspiring people. It has been a gift to have so many of them by my side, both at work and in my personal life. Therefore, I especially want to thank and dedicate this work to my lovely wife Amanda, to my beloved daughter Helena, and to my parents, Débora and Ernani, my greatest supporters and source of inspiration, as well as to all my family, friends, and colleagues. I particularly want to thank my mentor, colleague, and dear friend Prof. Dr. Guilherme Fritscher for all the opportunities entrusted to me during the last 9 years. Many thanks also to Prof. Dr. Angelo Menuci, dear colleague and friend with whom I have the pleasure to work and to continuously learn every day. I wish to thank my advisor during master’s and doctoral period, Prof. Dr. Rogério Pagnoncelli, for his trust and support, and my friend Prof. Dr. Orion Haas who made my Research and Clinical Fellowship in Bruges possible. I am very grateful to all professors, colleagues, and employees of the Pontifical Catholic University of Rio Grande do Sul (PUCRS), which was my second home during residency, masters, and doctorate courses, and where I am very proud to be an Associate Professor today. Thanks to the professors and friends from the Federal University of Rio Grande do Sul, School of Dentistry (FO-UFRGS), my alma-mater, where I graduated in 2013 and had the honor to work as an Assistant Professor in 2019. Special thanks to my dear friend and colleague Prof. Dr. Angelo Freddo, my advisor during the undergraduate course and a great partner during professorship as well. Thanks to the staff members, nurses, secretaries, residents, and fellows of the Division of Maxillofacial Surgery and Facial Plastic Surgery, Department of Surgery, AZ Sint-Jan Bruges-Oostende, Belgium, for their kindness, help, and for everything they taught me during my amazing time in West Flanders. Special thanks to my dear friends Yves Weinberg (Israel), Ugo Amadi (Italy), Thamer Alanezi (Kuwait), Anna Olejnik (Poland) and Giovanni Audino (Italy), with whom I had the pleasure to work during my time in Bruges. Thanks to the Brazilian Government Agency for Higher Education (CAPES) for the opportunity to live and study abroad during my PhD. Last but absolutely not least, what can I say about Prof. Dr. Gwen R.J. Swennen? I just wish more people had the opportunity to work and learn from such an inspiring person like him. It was a priceless opportunity that changed my mind and my perspectives for good. I have no words to express how grateful I am to him for receiving me in the middle of a very tough and uncertain period, during one of the worst parts of the Covid-19 pandemic. He and Valérie were so kind and truly treated me as a family member every time I was in Bruges or Knokke, really making me feel at home. I will never forget how amazing you are! One of the most remarkable things I learned from him was the slogan of Club Brugge— which I heard him repeating “a few” times and that I will certainly take for life: “No sweat, no glory!” Gwen, thanks for all the opportunities and for everything you taught me, not only in the field of maxillofacial surgery, but also regarding integrity, perfectionism, loyalty, and hard work. It was a great honor to be part of this “impossible” and amazing project. Thank you for your trust and for counting on Yves and me to go for it. Fernando de Oliveira Andriola DDS, MSc, PhD. Porto Alegre, Brazil, September 2023

Contents

1 Background  and Introduction to Minimally Invasive (MI) Orthognathic Surgery�������������������������������������������������������������������������������������������������   1 Fernando de O. Andriola, Yves Weinberg, and Gwen R.J. Swennen 2 A  New Concept Toward Minimally Invasive (MI) Orthognathic Surgery �����������  11 Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg 3 Minimally  Invasive (MI) Chin Osteotomy���������������������������������������������������������������  23 Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg 4 Minimally  Invasive (MI) Le Fort I Osteotomy���������������������������������������������������������  53 Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola 5 Minimally  Invasive (MI) Sagittal Split Osteotomy �������������������������������������������������  89 Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg 6 Minimally  Invasive (MI) Maxillary Expansion������������������������������������������������������� 125 Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola 7 Minimally  Invasive (MI) Mandible Constriction/Expansion��������������������������������� 151 Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola 8 Conditions  Toward Minimally Invasive (MI) Orthognathic Surgery ������������������� 163 Yves Weinberg, Fernando de O. Andriola, and Gwen R.J. Swennen

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Contributors

Fernando de O. Andriola, DDS, MSc, PhD  Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil Andriola Odontologia, Porto Alegre, Rio Grande do Sul, Brazil Yves  Weinberg, MD, DMD  Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel

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Background and Introduction to Minimally Invasive (MI) Orthognathic Surgery Fernando de O. Andriola, Yves Weinberg, and Gwen R.J. Swennen

Minimally invasive (MI) surgery has been described by Hunter in 1999 as a discipline that involves a novel way to perform operative procedures with the main goal of decreasing the sequelae of traditional surgery. In the last two and a half decades, MI surgical approaches were developed in different medical surgical fields and within Oral and Maxillofacial Surgery (OMFS) toward different OMFS procedures such as temporomandibular joint (TMJ), facial trauma and salivary gland surgery. In this chapter, the background of MI orthognathic surgery and development of new MI orthognathic surgical techniques are described. Based on evidence-based literature “MI mindset” parameters and considerations toward optimizing surgical efficiency and decreasing patient morbidity are outlined. Finally, a new “Minimally Invasive Orthognathics Algorithm” that summarizes the overall concept to enhance the Quality of Live (QoL) of patients with maxillofacial deformity undergoing orthognathic/orthofacial surgery is presented.

F. de O. Andriola (*) Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil Andriola Odontologia, Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected] G. R.J. Swennen Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected]

 eneral Considerations About Minimally G Invasive (MI) Surgery Minimally Invasive (MI) surgery is described as a discipline that involves a “novel way” to perform operative procedures, with the main goal of decreasing the sequelae of traditional surgical techniques [1]. MI surgical approaches have been incorporated in different medical surgical fields, being considered effective in both decreasing patient morbidity and improving esthetic results [1–4]. Thoracic surgery, neurosurgery, and feet and hand surgery are some examples of different areas in which MI surgical techniques were initially developed and published in the scientific literature [5–13]. Even though its definition is still considered unclear by some authors, it is usually associated with (1) enhanced and precise preoperative planning, (2) development of dedicated intraoperative techniques and instruments, and (3) specialized postoperative care. In this regard, endoscopically assisted surgery, piezosurgery, and intraoperative navigation are frequently mentioned as important tools to perform MI surgeries as well [3]. In recent decades, MI surgical approaches became “state-­ of-­the-art” when it comes to patient recovery and quality of life (QoL) during the postoperative period, since the wide range of possible applications can significantly help to prevent complications and allow the achievement of treatment goals in a safer, faster and more gentle manner [3]. By reducing soft tissue trauma and decreasing overall patient morbidity, the concept of MI surgery has been encouraging patients who were until recently reluctant and even averse to any kind of surgical procedure. The main reasons are that the recovery time is also shorter and considered much more comfortable regarding edema, bleeding, and pain [14] in comparison to conventional surgical approaches. In general terms, MI techniques are normally associated with smaller incisions, tunneling techniques to avoid extensive degloving of soft tissues, and decreased operating time, consequently enhancing the quality of tissue healing, reducing the risk of infection, and improving the whole postoperative experience.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_1

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 inimally Invasive (MI) Orthognathic M Surgery Likewise in other surgical fields, MI techniques were developed and are currently used in several Oral and Maxillofacial Surgery (OMFS) procedures. MI surgery was first introduced in OMFS through the development of endoscopic-­ assisted surgical approaches to treat salivary gland diseases, especially sialolithiasis [15–21]. By using less invasive techniques, the morbidity and some inherent complications following conventional surgical procedures of the parotid and submandibular glands (e.g., facial scars, nerve damages, numbness, and salivary fistulas) could be successfully reduced [21]. Meanwhile, the endoscope started being used for other surgical approaches, such as in neurological facial surgery [22, 23] and temporomandibular joint (TMJ) arthroscopy [24–28]. Moreover, different MI techniques to treat TMJ disorders (TMD) were developed, such as arthrocentesis and arthroscopic TMJ surgery [29–31]. Additionally, MI surgical techniques to treat condylar [32, 33] and other facial traumas, such as orbital fractures [34–36] were introduced. Besides the endoscopic-assisted techniques, intraoperative navigation, [37–39] distraction osteogenesis, [40, 41] and tissue engineering [42, 43] have also been described as alternatives to minimize patient morbidity. Although each of the latter technologies certainly provides specific advantages, special attention always needs to be paid to guarantee that their implementation will not extensively increase the overall surgical time, which would be a drawback toward the MI surgery philosophy. Toward orthognathic surgery, several MI techniques have been described and evaluated throughout the last decades, as described below (Sects. “Background of MI Orthognathic Surgery” and “MI Orthognathic Surgical Techniques”).

Background of MI Orthognathic Surgery MI orthognathic surgical techniques have been developed to minimize patient morbidity in relation to the conventional more “wide-open” approaches, aiming to reduce surgical operating time, intraoperative bleeding, trauma to the soft tissues, and postoperative discomfort [3]. Scientific evidence has shown that patients undergoing orthognathic surgery using small incisions and minimal dissection have less morbidity and present a faster postoperative recovery after different orthognathic procedures, [3, 4, 44] such as surgical-assisted rapid palatal expansion (SARPE), [45–48] Le Fort I, [46, 49, 50] sagittal split, [51–53] and chin [54] osteotomies. Together with the improved clinical outcome and patients’ positive feedback, the traditional philoso-

F. de O. Andriola et al. Table 1.1  “Minimally Invasive (MI) Mindset” parameters toward MI orthognathic surgery • Use of MI surgical techniques. • Smalla incisions. • Less subperiosteal degloving. • Care and protection of soft tissues. • Gentle retraction. • Delicate instruments. • Avoid unnecessary tissue trauma. • Surgical efficiency (decreasing surgical operating time). As small as possible, but big enough to provide an adequate safe access and avoid lacerations a

phy of “Big Surgeons, Big Incisions”, which for decades has guided surgical training and operation routine around the world, is gradually changing. The “less-degloving mindset” and enhancement of surgical efficiency are meanwhile considered as the key parameters toward decreasing postsurgical discomfort and shortening of the rehabilitation period of patients undergoing orthognathic surgery [3]. The main parameters to perform orthognathic surgical procedures following a “Minimally Invasive (MI) Mindset” based on the scientific literature [3] are summarized in Table 1.1.

MI Orthognathic Surgical Techniques According to AlAsseri and Swennen, [3] there is evidence in the scientific literature supporting that the application of MI techniques in orthognathic surgery is considered safe, feasible, and effective. Nevertheless, despite the reported distinct benefits of the available techniques, the steep surgical learning curve, operating time, and costs are important factors that should be considered before their routine clinical application. Several studies that describe and evaluate different MI orthognathic approaches have been published. In 1990 decade, Morselli [45] described a less traumatic technique toward the maxillary osteotomy used in surgically assisted rapid palatal expansion (SARPE) where no mucosal incision or mucoperiosteal reflection was necessary. The author used only a 2-mm osteotome to perform the midline, the horizontal, and the pterygomaxillary sutures osteotomies. A very high success rate was reported, and all 24 patients presented a rapid postoperative recovery with less postoperative pain. Regarding the incision length and the extent of degloving in different orthognathic surgical procedures, no significant changes were reported until Hernández-Alfaro et al. [47, 50] described a limited approach toward SARPE and the Le Fort I osteotomy through small buccal incisions followed by limited dissection. In the SARPE technique, pterygomaxillary

1  Background and Introduction to Minimally Invasive (MI) Orthognathic Surgery

(PTM) disjunction was performed under intravenous (IV) sedation through the “twist technique” by using a wide osteotome. For the Le Fort I, no significant neurovascular complications were recorded, and early hospital discharge was achieved for both mono- and multi-segmental osteotomies, effectively down fracturing the maxilla and allowing adequate visualization of the anatomy during surgery. No additional surgical operating time was required in comparison to conventional SARPE and Le Fort I approaches to successfully treat two large series of patients. During the Le Fort I osteotomy, piezoelectric surgery was also used to remove bone interferences from the posterior palatine neurovascular bundle. In order to perform a mandibular midline osteotomy, a vertical labial incision was described by Nadjmi et al. [54] as an interesting approach, avoiding an extended horizontal incision through the mentalis muscles. The short vertical midline incision in the lower lip frenulum was considered sufficient to provide an adequate access to the symphyseal region. Nevertheless, it is important to keep in mind that using a small incision does not necessarily mean that the surgical procedure will be less traumatic, since it still needs to be big enough to allow an adequate and safe access to the region of interest. In this regard, besides a conservative incision, appropriate surgical instruments as well as correct handling of the surgical wound and surrounding soft tissues also have an essential role, being even more important than the size of the incision itself. In summary, the incision should be “as small as possible, but big enough” to avoid excessive traction on the soft tissues and to allow a safe osteotomy and accurate stable rigid internal fixation. Otherwise, what is supposed to be an “advantage” can easily become a “drawback” by increasing the procedure’s difficulty and causing even a bigger trauma than the conventional orthognathic approaches.

Keep in Mind

The incision must be “as small as possible, but big enough” in order: 1. To provide an adequate and safe access. 2. To avoid potential lacerations by excessive traction on the soft tissues.

Although small incisions, minimal dissection, and degloving are the keystones of MI surgical techniques, the use of endoscopes, piezoelectric instruments, and intraoperative navigation have proven to be important tools toward MI surgery in various surgical specialties [3, 21]. Nevertheless, there is also still controversy in the literature regarding the longer duration, complexity, and steep learning curve of implementing some of these techniques into the daily clinical routine [3].

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Evidence-based literature supports that the endoscopic approach can have an important role in MI surgeries since it facilitates the use of smaller incisions, reduced subperiosteal degloving, and provides additional magnified visualization [2]. Endoscopic approaches and its advantages were described for the main orthognathic surgical techniques, in sagittal split osteotomies (SSO), intraoral vertical ramus osteotomies (IVRO), and in the treatment of condylar hyperplasia or idiopathic condylar resorption [55]. Toward the IVRO, for example, it gives the surgeon the possibility to better visualize the lingula (Spix spine) to properly control the vertical osteotomy from the sigmoid notch to the inferior mandibular border. Also, the distal and proximal segments and potential bony interferences in between can be better visualized [56]. Toward Le Fort I osteotomies, the use of endoscopic instruments allowed a safe separation of the pterygomaxillary suture through smaller incisions, [57] also being useful as a visual guidance in SARPE procedures. Mommaerts et al. [48] published an innovative endoscopic-­ assisted endonasal Le-Fort I corticotomy procedure toward Transpalatal Distraction (TPD). Regarding the operating time spent, however, there is still no consensus since some authors have found an increased surgical time [46] while others found no significant reduction in overall operating time [48] in comparison to conventional surgical approaches. All authors, however, described a significant reduction in postoperative edema and recovery time [3]. Therefore, it has been recommended that prior to clinical application, inexperienced surgeons start endoscopic handling and training on human or animal cadavers to ensure an adequate level of expertise [49, 51]. Ultrasonic or piezoelectric devices are other useful tools with proven efficacy toward bone cutting with soft tissue preservation, higher precision and control, and the capacity to provide a clean operating field due to its cavitation effect and its micromovement system [58, 59]. With the growing interest in MI orthognathic surgical techniques, the piezoelectric osteotome has been used as an excellent alternative to perform more conservative osteotomies in Le Fort I, [60] SARPE, [61] and mandibular surgical approaches [62]. The surgical operating time, blood loss level, neurosensory complications, and postoperative pain have been assessed as the main factors to determine how efficient and beneficial piezosurgery can be in orthognathic surgery. Similarly to the endoscope, there is no consensus regarding the effect on surgical operating time using piezoelectric instruments. While some studies report no difference, [63–65] other authors defend both the increase [66–70] and decrease [71] of overall operating time. In addition, blood loss was considered to be significantly less in five comparative studies when piezosurgery was used, [63, 64, 66, 70, 72] in contrast to another study [65] that found no difference when comparing the

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piezoelectric device to a Lindemann burr and chisel osteotomy approach. In regard to its neurosensory effect, the main interest was the injury to the inferior alveolar nerve (IAN) during the SSO procedure. Different clinical studies reported no or fast recovering IAN injury when using piezosurgery, [63, 64, 66–77] while one comparative study found less neurosensory disturbance when the SSO was performed by the reciprocating saw combined with chisels [65]. Furthermore, the safety and precision of piezosurgery were assessed in segmental Le Fort I osteotomies, [60] as well as in SARPE, [61] SSO, [63–65, 67–71, 73, 74, 78] IVRO, [62], genioplasty, [72, 75, 78] and also in some more critical mandibular procedures such as symphyseal [63, 64, 78], mandibular body, [63, 64] and total mandibular subapical [76] osteotomies. The consensus of most of these studies was that piezoelectric surgery has the potential to decrease the risk of IAN injury in orthognathic surgery. Moreover, the combined use of piezoelectric and endoscopic instruments was also assessed and found to be safe and effective [62]. Intraoperative navigation, which allows real-time evaluation of the position of surgical instruments and accurate transfer of the 3D virtual surgical treatment plan, [3, 79] represents another interesting surgical tool. Even though it has undeniable advantages and proven benefits (e.g., in orbital and reconstructive OMFS), it is unlikely that it will play a role in routine MI orthognathic surgery due to prolonged surgical operating time, learning curve, and higher cost. Over the last decades, besides the above-mentioned technologies, dedicated innovative surgical instruments have been developed by surgeons in order to perform orthognathic surgery in a more gentle, less traumatic, and more precise manner following the principles of MI surgery (Table  1.1) [3]. More recently, Swennen [4] developed and published a novel and revolutionary concept toward MI Orthognathic Surgery. Standardized “Step-by-Step Surgical Techniques” were presented for the five main orthognathic procedures with the purpose of increasing surgical efficiency and minimizing patient morbidity by introducing “Surgical Codes” for each MI surgical instrument and “Surgical Sequences and Template Bars” to guide each orthognathic surgical procedure. The described concept toward MI Orthognathic Surgery does not require endoscopic and piezosurgery technologies although they can be easily incorporated depending on the surgeon’s preferences. The whole new concept, comprising its philosophy, special dedicated MI orthognathic instruments, and the use of MI orthognathic instrument codes, surgical sequences, and template bars will be further addressed in Chap. 2. The standardized “Step-by-Step MI Orthognathic Surgical Techniques” will be described in detail and illustrated by high-quality graphic illustrations and pictures made on synthetic skulls, human cadaver, and anatomical dissected human cadaver specimens in Chaps. 3–7.

F. de O. Andriola et al.

 urgical Efficiency toward Decreasing S Operation Time in Orthognathic Surgery According to evidence-based research, one of the main parameters related to surgical patient morbidity has been defined as “the duration of the operation” [3]. Hence, increasing surgical efficiency toward decreasing the overall operation time is mandatory when following a “Minimally Invasive (MI) Mindset” (Table 1.1, Sect. “MI Orthognathic Surgical Techniques”). Identifying the main causes of surgical time loss and standardizing the clinical routine and surgical procedures performed in the “Operating Room” (OR) are the first steps to decrease overall surgical time and also the time spent between surgeries. Since the “Operating Surgeon” cannot make it happen alone, a team effort together with the “Surgical Assistants”, “Operating Nurse”, “Anesthesiologist”, and “Anesthesiologic Nurse” is required. Like a conductor of a philharmonic orchestra, the “Operating Surgeon” is responsible for the whole operation and therefore needs to coordinate each member of the team and control every single detail with full focus during the entire surgical procedure. Moreover, he also needs to rely on his team member’s commitment and focus to perform the surgical procedure in a safe way and to significantly decrease the operating time. Another responsibility of the “Operating Surgeon” is to be thoroughly involved in the individual 3D virtual surgical treatment plan of the patient by doing ideally the planning himself or in close collaboration with the planning assistant or engineer. Only in this way, the surgeon can be totally aware of each single detail which inherently will speed up the surgery and decrease potential complications. Moreover, all necessary information related to the patient’s operation, such as clinical photographs and exams, surgical templates, CBCT images, and the individualized 3D virtual surgical treatment, needs to be available in the OR and easily accessible to the whole team [80]. Standardization and systematically organizing all additional equipment, materials, and surgical instruments are crucial. Investing in training of both surgical assistants and nurses, and defining the responsibilities not only of each of them but also of the sterilization department are mandatory. Furthermore, briefing the entire team prior to each surgical procedure, including the anesthesiologist and his nurse, especially toward hypotensive anesthesia, are all essential to create the ideal environment toward a safe and highly efficient surgical workflow [4]. Important considerations toward increasing surgical efficiency are summarized in Table 1.2. The overall ­preoperative, perioperative, and postoperative conditions toward MI orthognathic surgery will be discussed in Chap. 8.

1  Background and Introduction to Minimally Invasive (MI) Orthognathic Surgery Table 1.2  Considerations toward optimizing surgical efficiency and decreasing operation time • Identifying causes of surgical time loss. • 3D virtual planninga • Briefing of the surgical team and the anesthesiologist. • Hypotensive anesthesia. • Operating room preparation. • Organization of surgical equipment and instruments. • Adequate surgical instruments. • Standardized surgical protocols. • Training of surgical assistants and nurses. • Surgeon’s learning curve and expertise. • Training and involvement of sterilization department.  Preferably self-planned by the surgeon or appropriate involvement of the surgeon in the planning process together with the assistant or engineer a

 inimally Invasive (MI) Orthognathics M Algorithm Based on evidence from the scientific literature [3] and 25 years of clinical experience, a novel and innovative surgical algorithm toward orthognathic surgery was published by

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Swennen [4] in order to increase surgical efficiency and minimize patient morbidity following a “Minimally Invasive (MI) Mindset” (Table 1.1). The new concept [4] and the whole idea behind his philosophy with (1) “Step-by-Step” standardization of MI surgical orthognathic techniques, (2) development of dedicated MI orthognathic instruments, and (3) the introduction of innovative surgical codes, sequences, and templates toward MI orthognathic surgery will be explained in-depth in Chap. 2. Based on the “MI Philosophy”, systematized “Step-by-­Step MI Orthognathic Surgical Techniques” [4] for each of the five main orthognathic surgical procedures will be addressed in detail in the technical chapters (Chaps. 3–7). Last but not least, the necessary conditions toward “MI Orthognathic Surgery” will be elaborated and presented in the final chapter (Chap. 8). Created by the authors (Swennen, Andriola and Weinberg), the “S.A.W. MI Orthognathics Algorithm” (Fig. 1.1) aims to illustrate and synthesize the overall concept to enhance Quality of Live (QoL) of patients undergoing orthognathic or orthofacial surgery to treat their maxillofacial deformities and overall facial appearance.

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F. de O. Andriola et al.

Minimally Invasive Orthognathics Algorithm

MI Approach (Reduce Trauma)

Efficiency (Reduce Time)

Standardized Routine

MI Instruments Hypotensive Anesthesia MI Techniques

Less bleeding

MI - Le Fort I

Better visulization

MI - Sagittal Split

Safer surgery

MI - Chin

Shorter procedure

MI - TPD

Team Preparation Nurses, Assistants, Anesthesiologist

Surgical Planning

MI - MD Midline Split Smaller Incisions*

Medication

Digital workflow

Infection control

3D Virtual Planning**

Swelling & Pain control

Higher Accuracy Higher Predictability

Less Degioving Tunnel approach Additional Care

Stability MI rigid fixation

OR Preparation Equipment, materials, photos, exams, CBCT

Conventional care

Lymph Drainage

Thermo-Therapy

Diet

Swelling & Pain control

Swelling control

Swelling & Pain control

Swelling control

AIMS Less Trauma

Less Pain

Less Morbidity

Fast Recovery

Enhanced Quality of Live (QoL) in Dentofacial Deformities Treatment

* As small as possible, but big enough in order to provide an adequate and safe access and to avoid potential lacerations by excessive traction on the soft tissues: ** Increase accuracy and anticipate premature bony contacts / interferences; MI: Minimally Invasive: TPD: Transpalatal Distraction: MD: Mandible: 3D: Three- dimensional; CBCT: Cone-beam computed tomography: OR: Operation room.

Fig. 1.1  The “S.A.W. MI Orthognathics Algorithm” summarizes the “MI Philosophy” which is used in daily clinical routine to minimize patient morbidity and increase surgical efficiency in the treatment of

maxillofacial deformities toward an enhanced Quality of Live (QoL) and an overall improvement of the postoperative experience and comfort

1  Background and Introduction to Minimally Invasive (MI) Orthognathic Surgery

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8 40. Huebsch RF.  The use of cortical bone to stimulate osteogenesis. Oral Surg Oral Med Oral Pathol. 1954;7(12):1273–5. https://doi. org/10.1016/0030-­4220(54)90275-­3. 41. McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg. 1992;89(1):1–10. 42. Weng YL. The experimental study of tissue engineered mandible condyle in the shape of human. Shanghai Kou Qiang Yi Xue. 2000;9(2):94–6. 43. Weng Y, Cao Y, Silva CA, Vacanti MP, Vacanti CA.  Tissue-­ engineered composites of bone and cartilage for mandible condylar reconstruction. J Oral Maxillofac Surg. 2001;59(2):185–90. https:// doi.org/10.1053/joms.2001.20491. 44. DeAngelis V. Orthodontic camouflaging of skeletal malocclusions: a clinical perspective. J Mass Dent Soc. 2009;57(4):20–3. 45. Morselli PG. Surgical maxillary expansion: a new minimally invasive technique. J Cranio-Maxillo-Facial Surg. 1997;25(2):80–4. https://doi.org/10.1016/s1010-­5182(97)80049-­2. 46. Wiltfang J, Kessler P. Endoscopically assisted Le fort I osteotomy to correct transverse and sagittal discrepancies of the maxilla. J Oral Maxillofac Surg. 2002;60(10):1142–5.; discussion 1146. https://doi.org/10.1053/joms.2002.34987. 47. Hernandez-Alfaro F, Mareque BJ, Diaz A, Pagés CM. Minimally invasive surgically assisted rapid palatal expansion with limited approach under sedation: a report of 283 consecutive cases. J Oral Maxillofac Surg. 2010;68(9):2154–8. https://doi.org/10.1016/j. joms.2009.09.080. 48. Mommaerts MY, Collado J, Mareque BJ.  Morbidity related to “endo-corticotomies” for transpalatal osteodistraction. J Craniomaxillofac Surg. 2008;36(4):198–202. https://doi. org/10.1016/j.jcms.2007.11.004. 49. Rohner D, Yeow V, Hammer B. Endoscopically assisted Le Fort I osteotomy. J Craniomaxillofac Surg. 2001;29(6):360–5. https://doi. org/10.1054/jcms.2001.0248. 50. Hernández-Alfaro F, Guijarro-Martínez R. “Twist technique” for pterygomaxillary dysjunction in minimally invasive Le Fort I osteotomy. J Oral Maxillofac Surg. 2013;71(2):389–92. https://doi. org/10.1016/j.joms.2012.04.032. 51. Troulis MJ, Nahlieli O, Castano F, Kaban LB. Minimally invasive orthognathic surgery: endoscopic vertical ramus osteotomy. Int J Oral Maxillofac Surg. 2000;29(4):239–42. 52. Raffaini M, Hernandez AF, Ghilardi R, Garcia LA.  The sagittal mandibular osteotomy under local anesthesia and intravenous sedation: four years of multicenter experience. Int J Adult Orthodon Orthognath Surg. 2002;17(4):267–71. 53. Mommaerts MY.  Endoscopically assisted sagittal split osteotomy for mandibular lengthening: technical note and initial experience. J Craniomaxillofac Surg. 2010;38(2):108–12. https://doi. org/10.1016/j.jcms.2009.04.007. 54. Nadjmi N, Stevens S, Van Erum R. Mandibular midline distraction using a tooth-borne device and a minimally invasive surgical procedure. Int J Oral Maxillofac Surg. 2015;44(4):452–4. https://doi. org/10.1016/j.ijom.2014.11.004. 55. Troulis MJ, Ramirez JL, Kaban LB. Endoscopic approach for mandibular orthognathic surgery. Facial Plast Surg Clin North Am. 2006;14(1):45–50. https://doi.org/10.1016/j.fsc.2005.11.003. 56. Kim K, McCain JP. Use of the endoscope in bisagittal split osteotomy. J Oral Maxillofac Surg. 2008;66(8):1773–5. https://doi. org/10.1016/j.joms.2007.11.033. 57. Sakai Y, Kobayashi S, Sekiguchi J, Ohmori K.  New method of endoscopic pterygomaxillary disjunction for a Le Fort Type I osteotomy. J Craniofac Surg. 1996;7(2):111–6. https://doi. org/10.1097/00001665-­199603000-­00006.

F. de O. Andriola et al. 58. Vercellotti T.  Technological characteristics and clinical indications of piezoelectric bone surgery. Minerva Stomatol. 2004;53(5):207–14. 59. Pavlíková G, Foltán R, Horká M, Hanzelka T, Borunská H, Sedý J. Piezosurgery in oral and maxillofacial surgery. Int J Oral Maxillofac Surg. 2011;40(5):451–7. https://doi.org/10.1016/j. ijom.2010.11.013. 60. Robiony M, Polini F, Costa F, Vercellotti T, Politi M. Piezoelectric bone cutting in multipiece maxillary osteotomies. J Oral Maxillofac Surg. 2004;62(6):759–61. https://doi.org/10.1016/j. joms.2004.01.010. 61. Robiony M, Polini F, Costa F, Zerman N, Politi M.  Ultrasonic bone cutting for surgically assisted rapid maxillary expansion (SARME) under local anaesthesia. Int J Oral Maxillofac Surg. 2007;36(3):267–9. https://doi.org/10.1016/j.ijom.2006.08.013. 62. Robiony M, Polini F, Costa F, Sembronio S, Zerman N, Politi M.  Endoscopically assisted intraoral vertical ramus osteotomy and piezoelectric surgery in mandibular prognathism. J Oral Maxillofac Surg. 2007;65(10):2119–24. https://doi.org/10.1016/j. joms.2006.03.048. 63. Landes CA, Stübinger S, Ballon A, Sader R.  Piezoosteotomy in orthognathic surgery versus conventional saw and chisel osteotomy. Oral Maxillofac Surg. 2008;12(3):139–47. https://doi.org/10.1007/ s10006-­008-­0123-­7. 64. Landes CA, Stübinger S, Rieger J, Williger B, Ha TKL, Sader R.  Critical evaluation of piezoelectric osteotomy in orthognathic surgery: operative technique, blood loss, time requirement, nerve and vessel integrity. J Oral Maxillofac Surg. 2008;66(4):657–74. https://doi.org/10.1016/j.joms.2007.06.633. 65. Shirota T, Kamatani T, Yamaguchi T, Ogura H, Maki K, Shintani S. Effectiveness of piezoelectric surgery in reducing surgical complications after bilateral sagittal split osteotomy. Br J Oral Maxillofac Surg. 2014;52(3):219–22. https://doi.org/10.1016/j.bjoms.2013.11.015. 66. Rana M, Gellrich N-C, Rana M, Piffkó J, Kater W. Evaluation of surgically assisted rapid maxillary expansion with piezosurgery versus oscillating saw and chisel osteotomy—a randomized prospective trial. Trials. 2013;14:49. https://doi.org/10.1186/1745-­6215-­14-­49. 67. Gruber RM, Kramer F-J, Merten H-A, Schliephake H. Ultrasonic surgery—an alternative way in orthognathic surgery of the mandible. A pilot study. Int J Oral Maxillofac Surg. 2005;34(6):590–3. https://doi.org/10.1016/j.ijom.2005.06.006. 68. Geha HJ, Gleizal AM, Nimeskern NJ, Beziat J-L. Sensitivity of the inferior lip and chin following mandibular bilateral sagittal split osteotomy using Piezosurgery. Plast Reconstr Surg. 2006;118(7):1598– 607. https://doi.org/10.1097/01.prs.0000232360.08768.de. 69. Nordera P, Spanio di Spilimbergo S, Stenico A, Fornezza U, Volpin L, Padula E.  The cutting-edge technique for safe osteotomies in craniofacial surgery: the piezosurgery bone scalpel. Plast Reconstr Surg. 2007;120(7):1989–95. https://doi.org/10.1097/01. prs.0000287328.56050.4e. 70. Spinelli G, Lazzeri D, Conti M, Agostini T, Mannelli G. Comparison of piezosurgery and traditional saw in bimaxillary orthognathic surgery. J Craniomaxillofac Surg. 2014;42(7):1211–20. https://doi. org/10.1016/j.jcms.2014.02.011. 71. Bertossi D, Lucchese A, Albanese M, Turra M, Faccioni F, Nocini P, et  al. Piezosurgery versus conventional osteotomy in orthognathic surgery: a paradigm shift in treatment. J Craniofac Surg. 2013;24(5):1763–6. https://doi.org/10.1097/ SCS.0b013e31828f1aa8. 72. Peter B.  Piezosurgery-assisted sliding genioplasty: a method for reduction of complications. Eur J Plast Surg. 2010;33:183–7. 73. Beziat J-L, Bera J-C, Lavandier B, Gleizal A.  Ultrasonic osteotomy as a new technique in craniomaxillofacial surgery. Int J Oral

1  Background and Introduction to Minimally Invasive (MI) Orthognathic Surgery Maxillofac Surg. 2007;36(6):493–500. https://doi.org/10.1016/j. ijom.2007.01.012. 74. Monnazzi MS, Real Gabrielli MF, Passeri LA, Cabrini Gabrielli MA, Spin-Neto R, Pereira-Filho VA. Inferior alveolar nerve function after sagittal split osteotomy by reciprocating saw or piezosurgery instrument: prospective double-blinded study. J Oral Maxillofac Surg. 2014;72(6):1168–72. https://doi.org/10.1016/j. joms.2013.11.007. 75. Rullo R, Festa VM, Rullo F, Trosino O, Cerone V, Gasparro R, et al. The use of piezosurgery in genioplasty. J Craniofac Surg. 2016;27(2):414– 5. https://doi.org/10.1097/SCS.0000000000002473. 76. Scolozzi P, Herzog G. Total mandibular subapical osteotomy and Le Fort I osteotomy using piezosurgery and computer-aided designed and manufactured surgical splints: a favorable combination of three techniques in the management of severe mouth asymmetry in

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parry-Romberg syndro. J Oral Maxillofac Surg. 2014;72(5):991–9. https://doi.org/10.1016/j.joms.2013.09.044. 77. Ueki K, Hashiba Y, Marukawa K, Okabe K, Alam S, Nakagawa K, et  al. Assessment of pterygomaxillary separation in Le fort I Osteotomy in class III patients. J Oral Maxillofac Surg. 2009;67(4):833–9. https://doi.org/10.1016/j.joms.2008.11.019. 78. Gilles R, Couvreur T, Dammous S. Ultrasonic orthognathic surgery: enhancements to established osteotomies. Int J Oral Maxillofac Surg. 2013;42(8):981–7. https://doi.org/10.1016/j.ijom.2012.12.004. 79. Bianchi A, Badiali G, Piersanti L, Marchetti C. Computer-assisted piezoelectric surgery: a navigated approach toward performance of craniomaxillofacial osteotomies. J Craniofac Surg. 2015;26(3):867– 72. https://doi.org/10.1097/SCS.0000000000001360. 80. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017.

2

A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg

Combined orthodontic-surgical treatment of congenital and acquired maxillofacial deformities has been well developed in the past to correct dental malocclusions, enhance facial appearance and improve nasal oropharyngeal airway. Moreover, the use of the same orthognathic surgical techniques, even without or with limited orthodontics has raised enormously in the last decade to functionally treat patients with Obstructive Sleep Apnea Syndrome (OSAS) and improve overall facial appearance in both aesthetic and transgender patients. Ancillary surgical procedures such as bone augmentation, bone recontouring, use of patient-­ specific implants (PSIs), liposuction, liposculpture, and facial cosmetic procedures are often combined with orthognathic surgical techniques. Meanwhile, there is clear evidence in the scientific literature [1] that minimally invasive (MI) orthognathic surgical techniques have the potential to decrease patient morbidity and lead to faster postoperative recovery in comparison to conventional surgical approaches (Chap. 1). Hunter [2] described MI  surgery as the discipline that involves operative procedures in a novel way to diminish the sequelae of standard surgical care. Based on 25 years of clinical experience, continuous self-reflection, research, innovation, and education, a new concept toward “MI Orthognathic

Surgery” was developed by the first author (GS) based on Hunter’s philosophy. On the basis of a “MI Mindset” (Chap. 1, Sect. “Background of MI Orthognathic Surgery”), the new concept toward “MI Orthognathic Surgery” consists of five principles (Table 2.1) with the main goals of increasing surgical efficiency and safety in order to minimize patient morbidity and to improve postoperative recovery. The necessary conditions to perform “MI Orthognathic Surgery” are outlined in the final chapter of this atlas (Chap. 8). The main pillars of the “New Concept toward MI Orthognathic Surgery” to reduce patient morbidity are: 1.  Standardization and systematization to increase safety of orthognathic surgical procedures and decrease overall surgical operating time. 2. Gentle handling of the surrounding soft tissue envelope to avoid unnecessary trauma, to maximize an adequate blood supply and to reduce interstitial edema.

G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected]

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_2

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12 Table 2.1 The five principles of a “New Concept toward MI Orthognathic Surgery” to increase surgical efficiency and safety toward reducing patient morbidity 1. Step-by-step standardization of “MI Orthognathic Surgical Techniques” to increase surgical efficiency (Sect. “Step-by-Step Standardization of “MI Orthognathic Surgical Techniques” to Increase Surgical Efficiency”). 2. Optimization of vascular blood supply and decrease of interstitial edema and swelling to improve postoperative recovery (Sect. “Optimization of Vascular Blood Supply and Decrease of Interstitial Edema and Swelling to Improve Postoperative Recovery”). 3. Development of dedicated “MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to allow a less invasive approach and to create a common language among the surgical team (Sect. “Development of Dedicated “MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to Allow a Less Invasive Approach and to Create a Common Language Among the Surgical Team”). 4. Creation of dedicated “MI Orthognathic Surgical Sequences” and “MI Orthognathic Sequence Template Bars” to facilitate instrumentation table organization and increase surgical efficiency (Sect. “Creation of Dedicated “MI Orthognathic Surgical Sequences” and “MI Orthognathic Sequence Template Bars” to Facilitate Instrumentation Table Organization and Increase Surgical Efficiency”). 5. Dedicated storage of “MI Orthognathic Instruments and Sequence Template Bars” to optimize gathering, cleaning, and sterilization processes toward a time efficient and cost-effective clinical routine (Sect. “Dedicated Storage of “MI Orthognathic Instruments and Sequence Template Bars” to Optimize Gathering, Cleaning, and Sterilization Processes Toward a Time-Efficient and CostEffective Clinical Routine”).

 tep-by-Step Standardization of “MI S Orthognathic Surgical Techniques” to Increase Surgical Efficiency Standardization and systematization have proven to be the keys to improve efficiency in the daily clinical routine of combined orthodontic-surgical treatment of maxillofacial deformities according to the first author’s (GS) personal experience (Table 2.2). In 2005, when Cone-beam CT (CBCT) was not the clinical “state-of-the-art” yet, a standardized and systematized three-dimensional (3D) cephalometry quality control system was developed with a “step-by-step” method for accurate and reliable definition of 3D cephalometric dental, hard and soft tissue landmarks and planes [3]. A standardized workflow process toward 3D virtual planning of orthognathic surgery in the daily clinical routine was then published in 2009 [4]. A citation-based metrics study published by Susarla et  al. [5] using three different citation databases (Web of Science search engine, Google Scholar, and PubMed) showed that the latter scientific paper had the highest citation index in the field of orthognathic surgery. A more recent bibliometric analysis of the top 100 cited articles on orthognathic surgery by Grillo [6] using Google Scholar citations, listed this paper

G. R.J. Swennen et al.

[4] on n°8, while three other papers of the author (GS) were listed on n°26, [7] n°35, [8] and n°53, [9] respectively. The fact that some of these papers [3, 9] were also listed as important milestones in the “timeline of orthognathic surgery planning evolution” by Barretto et al. [10] in a recent paper, highlights the importance of standardization and systematization in the daily clinical workflow of orthognathic surgery. In 2014, a “10 step-by-step” protocol toward clinically focused 3D virtual planning of orthognathic surgery was published [11] and further optimized [12] in order to allow its integration into the daily clinical routine in a user-friendly way. The standardized sequence of ten consecutive virtual planning steps significantly decreased the overall virtual treatment planning time in the author’s (GS) daily orthognathic practice [11]. Hence, the positive impact of standardizing and systematizing 3D virtual diagnosis, workflow, and planning led to the idea of doing the same toward orthognathic surgical procedures. In 2020, [13] the initial and basic part of the novel “MI Orthognathic Algorithm” (Chap. 1, Sect. “Minimally Invasive (MI) Orthognathics Algorithm”) was introduced by “Step-by-Step Standardization” of the five main “MI Orthognathic Surgical Techniques” to increase surgical efficiency. In this atlas, each technique has been further elaborated and described in more detail (Table  2.3) in the next chapters (Chaps. 3, 4, 5, 6, and 7). Table 2.2  The author’s (GS) personal Odyssey toward standardization and systematization in combined orthodontic-surgical treatment of maxillofacial deformities • “Step-by-step” standardization of 3D cephalometry (Swennen, Schutyser and Hausamen 2005) [3]. • “Step-by-step” workflow process toward 3D virtual planning (Swennen, Mollemans and Schutyser 2009) [4]. • “Step-by-step” 3D virtual planning of orthognathic surgery (Swennen, 2014, 2017) [11, 12]. • “Step-by-step” orthognathic surgical procedures (Swennen 2020) [13]. Table 2.3  Step-by-step “MI Orthognathic Surgical Techniques” for the main orthognathic procedures • MI Chin osteotomy (Chap. 3). • MI Le Fort I osteotomy (Chap. 4). • MI Sagittal Split osteotomy (Chap. 5). • MI Maxillary Expansion (Chap. 6). • MI Mandible Constriction/Expansion (Chap. 7).

The key to: 1. Decrease patient morbidity. 2. Improve postoperative recovery in orthognathic surgery. is the combination of: “Individualized 3D virtual treatment planning”. “MI orthognathic surgical techniques”.

2  A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery

 ptimization of Vascular Blood Supply O and Decrease of Interstitial Edema and Swelling to Improve Postoperative Recovery In order to decrease patient morbidity and improve postoperative recovery after orthognathic surgery it is crucial to optimize vascular blood supply and decrease interstitial edema and soft tissue swelling. Furthermore, osteotomies and consecutive rigid fixation or distractor placement need to be performed in a safe, accurate, and stable way. Whatever “MI Orthognathic Surgical Technique” (Table 2.3) is used, five surgical requirements always need to be fulfilled (Table 2.4), following the “MI Mindset” parameters toward “MI Orthognathic Surgery” (Chap. 1, Table 1.1). As previously mentioned (Chap. 1, Sect. “MI Orthognathic Surgical Techniques”), it must be kept in mind that the incision should be “as small as possible, but big enough” in order to avoid potential lacerations by excessive traction on the soft tissues, however providing an adequate and safe access toward the specific osteotomy region. In addition to being small, the incision must: (1) always respect crucial anatomic structures, such as vessels and nerves; (2) be strategically created to maintain an adequate blood supply of the surrounding soft tissue envelope; and (3) allow a tension-free closure of the surgical wound. Subperiosteal degloving using “tunnel approaches” needs to be as minimal as possible but it also must provide an adequate and safe access to perform the osteotomy and fixation of the osteotomized bony parts or placement of a distraction device. Moreover, the degloving always needs to be performed atraumatically and in a strictly subperiosteal plane with gentle handling and respect to the surrounding soft tissue envelope (including periosteum, muscles, and neurovascular structures) to avoid unnecessary trauma, maximizing the blood supply and reducing interstitial edema. Also, the surrounding soft tissue envelope needs to be well protected during corticotomy, osteotomy, and subsequent mobilization of the bony segments against burs, saws, piezoelectric Table 2.4  Requirements to optimize vascular blood supply, decrease interstitial edema and soft tissue swelling during “MI Orthognathic Surgical Techniques” 1. Minimal incision of the soft tissue layers. 2. Minimal subperiosteal degloving. 3. Minimal tension and protection of the surrounding soft tissues during corticotomy, osteotomy, and mobilization of the osteotomized segments. 4. Minimal tension and protection of the surrounding soft tissues during rigid fixation or placement of a distraction device. 5. Tension-free closure of the soft tissue layers.

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devices, and chisels with minimal tension. During rigid fixation of the osteotomized segments or placement of a distraction device, the surrounding soft tissue envelope also needs to be well protected to avoid soft tissue lacerations, and retraction or compression of the soft tissues needs to be restricted to the minimum. Finally, adequate soft tissue closure needs to be performed without any tension. Controlling soft tissue swelling, decreasing interstitial edema, and enhancing optimal vascular blood supply cannot be managed by the “Operating Surgeon” alone. Gentle manipulation and management of the soft tissues with appropriate positioning of the retractors along the ideal vectors by the “Operating Surgeon” and “Surgical Assistants” during the entire MI orthognathic surgical procedure are crucial. “Surgical Assistants” also have an important role to preserve the surrounding soft tissue envelope, since excessive compression, heating, traction, or lacerations may negatively interfere with the surgical wound healing, causing interstitial edema and increasing postoperative swelling. However, it remains the exclusive responsibility of the “Operating Surgeon”, to teach, train, and always coordinate his surgical team, including the “Operating Nurse”. To create a common language among the surgical team (“Operating Surgeon”, “Surgical Assistants”, and “Operating Nurse”), dedicated “MI Orthognathic Instruments” with individualized “MI Orthognathic Surgical Codes” (Sect. “Development of Dedicated “MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to Allow a Less Invasive Approach and to Create a Common Language Among the Surgical Team”) and standardized “MI Orthognathic Surgical Sequences” (Sect. “MI Orthognathic Surgical Sequences”) with “MI Orthognathic Sequence Template Bars” (Sect. “MI Orthognathic Sequence Template Bars”) were developed. In this atlas, toward teaching and training, thoughtful attention has been paid to add dedicated “Tricks”, “Tips”, and “Attention” boxes (Chaps. 3, 4, 5, 6, and 7) on the different “MI Orthognathic Surgical Techniques” with valuable information for both young and experienced surgeons.

 evelopment of Dedicated “MI Orthognathic D Instruments” and “MI Orthognathic Surgical Codes” to Allow a less Invasive Approach and to Create a Common Language among the Surgical Team

In order to increase surgical efficiency, optimize vascular blood supply and decrease interstitial edema and soft tissue swelling (Sect. “Optimization of Vascular Blood Supply and * Dedicated “MI orthognathic instruments” need to fulfill the above-­ Decrease of Interstitial Edema and Swelling to Improve mentioned requirements in regard to their specific needs (Sect. Postoperative Recovery”) dedicated “MI Orthognathic “Development of Dedicated “MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to Allow a Less Invasive Approach and Instruments” and individual “MI Orthognathic Surgical Codes” were developed. to Create a Common Language Among the Surgical Team”)

G. R.J. Swennen et al.

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 rthognathic Instrument Codification Using O “MI Orthognathic Surgical Codes” Coding of “MI Orthognathic Instruments” (Table  2.5) has several advantages. It allows to create a common language among the surgical team (“Operating Surgeon”, “Surgical Assistants”, and “Operating Nurse”), building up “MI Orthognathic Surgical Sequences” (Sect. “MI Orthognathic Surgical Sequences”) and “MI Orthognathic Sequence Template Bars" (Sect. “MI Orthognathic Sequence Template Bars”) to facilitate instrumentation table organization, surgical efficiency and storage, cleaning, and sterilization of the “MI Orthognathic Instruments”.

Table 2.6  Novel developed “MI Orthognathic Instruments” to fulfil “MI Philosophy” principles MI instruments MI1

MI2

MI3b Mx1b Mx2R, Mx2Lb Mx3b

 ovel Orthognathic Instruments to Fulfil “MI N Philosophy” Principles The novel “MI Orthognathic Instruments” that were developed to perform “MI Orthognathic Surgical Techniques” (Chaps. 3, 4, 5, 6, and 7) following the “MI Mindset” parameters (Chap. 1, Table 1.1) and that fulfil the requirements to optimize vascular blood supply, decrease interstitial edema and soft tissue swelling (Table 2.4) are listed in Table 2.6. The sharp double-sided raspatorium (MI1) was developed as one of the most crucial instruments toward all MI orthognathic surgery procedures (Chaps. 3, 4, 5, 6, and 7). The large part is sharp and designed to prepare the subperiosteal tunnels, while the small part allows to find more easily the subperiosteal plane in the medial paranasal (Chap. 4), retromolar, lingual (Chap. 5), and maxillary midline (Chap. 6) regions. Moreover, it allows positioning of osteosynthesis plates, MI guides, and MI-PSIs correctly on the bony surface. The blunt double-sided elevator (MI2) was developed to protect the soft tissues during all MI orthognathic surgery procedures (Chaps. 3, 4, 5, 6, and 7). Although not specifically mentioned in the “Surgical Codes” and “Surgical Sequence” for the “MI Chin Osteotomy” (Chap. 3, Table 3.1), Table 2.5  Codification of “MI Orthognathic Instruments” using “MI Orthognathic Surgical Codes” Coding Mx Md Ch MI RT HK OS BI SEQ

Designation Maxilla Mandible Chin Minimally invasive Retractor Hooks Osteotomes Basic instruments Sequence templates

Instrument codes Mx1 – Mx5 Md1 – Md9 Ch1 MI1 – MI4 RT1 – RT3 HK1 – HK3 OS1 – OS7 BI1 – BI3, BI-TAP SEQ1 – SEQ19

L1® MI Orthognathics (KLS Martin, Tuttlingen) developed with clinician G.R.J. Swennen

Mx4S, Mx4L Md1b Md4–9 HK2b BI2 BI-TAP

MI orthognathic surgical technique MI Chin, MI Le Fort I, MI SSO, MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI Le Fort I, MI SSO, MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI Chin MI Le Fort I MI Le Fort I, MI Maxillary Expansion MI Le Fort I, MI Maxillary Expansion MI Le Fort I MI SSO MI SSO MI Le Fort I MI Le Fort I MI Chin, MI Le Fort I, MI SSO, MI Maxillary Expansion, MI Mandible Constriction/ Expansion

Requirementsa 2,3

3,4

1,2,3,4 1,2,3,4 1,2,3,4 2,3,4 3 1,2,3 4 1,3 1,2,3,4

MI Minimally Invasive, Mx Maxilla, Md Mandible, HK Hook, BI Basic Instrument L1® MI Orthognathics (KLS Martin, Tuttlingen, Germany) developed with clinician G.R.J. Swennen a Requirements to optimize vascular blood supply, decrease interstitial edema and soft tissue swelling during MI orthognathic surgical procedures, according to Table 2.4 b Intelligent handgrip

it can be helpful to protect the soft tissues if MI guides and MI patient-specific implants (PSIs) are used. The twisted blunt elevator (MI3) is a double-sided MI instrument created to retract and protect the mental nerve and submandibular soft tissues in the subperiosteal tunnels during the “MI Chin Osteotomy” (Chap. 3). The dedicated double-retractor (Mx1) was developed to allow simultaneous retraction of the paranasal soft tissues and to avoid compression on the anaesthesiologic nasotracheal tube during the “MI Le Fort I Osteotomy” (Chap. 4). The curved soft tissue retractors (Mx2R and Mx2L) were specially designed to respectively protect the soft tissues in the right and left subperiosteal tunnels during the “MI Le Fort I” (Chap. 4) and “MI Maxillary Expansion” (Chap. 6). The thin malleable soft-tissue retractor (Mx3) is used to protect the nasal mucosa during “MI Le Fort I Osteotomy” (Chap. 4) and “MI Maxillary Expansion” (Chap. 6). It presents a long handle that can be attached with mosquito forceps to the surgical drapes around the patient’s head on the contralateral side. Short and long thin bone spreaders (Mx4S and Mx4L) were developed to perform the anterior and posterior down

2  A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery

fracture of the maxilla through a tunnel approach with consecutive mobilization during the “MI Le Fort I Osteotomy” (Chap. 4). The small channel retractors (Md1) were designed to perform the buccal and lingual corticotomies through a tunnel approach during the “MI Sagittal Split Osteotomy” (Chap. 5) and to protect the surrounding soft tissues and anatomic structures. The MI spacers (Md4 to Md9) were created to perform “trivector seating” [13] of the proximal segments and to avoid condylar torque during the “MI Sagittal Split Osteotomy” (Chap. 5). The small hooklet retractor (HK2) was created to retract the mobilized maxilla after down fracturing with minimal tension on the soft tissues and to avoid compression of the lower lip during the “MI Le Fort I Osteotomy” (Chap. 4). A standardized 10 mm control instrument (BI2) was created to easily verify and control vertical maxillary repositioning during the “MI Le Fort I Osteotomy” (Chap. 4). The double-sided mallet (BI-TAP), with both silicon and metal sides, was designed to be used within all different types of osteotomies during all MI orthognathic surgery procedures (Chaps. 3, 4, 5, 6, and 7).

 odified Conventional Orthognathic M Instruments to Fulfil “MI Philosophy” Principles In order to develop the “MI Orthognathic Surgical Codes” (Sect. “Orthognathic Instrument Codification using “MI Orthognathic Surgical Codes””) and “MI Orthognathic Surgical Sequences” (Sect. “MI Orthognathic Surgical Sequences”), some basic conventional instruments (such as retractors, hooks, and osteotomes) that have been used in orthognathic surgery for many years were slightly modified according to the “MI Mindset” (Table 1.1, Chap. 1) parameters and to fulfil the requirements to optimize vascular blood supply, decrease interstitial edema and soft tissue swelling. These instruments (Table 2.7) were also coded and eventually received “Intelligent Handgrips” (Sect. “The Rationale Behind the “Intelligent Handgrip””) according to their function: • • • • • • • • •

V-shaped elevator (MI4). Chin holder (Ch1). Septum/bone scissors (Mx5). Mandibular ramus retractor (Md2). Mandibular bone holding and repositioning forceps (Md3). Soft tissue retractor (RT1). Large soft tissue retractor (RT2). Small soft tissue retractor (RT3). Delicate soft tissue double hook (HK1).

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Table 2.7  Modified conventional orthognathic instruments to fulfil “MI Philosophy” principles MI instruments MI4 Ch1b Mx5 Md2b Md3 RT1b

RT2b RT3b

HK1

HK3 OS1 OS2 OS3 OS4

OS5 OS6

OS7 BI1 BI3

NS

MI orthognathic surgical technique MI SSO MI Chin MI Le Fort I MI SSO MI SSO MI Chin, MI Le Fort I, MI SSO MI Mandible Constriction/ Expansion MI SSO, MI Maxillary Expansionc MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI Chin, MI Le Fort I, MI Mandible Constriction/ Expansion MI Le Fort I MI Le Fort I, MI Maxillary Expansiond MI Le Fort I, MI Maxillary Expansion MI Le Fort I, MI Maxillary Expansion MI SSO, MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI Chin, MI SSO MI Chin, MI Le Fort I, MI SSO, MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI-Maxillary Expansionc MI Le Fort I, MI Chin MI Chin, MI Le Fort I, MI SSO MI Maxillary Expansion, MI Mandible Constriction/ Expansion MI Maxillary Expansion

Requirementsa 2 1,2,3,4 1,2,3 1,2,3 1,2,4 1,2,3,4,5

3,4 1,2,3,4,5

1, 5

5 3 1,2,3 1,2,3 1,2,3

1,2,3 1,2,3

3 1,2,3,4 1,2,4

1,2

MI Minimally Invasive, Ch Chin, Mx Maxilla, Md Mandible, RT Retractor, HK Hook, OS Osteotome, BI Basic Instrument, NS Nose Speculum L1® MI Orthognathics (KLS Martin, Tuttlingen, Germany) developed with clinician G.R.J. Swennen a Requirements to optimize vascular blood supply, decrease interstitial edema, and soft tissue swelling during MI orthognathic surgical procedures, according to Table 2.4 b Intelligent handgrip c In case a pterygomaxillary dysjunction is performed during “MI Maxillary Expansion” d In case a septal release is performed during “MI Maxillary Expansion”

• • • • • • •

Delicate soft tissue hook (HK3). Septum osteotome (OS1). Straight osteotome with blunt protection (OS2). Angled osteotome with blunt protection (OS3). Sharp thin osteotome (OS4). Blunt wedge osteotome (OS5). Sharp large osteotome (OS6).

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• • • •

G. R.J. Swennen et al.

Sharp curved osteotome (OS7). Slightly hooked caliper (BI1). Long curved clamp (BI3). Short nasal speculum (NS).

The Rationale behind the “Intelligent Handgrip” Based on many years of experience, engineers who develop surgical instruments have the knowledge to facilitate the handling of a particular instrument by its individual handgrip. Different functional grip designs and handle sizes can help and guide the “Operating Surgeon” and “Surgical Assistants” toward proper positioning of the instrument and to apply the correct amount of force during soft tissue retraction. In close collaboration with engineers with long-time experience, different types of “Intelligent Handgrips” could be developed and applied to some of the novel (Table 2.6) and modified (Table 2.7) MI orthognathic instruments. The functional design and handgrip of the MI3 twisted blunt elevator (MI3) allows both the right- and left-handed “Operating Surgeon” to retract and protect the mental nerve and submandibular soft tissues in both the right and the left subperiosteal tunnels during the “MI Chin Osteotomy” (Chap. 3). The handgrip of the Mx1 double retractor avoids lateral traction and compression on the paranasal soft tissues and can be handled by the “Surgical Assistant” with only one hand during the “MI Le Fort Osteotomy” (Chap. 4). The flexible handgrips of the Mx2(R/L) curved and the Mx3 thin malleable soft tissue retractors avoid extensive compression on the soft tissues during the “MI Le Fort I Osteotomy” (Chap. 4) and “MI Maxillary Expansion” (Chap. 6). The design of the Md1 small channel retractors allows their stable positioning in the small buccal and lingual subperiosteal tunnels during the “MI Sagittal Split Osteotomy” (Chap. 5) in order to provide minimal degloving and simultaneously appropriate protection of the surrounding soft tissues and anatomic structures. The handgrip of the Md2 vertical ramus retractor guides the “Surgical Assistant” to hold it in a stable position with the proper amount of traction on the soft tissues during the “MI Sagittal Split Osteotomy” (Chap. 5). The functional design and handgrip of the HK2 small hooklet retractor guide the “Surgical Assistant” to retract the mobilized maxilla with minimal tension on the surrounding soft tissue envelope and without compression of the lower lip during the “MI Le Fort I Osteotomy” (Chap. 4). The grip design and different handle sizes of the RT1, large RT2, and small RT3 soft tissue retractors guide both the “Surgical Assistants” and “Operating Surgeon” to apply the appropriate force of retraction on the soft tissues during the different MI orthognathic surgical procedures (Chap. 3, 4, 5, 6, and 7).

 reation of Dedicated “MI Orthognathic C Surgical Sequences” and “MI Orthognathic Sequence Template Bars” to Facilitate Instrumentation Table Organization and Increase Surgical Efficiency In order to facilitate surgical instrumentation table organization by the “Operating Nurse” and increase the surgical efficiency of the surgical team (“Operating Surgeon”, “Surgical Assistant”, and “Operating Nurse”), “MI Orthognathic Surgical Sequences” (Sect. “MI Orthognathic Surgical Sequences”) and “MI Orthognathic Sequence Template Bars” (Sect. “MI Orthognathic Sequence Template Bars”) were developed. The combination of step-by-step standardization of “MI Orthognathic Surgical Techniques” (Sect. “Step-by-Step Standardization of “MI Orthognathic Surgical Techniques” to Increase Surgical Efficiency”) and “MI Orthognathic Instruments” (Sects. “Novel Orthognathic Instruments to Fulfil “MI Philosophy” Principles” and “Modified Conventional Orthognathic Instruments to Fulfil “MI Philosophy” Principles”) with specific “MI Orthognathic Surgical Codes” (Sect. “Development of Dedicated “MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to Allow a Less Invasive Approach and to Create a Common Language Among the Surgical Team”) enabled the creation of specific sequences for each MI orthognathic surgical procedure by arranging the letter codes of the required MI instruments in a systematized order (Table  2.8). The introduction of dedicated MI sequence (SEQ) template bars (Figs.  2.1, 2.2, 2.3, 2.4 and 2.5) allows us to easily transfer the specific surgical sequence of required MI orthognathic instruments to the surgical team in the operation room. Table 2.8  “MI Orthognathic Surgical Sequences” based on the “MI Orthognathic Surgical Codes” for the five “MI Orthognathic Surgical Techniques” • MI Chin Osteotomy (Chap. 3)  HK1 RT1 RT1 MI1 Ch1 MI3 OS5 BI-TAP OS6 BI3 • MI Le Fort I Osteotomy (Chap. 4)  HK1 RT1 RT1 MI1 MI2 BI1 Mx1 OS1 BI-TAP Mx2L Mx2R Mx3 OS2 OS3 OS5 Mx4S Mx4L HK2 MX5 BI2 BI3 HK3 • MI Sagittal Split Osteotomy (Chap. 5)  RT1 RT2 MI1 MI2 Md1 MI4 Md2 Md1 OS4 BI-TAP OS5 OS6 Md3 BI3 Md4–9 • MI Maxillary Expansion (Chap. 6)  NS MI1 Mx2R/Mx2L RT3 MI2 Mx3 OS2 OS3 RT3 OS4 OS6 (OS7) (RT2) • MI Mandible Constriction/Expansion (Chap. 7)  HK1 RT1 RT1 MI1 RT3 RT3 MI2 OS4 BI-TAP OS6 From Swennen [13]; with permission

2  A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery

Fig. 2.1  “MI Chin Surgical Sequence Template Bars” with “MI Orthognathic Instruments” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) required for the “MI Chin Osteotomy” (Graphic

MI Orthognathic Surgical Sequences

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illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Note how the necessary MI instruments are arranged in a systematic order by the three dedicated sequence (SEQ) template bars

cedure: “MI Chin Osteotomy” (Chap. 3, Sect. ““MI Chin Osteotomy” Instruments and “MI Chin Osteotomy” Surgery The systematized “MI Orthognathic Surgical Sequences” Instrumentation Table Organization”, Fig. 3.1); “MI Le Fort based on the specific “MI Orthognathic Surgical Codes” for I Osteotomy” (Chap. 4, Sect. ““MI Le Fort I Osteotomy” each of the “MI Orthognathic Surgical Techniques” (Chaps. Instruments and “MI Le Fort I Osteotomy” Surgery 3, 4, 5, 6, and 7) are listed in Table 2.8. Instrumentation Table Organization”, Fig. 4.1); “MI Sagittal Split Osteotomy” (Chap. 5, Sect. ““MI Sagittal Split Osteotomy” Instruments and “MI Sagittal Split Osteotomy” MI Orthognathic Sequence Template Bars Surgery Instrumentation Table Organization”, Fig. 5.1); “MI Maxillary Expansion” (Chap. 6, Sect. ““MI Maxillary The “MI Orthognathic Sequence Template Bars” that trans- Expansion” Instruments and “MI Maxillary Expansion” fer the systematized “MI Orthognathic Surgical Sequences” Surgery Instrumentation Table Organization”, Fig. 6.1) and based on the specific “MI Orthognathic Surgical Codes” for “MI Mandible Constriction/Expansion” (Chap. 7, Sect. ““MI each of the “MI Orthognathic Surgical Techniques” (Chaps. Mandible Constriction/Expansion” Instruments and Surgery 3–7) are listed in Table 2.9 and illustrated in Figs. 2.1, 2.2, Instrumentation Table Organization”, Fig. 7.1). Even if the 2.3, 2.4 and 2.5. Toward further standardization, each of the “Operating Nurse” needs to be replaced during the surgery, 19 MI sequence (SEQ) template bars is labelled and num- the instrumentation table always remains organized, which bered with different locking mechanisms in order to helps to increase overall surgical efficiency. In case one of avoid confusion. Depending on the MI orthognathic surgical the MI orthognathic surgical procedures is combined with procedure, the “Operating Nurse” places the relevant MI another one, which is very common in the treatment of maxsequence (SEQ) template bars on top of the surgical instru- illofacial deformities, the “Operating Nurse” changes the MI mentation table and knows exactly which MI-coded instru- sequence (SEQ) template bars and can reorganize all MI ments need to be taken out of the dedicated storage container orthognathic instruments very efficiently. (Sect. “Dedicated Storage of “MI Orthognathic Instruments Last but not least, passing of the relevant MI orthognathic and Sequence Template Bars” to Optimize Gathering, instruments requested by the “Operating Surgeon” or Cleaning, and Sterilization Processes Toward a Time-­ “Surgical Assistants” turns out to be very fluent and efficient Efficient and Cost-Effective Clinical Routine”). This enables in regard to the “Operating Nurse” due to the enhanced comthe “Operating Nurse” to organize the instrumentation table munication provided by the innovative common language in a very fast and efficient way during the entire surgical pro- among the surgical team (Sect. “Development of Dedicated

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Fig. 2.2  “MI Le Fort I Surgical Sequence Template Bars” with “MI Orthognathic Instruments” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) required for the “MI Le Fort I Osteotomy”. Note

G. R.J. Swennen et al.

how the necessary MI instruments are arranged in a systematic order by the six dedicated sequence (SEQ) template bars (Graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

2  A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery

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Fig. 2.3  “MI SSO Surgical Sequence Template Bars” with “MI Orthognathic Instruments” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) required for the “MI Sagittal Split Osteotomy”. Note how the necessary MI instruments are arranged in a systematic

order by the four dedicated sequence (SEQ) template bars (Graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

Fig. 2.4  “MI Maxillary Expansion Surgical Sequence Template Bars” with “MI Orthognathic Instruments” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) required for the “MI Maxillary Expansion”. Note how the necessary MI instruments are arranged in a

systematic order by the three dedicated sequence (SEQ) template bars (Graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

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G. R.J. Swennen et al.

Fig. 2.5  “MI Mandible Constriction / Expansion Surgical Sequence Template Bars” with “MI Orthognathic Instruments” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) required for the “MI Mandible Constriction/Expansion”. Note how the necessary MI instru-

ments are arranged in a systematic order by the three dedicated sequence (SEQ) template bars (Graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

Table 2.9  “MI Orthognathic Surgical Template Bars” for the “MI Orthognathic Surgical Techniques”

“MI Orthognathic Instruments” and “MI Orthognathic Surgical Codes” to Allow a Less Invasive Approach and to Create a Common Language Among the Surgical Team”), which considerably facilitates the decrease of overall operating time.

MI sequence bar SEQ1 SEQ2 SEQ3 SEQ4 SEQ5 SEQ6 SEQ7 SEQ8 SEQ9 SEQ10 SEQ11 SEQ12 SEQ13 SEQ14 SEQ15 SEQ16 SEQ17 SEQ18 SEQ19

MI orthognathic surgical technique MI Le Fort I 1/6 MI Le Fort I 2/6 MI Le Fort I 3/6 MI Le Fort I 4/6 MI Le Fort I 5/6 MI Le Fort I 6/6 MI SSO 1/4 MI SSO 2/4 MI SSO 3/4 MI SSO 4/4 MI Chin 1/3 MI Chin 2/3 MI Chin 3/3 MI Le Fort I Expansion 1/3 MI Le Fort I Expansion 2/3 MI Le Fort I Expansion 3/3 MI Mandible Constriction/Expansion 1/3 MI Mandible Constriction/Expansion 2/3 MI Mandible Constriction/Expansion 3/3

SEQ Sequence Bars. L1® MI Orthognathics (KLS Martin, Tuttlingen, Germany) developed with clinician G.R.J. Swennen

 edicated Storage of “MI Orthognathic D Instruments and Sequence Template Bars” to Optimize Gathering, Cleaning, and Sterilization Processes Toward a Time-­ Efficient and Cost-Effective Clinical Routine An important economic factor to hospitals as well as public and private health systems is cost-effectiveness. A relevant issue that is often undervalued in the clinical routine of orthognathic surgery is the storage and logistics of the surgical instruments toward: (1) Efficient surgical instrumentation table organization by the “Operating Nurse”; (2) Gathering of the instruments at the end of the entire surgical procedure without loss of instruments; and (3) Optimal cleaning and

2  A New Concept Toward Minimally Invasive (MI) Orthognathic Surgery

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Fig. 2.6  Dedicated storage of “MI Orthognathic Instruments and Sequence Template Bars” (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Note that all MI instruments to perform all five MI orthognathic surgical procedures (Chaps. 3–7) described in this

atlas are stored in two box containers in a highly systematized manner including the sequence (SEQ) template bars (Graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

sterilization of both surgical instruments and trays at the sterilization department without damage or loss. As a part of the “New Concept toward MI Orthognathic Surgery”, a dedicated and intuitive storage of “MI Orthognathic Instruments and Sequence Template Bars” was developed and illustrated in Fig.  2.6. Arranging each MI coded orthognathic instrument and sequence template bar in

a systematized and standardized way in the dedicated storage containers facilitates an easy “take-out /put-back” by the “Operating and Sterilization Nurses”. Moreover, the delicate MI instruments are protected from damage and loss, and the overall logistics, especially toward the sterilization department are optimized. Last but not least, it has the potential to improve time efficiency and cost-effectiveness.

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References 1. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 2. Hunter JG. Minimally invasive surgery: the next frontier. World J Surg. 1999;23:422–4. 3. Swennen GRJ, Schutyser F, Hausamen J-E.  Three-dimensional cephalometry. A color atlas and manual. Springer; 2005. 4. Swennen GRJ, Mollemans W, Schutyser F.  Three-dimensional treatment planning of orthognathic surgery in the era of virtual planning. J Oral Maxillofac Surg. 2009;67:2080–92. https://doi. org/10.1016/j.joms.2009.06.007. 5. Susarla SM, Tveit M, Dodson TB, Kaban LB, Hopper RA, Egbert MA.  What are the defining characteristics of the most cited publications in orthognathic surgery? Int J Oral Maxillofac Surg. 2018;47:1411–9. https://doi.org/10.1016/j.ijom.2018.04.016. 6. Grillo G.  Orthognathic surgery: a bibliometric analysis op the top 100 cited articles. J Oral Maxillofac Surg. 2021;79:2339–49. https://doi.org/10.1016/j.joms.2021.06.004. 7. Kramer FJ, Baethge C, Swennen G, Teltzrow T, Schulze A, Berten J, Brachvogel P. Intra- and perioperative complications of the Lefort I osteotomy: a prospective evaluation. J Craniofac Surg. 2004;15:971– 7. https://doi.org/10.1097/00001665-­200411000-­00016.

G. R.J. Swennen et al. 8. Swennen GRJ, Mollemans W, De Clercq C, Abeloos J, Lamoral P, Lippens F, Neyt N, Casselman J, Schutyser F.  A cone-beam computed tomography triple scan procedure to obtain a three dimensional augmented virtual skull model appropriate for orthognathic surgery planning. J Craniofac Surg. 20:297–307. https://doi. org/10.1097/SCS.0b013e3181996803. 9. Swennen GRJ, Barth EL, Eulzer C, Schutyser F. The use of a new 3D splint and double CT scan procedure to obtain an accurate anatomic virtual augmented model of the skull. Int J Oral Maxillofac Surg. 2007;36:146–52. https://doi.org/10.1016/j.ijom.2006.09.019. 10. Barretto MDA, Melhem-Elias F, Deboni MCZ.  The untold history of planning in orthognathic surgery: a narrative review from the beginning to virtual surgical simulation. J Stomatol Oral Maxillofac Surg. 2022;123:e251–9. https://doi.org/10.1016/j. jormas.2022.04.002. 11. Swennen GRJ. Timing of three-dimensional virtual treatment planning of orthognathic surgery: a prospective single-surgeon evaluation on 350 consecutive cases. Oral Maxillofac Surg Clin North Am. 2014;26:475–85. https://doi.org/10.1016/j.coms.2014.08.001. 12. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017. 13. Swennen GRJ.  Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi.org/10.1016/j.cxom.2020.05.009.

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Minimally Invasive (MI) Chin Osteotomy Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg

Step-by-step standardization of minimally invasive (MI) orthognathic surgical techniques increases surgical efficiency and decreases patient morbidity. In this chapter, an innovative systematized “10 step-by-step approach” toward the chin osteotomy following a “MI philosophy and mindset” is outlined in detail. General considerations regarding the preparation of the patient, instrumentation table, and operating room toward the MI chin osteotomy are well described. Dedicated newly developed MI orthognathic surgical instruments allow to optimize the vascular blood supply and decrease interstitial edema and swelling after a chin osteotomy which enhances postoperative fast recovery of the patient. Moreover, the introduction of MI orthognathic surgical codes, MI orthognathic surgical sequences, and MI orthognathic sequence template bars create a common language among the surgical team ("Operating Surgeon", "Surgical Assistants", and "Operating Nurse") which increases surgical efficiency and additionally decreases patient morbidity. Furthermore, systematization of storage of the  MI orthognathic instruments and MI surgical sequence template bars allows us to optimize their gathering, cleaning, and sterilization process toward a more time-efficient and cost-effective clinical routine. Every single step of the MI approach toward the chin osteotomy is illustrated in detail by high-quality graphic illustrations and

G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected]

pictures made on synthetic skulls, human cadavers, and anatomically dissected human cadaver specimens. Finally, the limits of the described MI surgical technique toward the chin osteotomy are summarized.

 eneral Considerations Regarding the “MI G Chin Osteotomy” Surgical Procedure In this chapter (Sect. “The “10 Step-by-Step MI Chin Osteotomy” Surgical Technique”), a “10 Step-by-Step” surgical technique (see Table 3.2) to perform a chin osteotomy in a systematized minimally invasive (MI) way will be described in detail. Individualized and clinically focused 3D virtual treatment planning of the chin can incorporate a combination of 3D translational (anteroposterior, transversal, and vertical) and rotational (“Roll”, “Pitch”, and “Yaw”) movements of the bony chin in regard and respect to the overlying soft tissue mask [1]. Most of these movements can be safely performed and transferred in an accurate way through the below-described MI approach. The limits, however, of the presented “MI Chin Osteotomy” surgical technique are outlined at the end of this chapter. Based on the background of MI surgery in other surgical fields (Chap. 1) and supported by evidence-based medicine [2] an innovative concept and rationale were developed toward “MI Orthognathic Surgery” (Chap. 2) in order to reduce overall patient morbidity by the combination of increasing surgical efficiency and decreasing surgical trauma through minimized degloving and compression of the surrounding soft tissue envelope. In specific regard toward the “MI Chin Osteotomy”, the following general considerations need to be taken into account by the surgical team: 1. Organization of the surgical instrumentation table by the “Operating Nurse” (Sect. ““MI Chin Osteotomy” Instruments and “MI Chin Osteotomy” Surgery Instrumentation Table Organization”).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_3

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2. Preparation of the patient in the operating room by the “Operating Surgeon”, “Assistant 1” and “Assistant 2” (Sect. “Patient and Operating Room Preparation Toward the “MI Chin Osteotomy” Surgical Procedure”)

“ MI Chin Osteotomy” Instruments and “MI Chin Osteotomy” Surgical Instrumentation Table Organization In order to improve the efficiency of the overall surgical team during an “MI Chin Osteotomy”, “MI Chin surgical sequence template bars” were developed to indicate in a systematic order the required MI coded instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) [3] (Chap. 2). The “Operating Nurse” places the three dedicated “MI Chin surgical sequence template bars” on top of the surgical instrumentation table (Fig. 3.1) which allows a fast, easy, and standardized organization of the relevant MI orthognathic instruments not only at the initiation but also during the entire surgical procedure. Moreover, the “Operating Nurse” is able to follow and knows at any moment which “MI Chin” orthognathic instrument is needed by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” to smoothly perform the “MI Chin Osteotomy”. The “Surgical Codes” and “Surgical Sequence” toward the “MI Chin Osteotomy” are mentioned in Table 3.1.

G. R.J. Swennen et al.

 atient and Operating Room Preparation P Toward the “MI Chin Osteotomy” Surgical Procedure To perform a “MI Chin Osteotomy”, the patient is placed in a supine position on the surgical operating table by the “Anesthesiologic team” in close collaboration with the “Operating Surgeon” who personally positions the patient’s head using a dedicated head support (Chap. 8) in a “neutral horizontal position” in a way that head extension is avoided during the surgical procedure similar as in the “MI Le Fort I Osteotomy” (Chap. 4)”, MI Sagittal Split Osteotomy” (Chap. 5) and “MI Mandible Constriction/Expansion”  (Chap. 7) surgical procedures. After nasotracheal intubation by the anesthesiologist and correct positioning of the tube (Chap. 8), local anesthesia (Xylocaine® 1% with adrenaline 1:200.000) is administered by “Assistant 2” both in the superficial mucosal and deep subperiosteal plane of the chin for localized vasoconstriction and hemostasis. Moreover, “Assistant 2” also positions the two operating reflector lights (most ideally L.E.D.) in an ideal position above the patient—one straight above the patient’s head and the second above the legs with a 45-degree inclination angle toward the patient's face. Meanwhile “Assistant 1” is scrubbing in order to start disinfection of the patient’s head and surgical draping immediately once the patient is intubated in order not to lose valuable time. Antisepsis of the face is performed by “Assistant 1” with Hibidil® (50  mg/100  ml chlorhexidine digluconate

Fig. 3.1  MI orthognathic instruments used to perform the “MI Chin Osteotomy” systematically organized on the surgical instrumentation table by the “Operating Nurse” (graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

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3  Minimally Invasive (MI) Chin Osteotomy

cutaneous solution, Hälsa Pharma GmbH, Münster, Germany) and consecutively disinfection of the mouth with Hextril® (1 mg/ml hexetidine mouth rinsing, Famar Orléans, Orléans, France) once all sterile drapes have been applied. Prior to surgery, the wax bite that was taken in centric relation (CR) during the “pre-surgical workup” is verified, occlusal grinding is performed if necessary and final fitting of the intermediate and final splints on the patient is checked by “Assistant 1”. Lastly, a steroidal ointment is applied on both the upper and lower lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-den-­Berg, Belgium) by one of the assistant surgeons. Intravenous (IV) antibiotics (2 g Amoxicillin Clavulanic Acid 2000 mg/200 mg intravenous injection, Augmentin®, GlaxoSmithKline, Singapore) are administered by the anesthesiologist only once in a single dose unless additional bone-grafting or lipo-filing is performed where these are continued postoperatively for 1 week orally. In case of peniTable 3.1 “Surgical Codes” and “Surgical Sequence” for the “Minimally Invasive (MI) Chin Osteotomy” orthognathic surgical procedure MI Chin Osteotomy HK1 RT1 RT1 MI1 Ch1 MI3 OS5 BI-TAP OS6 BI3 (HK) hook; (RT) retractor; (MI) minimally invasive; (OS) osteotome; (BI) basic instrument; (Ch) chin (From Swennen [3]; with permission)

a

Fig. 3.2  Positioning of the “Operating Surgeon”, surgical “Assistant 1”, surgical “Assistant 2”, “Operating Nurse”, and anesthesiologist are shown in the operating room (graphic illustrations from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany): overview (a) and

cillin allergy, 600 mg of clindamycin (Clindamycin Sandoz® 600  mg/4  ml intravenous injection, Sandoz Canada Inc. Boucherville, QC, Canada) is administered by intravenous injection in a single dose and continued orally for 1 week if indicated. Corticosteroids are given in a single high dose (250  mg methylprednisolone intravenous injection, Solu-­ Medrol®, Pfizer Manufacturing, Puurs, Belgium) at the start of the surgery and repeated postoperatively at the recovery unit (80  mg methylprednisolone intramuscular injection, Depo-Medrol®, Pfizer Manufacturing, Puurs, Belgium). Tranexamine acid (500  mg/5  ml tranexamine acid intravenous injection, Exacyl®, Sanofi, Gentilly, France) is administered 1 g directly IV after induction, and another 1 g in the 1  L NaCl drip infusion at initiation of the surgery unless ­contraindications. The anesthesiologic management is furthermore explained in Chap. 8. To perform a “MI Chin Osteotomy”, the right-handed “Operating Surgeon” is positioned in front of the patient’s head (sitting or standing) while “Assistant 1” and “Assistant 2” are placed aside, on the right and left sides, respectively (Fig.  3.2). This particular position allows the “Operating Surgeon” to have the most ideal view to evaluate overall symmetry during the entire “MI Chin Osteotomy” surgical procedure. The “Operating Nurse” is ideally positioned at the right side of the patient’s thorax and “Assistant 1”, while the anesthesiologist is positioned at the left side of the patient’s feet (Fig. 3.2).

b

view from the “Operating Surgeon” sitting (or standing) position at the head of the patient (b) during the “MI Chin Osteotomy” surgical procedure

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 he “10 Step-by-Step MI Chin Osteotomy” T Surgical Technique The “10 Step-by-Step” surgical technique (Table  3.2) to perform a chin osteotomy in a systematized minimally invasive (MI) way has initially been described concisely and accordingly illustrated on cadaver pictures [3]. In this chapter, the surgical technique has been elaborated in much more detail toward the overall surgical team using the combination of human cadaver, synthetic skull pictures, and high-­ professional illustration graphics. Cadaver illustrations have been made on an edentulous human cadaver with upper and lower jaw prosthesis to mimic a realistic situation. Special attention was taken to describe in detail the role of each member of the surgical team (“Operating Nurse”, “Assistant 1”, “Assistant 2”, and the “Operating Surgeon”) using the surgical codes and the dedicated “MI Chin Osteotomy” surgical sequence (Table  3.1). The latter is mentioned on the “MI Chin surgical sequence template bars” toward the “Operating Nurse” (Sect. “General Considerations regarding the “MI Chin Osteotomy” Surgical Procedure ”) in order to increase overall surgical efficiency and decrease patient morbidity. In this chapter the “MI Chin” orthognathic surgical technique is explained toward the right-handed “Operating Surgeon” but could of course easily be modified toward the left-handed “Operating Surgeon”. An educational graphic video (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany), available on YouTube (­https://www. youtube.com/watch?v=CqOmWaKoOZM), has been made in close collaboration with highly skilled graphic engineers based on the combination of human cadaver pictures, initial synthetic skull pictures and personal designs (GS) that are not mentioned in this chapter. Note that throughout this chapter right and left are used in regard to the position of the “Operating Surgeon” sitting or standing at the head of the patient and looking toward the patient’s body along the facial midline. Table 3.2 The “10 Step-by-Step MI Chin Osteotomy” Surgical Technique “Step 1” “Step 2” “Step 3” “Step 4” “Step 5” “Step 6” “Step 7” “Step 8” “Step 9” “Step 10”

MI soft tissue approach to the chin MI access to the bony chin MI exposure of the bony chin Marking the skeletal chin midline toward the lower dental midline Marking a horizontal reference line in the midline MI exposure of the unilateral bony chin by subperiosteal tunneling MI chin osteotomy Completion of the MI chin osteotomy MI mobilization of the bony chin after osteotomy MI repositioning and rigid fixation of the chin in its three-dimension (3D) virtual planned position

(From Swennen [3]; with permission)

Step 1—MI Soft Tissue Approach to the Chin Using cheek retractors held by the “Operating Surgeon”, intermaxillary fixation (IMF) is performed by “Assistant 1” with a 0.4-mm orthodontic steel wire using a “wire twister forceps” and a “double-sided Luniatschek”, securing the upper central and four lower incisors (Fig. 3.3a). In case of an important sagittal overbite, two wire loops are applied laterally instead of a single frontal wire loop to prevent pulling off the orthodontic braces. After the wire’s twisted part is cut using a “wire cutter”, the “Operating Surgeon” hyperextends the patient’s head in order to position the chin horizontally and parallel to the floor. The MI approach toward the chin osteotomy starts when the “Operating Surgeon” gently places a delicate soft tissue double hook (HK1) in the midline of the lower lip mucosa at approximately 10  mm of its border, and offers HK1 to “Assistant 2”, who takes it with his left hand. With his other hand, “Assistant 2” holds a slightly curved soft tissue retractor (RT1) to retract the labial soft tissues of the lower lip at the left side of the patient’s head. At the same time, “Assistant 1” is holding the aspiration device with his right hand and another soft tissue retractor (RT1) with his left hand. The “Operating Surgeon” sitting at the head of the patient, is now able to control the symmetrical positioning of both RT1 soft tissue retractors (Figs. 3.3a and 3.4a) which is crucial toward the correct orientation of the mucosal incision. The right-handed “Operating Surgeon” performs now a slight curvilinear incision using a #15 scalpel high in the mucosa of the lower lip. The incision of approximately 2 cm is performed from the left to the right lower lateral incisor, 1 cm below the transition of the wet to dry vermilion, along its outer contour (Figs.  3.3b and 3.4b). Consecutively, he gently takes the mucosa in the midline with an anatomical forceps (Figs.  3.3c and 3.4c) and starts dissecting “strictly submucosal” a vestibular flap, while identifying the mentalis muscles (Figs. 3.3c and 3.4c). Meanwhile, “Assistant 1” keeps holding the RT1 soft tissue retractor and the aspiration device with his left and right hands, respectively. “Assistant 2”, on the other side, still has the other RT1 soft tissue retractor in his right hand and the soft tissue double hook (HK1) in his left hand.

Trick

During submucosal sharp dissection with the #15 scalpel, the “Operating Surgeon” keeps the mucosa gently and strictly in the midline with a forceps, without changing its position. In this way, the “Operating Surgeon” is able to stay in the submucosal plane and avoids accidental lacerations or perforations of the mucosa.

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a

b

c

Fig. 3.3  The MI soft tissue approach to the chin (Step 1) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen,

Germany; modified by FOA) (b, c). Note the high mucosal curved incision in the lower lip (b) and the submucosal sharp dissection of the vestibular flap (c). Clinical pictures made by ©Valérie Swennen Boehlen. All rights reserved

Step 2—MI Access toward the Bony Chin

through the mentalis muscles and the periosteum until the bone using the same #15 scalpel. The deep-layer incision is performed approximately 5 mm below the mucosal incision, in order to create a good muscle bulk for appropriate double-­ layer closure of the wound (Fig. 3.5c). The length of the deep incision is slightly shorter than the superficial mucosal incision, approximately 15 mm, and centered on the midline.

On request of the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” remove all MI instruments from the patient’s mouth. The “Operating Surgeon” now supports the chin from below with his left hand (Fig. 3.5a–c) and keeps it in the horizontal plane while incising the deep soft tissue layers

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a

b

c

Fig. 3.4  The MI soft tissue approach to the chin (Step 1) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

(a–c). Note the high mucosal curved incision in the lower lip (b) and the sharp dissection of the vestibular flap (c). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Step 3—MI Exposure of the Bony Chin Attention!

The “Operating Surgeon” supports the chin himself to have a better control during the deep-layer incision and to avoid accidental perforation of the skin which otherwise could happen in case of a very hypoplastic chin.

While still supporting the chin with his left hand, the “Operating Surgeon” now performs a strictly subperiosteal sliding dissection of the chin in the midline toward the mandibular symphysis using the large side of a sharp double-­ sided raspatorium (MI1) (Fig. 3.6a–d).

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a

b

c

Fig. 3.5  The MI access toward the bony chin (Step 2) is shown on a synthetic skull (a) and on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany; modified by FOA) (b, c). Note that all MI instruments have been removed, so that the right-handed

“Operating Surgeon” can support the chin and hold the lower lip with his left hand in order to perform the deep-layer incision through the mentalis muscles and periosteum with his right hand. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

After reaching the inferior border, the “Operating Surgeon” turns the MI1 raspatorium approximately 45 degrees to the right side (Fig. 3.7a) to create a subperiosteal pocket around the chin border in order to position a chin retractor (Ch1). Note that at this time no other MI instrument is in the patient’s mouth.

The “Operating Nurse”, who is perfectly aware of the “MI Chin operating sequence” due to the dedicated “MI Chin surgical sequence template bars” (Sect. “General Considerations regarding the “MI Chin Osteotomy” Surgical Procedure”), now automatically gives the right-handed “Operating Surgeon” the Ch1 retractor correctly in his right

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G. R.J. Swennen et al.

a

b

c

d

Fig. 3.6  MI exposure of the bony chin (Step 3) using a sharp raspatorium (MI1) (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration

(L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b), and a synthetic skull (c, d). Note the strictly subperiosteal sliding movement of the MI1 raspatorium toward the mandibular symphysis. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

hand. The insertion of the Ch1 retractor, which requires a certain learning curve, consists in sliding the tip of Ch1 along the midline (in the same manner as the sliding movement

with the MI1 raspatorium) toward the mandibular symphyseal border by following the strict subperiosteal path that was previously created (Fig. 3.7b, c).

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

c

Fig. 3.7  MI exposure of the bony chin (Step 3) using a sharp raspatorium (MI1) (a) and Ch1 retractor (b, c) (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on a synthetic skull. Note the 45-degree turn to the right of the MI1 raspatorium (a) at the border of

Attention!

Supporting the chin by the Ch1 retractor is crucial during the entire “MI Chin Osteotomy” surgical procedure especially when rigid fixation after a Le Fort I osteotomy was already performed to avoid changes of

the mandibular symphysis and the typical sliding insertion technique of the Ch1 retractor (b, c). Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

the final maxillary position leading to surgical inaccuracy or jeopardizing its stability by uncontrolled vertical downward forces.

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G. R.J. Swennen et al.

b

c

Fig. 3.8  MI exposure of the bony chin (Step 3) and positioning of the Ch1 retractor and two RT1 soft tissue retractors (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

After reaching and crossing the lower chin border, an extension movement with the right arm is performed in order to hook the tip of the Ch1 retractor around the mandibular symphysis into the subperiosteal pocket and lift up the chin so that its anterior surface becomes parallel to the floor (Figs. 3.8a–c and 3.9a, b). This position of the Ch1 retractor will clearly facilitate all the next steps of the “MI Chin” procedure to the “Operating Surgeon”.

 tep 4—Marking the Skeletal Chin Midline S toward the Lower Dental Midline In order to mark the chin midline, the “Operating Surgeon” now handles the Ch1 retractor to “Assistant 2”. Due to the intelligent handgrip (Chap. 2, Sect. “The Rationale behind the “Intelligent Handgrip””) of the Ch1 retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany),

3  Minimally Invasive (MI) Chin Osteotomy

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a

b

Fig. 3.9  Positioning of the Ch1 retractor is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, b). Note that the anterior surface of the chin is parallel to the floor due to the

intelligent handgrip of the MI instrument Ch1 (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

“Assistant 2” is able to support and hold the anterior surface of the bony chin parallel to the floor by keeping its grip in close contact to the patient’s chest with his left hand. “Assistant 2” inserts a RT1 retractor to keep the oral mucosa away on the left side with his right hand, while “Assistant 1” does the same on the right side with his left hand. The “Operating Surgeon” further degloves the chin midline in a strict subperiosteal plane without degloving

the mandibular border and places the two RT1 retractors which are held by “Assistant 1” and “Assistant 2” now into the wound, on the bone and parallel to the midline of the chin in order to protect the soft tissues laterally (Fig.  3.10a–c). Using a fine short 1  mm Lindemann burr, the “Operating Surgeon” firstly creates some vertical landmarks toward the lower dental midline and secondly connects them starting from below (Fig. 3.11a, b) while protecting the soft tissues superiorly using the MI1 raspatorium with his left hand.

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G. R.J. Swennen et al.

b

c

Fig. 3.10  Marking the chin midline (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note that the right-­

handed “Operating Surgeon” holds the MI1 raspatorium with his left hand to protect the soft tissues when he is marking the chin midline toward the lower dental midline using a fine short Lindemann burr. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

Fig. 3.11  Marking the chin midline (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a, b). Note that the midline landmarks are first marked toward the lower dental midline

by drilling small holes that are consecutively connected to a thin vertical reference line by a short thin Lindemann burr. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Meanwhile, “Assistant 1” is taking care of the aspiration device with his right hand.

 tep 5—Marking a Horizontal Reference Line S in the Midline

Attention!

During the entire “MI Chin Osteotomy” surgical procedure, special care must be taken, by both “Assistant 1” and “Assistant 2” to retract the soft tissues strictly “ad minima” in order to avoid tearing the mucosa or creating lacerations by unnecessary tension on the soft tissues.

Tip

The vertical reference in the chin’s midline needs to be marked according to the patient’s lower dental midline which will be aligned at the end of the MI orthognathic surgical procedure to its individual upper dental and facial midlines. Also, the vertical chin reference midline needs to be long enough to be visible during rigid internal fixation of the chin in its new position.

The “Operating Surgeon” will now mark a horizontal reference line in the middle of the bony chin using a fine short 1  mm Lindemann burr while the chin is still supported by “Assistant 2” who holds the Ch1 retractor with his left hand in close contact with the patient’s chest. The horizontal reference line of approximately 2 cm and 5 mm below the lower frontal teeth’ apexes is slightly inclined downward to both sides of the mandibular lower border. Typically, the right-handed “Operating Surgeon” starts to mark the horizontal reference line at the left side with a fine short 1 mm Lindemann burr in his right hand and holding the MI1 raspatorium with his left hand in order to protect the upper soft tissues, while “Assistant 1” (left hand) and “Assistant 2” (right hand) protect the soft tissues laterally with the RT1 retractors (Fig. 3.12a–c). “Assistant 1” is meanwhile taking care of the aspiration device with his right hand. The “Operating Surgeon” then copy paste the left horizontal reference line to the right by marking initially three small landmarks and then connecting these with the same Lindemann burr.

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G. R.J. Swennen et al.

b

c

Fig. 3.12  Marking a horizontal reference line in the midline of the bony chin (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and

a synthetic skull (c). Note the slightly downward inclination of the horizontal reference line toward the mandible border. Also note that the vertical level of the horizontal reference line is estimated at approximately 5 mm below the lower frontal teeth apexes, since during surgery these normally cannot be visualized through the bone. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

In this step, in case important vertical movements such as “Intrusion / Extrusion” or “Roll” corrections were virtually planned, additional vertical bony reference landmarks may be marked medially from both canines according to the 3D virtual treatment plan [1]. Moreover, if an important

t­ransverse midline correction needs to be transferred, an additional vertical reference line can be marked on the lower part of the bony chin according to the 3D virtual surgical treatment plan.

3  Minimally Invasive (MI) Chin Osteotomy

Tip

3D virtual planning using the combination of 3D surface and volume rendering of the patient’s anatomy provides crucial information toward the design and transfer of the “MI Chin Osteotomy” (See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.)

 tep 6—MI Exposure of the Unilateral Bony S Chin by Subperiosteal Tunnelling After marking the vertical (Step 4, Sect. “Step 4—Marking the Skeletal Chin Midline toward the Lower Dental Midline”) and horizontal (Step 5, Sect. “Step 5—Marking a Horizontal Reference Line in the Midline”) reference lines, the right-­ handed “Operating Surgeon” now moves himself into a slightly two-third right position in relation to the patient’s head. Simultaneously, “Assistant 1” adjusts the operating light along the vector of the left subperiosteal tunnel that will be created in this step and holds a RT1 retractor with his right hand to retract the soft tissues at the right side of the wound. Meanwhile, he takes care of the aspiration with his left hand. “Assistant 2” removes the RT1 retractor from the wound to retract the labial soft tissues at the right side and continues to support the chin with the Ch1 retractor. The “Operating Surgeon” now puts his left hand at the mandibular border at the level of the premolars and creates a strictly subperiosteal tunnel from the chin midline toward the mandibular border with the large side of the sharp MI1 raspatorium. Once he has reached the mandibular border, he lifts up the MI1 raspatorium to open the subperiosteal tunnel in order to visualize the mental nerve coming out of the mental foramen. After the nerve is well identified, he performs a 45-degree turn to the left in order to create a small subperiosteal pocket at the mandibular border where a twisted blunt MI3 elevator will be positioned to perform the chin osteotomy (Step 7, Sect. “Step 7—MI Chin Osteotomy”).

Tip

In order to create the unilateral subperiosteal tunnel in a safe way toward the mental nerve, the “Operating Surgeon” identifies with his middle finger the lower mandibular border below the premolars to guide the sliding degloving movement of the MI1 raspatorium below the mental foramen.

37

In cases where the mental nerve cannot be identified directly by this maneuver, the “Operating Surgeon” brings back the MI1 raspatorium to the chin midline and repeats the same sliding movement slightly more superior in a second attempt to identify the mental nerve. The “Operating Surgeon” then changes his position into a slightly two-third left position and creates the subperiosteal tunnel on the right side in the same way (Figs.  3.13, 3.14, 3.15, and 3.16). “Assistant 2”, who is still supporting the bone chin with the Ch1 retractor in his left hand, places his RT1 retractor back into the wound at the left side with his right hand. Meanwhile, “Assistant 1” removes his RT1 from the wound and uses it to retract the labial soft tissues on the right side while taking care of the aspiration with his right hand.

Tip

It is crucial to create only narrow and straight subperiosteal tunnels with minimal degloving of the periosteum. This will ensure a stable positioning of the MI3 twisted blunt elevator in the subperiosteal pockets at the mandibular border during the chin osteotomy (Step 7, Sect. “Step 7—MI Chin Osteotomy”).

Step 7—MI Chin Osteotomy Once the subperiosteal tunnels have been created on both sides to expose the bony chin (Step 6, Sect. “Step 6—MI Exposure of the Unilateral Bony Chin by Subperiosteal Tunnelling”) and the mental nerves have been identified, the “Operating Surgeon” changes again into the slightly two-­ third right position and inserts a twisted blunt MI3 elevator along the contralateral tunnel into the subperiosteal pocket at the left mandibular inferior border. The curvature of the blunt tip of the dedicated MI3 twisted blunt elevator presents a discrete difference in angulation between both sides, in a way that one side adapts perfectly toward the left inferior mandibular border, while the other side was designed to adapt on the right side. Moreover, the MI3 twisted blunt elevator can be used for both sides by the right-handed as well as the left-handed surgeon. To perform the chin osteotomy on the left side, the “Operating Surgeon” positions the twisted blunt MI3 elevator into the ipsilateral subperiosteal tunnel and holds it upward with a specific handgrip with his left hand to protect both the ipsilateral mental nerve and submandibular anatomic structures. Using a short 1  mm Lindemann burr, he performs at first a unilateral “guiding chin corticotomy”

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a

b

c

d

Fig. 3.13  MI exposure of the unilateral right bony chin by subperiosteal tunnelling (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull. Note the inclination of the MI1 raspatorium toward the mandible lower border at the level of the right lower premolars (a) and

the 45-degree turn of the MI1 raspatorium to the right in the subperiosteal pocket at the right mandibular border (b). Also note that the MI1 raspatorium is then replaced by the “Operating Surgeon” by the MI3 twisted blunt elevator following the same subperiosteal path (c, d). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

3  Minimally Invasive (MI) Chin Osteotomy

Fig. 3.14  MI exposure of the unilateral right bony chin by subperiosteal tunnelling (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown in a “transparency view” after overlay of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull picture. Note how the curvature of the blunt tip of the MI3 twisted blunt elevator is supported by the right hand of the right-handed “Operating Surgeon” in the subperiosteal pocket at the right lower mandibular border. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

starting at the left lower mandibular border below the mental foramen toward the horizontal inclined reference line that was previously created (Step 5, Sect. “Step 5—Marking a Horizontal Reference Line in the Midline”). In case both foramina are symmetric, the chin corticotomy line is marked 5  mm below the mental foramen to avoid the loop of the mental nerve. In case 3D virtual planning shows that the mental foramina are at a different vertical level, the chin corticotomy line can accordingly be modified. To facilitate the “Operating Surgeon” to perform the left “guiding chin corticotomy”, “Assistant 2” supports the chin with the Ch1 retractor with his left hand and retracts the

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labial soft tissues with his right hand using a RT1 retractor. Simultaneously, “Assistant 1” adjusts the operating light along the vector of the left subperiosteal tunnel and protects the soft tissues at the right side of the wound with a RT1 retractor with his right hand while taking care of the aspiration with his left hand. After having performed the “guiding chin corticotomy” at the left side, the “Operating Surgeon” moves himself again into a slightly two-third position to the left and requests both assistants to “switch” the MI orthognathic instruments. “Assistant 2” moves now the operating light to the contralateral side along the vector of the right subperiosteal tunnel, positions his RT1 retractor in the wound at the left side and takes care of the aspiration device with his right hand. Meanwhile “Assistant 1” takes over the Ch1 retractor with his right hand while retracting the labial soft tissues at the right side (Fig. 3.17a, b). After the “guiding chin corticotomy” at the right side is completed, the “Operating Nurse” replaces the handpiece by the reciprocating saw, while the “Operating Surgeon” moves himself again into a slightly two-third right position in order to perform the chin osteotomy at the left side. Both “Assistant 1” and “Assistant 2” handle the positioning of the light, aspiration, and positioning of the MI instruments exactly as during the ipsilateral “guiding chin corticotomy”. The “Operating Surgeon” supports the twisted blunt MI3 elevator at the left side with his left hand and brings the reciprocating saw in the previously created ipsilateral “guiding chin corticotomy”. The blunt tip of the reciprocating saw is then pushed by the “Operating Surgeon” against the MI3 twisted blunt elevator in the subperiosteal pocket in order to provide the necessary space to perform a clear cut of the lower left mandibular border. The unilateral left chin osteotomy is now performed from lateral to medial crossing the midline, going through both outer and inner cortexes. It is crucial that “Assistant 1” protects well the soft tissues with the RT1 retractor on the bone while the reciprocating saw crosses the midline. The “Operating Surgeon” and both “Assistants 1 and 2” now again “switch” positioning and MI instruments, respectively, to perform the same procedure at the contralateral right side (Figs. 3.18 and 3.19). Pictures on an anatomically

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a

b

c

d

Fig. 3.15  MI exposure of the unilateral right bony chin by subperiosteal tunnelling (Step 6) and positioning of the MI orthognathics instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, b) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

(c, d). Note the inclination of the MI1 raspatorium toward the mandibular border at the level of the lower premolars (a, c). Also note that the MI1 raspatorium is then replaced by the “Operating Surgeon” by the MI3 twisted blunt elevator (b, d). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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a

b

Fig. 3.16  Positioning of the MI3 twisted blunt elevator (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (Step 6) is shown on an anatomical dissected human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) in a two-third profile view from the left (a), a two-third left view from above (“Operating Surgeon’s” view) (b), and a detailed view focused

on the right lower mandibular border (c). Note how the MI3 instrument is positioned at the lower mandibular border to protect both the neurovascular bundle of the mental nerve and the submandibular soft tissues due to the dedicated curvature of its blunt tip. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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c

Fig. 3.16 (continued)

a

Fig. 3.17  Marking the MI chin corticotomy at the right side and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a) and

b

a synthetic skull picture (b). Note that the unilateral corticotomy with a short fine 1 mm Lindemann burr will allow an easier and accurate osteotomy of the chin. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

c

b

Fig. 3.18  The MI chin osteotomy (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a) and a  synthetic skull (c, d). Note that the

reciprocating saw is placed into the previously created corticotomy to ensure a clear osteotomy cut at the mandibular border while the submandibular soft tissues are protected by the “Operating Surgeon” with the MI3 twisted blunt elevator. Also note how the reciprocating saw crosses the midline during the chin osteotomy (d). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Attention!

The “Operating Surgeon” must make sure that the osteotomy goes until the inferior border’s end, throughout the mandibular base.

Trick

Initially, the reciprocating saw is used more horizontally (laterally) and the “Operating Surgeon” then gradually changes its inclination to a vertical position toward the chin midline (Figs. 3.18c, d and 3.19).

Step 8—Completion of the MI Chin Osteotomy After the “Operating Surgeon” has performed the chin osteotomy with the reciprocating saw (Step 7, Sect. “Step 7—MI Chin Osteotomy”), “Assistant 1” and “Assistant 2” remove Fig. 3.19  The MI chin osteotomy (Step 7) and positioning of the MI both RT1 retractors from the wound. orthognathic instruments (L1® MI Orthognathics, KLS Martin, The “Operating Surgeon” now takes a blunt wedge osteoTuttlingen, Germany) are shown in a “transparency view” after overlay tome (OS5) and a mallet (BI-TAP) with his left and right of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the syn- hands, respectively. In this step, it is crucial that “Assistant thetic skull picture. Note how the “Operating Surgeon” supports the 2” continues to support the chin with the Ch1 retractor, while MI3 twisted blunt elevator at the lower mandibular border. Also note “Assistant 1” is taking care of the aspiration with his right the change of the inclination of the reciprocating saw from lateral hand. toward the chin midline. Clinical pictures made by ©Valérie Swennen-­ The “Operating Surgeon” then performs a single “strong Boehlen. All rights reserved tap” on the blunt OS5 wedge osteotome with the silicon part of the BI-TAP mallet, which is in most cases sufficient to dissected human cadaver specimen illustrate how the MI3 mobilize the osteotomized chin (Fig. 3.21a–c. twisted blunt elevator protects the soft tissues toward the reciprocating saw (Fig. 3.20a, b). The osteotomy design of the above-described “sliding Step 9—MI Mobilization of the Bony Chin after chin osteotomy” can easily be modified toward a “shield Osteotomy chin osteotomy” or “box chin osteotomy” using the same principles described in this and the following steps. In case the osteotomized chin is not sufficiently mobilized at Moreover, a vertical cut of the osteotomized bony chin can the mandibular border (Step 8, Sect. “Step 8—Completion of be combined in case constriction or widening of the bony the MI Chin Osteotomy”), the “Operating Surgeon” can chin is required. Also, an ostectomy of the medial part of the insert an 8-mm sharp osteotome (OS6) in the osteotomy line bony chin can be performed using the same principles with on both sides in order to further mobilize the osteotomized the reciprocating saw or piezoelectric ultrasonic device. chin and to avoid an unfavorable split pattern at the mandibular border. The “Operating Surgeon” therefore inserts the sharp OS6 osteotome at the level of the mandibular border (Fig. 3.22a– Tip c) and performs a 45-degree twist with his right hand while Before activating the reciprocating saw, the “Operating supporting the chin with his left hand. Meanwhile, it is Surgeon” pushes its tip against the MI3 twisted blunt important that “Assistant 2” keeps supporting the chin with elevator to facilitate a clear and complete osteotomy his left hand with the Ch1 retractor but now without force, cut at the lower mandibular border reducing the risk of while “Assistant 1” is still taking care of the aspiration with a mandibular border bad split. his right hand.

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a

b

Fig. 3.20  Positioning of the MI3 twisted blunt elevator (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown from the left two-third view (a) and more detailed from the right (b) on an anatomical dissected human cadaver specimen (Department of Anatomy

and Embryology, University of Maastricht, the Netherlands). Note how the MI3 instrument protects the neurovascular bundle of the mental nerve toward the reciprocating saw. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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a

b

c

Fig. 3.21  Completion of the MI chin osteotomy (Step 8) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics,

Tip

Note that at this stage “Assistant 2” is still supporting the chin with the Ch1 retractor but without force, allowing the “Operating Surgeon” to further mobilize the osteotomized chin at the mandibular border level if necessary.

KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note that the chin is well supported with the Ch1 retractor by “Assistant 2” while the “Operating Surgeon” taps with the BI-TAP mallet on the blunt OS5 wedge osteotome. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 10—MI Repositioning and Rigid Fixation S of the Chin in its 3D Virtual Planned Position After adequate mobilization of the osteotomized bony chin segment (Step 9, Sect. “Step 9—MI Mobilization of the Bony Chin After Osteotomy”), the “Operating Surgeon” takes over the Ch1 retractor with his left hand to move the

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

c

Fig. 3.22  MI mobilization of the bony chin after osteotomy (Step 9) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), graphic illustration (L1® MI

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the positioning of the sharp OS6 osteotome into the chin osteotomy at the right mandibular border in case further mobilization is necessary. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

osteotomized bony chin segment into its “approximate” virtual planned position. The “Operating Surgeon” then handles the Ch1 retractor to “Assistant 1” who takes it with his right hand and protects the soft tissues with his left hand using a RT1 retractor placed in the wound on the bone. “Assistant 2”, does the same with another RT1 at the left side while taking care of the aspiration with his left hand.

The “Operating Surgeon” now positions a pre-bended osteosynthesis chin plate (KLS Martin, Tuttlingen, Germany) in the correct position on the mandible using a clamp (BI3) with his left hand and consecutively drills and inserts two 7 mm (2.0) screws in the upper holes of the chin plate to fix it (Figs.  3.23a–c, 3.24a–c, and 3.25a). Consecutively, the “Operating Surgeon” takes over again the Ch1 retractor from

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a

b

c

d

Fig. 3.23  MI repositioning and rigid fixation of the chin in its new 3D virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on graphic illustrations (L1® MI Orthognathics, KLS Martin,

Tuttlingen, Germany) (a–d). Note the retraction of the soft tissues with two RT1 retractors, the support of the chin in its new position by the Ch1 retractor and how the pre-bended osteosynthesis plate is held with the BI3 instrument while inserting the upper screws

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

c

d

Fig. 3.24  MI repositioning and rigid fixation of the chin in its 3D virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on a synthetic skull (a–d). Note the positioning of the RT1 retractors, the

Ch1 retractor and the BI3 keeping the pre-bended chin osteosynthesis plate (KLS Martin, Tuttlingen, Germany) in its correct position. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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a

b

c

d

Fig. 3.25  MI repositioning and rigid fixation of the chin in its 3D virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a–d). Note the positioning of the RT1 retractors, the Ch1 retractor and the BI3 keeping the

pre-bended chin osteosynthesis plate (KLS Martin, Tuttlingen, Germany) in the correct position (a, b). Also note the positioning of the double hook (HK1) and two RT1 retractors prior to the deep-layer closure (c) and consecutive removal of the HK1 prior to the superficial mucosa closure. Clinical pictures made by ©Valérie SwennenBoehlen. All rights reserved

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3  Minimally Invasive (MI) Chin Osteotomy

a

b

Fig. 3.26  Final wound closure after MI repositioning and rigid fixation of the chin in its new 3D virtual planned position (Step 10) is shown on graphic illustrations (L1® MI Orthognathics, KLS Martin,

Tuttlingen, Germany; modified by FOA) (a, b). Note that there may not be any tension on the “superficial-layer” mucosal closure

“Assistant 1” to hold the bony chin segment now in the “exact” 3D virtual planned position and fix it with two other 7  mm (2.0) screws in the lower holes of the chin plate (Figs. 3.23d, 3.24d, and 3.25b). In cases of important “Roll” or “Yaw” movements, an additional straight linear two-hole plate (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) can be placed unilaterally. Moreover, on some occasions, instead of using a pre-bended chin plate, two straight linear two-hole plates (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) can be used in case no anteroposterior changes are required. After rigid internal fixation of the osteotomized bony chin, the “Operating Surgeon” rinses the wound abundantly with saline (NaCl) solution, cleans the patient’s face, and humidifies his hands to manually check the new contour of the mandible border by manual palpation. In case relevant bony steps are still palpable, these should be corrected by “bony-grinding” or “bone-grafting” prior to final wound closure. Moreover, in cases of relevant extrusion movements, the bony chin osteotomy gaps should be bone-grafted unilaterally or on both sides. Toward an adequate “double-layer” closure of the “MI Chin Osteotomy” wound, after extensive rinsing with saline (NaCl) solution, the “Operating Surgeon” places the double hook (HK1) inside the wound on its most anterior position and consecutively hands it to “Assistant 2”, who holds it with

his left hand. Meanwhile, “Assistant 2” retracts the labial soft tissues at the left side with a RT1 retractor in his right hand while “Assistant 1” does the same at the contralateral side with another RT1 in his left hand and takes care of the aspiration with his right hand. At first, the "Operating Surgeon”, performs the “deep-layer” closure (Fig. 3.25c, d and 3.26a) of the two mentalis muscles using two bilateral single Vicryl 3.0 non rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) sutures with an additional suture in the midline. Secondly, the mucosal “superficial-­ layer” is closed (Fig.  3.26b) by the “Operating Surgeon” with a running Vicryl 4.0 rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) suture without tension from right to left while the labial soft tissues are gently retracted by both “Assistant 1” and “Assistant 2” with RT1 retractors. At the end of the entire “MI  Chin Osteotomy” surgical procedure, after abundant rinsing of the wound with saline (NaCl) solution and aspiration of the airway, orthodontic wax is applied at the lower braces from canine to canine to protect the mucosal chin wound. After cleaning the patient’s face, suture strips of 5  mm are applied to define the plica labio-mentalis or to stretch it in regard to the individualized clinical-focused 3D virtual planning. Consecutively, a chin compression bandage is applied using 10 mm suture strips followed by application of a steroid ointment (Elocom®

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0.1%, NV Schering-Plough Labo, Heist-op-den-Berg, Belgium) on both lips and final adaptation of a cooling face mask (Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/ Allgäu, Germany) without any tension on the skin for postoperative thermo-therapy, which is continued for 1  week (Chap. 8).

Attention!

The “superficial-layer” mucosal suture must be performed without any tension to avoid scar tissue formation.

Excessive chin asymmetry In case important chin asymmetry needs to be corrected, an isolate “MI Chin Osteotomy” approach may not be sufficient and needs to be combined with an additional “MI Sagittal  Split  Osteotomy” (Chap. 5) approach to properly address the chin asymmetry deformity. For cases like this, guides and patient-specific implants (PSI's) and/or intra-operative Cone-Beam CT (IO-CBCT) can be extremely useful. “Chin-wing Osteotomy” The described isolate “MI Chin Osteotomy” approach does not allow to perform a “Chin-wing Osteotomy” and needs to be combined with a bilateral “MI Sagittal Split Osteotomy (Chap. 5)” approach.

Limits of the “MI Chin Osteotomy” Surgical Technique

Surgical experience The “10 Step-by-Step” surgical procedure described in this chapter and the accompanying graphic video are valuable for “in-depth” study of the MI technique (https:// www.youtube.com/watch?v=CqOmWaKoOZM). Dedicated phantom, cadaver or live-surgery courses are recommended. Following the described MI orthognathic principles in this chapter, every orthognathic surgeon should be able to master the “MI Chin Osteotomy” after his individual “learning curve”.

References 1. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017. 2. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 3. Swennen GRJ. Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi. org/10.1016/j.cxom.2020.05.009.

4

Minimally Invasive (MI) Le Fort I  Osteotomy Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola

Step-by-step standardization of minimally invasive (MI) orthognathic surgical techniques increases surgical efficiency and decreases patient morbidity. In this chapter, an innovative systematized “10 step-by-step approach” toward the Le Fort I osteotomy following a “MI philosophy and mindset” is outlined in detail. General considerations regarding the preparation of the patient, instrumentation table, and operating room toward the MI Le Fort I osteotomy are well described. Dedicated newly developed MI orthognathic surgical instruments allow to optimize the vascular blood supply and decrease of interstitial edema and swelling after a Le Fort I osteotomy which enhances postoperative fast recovery of the patient. Moreover, the introduction of MI orthognathic surgical codes, MI orthognathic surgical sequences and MI orthognathic sequence template bars create a common language among the surgical team (“Operating Surgeon”, “Surgical Assistants”, and “Operating Nurse”) which increases surgical efficiency and additionally decreases patient morbidity. Furthermore, systematization of storage of the  MI orthognathic instruments and MI surgical sequence template bars allows to optimize their gathering, cleaning, and sterilization process toward a more time-efficient and costeffective clinical routine. Every single step of the

G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected]

MI approach toward the Le Fort I osteotomy is illustrated in detail by high-quality graphic illustrations and pictures made on synthetic skulls, human cadaver, and anatomically dissected human cadaver specimens. Finally, the limits of the described MI  surgical technique toward the Le Fort I osteotomy are summarized.

 eneral Considerations Regarding the “MI Le G Fort I Osteotomy” Surgical Procedure In this chapter (Sect. “The “10 Step-by-Step MI Le Fort I Osteotomy” Surgical Technique”), a “10 Step-by-Step” surgical technique (see Table 4.2) to perform a Le Fort I osteotomy in a systematized minimally invasive (MI) way will be described in detail. Individualized and clinically focused 3D virtual treatment planning of the maxilla can incorporate a combination of 3D translational (anteroposterior, transversal, and vertical) and rotational (“Roll”, “Pitch”, and “Yaw”) movements of the osteotomized maxilla in regard to the final occlusion, airway, and overlying soft tissue mask [1]. Most of these movements can be safely performed and transferred in an accurate way through the below-described MI approach. The limits of the presented “MI Le Fort I Osteotomy” surgical technique, however, are outlined at the end of this chapter. Based on the background of MI surgery in other surgical fields (Chap. 1) and supported by evidence-based medicine [2] a new innovative concept and rationale was developed toward “MI Orthognathic Surgery” (Chap. 2) in order to reduce overall patient morbidity by the combination of increasing surgical efficiency and decreasing surgical trauma through minimized degloving and compression of the surrounding soft tissue envelope. In specific regard toward the “MI Le Fort I Osteotomy”, the following general considerations need to be taken into account by the surgical team:

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_4

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1. Organization of the surgical instrumentation table by the “Operating Nurse” (Sect. ““MI Le Fort I Osteotomy” Instruments and “MI Le Fort I Osteotomy” Surgery Instrumentation Table Organization”) 2. Preparation of the patient in the operating room by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” (Sect. “Patient and Operating Room Preparation Toward the “MI Le Fort I Osteotomy” Surgical Procedure”)

“ MI Le Fort I Osteotomy” Instruments and “MI Le Fort I Osteotomy” Surgical Instrumentation Table Organization In order to improve the efficiency of the overall surgical team during an “MI Le Fort I Osteotomy”, “MI Le Fort I surgical

G. R.J. Swennen et al.

sequence template bars” were developed to indicate in a systematic order the required MI coded instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) [3] (Chap. 2). The “Operating Nurse” places the six dedicated “MI Le Fort I surgical sequence template bars” on top of the surgical instrumentation table (Fig. 4.1) which allows a fast, easy, and standardized organization of the relevant MI orthognathic instruments not only at the initiation but also during the entire surgical procedure. Moreover, the “Operating Nurse” is able to follow and knows at any moment which “MI Le Fort I” orthognathic instrument is needed by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” to smoothly perform the “MI Le Fort I Osteotomy”. The “Surgical Codes” and “Surgical Sequence” toward the “MI Le Fort I Osteotomy” are mentioned in Table 4.1.

Fig. 4.1  MI orthognathic instruments used to perform the “MI Le Fort I Osteotomy” systematically organized on the surgery instrumentation table by the “Operating Nurse” (graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

4  Minimally Invasive (MI) Le Fort I Osteotomy Table 4.1  “Surgical Codes” and “Surgical Sequence” for the “Minimally Invasive (MI) Le Fort I Osteotomy” orthognathic surgical procedure MI Le Fort I Osteotomy HK1 RT1 RT1 MI1 MI2 BI1 Mx1 OS1 BI-TAP Mx2L Mx2R Mx3 OS2 OS3 OS5 Mx4S Mx4L HK2 MX5 BI2 BI3 HK3 (HK) hook; (RT) retractor; (MI) minimally invasive; (BI) basic instrument; (OS) osteotome; (Mx) maxilla From Swennen [3]; with permission

 atient and Operating Room Preparation P Toward the “MI Le Fort I Osteotomy” Surgical Procedure To perform a “MI Le Fort I Osteotomy”, the patient is placed in a supine position on the operating table by the “Anesthesiologic team” in close collaboration with the “Operating Surgeon” who personally positions the patient’s head by a dedicated head support (Chap. 8) in a “neutral horizontal position” in a way that head extension is avoided during the surgical procedure similar as in the “MI Chin Osteotomy” (Chap. 3), “MI Sagittal Split Osteotomy” (Chap. 5), and “MI Mandible Constriction / Expansion”  (Chap. 7),  surgical procedures. After nasotracheal intubation by the anesthesiologist and correct positioning of the tube (Chap. 8), local anesthesia (Xylocaine® 1% with adrenaline 1:200.000) is administered by “Assistant 2” both in the submucosal plane between the upper canines and in the deep subperiosteal plane at the Le Fort I level for localized vasoconstriction and hemostasis. Moreover, “Assistant 2” positions the two operating reflector lights (most ideally L.E.D.) in an ideal position above the patient—one straight above the head and the second above the legs with a 45-degree inclination angle toward the patient’s face. Meanwhile “Assistant 1” is scrubbing in order to start disinfection of the patient’s head and surgical draping immediately once the patient is intubated in order not to lose valuable time. Antisepsis of the face is performed by “Assistant 1” with Hibidil® (50  mg/100  ml chlorhexidine digluconate cutaneous solution, Hälsa Pharma GmbH, Münster, Germany) and consecutively disinfection of the mouth with Hextril® (1 mg/ml hexetidine mouth rinsing, Famar Orléans,

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Orléans, France) once all sterile drapes have been applied. Prior to surgery, the wax-bite that was taken in centric relation (CR) during the “pre-surgical workup” (Chap. 8) is always verified, occlusal grinding is performed if necessary and final fitting of the intermediate and final splints on the patient checked by “Assistant 1”. Lastly, a steroidal ointment is applied on both the upper and lower lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-den-Berg, Belgium) by one of the assistant surgeons. Intravenous (IV) antibiotics (2  g amoxicillin clavulanic acid 2000  mg/200  mg intravenous injection, Augmentin®, GlaxoSmithKline, Singapore) are administered by the anesthesiologist only once in a single dose unless additional bone grafting or lipo-filling is performed where these are continued postoperatively for 1 week orally. In case of penicillin allergy, 600  mg of clindamycin (Clindamycin Sandoz® 600  mg/4  ml intravenous injection, Sandoz Canada Inc. Boucherville, QC, Canada) is administered by intravenous injection in a single dose and continued orally for 1 week if indicated. Corticosteroids are given in a single high dose (250  mg methylprednisolone intravenous injection, Solu-­ Medrol®, Pfizer Manufacturing, Puurs, Belgium) at the start of the surgery and repeated postoperatively at the recovery unit (80  mg methylprednisolone intramuscular injection, Depo-Medrol®, Pfizer Manufacturing, Puurs, Belgium). Tranexamic-acid (500 mg/5 ml tranexamic acid intravenous injection, Exacyl®, Sanofi, Gentilly, France) is administered 1  g directly IV after induction and another 1  g in the 1  L NaCl drip infusion at initiation of the surgery unless contraindications. The anesthesiologic management is furthermore explained in Chap. 8. To perform a “MI Le Fort I Osteotomy”, the right-handed “Operating Surgeon” is positioned in front of the patient’s head (sitting or standing) while “Assistant 1” and “Assistant 2” are placed aside, on the right and left sides, respectively (Fig.  4.2). This particular position allows the “Operating Surgeon” to have the most ideal view to evaluate overall symmetry during the entire “MI Le Fort I Osteotomy” surgical procedure, especially regarding the upper dental midline and maxillary occlusal plane. The “Operating Nurse” is ideally positioned at the right side of the patient’s thorax and “Assistant 1”, while the anesthesiologist is positioned at the left side of the patient’s feet (Fig. 4.2).

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a

Fig. 4.2  Positioning of the “Operating Surgeon”, surgical “Assistant 1”, surgical “Assistant 2”, “Operating Nurse”, and anesthesiologist are shown in the operating room (graphic illustrations from L1® MI Orthognathics,

 he “10 Step-by-Step MI Le Fort T I Osteotomy” Surgical Technique The “10 Step-by-Step” surgical technique (Table 4.2) to perform a Le Fort I osteotomy (non-segmental or segmental) in a systematized minimally invasive (MI) way has initially been described concisely and accordingly illustrated on cadaver pictures [3]. In this chapter, the surgical technique has been elaborated in much more detail toward the overall surgical team using the combination of human cadaver, synthetic skull pictures, and high-professional illustrations graphics. Cadaver illustrations have been made on an edentulous human cadaver with upper and lower jaw prosthesis to mimic a realistic situation. Special attention was taken to describe in detail the role of each member of the surgical team (“Operating Nurse”, “Assistant 1”, “Assistant 2”, and the “Operating Surgeon”) using the surgical codes and the dedicated “MI Le Fort I Osteotomy” surgical sequence (Table 4.1). The latter is mentioned on the “MI Le Fort I surgical sequence template bars” toward the “Operating Nurse” (Sect. “General Considerations Regarding the “MI Le Fort I Osteotomy” Surgical Procedure”) in order to increase overall surgical efficiency and decrease patient morbidity. In this chapter, the “MI Le Fort I” orthognathic surgical technique is explained toward the right-handed “Operating Surgeon” but could of course easily be modified toward the left-handed “Operating Surgeon”. An educational graphic video (L1® MI Orthognathics, KLS Martin,

G. R.J. Swennen et al.

b

KLS Martin, Tuttlingen, Germany): overview (a) and view from the “Operating Surgeon” sitting (or standing) position at the head of the patient (b) during the “MI Le Fort I Osteotomy” surgical procedure

Table 4.2  The “10 Step-by-Step MI Le Fort I Osteotomy” Surgical Technique “Step 1” “Step 2” “Step 3” “Step 4” “Step 5” “Step 6” “Step 7” “Step 8”

“Step 9” “Step 10”

MI soft tissue approach to the Le Fort I osteotomy MI subperiosteal dissection of the medial pillar of the maxilla Marking landmarks for vertical repositioning of the maxilla Degloving of the nasal floor and septum release MI exposure of the maxilla by subperiosteal tunnelling MI Le Fort I corticotomy MI osteotomy of the medial and lateral maxillary pillars MI down fracture and pterygomaxillary (PTM) dysjunction followed by mobilization of the osteotomized maxilla Remodelling of the nasal floor, nasal septum, and removal of potential premature bone contacts MI repositioning and rigid fixation of the maxilla in its three-dimensional (3D) virtual planned position

From Swennen [3]; with permission

Tüttlingen, Germany), available on YouTube (https://www. youtube.com/watch?v=CqOmWaKoOZM), has been made in close collaboration with highly skilled graphic engineers based on the combination of human cadaver pictures, initial synthetic skull pictures and personal designs (GS) that are not mentioned in this chapter. Note that throughout this chapter right and left are used in regard to the position of the righthanded “Operating Surgeon” sitting or standing at the head of the patient and looking toward the patient’s body along the facial midline.

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 tep 1—MI Soft Tissue Approach to the Le Fort S I Osteotomy The MI approach toward the Le Fort I osteotomy starts when the “Operating Surgeon” gently places a delicate soft tissue double hook (HK1) in the midline of the upper lip mucosa at approximately 5 mm of its border, and offers the HK1 double hook to “Assistant 2” who takes it with his right hand. With his other hand, “Assistant 2” holds a slightly curved soft tissue retractor (RT1) to retract the labial soft tissues of the upper lip at the left side of the patient’s head. At the same time, “Assistant 1” is holding the aspiration device with his right hand and another slightly curved soft tissue retractor (RT1) with his left hand. The “Operating Surgeon”, sitting or standing at the head of the patient (Fig. 4.2), is now able to control the symmetrical positioning of both RT1 retractors (Fig. 4.3a, b), which is crucial toward the correct orientation of the mucosal incision. The right-handed “Operating Surgeon” now performs a slight curvilinear incision using a Colorado needle monopolar electrosurgical unit (or a #15 scalpel) in the mucosa of the upper lip. The mucosal superficial layer incision of approximately 20 mm is performed from the left to the right upper lateral incisor and converts slightly to the buccal frenulum in the midline (Fig. 4.4a-d). Meanwhile, “Assistant 1” keeps holding the RT1 retractor and the aspiration device with his left and right hands, a

Fig. 4.3  MI soft tissue approach to the Le Fort I osteotomy (Step 1) and positioning of MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the

respectively. “Assistant 2”, on the other side, still has the soft tissue double HK1 double hook in his right hand and another RT1 retractor in his left hand. Consecutively, the “Operating Surgeon” gently takes the mucosa with an anatomical forceps and after dissecting a “strict” submucosal vestibular flap, he incises the deep soft tissue layers through the nasolabial muscles and the periosteum until the bone using a #15 scalpel (Fig.  4.5a-c). The deep-layer incision is performed from the left to the right approximately at the level of the nasal base, in order to create a proper muscle bulk for paranasal cross-suturing (Step 10, Sect. “Step 10—MI Repositioning and Fixation of the Maxilla in its 3-Dimensional (3D) Virtual Planned Position”). The length of the deep-layer incision is the same as the superficial-layer mucosal incision, approximately 20  mm, and centered on the midline.

Tip

The “Operating Surgeon” must take care to create a proper muscle bulk toward appropriate cross-suturing of the nasolabial muscles during final wound closure (Step 10, Sect. “Step 10—MI Repositioning and Fixation of the Maxilla in its 3-Dimensional (3D) Virtual Planned Position”).

b

Netherlands) (a) and graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b). Note the important symmetric positioning of both RT1 retractors toward the HK1 double hook. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 4.4  MI soft tissue approach to the Le Fort I osteotomy (Step 1) and positioning of MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands) (a, b) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (c, d). Note the slightly curvilinear superficial-layer mucosal incision. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 2—MI Subperiosteal Dissection S of the Medial Pillar of the Maxilla

degloving along the outer part of the right lateral nasal wall (which is the medial pillar of the right maxilla), using the large side of the double-sided sharp raspatorium (MI1) in combination with the curved side of the blunt double-sided elevator (MI2) to retract the right paranasal soft tissues (Fig. 4.6a, b, c). During the subperiosteal dissection of the right medial pillar of the maxilla, “Assistant 1” continues to gently

Once the MI soft tissue access to the Le Fort I (Step 1, Sect. “Step 1—MI Soft Tissue Approach to the Le Fort I Osteotomy”) has been performed, the soft tissue HK1 double hook is removed by “Assistant 2”. The “Operating Surgeon” now performs a strict and minimal subperiosteal

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a

b

c

Fig. 4.5  MI soft tissue approach to the Le Fort I osteotomy (Step 1) and positioning of MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany, modified by FOA) (b) and a  synthetic skull (c). Note the double-layer incision. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

retract the labial soft tissues of the right upper lip with the RT1 retractor in his left hand while he performs fine aspiration using his right hand. “Assistant 2” is supporting the position of the head at this stage with both of his hands. Subsequently, the “Operating Surgeon” degloves the nasal mucosa at the inner part of the right lateral nasal wall,

using both the large (Fig. 4.7a, c) and the small (Fig. 4.7b) side of the double-sided sharp MI1 raspatorium. When the same procedure is consecutively performed on the contralateral side, “Assistant 2” gently retracts the labial soft tissues of the left upper lip with a RT1 retractor while “Assistant 1” continues aspiration, both with their right hands.

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Fig. 4.6  MI subperiosteal dissection of the right medial pillar of the maxilla (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration

(L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the strict and minimal dissection of the outer part of the medial pillar of the right maxilla. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 3—Marking Landmarks for Vertical S Repositioning of the Maxilla

landmarks are created on the paranasal bone for final vertical repositioning of the maxilla. The “Operating Surgeon” now places a dedicated double-­ retractor (Mx1) in the small wound subperiosteally on the paranasal bone and handles it to “Assistant 2” who takes it with his right hand. With his left hand “Assistant 2” retracts

Once MI subperiosteal dissection of the medial pillars of the maxilla (Step 2, Sect. “Step 2—MI Subperiosteal Dissection of the Medial Pillar of the Maxilla”) has been performed,

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a

b

c

Fig. 4.7  MI subperiosteal dissection of the right medial pillar of the maxilla (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and

a synthetic skull (c). Note the strict subperiosteal dissection of the inner part of the medial right pillar of the maxilla. Also note that the RT1 retractor is only retracting the upper labial soft tissues at the right side and is not positioned into the wound in this step. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

and protects the mucosal soft tissues, gingiva, and teeth with the curved part of the double-sided blunt MI2 elevator, firstly at the right inferior part of the small wound. “Assistant 1” meanwhile gently retracts the right labial soft tissues with a RT1 retractor with his left hand and performs fine aspiration with his right hand to clearly visualize the anatomical area.

The “Operating Surgeon” now takes the slightly hooked caliper (BI1) with his left hand and holds it parallel to the facial midline while he marks two landmarks with a fine short 1 mm Lindemann burr (Fig. 4.8a, b) for final control and repositioning of the maxilla (Step 10, Sect. “Step 10— MI Repositioning and Fixation of the Maxilla in its

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Fig. 4.8  Marking landmarks for vertical repositioning of the maxilla (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b), and a synthetic

skull (c). Note that retraction of the soft tissues may be performed by the use of a dedicated Mx1  double-retractor (a–b) or two small RT1 retractors (c) depending on the surgeon’s preference. If two RT1 retractors are chosen, retraction must be strictly vertical and medial to avoid laceration of the small wound. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

3-Dimensional (3D) Virtual Planned Position”). The first landmark is created below the Le Fort I level medial from the canine apex, while the second landmark is marked above the Le Fort I level parallel to the patient’s facial midline, in regard to the final vertical repositioning of the maxilla. Subsequently, “Assistants 1 and 2” switch the Mx1 double-­

retractor and the “Operating Surgeon” creates the landmarks in the same way on the left side. Note that at this stage, retraction can also be achieved by using two small RT1 retractors (Fig. 4.8c), held by “Assistants 1 and 2” instead of the Mx1 double retractor depending on the surgeon’s preference.

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Trick

If, for example, a 1.5-mm intrusion is aimed, the initial distance between the landmarks is put on 11.5 mm and reduced to 10.0 mm after maxillary repositioning (Step 10, Sect. “Step 10—MI Repositioning and Fixation of the Maxilla in its 3-Dimensional (3D) Virtual Planned Position”) (See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.)

 tep 4—Degloving of the Nasal Floor S and Septum Release After marking landmarks for vertical repositioning of the maxilla (Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”), degloving of the nasal floor and septal release needs to be performed. The “Operating Surgeon” continues the degloving of the nasal mucosa now at the level of the nasal floor using the large side of the double-sided sharp MI1 raspatorium (Fig.  4.9a, b), while “Assistant 2” holds the Mx1 ­double-­retractor in the maxillary midline with both of its edges placed subperiosteally on the bone. In case of a supraspinal Le Fort I osteotomy, the “Operating Surgeon” degloves the nasal mucosa from the Anterior Nasal Spine (ANS) with a

Fig. 4.9  Degloving of the nasal floor and septum release (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the large part of the MI1 raspatorium that he holds in his right hand supported with his left hand. “Assistant 2” then removes the Mx1 double-retractor. The “Operating Surgeon” now inserts his left middle finger in the patient’s mouth toward the posterior border of the hard palate at the level of the Posterior Nasal Spine (PNS) for protection and control during the septal release. He inserts a septum osteotome (OS1) converging downward above the ANS, and instructs “Assistant 2” to gently tap on it with the metal side of the mallet (BI-TAP), until the bony septum is fully released along the nasal floor to the back (Fig. 4.10a-c). Care should be taken to make sure that the tapping is well controlled following the instructions of the “Operating Surgeon”. “Assistant 1” takes care of fine aspiration during the degloving of the nasal floor and septal release with his right hand. In case of a segmental two- or three-piece Le Fort I osteotomy, the median or paramedian vertical cuts are initiated at this moment with a fine short 1 mm Lindemann burr or piezoelectric ultrasonic device.

Attention!

Tactile control by the “Operating Surgeon” at the posterior border of the hard palate during the septum release is important to avoid complications and bleeding.

b

the Netherlands) (a) and a synthetic skull (b). Note the degloving of the nasal mucosa from the right nasal floor and anterior nasal spine (ANS). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 4.10  Degloving of the nasal floor and septum release (Step 4) using the OS1 septum osteotome (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

(a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the position of the OS1 septum osteotome along the nasal floor. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 5—MI Exposure of the Maxilla by S Subperiosteal Tunnelling

Exposure of the Unilateral Bony Chin by Subperiosteal Tunnelling”). The right-handed “Operating Surgeon” now moves himself into a slightly two-third right position in relation to the patient’s head. Simultaneously, “Assistant 1” adjusts the operating light along the vector of the left subperiosteal tunnel that will be created in this step. The “Operating Surgeon” now puts his left index/middle finger intra-orally at the level

After degloving of the nasal floor and septal release (Step 4, Sect. “Step 4—Degloving of the Nasal Floor and Septum Release”), MI exposure of the maxilla by subperiosteal tunnelling needs to be performed comparable to the “MI Chin Osteotomy” approach (Chap. 3, Sect. “Step 6—MI

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a

b

c

d

Fig. 4.11  MI exposure of the left hemi-maxilla by subperiosteal tunnelling (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration

(L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a  synthetic skull (c, d). Note the position of the index finger of the “Operating Surgeon” (c, d) and the 45-degree turn of the MI1 raspatorium (d). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

of the left crista infra-zygomatica (CIZ). With the large side of the sharp MI1 raspatorium in his right hand, he creates in a single sliding movement a strict subperiosteal tunnel from the left paranasal region toward the left CIZ (Fig. 4.11a-c) and turns it 45-degrees to create a small subperiosteal pocket at the posterior part of the left CIZ (Fig.  4.11d). He then inserts a flexible curved soft tissue retractor specially

designed for the left side (Mx2L) into the left subperiosteal tunnel (Fig. 4.12a) toward the posterior part of the left CIZ (Fig. 4.13) and offers it to “Assistant 2” who takes it with his left hand. With his right hand, “Assistant 2” now  places a RT1 retractor on the bone of the left medial pillar of the maxilla and inclines it medially to avoid laceration of the small

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Fig. 4.12  MI exposure of the left hemi-maxilla by subperiosteal tunnelling (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, c), a synthetic skull (b)

and a  graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (d). Note the position of the dedicated flexible Mx2L and Mx3 soft tissue retractors, and the medial orientation of the RT1 to protect the soft tissues. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

wound (Fig.  4.12b). Meanwhile “Assistant 1” retracts the labial soft tissues at the right side with a RT1 retractor with his left hand and takes care of the aspiration with his right hand. The “Operating Surgeon” now gently inserts a thin malleable soft tissue retractor (Mx3) (Fig. 4.12b-c) between the nasal mucosa and the inner surface of the left lateral nasal wall. The

long intelligent handgrip (Chap. 2) of the Mx3 malleable soft tissue retractor is consecutively attached and immobilized to the surgical drapes around the patient’s head with a mosquito forceps on the contralateral side. The left hemi-maxilla is now exposed in a MI way (Fig.  4.12b-d) with, however, a good overview of the surgical site to perform the Le Fort I corticotomy (Step 6, Sect. “Step 6—MI Le Fort I Corticotomy”) and

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Tip

The “Operating Surgeon” places his index/middle finger in the upper vestibulum while creating the subperiosteal tunnel toward the CIZ in order to guide an appropriate inclination and to protect the soft tissues.

Step 6—MI Le Fort I Corticotomy

Fig. 4.13  Positioning of the dedicated flexible curved soft tissue Mx2L retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands). Note how the curved Mx2L retractor is held in close contact with the left crista infra-zygomatica (CIZ) by the “Operating Surgeon” in order to protect the soft tissues. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

osteotomy (Step 7, Sect. “Step 7—MI Osteotomy of the Medial and Lateral Maxillary Pillars”) in a safe way. Once these are performed, the same step is performed on the right side. “Assistant 2” removes the RT1 retractor and Mx2L curved soft tissue retractor to take over the aspiration, in order to keep the surgical site nicely dry. “Assistant 1” will then place a RT1 retractor on the bone of the right medial pillar of the maxilla with his right hand and hold the specially designed curved soft tissue retractor for the right side (Mx2R) with his left hand after it has been correctly placed by the “Operating Surgeon” in the right subperiosteal tunnel behind the right CIZ. Trick

Behind the CIZ, the “Operating Surgeon” makes a 45-degree turn with the large side of the MI1 raspatorium in order to create the space to insert the curved soft tissue retractors (Mx2R or Mx2L).

Attention!

Careful retraction of the soft tissues is crucial to avoid tears and lacerations of the small wound. The intelligent handgrips (Chap. 2) of the Mx2R, Mx2L, and Mx3 MI orthognathic instruments help to avoid this.

After MI exposure of the hemi-maxilla by subperiosteal tunnelling (Step 5, Sect. “Step 5—MI Exposure of the Maxilla by Subperiosteal Tunnelling”), the “Operating Surgeon” needs to make sure that all the soft tissue retractors (Mx2R or Mx2L, RT1, and Mx3) are well positioned and held properly to protect the soft tissues, the teeth, and the infra-orbital nerve. The right-handed “Operating Surgeon”, who started with the exposure of the left hemi-maxilla, will first perform in this step the Le Fort I corticotomy on the left side followed by the MI osteotomy of the medial and lateral maxillary pillars (Step 7, Sect. “Step 7—MI Osteotomy of the Medial and Lateral Maxillary Pillars”). The “Operating Surgeon” takes over the curved soft tissue Mx2L retractor from “Assistant 2” and pushes it with his left hand from outside or inside into close contact with the left CIZ. He then initiates the Le Fort I corticotomy from lateral to medial with the reciprocating saw that he holds with his right hand (Fig. 4.14a, b, 4.15a, b, 4.16 and 4.17). Prior to reaching the left lateral nasal wall, he handles the curved soft tissue Mx2L retractor again to “Assistant 2” and takes with his left hand the malleable soft tissue Mx3 retractor to control and protect the nasal soft tissues while performing the Le Fort I corticotomy through the left lateral nasal wall. The “Operating Surgeon” now takes over again the curved soft tissue Mx2L retractor from “Assistant 2” in order to safely perform a back-cut (Fig. 4.15c, d) at the left CIZ and avoid injury of the soft tissues and blood vessels, while “Assistant 2” inclines the patient’s head slightly to the right. If impaction is planned, another corticotomy is performed higher in the same manner, depending on the 3D virtual treatment plan, and the bone in between is removed. While the “Operating Surgeon” performs the Le Fort I corticotomy on the left side, “Assistant 2” continues to hold the RT1 retractor at the left medial pillar of the maxilla, and also the curved soft tissue Mx2L retractor intermittently as described above. “Assistant 1” continues to perform fine aspiration. Special care must be taken to keep the surgical field dry so that the “Operating Surgeon” can clearly identify the vertical landmarks (Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”) in order to perform the Le Fort I corticotomy in between the upper and lower ones. Once the MI osteotomy of the medial and lateral pillars (Step 7, Sect. “Step 7—MI Osteotomy of the Medial and

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Fig. 4.14  MI Le Fort I corticotomy at the left side (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a) and a graphic illustration (L1® MI Orthognathics,

Lateral Maxillary Pillars”) of the left hemi-maxilla has been performed, the Le Fort I corticotomy will be carried out at the right side in the same way. “Assistant 1” will then hold the RT1 with his right hand and the curved soft tissue Mx2R retractor with his left hand, while “Assistant 2” takes care of fine aspiration to keep the right surgical site nicely dry.

KLS Martin, Tuttlingen, Germany) (b). Note how the positioning of the flexible soft tissue Mx2L, Mx3 retractors, and the RT1 retractor enables appropriate visualization in order to protect the teeth and to orientate the Le Fort I corticotomy between the landmarks. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Attention!

During the Le Fort I corticotomy, the “Operating Surgeon” holds the curved soft tissue Mx2L or Mx2R retractors himself in close contact to the bone for optimal control in order to avoid accidental lacerations.

Tip

Tip

When the “Operating Surgeon” takes over the curved soft tissue Mx2L (or Mx2R) retractors during the Le Fort I corticotomy with the reciprocating saw, “Assistants 1 and 2” need intermittently to support the patient’s head in a stable position.

It is crucial that “Assistants 1 and 2” clearly visualize the vertical landmarks (Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”) using fine aspiration while the “Operating Surgeon” performs the Le Fort I corticotomy in between.

Trick

During the Le Fort I corticotomy at the lateral part, the reciprocating saw is kept initially more horizontally by the “Operating Surgeon” who then changes its inclination gradually more vertical toward the lateral nasal wall.

 tep 7—MI Osteotomy of the Medial S and Lateral Maxillary Pillars After MI exposure of the hemi-maxilla by subperiosteal tunnelling (Step 5, Sect. “Step 5—MI Exposure of the Maxilla by Subperiosteal Tunnelling”) and MI Le Fort I corticotomy (Step 6, Sect. “Step 6—MI Le Fort I Corticotomy”), the “Operating Surgeon” now performs the MI osteotomy of the

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a

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c

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Fig. 4.15  MI Le Fort I corticotomy at the left side (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a– d). Note the positioning of the flexible soft tissue Mx2L and Mx3 retractors to protect the soft tissues from the reciprocating saw during

the Le Fort I corticotomy and back-cut. Also note the change of inclination of the reciprocating saw as the “Operating Surgeon” moves it toward the midline. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

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Fig. 4.16  Positioning of the flexible soft tissue Mx2L and Mx3 retractors (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands). Note how the flexible soft tissue Mx2L and Mx3 retractors are held in close contact to the left CIZ by the “Operating Surgeon” and toward the medial side of the lateral nasal wall by “Assistant 2”, respectively, to protect the soft tissues against the reciprocating saw. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

medial and lateral maxillary pillars of the ipsilateral maxilla until the level of the pterygoid plates. The right-handed “Operating Surgeon” performs first the osteotomy of the left medial maxillary pillar using a straight osteotome (OS2) with a blunt protection that he inserts into the Le Fort I corticotomy at the level of the medial maxillary pillar (Fig.  4.18a-d  and 4.19). At this stage, “Assistant 2” holds the RT1 retractor on the left medial maxillary pillar above the Le Fort I corticotomy with his right hand, and the curved soft tissue Mx2L retractor at the left CIZ with his left hand. “Assistant 1” performs fine aspiration with his left hand while tapping with the metal part of the BI-TAP mallet

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Fig. 4.17  MI Le Fort I corticotomy at the left side (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown in a “transparency view” after overlay of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull picture. Note the positioning of the flexible soft tissue Mx2L and Mx3 retractors to protect the soft tissues from the reciprocating saw during the Le Fort I corticotomy and back-cut. Also note the change of inclination of the reciprocating saw as the “Operating Surgeon” moves it medially. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

on the straight OS2 osteotome following the clear instructions of the “Operating Surgeon”. As an alternative, the tapping at this stage can also be performed by the “Operating Nurse”. This “tapping” action is performed until a dull sound is heard, indicating that the medial pterygoid plate has been reached. Consecutively, the “Operating Surgeon” removes the straight OS2 osteotome and inserts the angled osteotome (OS3), also with a blunt protection, into the Le Fort I corticotomy at the left CIZ (Fig. 4.20a-d, 4.21a-c and 4.22). He now asks “Assistant 1” to perform the tapping with the

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Fig. 4.18  MI osteotomy of the left medial maxillary pillar (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), an anatomical dissection human cadaver specimen

(Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (b), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (c) and a synthetic skull (d). Note the inclination of the straight OS2 osteotome and its blunt protection. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Tip

The “Operating Surgeon” needs to give clear instructions to “Assistants 1 and 2” to perform intermittent tapping with the BI-TAP mallet to control the osteotomy of the medial and lateral maxillary pillars toward the pterygoid plate in order to stop in time.

Attention!

Controlling direction, strength, and deepness of the osteotomy of the medial and lateral maxillary pillars is crucial to prevent complications, especially bleeding.

Fig. 4.19  MI osteotomy of the left medial maxillary pillar (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown in a “transparency view” after overlay of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull picture. Note the inclination of the straight OS2 osteotome and its blunt protection. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

BI-TAP mallet  in the same way as the medial osteotomy until a dull sound is noticed. However, since the lateral maxillary pillar is not straight as the medial pillar, the “Operating Surgeon” must gradually modify the inclination of the angled OS3 osteotome during tapping in order to control that it remains at the bony level and follows the Le Fort I corticotomy toward the pterygoid plate. Once the “Operating Surgeon” has completed the osteotomy of both the medial and lateral maxillary pillars at the left side, he performs the same procedure at the right side after MI exposure of the right hemi-maxilla by subperiosteal tunnelling (Step 5, Sect. “Step 5—MI Exposure of the Maxilla by Subperiosteal Tunnelling”) and MI Le Fort I corticotomy (Step 6, Sect. “Step 6—MI Le Fort I Corticotomy”). “Assistant 1” will now hold the RT1 retractor with his left hand and the curved soft tissue Mx2R retractor with his right hand while “Assistant 2” takes care of fine aspiration to keep the right surgical site nicely dry.

 tep 8—MI Down Fracture S and Pterygomaxillary (PTM) Dysjunction Followed by Mobilization of the Osteotomized Maxilla After bilateral MI osteotomy of both the medial and the lateral maxillary pillars (Step 7, Sect. “Step 7—MI Osteotomy of the Medial and Lateral Maxillary Pillars”), MI down fracture of the osteotomized maxilla, pterygomaxillary (PTM) dysjunction, and mobilization can be performed. The “Operating Surgeon” now places the Mx1 double-­ retractor in the small wound on the paranasal bone above the Le Fort I osteotomy and handles it to “Assistant 2” who takes it with his right hand and takes care of the aspiration with his left hand to clearly visualize the surgical site. Meanwhile, “Assistant 1” gently retracts the soft tissues by holding a RT1 retractor on the right medial maxillary pillar that he inclines inside and the curved soft tissue Mx2R retractor at the right CIZ with his left and right hands, respectively. The “Operating Surgeon” now initiates the anterior down fracture of the osteotomized maxilla by using a sharp 8-mm osteotome (OS6) that he inserts at the left paranasal level into the le Fort I osteotomy. By twisting it in a “controlled way”, he can create just enough space for the insertion of a thin and short bone spreader (Mx4S) on the contralateral side (Fig.  4.23a  -c). He then asks “Assistant 2” to remove the Mx1 double-retractor and performs again in a “controlled way” the anterior down fracture of the maxilla until an anterior separation of approximately 8 mm is achieved. At this

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Fig. 4.20  MI osteotomy of the left lateral maxillary pillar (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (b), a graphic illustration (L1® MI Orthognathics,

KLS Martin, Tuttlingen, Germany) (c), and a synthetic skull (d). Note the position of the angled OS3 osteotome which is guided by the “Operating Surgeon” holding the curved soft tissue Mx2L retractor with his left middle finger in close contact with the crista infra-­ zygomatica (CIZ). Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

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Fig. 4.21 Positioning of the angled OS3 osteotome (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a–c).

Note the importance of the blunt protection of the angled OS3 osteotome toward the neurovascular bundle, venous plexus, and maxillary artery during the osteotomy of the left lateral maxillary pillar. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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sists of two important consecutive movements: (1) the “Operating Surgeon” at first opens the Mx4S (or Mx4L) bone spreader vertically (Fig. 4.25b) in a “controlled way” under manual guidance holding the osteotomized maxilla in his left hand to dysjunct the PTM suture and (2) secondly performs a counter-clockwise (CCW) rotation with the Mx4S (or Mx4L) bone spreader in order to mobilize the osteotomized maxilla downward and forward (Fig.  4.25c). Once this is done, “Assistant 2” places a RT1 retractor at the left medial maxillary pillar so that the “Operating Surgeon” can perform the same procedure at the left side (Fig. 4.25d), which will finally  complete the entire mobilization of the osteotomized maxilla. Attention!

During the anterior Le Fort I down fracture of the maxilla, it is important not to open more than approximately 8 mm in the front in order to avoid a potential fracture of the maxilla at the transverse suture. Fig. 4.22  MI osteotomy of the left lateral maxillary pillar (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown in a “transparency view” after overlay of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull picture. Note the inclination of the angled OS3 osteotome and its blunt protection. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

stage, the “Operating Surgeon” first further degloves the mucosa of the entire nasal floor to the back by using the large side of the sharp double-sided MI1 raspatorium. Consecutively, the “Operating Surgeon” removes the sharp OS6 osteotome and relocates the Mx4S bone spreader toward the region of the right CIZ (or switches it toward the longer Mx4L bone spreader in case of a longer maxilla) with his right hand (Fig.  4.24a-c). Once the Mx4S (or Mx4L) bone spreader is correctly inserted at the bony level into the Le Fort I osteotomy at the right CIZ (Fig.  4.25a), the “Operating Surgeon” instructs “Assistant 1” to remove both the RT1 retractor and curved soft tissue Mx2R retractor and holds the osteotomized maxilla intra-orally with his left hand. Since no osteotome is used to perform the PTM dysjunction in the described technique, the following stage con-

 tep 9—Remodelling of the Nasal Floor, Nasal S Septum, and Removal of Potential Premature Bone Contacts After the MI Le Fort I down fracture, pterygomaxillary (PTM) dysjunction and adequate mobilization of the osteotomized maxilla (Step 8, Sect. “Step 8—MI Down Fracture and Pterygomaxillary (PTM) Dysjunction Followed by Mobilization of the Osteotomized Maxilla”), remodelling of the nasal floor, nasal septum, and removal of potential premature contacts can be performed. The “Operating Surgeon” reinserts the Mx1 double-­ retractor in the small wound on the paranasal bone above the Le Fort I osteotomy and handles it to “Assistant 2” who takes it with his right hand. The osteotomized maxilla is now gently pulled down by “Assistant 2” using a blunt hook (HK2) that he positions with his left hand on the left nasal floor or left paranasal bone of the mobilized maxilla. This maneuver creates the necessary space and surgical overview for the “Operating Surgeon” to remove fragmented bone particles

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Fig. 4.23  MI anterior Le Fort I down fracture (Step 8) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics,

KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the position of the sharp OS6 osteotome and the Mx4S bone spreader. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 4.24  MI posterior right Le Fort I down fracture, pterygomaxillary (PTM) dysjunction (Step 8), and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), an anatomical dissection human cadaver specimen (Department of Anatomy

and Embryology, University of Maastricht, the Netherlands) (b) and a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (c). Note the position of the Mx4S (or Mx4L) bone spreader in the subperiosteal tunnel at the right lateral maxillary pillar. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 4.25  MI posterior right Le Fort I down fracture and pterygomaxillary (PTM) dysjunction (a, b) followed by mobilization of the osteotomized maxilla (c, d) (Step 8) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull. Note how the “Operating

Surgeon” has the maxilla in his left hand while he performs in a “controlled way” the PTM dysjunction and posterior Le Fort I down fracture followed by mobilization of the maxilla with the Mx4S (or Mx4L) bone spreader in his right hand. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

and premature bone contacts with the septum scissors (Mx5) (Fig. 4.26a, c) or a “pine-tree” burr (Fig. 4.26b, d). Moreover, the bony septum (vomer) can be removed and both the nasal apertura/base and ANS can be modified and reshaped depending on the individual 3D virtual planning.

“Assistant 1” meanwhile performs aspiration with a large diameter device with his left hand and protects the mucosal soft tissues and gingiva with the curved part of the double-­ sided blunt MI2 elevator, that he holds with his right hand, during the reshaping of the nasal base and/or ANS.

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Fig. 4.26  Remodelling of the nasal floor, nasal septum, removal of potential premature bone contacts (Step 9) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

Subsequently, if indicated, reduction of the cartilaginous nasal septum can be performed. After incision with a #15 scalpel, the surrounding nasal mucosa is degloved by the “Operating Surgeon” using the small part of the double-­ sided sharp MI1 raspatorium, and the lower part of the septum is reduced with the Mx5 septum scissors.

(a, b) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (c, d). Note that the HK2 hook may be placed on the upper dental orthodontic wire but preferably on the maxillary bone in order not to detach the upper braces. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Tip

The Anterior Nasal Spine (ANS), being one of the nasal tip supporting mechanisms can be remained untouched, reduced, completely removed or reshaped depending on the intended clinical effect of the MI Le Fort I on the nose.

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Toward the reduction of the cartilaginous nasal septum, the Mx1 double-retractor is temporarily removed. It allows the “Operating Surgeon” to hold the maxilla with his left hand keeping the nasal septum in between his left middle and index fingers in order to more easily incise the perichondrium and dissect the nasal mucosa to identify the cartilaginous septum.

In case bony contacts need to be removed in the posterior maxilla at the right side, “Assistant 2” inserts the Mx1 double-­ retractor with his right hand while he pulls down the osteotomized maxilla with the HK2 hook with his left hand. Meanwhile, “Assistant 1” gently retracts the soft tissues by holding a RT1 retractor on the right medial maxillary pillar that he inclines inside and the curved soft tissue Mx2R retractor at the right CIZ with his left and right hands, respectively. The “Operating Surgeon” can now, in a “controlled way”, remove potential interferences and posterior bony contacts with his right hand using the Mx5 scissors, a Hyak sphenoidal punch, or a burr, while he aspirates himself with his left hand. The same procedure can then be performed at the contralateral side. In case of hypertrophic inferior nasal conchae or impaction of more than 5 mm of the osteotomized maxilla, an inferior turbinectomy can be performed at this stage. After incising the nasal floor mucosa with a #15 scalpel and creating a mucosal flap, the “Operating Surgeon” performs a lateral luxation of the inferior concha with the straight part of the double-side blunt MI2 elevator. By the use of a long-­ curved clamp (BI3) and a Colorado needle monopolar ­electrosurgical unit, the two anterior thirds of the inferior concha(s) can be removed. Suturing of the nasal mucosa with a thin absorbable suture (Vicryl 5–0, Ethicon, Johnson and Johnson, Somerville, NJ, USA) is performed. In those cases where 2- or 3- piece segmentation of the osteotomized maxilla is necessary, the segmental Le Fort I osteotomy (2- or 3- piece) can be completed in the nasal floor at this stage in a MI way.

 tep 10—MI Repositioning and Fixation S of the Maxilla in its 3-Dimensional (3D) Virtual Planned Position After remodelling of the nasal floor and septum, and removal of potential interfering anterior and/or posterior bony contacts (Step 9, Sect. “Step 9—Remodelling of the Nasal Floor, Nasal Septum, and Removal of Potential Premature Bone Contacts”), MI repositioning and rigid fixation of the osteotomized maxilla in its 3-Dimentional (3D) virtual planned

Fig. 4.27  MI repositioning prior to fixation of the maxilla in its 3-dimensional (3D) virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Note that the vertical repositioning of the osteotomized maxilla is verified by the “Operating Surgeon” at the right side with the BI2 control instrument using the vertical landmarks that were created on the paranasal bone in Step 3

position is the final step of the “MI Le Fort I Osteotomy” surgical technique. In case of conventional transfer of the individual 3D virtual treatment plan without “patient-specific implants (PSIs)”, maxillary repositioning is performed with individualized 3D printed inter-occlusal splints combined with vertical measurements (Fig. 4.27). In this case, intermaxillary fixation (IMF) needs to be performed and the “Operating Nurse” gives Assistant 1″ and “Assistant 2” two cheek retractors which are placed into the mouth on the right and left sides, respectively. The “Operating Surgeon” now guides the maxilla into the 3D virtual planned intermediate or final occlusion with the intermediate or final splint. First, he holds it in place with his left hand and “Assistant 1” performs the IMF with 0.4 mm orthodontic steel wire-loops at the right side. Then the “Operating Surgeon” switches hands to allow “Assistant 2” to repeat this action on the left side and to complete the IMF by placing a third wire-loop in the front immediately afterward with his right hand. The “Operating Surgeon” must control the vertical repositioning of the osteotomized maxilla by measuring the previously placed vertical paranasal landmarks (Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”), while autorotating and guiding the bimaxillary complex in centric relation (CR). In case anterior and/or posterior bony interferences are still present, these need to be removed as described above (Step 9, Sect. “Step 9—Remodelling of the Nasal Floor, Nasal Septum, and Removal of Potential Premature Bone Contacts”). At this stage, “Assistant 2” is holding the Mx1 double-retractor with his right hand while “Assistant 1” takes care of fine aspiration.

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Fig. 4.28 MI repositioning and fixation of the maxilla in its 3-­dimensional (3D) virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic

illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the positioning of the first 2.0 L-plate (KLS Martin, Tuttlingen, Germany) and its fixation on the osteotomized maxilla at the right side. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

The “Operating Surgeon” then handles over the bimaxillary complex to “Assistant 1” who takes it in the correct CR and vertical position with his right hand while he places a RT1 retractor with his left hand on the right paranasal bone to protect the soft tissues. After appropriate bending, the “Operating Surgeon” fixates a first “L-plate” on the right

paranasal area of the osteotomized maxilla with two 5 mm (2.0) screws after initial drilling (Fig. 4.28a -c). “Assistant 2” meanwhile takes care of the aspiration device to visualize in an appropriate way the right paranasal vertical landmarks and simultaneously protects the mucosal soft tissues, gingiva, and teeth at the right inferior part of the small maxillary

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Fig. 4.29 MI repositioning and fixation of the maxilla in its 3-­dimensional (3D) virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

(b) and a synthetic skull (c). Note the fixation of the 2.0 L-plate (KLS Martin, Tuttlingen, Germany) on the osteotomized maxilla at the right side followed by vertical control with the angled BI1 caliper (a) or the standardized BI2 control instrument (b, c). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

wound with the curved part of the MI2 double-sided elevator or the aspiration device. The “Operating Surgeon” now takes over again the bimaxillary complex from “Assistant 1” and after he has verified once again its CR position and correct vertical repositioning of the maxilla using the angled BI1

caliper (Fig. 4.29a) or the standardized 10 mm control instrument  (BI2) (Fig.  4.29b, c), he fixates the right paranasal “L-plate” with two other 5 mm screws. “Assistants 1 and 2” switch their MI orthognathic instruments and the “Operating Surgeon” then fixates in the same manner a second “L-plate”,

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Fig. 4.30 MI repositioning and fixation of the maxilla in its 3-­dimensional (3D) virtual planned position (Step 10) with MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen,

Germany) (b, c) and a synthetic skull (d). Note the facilitated insertion of the two-hole linear MI plate due to its tap (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) held by the long BI3 clamp and its fixation on the right lateral maxillary pillar. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

this time at the left paranasal area of the osteotomized maxilla, after controlling its vertical repositioning. Once this is done, the “Operating Surgeon” places two additional straight linear two-holes MI plates (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

(Fig. 4.30a-d) at the lateral maxillary pillars. At this stage, “Assistants 1 and 2” alternate the curved soft tissue Mx2R and Mx2L retractors while holding a RT1 retractor at the paranasal level as described previously in this chapter (Steps 6 and 7, Sects. “Step 6—MI Le Fort I Corticotomy” and

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Fig. 4.31  Final MI repositioning and fixation of the maxilla in its 3-dimensional (3D) virtual planned position (Step 10) are shown on a synthetic skull (a) and graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b). Note the final rigid fixation

“Step 7—MI Osteotomy of the Medial and Lateral Maxillary Pillars”). In order to facilitate the insertion and fixation of the straight linear two-holes MI plates in the subperiosteal tunnels, the “Operating Surgeon” grasps the dedicated MI plate by its tap using the long BI3 clamp (Fig. 4.30a-d). Depending on the surgeon’s preference, a 1.5-mm instead of a 2.0-mm osteosynthesis system can be used toward fixation of the maxilla in its new position.

Trick

The vertical landmarks on the paranasal bone must be visualized and controlled on both sides to ensure that the osteotomized maxilla is fixated in its correct 3D virtual planned position. Therefore, at this stage, “Assistants 1 and 2” need to switch for a few moments their MI orthognathic instruments (Mx1 and RT1) on request of the “Operating Surgeon”.

with 2.0 miniplates. The taps on the two-hole linear MI plates are usually removed after fixation. Clinical picture made by ©Valérie Swennen-­ Boehlen. All rights reserved

(See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.)

Trick

To control vertical repositioning of the osteotomized maxilla, the “Operating Surgeon” verifies the final 10.0  mm distance between the paranasal landmarks (Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”) with an angled caliper (BI1) or a standardized control instrument (BI2). (See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.)

Attention!

Maxillary repositioning is performed by the use of vertical measurements in combination with an intermediate 3D printed splint in case of a “Maxilla-First” Sequence Transfer or with a final splint (or no splint) in case of a “Mandible-First” Sequence Transfer.

Tip

The combination of the BI3 clamp and the tap on the two-holes linear MI plates allows their easy insertion inside the subperiosteal tunnels, as well as good control during drilling and fixation.

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In case of a “splint-less” transfer of the individual 3D virtual treatment plan with a PSI, maxillary repositioning is performed by using a MI surgical guide in combination with an MI PSI. The first steps (Steps 1, 2, 4, Sects. “Step 1—MI Soft Tissue Approach to the Le Fort I Osteotomy”, “Step 2—MI Subperiosteal Dissection of the Medial Pillar of the Maxilla”, “Step 4—Degloving of the Nasal Floor and Septum Release”) remain identical as described before in this chapter. To allow the “Operating Surgeon” to place the MI surgical guide correctly on the paranasal bone a

through the MI approach, “Assistant 2” retracts the soft tissues with the Mx1 double-retractor with his right hand and a RT1 retractor in his left hand. Meanwhile, “Assistant 1” holds another RT1 retractor with his left hand and takes care of fine aspiration with his right hand. The “Operating Surgeon” can now insert and correctly adapt the MI surgical guide to the paranasal bone (Fig.  4.32a) for final 3D repositioning of the maxilla (alternative to Step 3, Sect. “Step 3—Marking Landmarks for Vertical Repositioning of the Maxilla”). b

c

Fig. 4.32 MI repositioning and fixation of the maxilla in its 3-­dimensional (3D) virtual planned position (Step 10) with a minimally invasive patient-specific implant (MI PSI) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a–c). Note the MI surgical guide to transfer the anterior Le Fort I cor-

ticotomy (a) and final rigid fixation with a MI PSI (IPS® implant, KLS Martin, Tuttlingen, Germany) (b,c). Also note that the MI PSI can be combined with two additional two-hole linear MI plates at the lateral maxillary pillars (c)

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Once this is done, the “Operating Surgeon” marks all repositioning holes with a 1-mm or 1.2-mm drill and the initiation of the Le Fort I corticotomy in the paranasal area with the reciprocating saw by the use of the sleeves and the lower part of the horizontal bar of the MI surgical guide (Fig. 4.32a). The “Operating Surgeon” then removes the MI surgical guide and continues with the following steps (Steps 5–9, Sects. “Step 5—MI Exposure of the Maxilla by Subperiosteal Tunnelling”, “Step 6—MI Le Fort I Corticotomy”, “Step 7— MI Osteotomy of the Medial and Lateral Maxillary Pillars”, “Step 8—MI Down Fracture and Pterygomaxillary (PTM) Dysjunction Followed by Mobilization of the Osteotomized Maxilla”, “Step 9—Remodelling of the Nasal Floor, Nasal Septum, and Removal of Potential Premature Bone Contacts”) as previously outlined in this chapter. In the final step (Step 10, Sect. “Step 10—MI Repositioning and Fixation of the Maxilla in its 3-Dimensional (3D) Virtual Planned Position”), the” Operating Surgeon” repositions the osteotomized maxilla according to the individualized 3D virtual treatment plan by fixating the MI PSI first on the mobile maxilla and then on the midface using 7  mm (1.5 or 2.0) screws (Fig.  4.32b). Additional straight two-holes linear MI plates (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (Fig.  4.32c) can be placed, depending on the surgeon’s preference. After final repositioning, rigid fixation of the maxilla and extensive rinsing with saline (NaCl) solution, “double-layer” closure of the “MI Le Fort I” wound is performed with paranasal cross-sutures of the nasolabial muscles (Fig.  4.33). Therefore, all MI instruments are removed from the surgical field. The “Operating Surgeon” now places a first single soft tissue hook (HK3) in the midline of the lower mucosa and handles it over to “Assistant 1” who takes it with his right

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hand. He then places a second single soft tissue hook (HK3) in the midline of the upper mucosa (Fig. 4.33) which he handles over to “Assistant 2” who takes it with his right hand. Both “Assistants 1 and 2” then place two RT1 retractors outside the wound to retract the upper labial soft tissues with their left hands. At first, the “Operating Surgeon” performs the “deep-­ layer” closure of the nasolabial muscles using two bilateral cross-sutures (Fig.  4.33) with a Vicryl 3.0 non-rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) and an additional suture in the midline. Secondly, the “superficial-layer” mucosa is closed by the “Operating Surgeon” with a running Vicryl 4.0 rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) suture, similar to the closure of the “MI Chin” wound (Chap. 3, Sect. “Step 10—MI Repositioning and Rigid Fixation of the Chin in its 3D Virtual Planned Position”), without tension from the right to the left while the labial soft tissues are gently retracted by both “Assistant 1” and “Assistant 2” with RT1 retractors. After wound closure, abundant rinsing with saline (NaCl) solution, aspiration of the mouth and airway are performed and “guiding inter-occlusal elastics” (Chap. 8) are placed. The patient’s face is cleaned with saline (NaCl) solution and long 5 mm suture strips (Chap. 8) are adapted at the level of the “subnasale” anthropometric landmark to define the nasolabial angle and control of swelling for 1  week. A steroid ointment is applied on both lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-­ den-Berg, Belgium) and before the patient leaves the operating room, a cooling face mask (Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/Allgäu, Germany) is installed without any tension on the skin for postoperative thermo-­ therapy (Chap. 8), which is continued for 1 week.

Limits of the “MI Le Fort I Osteotomy” Surgical Technique

Fig. 4.33  “Deep-layer” closure with paranasal cross-sutures of the nasolabial muscles after MI repositioning and rigid fixation of the maxilla in its new 3D virtual planned position (Step 10) is shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany; modified by FOA)

Surgical experience The “10 Step-by-­Step” surgical procedure described in this chapter and the accompanying graphic video are valuable for “in-­depth” study of the MI technique (https:// www.youtube.com/watch?v=CqOmWaKoOZM). Dedicated phantom, cadaver, or live surgery courses are recommended. Following the described MI orthognathic principles in this chapter, every orthognathic surgeon should be able to master the “MI Le Fort I Osteotomy” after his individual “learning curve”. Previous maxillary orthognathic surgery with need for plate removal *.

4  Minimally Invasive (MI) Le Fort I Osteotomy

Maxillary posterior intrusion of more than 2 mm *. Maxillary posterior extrusion with the need for bone graft interpositioning *. High Le Fort I osteotomy *. Need for adjuvant unilateral or bilateral zygomatic osteotomy *. Important midfacial asymmetry that would need additional midfacial contouring with bone grafts or patient-specific implants (PSIs) *. Syndromic condition including cleft lip and palate *. *All these can be performed following the same principles but would need a larger incision with more subperiosteal degloving.

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References 1. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017. 2. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 3. Swennen GRJ. Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi. org/10.1016/j.cxom.2020.05.009.

5

Minimally Invasive (MI) Sagittal Split Osteotomy Gwen R.J. Swennen, Fernando de O. Andriola, and Yves Weinberg

Step-by-step standardization of minimally invasive (MI) orthognathic surgical techniques increases surgical efficiency and decreases patient morbidity. In this chapter, an innovative systematized “10 step-by-step approach” toward the sagittal split osteotomy following a “MI philosophy and mindset” is outlined in detail. General considerations regarding the preparation of the patient, instrumentation table and operating room toward the MI sagittal split osteotomy are well described. Dedicated new developed MI orthognathic surgical instruments allow to optimize the vascular blood supply and decrease of interstitial edema and swelling after a chin osteotomy which enhances postoperative fast recovery of the patient. Moreover, the introduction of MI orthognathic surgical codes, MI orthognathic surgical sequences and MI orthognathic surgical sequence template bars creates a common language among the surgical team (“Operating Surgeon”, “Surgical Assistants”, and “Operating Nurse”) which increases surgical efficiency and additionally decreases patient morbidity. Furthermore, systematization of storage of MI orthognathic instruments and MI surgical sequence template bars allows to optimize their gathering, cleaning, and sterilization process toward a more time-­ efficient and cost-effective clinical routine. Each single step of the MI  approach toward the sagittal split osteotomy is illustrated in detail by high-quality graphic illustrations and

G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected]

pictures made on synthetic skulls, human cadaver, and anatomical dissected human cadaver specimens. Finally, the limits of the described MI surgical technique toward the sagittal split osteotomy are summarized.

 eneral Considerations Regarding the “MI G Sagittal Split Osteotomy” Surgical Procedure In this chapter (Sect. “The “10 Step-by-Step MI Sagittal Split Osteotomy” Surgical Technique”), a “10 Step-by-Step” surgical technique (see Table 5.2) to perform a sagittal split osteotomy in a systematized minimally invasive (MI) way will be described in detail. Individualized and clinically focused 3D virtual treatment planning of the mandible incorporates especially 3D translational (anteroposterior, transversal, and vertical) and rotational (“Roll”, “Pitch”, and “Yaw”) movements of the distal mandibular segment in relation to both proximal segments, the temporomandibular joint (TMJ), the airway, and the overlying soft tissue mask. However, minor rotational (“Roll”, “Pitch”, and “Yaw”) movements of both proximal segments in respect to the TMJ can be included [1]. Most of these movements can be safely performed and transferred in an accurate way through the below described MI surgical approach. The limits of the presented “MI Sagittal Split Osteotomy” surgical technique, however, are outlined at the end of this chapter. Based on the background of MI surgery in other surgical fields (Chap. 1) and supported by evidence-based medicine, [2] an innovative concept and rationale were developed toward “MI Orthognathic Surgery” (Chap. 2) in order to reduce overall patient morbidity by the combination of increasing surgical efficiency and decreasing surgical trauma through minimized degloving and compression of the surrounding soft tissue envelope. In specific regard toward the “MI Sagittal Split Osteotomy”, the following general considerations need to be taken into account by the surgical team:

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_5

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1. Organization of the surgical instrumentation table by the “Operating Nurse” (Sect. ““MI Sagittal Split Osteotomy” instruments and “MI Sagittal Split Osteotomy” Surgery Instrumentation Table Organization”). 2. Preparation of the patient in the operating room by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” (Sect. “Patient and Operating Room Preparation Toward the “MI Sagittal Split Osteotomy” Surgical Procedure”).

“ MI Sagittal Split Osteotomy” Instruments and “MI Sagittal Split Osteotomy” Surgical Instrumentation Table Organization In order to improve the efficiency of the overall surgical team during an “MI Sagittal Split Osteotomy”, “MI Sagittal Split surgical sequence bars” were developed to indicate in a systematic order the required MI coded instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) [3] (Chap. 2). The “Operating Nurse” places the four dedicated “MI Sagittal Split surgical sequence template bars” on top of the surgical instrumentation table (Fig. 5.1) which allows a fast, easy and standardized organization of the relevant MI orthognathic instruments not only at the initiation but also during the entire surgical procedure. Moreover, the “Operating Nurse” is able to follow and knows at any moment which “MI Sagittal Split” orthognathic instrument

Fig. 5.1  MI orthognathic instruments used to perform the “MI Sagittal Split Osteotomy” systematically organized on the surgical instrumentation table by the “Operating Nurse” (graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

G. R.J. Swennen et al. Table 5.1  “Surgical Codes” and “Surgical Sequence” for the “Minimally Invasive (MI) Sagittal Split Osteotomy” orthognathic surgical procedure MI Sagittal Split Osteotomy RT1 RT2 MI1 MI2 Md1 MI4 Md2 Md1 OS4 BI-TAP OS5 OS6 Md3 BI3 Md4–9. (RT) Retractor; (MI) Minimally Invasive; (Md) Mandible; (OS) Osteotome; (BI) Basic Instrument. (From Swennen [3]; with permission)

is needed by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” to smoothly perform the “MI Sagittal Split Osteotomy”. The “Surgical Codes” and “Surgical Sequence” toward the “MI Sagittal Split  Osteotomy” are mentioned in Table 5.1.

 atient and Operating Room Preparation P toward the “MI Sagittal Split Osteotomy” Surgical Procedure To perform a “MI Sagittal Split Osteotomy”, the patient is placed in a supine position on the surgical operating table by the “Anesthesiologic team” in close collaboration with the “Operating Surgeon”, who personally positions the patient’s head using a dedicated head support (Chap. 8) in a “neutral horizontal position” in a way that head extension is avoided during the surgical procedure similar as in the “MI Chin Osteotomy” (Chap. 3), MI Le Fort I Osteotomy” (Chap. 4) and “MI Mandible Constriction / Expansion” (Chap. 7) surgical procedures. After nasotracheal intubation by the anesthesiologist and correct positioning of the tube (Chap. 8), local anesthesia (Xylocaine® 1% with adrenaline 1:200.000) is administered by “Assistant 2” bilaterally in the posterior buccal mucosa at the level of the buccal and lingual corticotomies and in between. Moreover, “Assistant 2” also positions the two operating reflector lights (most ideally L.E.D.) in an ideal position above the patient. One from the right side of the patient’s head (in case the right SSO is performed at first) and the second above the patient’s legs with a 45-degree inclination angle toward the patient’s face. Meanwhile “Assistant 1” is scrubbing to start disinfection of the patient’s head and surgical draping immediately once the patient is intubated in order not to lose valuable time. Antisepsis of the face is performed by “Assistant 1” with Hibidil® (50 mg/100 ml chlorhexidine digluconate cutaneous solution, Hälsa Pharma GmbH, Münster, Germany), and consecutively disinfection of the mouth with Hextril® (1 mg/ ml hexetidine mouth rinsing, Famar Orléans, Orléans, France) once all sterile drapes have been applied. Prior to surgery, the wax-bite that was taken in centric relation (CR) during the “pre-surgical workup” is verified,

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Fig. 5.2  Positioning of the “Operating Surgeon”, surgical “Assistant 1”, surgical “Assistant 2”, “Operating Nurse”, and anesthesiologist are shown in the operating room (graphic illustrations from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany): overview (a) and

view from the “Operating Surgeon” sitting (or standing) position at the right side of the patient’s head (b) during the “MI Sagittal Split Osteotomy” surgical procedure

occlusal grinding is performed if necessary and fitting of both the intermediate and final splints on the patient is checked by “Assistant 1”. Lastly, a steroidal ointment is applied on both the upper and lower lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-den-Berg, Belgium) by one of the assistant surgeons. Intravenous (IV) antibiotics (2  g amoxicillin clavulanic acid 2000  mg/200  mg intravenous injection, Augmentin®, GlaxoSmithKline, Singapore) are administered by the anesthesiologist only once in a single dose unless additional bone-grafting or lipo-filing is performed where these are continued postoperatively for 1 week orally. In case of penicillin allergy, 600 mg of clindamycin (Clindamycin Sandoz® 600  mg/4  ml intravenous injection, Sandoz Canada Inc. Boucherville, QC, Canada) is administered by intravenous injection in a single dose and continued orally for 1 week if indicated. Corticosteroids are given in a single high dose (250  mg methylprednisolone intravenous injection, Solu-­ Medrol®, Pfizer Manufacturing, Puurs, Belgium) at the start of the surgery and repeated postoperatively at the recovery unit (80  mg methylprednisolone intramuscular injection, Depo-Medrol®, Pfizer Manufacturing, Puurs, Belgium). Tranexamic acid (500 mg/5 ml tranexamic acid intravenous injection, Exacyl®, Sanofi, Gentilly, France) is administered 1  g directly IV after induction, and another 1  g in the 1-L

NaCl drip infusion at initiation of the surgery unless contraindications. The anesthesiologic management is furthermore elaborated in Chap. 8. To perform a “MI Sagittal Split Osteotomy”, the right-­ handed “Operating Surgeon” is positioned at the right side of the patient’s head (sitting or standing) while “Assistant 1” is positioned in front of him at the opposite side and “Assistant 2” at the head of the patient (Fig.  5.2). The “Operating Nurse” is ideally positioned at the right side of the patient’s thorax next to the “Operating Surgeon”, while the anesthesiologist is positioned at the left side of the patient’s feet (Fig. 5.2).

 he “10 Step-by-Step MI Sagittal Split T Osteotomy” Surgical Technique The “10 Step-by-Step” surgical technique (Table 5.2) to perform a sagittal split osteotomy in a systematized minimally invasive (MI) way has initially been described concisely and accordingly illustrated on cadaver pictures [3]. In this chapter, the surgical technique has been elaborated in much more detail toward the overall surgical team using the combination of human cadaver, synthetic skull pictures, and high-­ professional illustration graphics. Cadaver illustrations have been made on an edentulous human cadaver with upper and

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92 Table 5.2 The “10 Step-by-Step MI Sagittal Split Osteotomy” Surgical Technique “Step 1” “Step 2” “Step 3” “Step 4” “Step 5” “Step 6” “Step 7” “Step 8” “Step 9” “Step 10”

MI soft tissue approach to the sagittal split osteotomy of the mandible MI access toward the buccal corticotomy of the horizontal mandibular ramus MI buccal corticotomy of the horizontal mandibular ramus MI retromolar degloving MI access toward the lingual corticotomy of the vertical mandibular ramus MI lingual corticotomy of the vertical mandibular ramus MI completion of the sagittal split osteotomy MI mobilization of the mandibular segments after sagittal split osteotomy “Trivector seating” of the mandibular proximal segment MI rigid fixation of the sagittal split osteotomy

(From Swennen [3]; with permission)

lower jaw prosthesis to mimic a realistic situation. Special attention was taken to describe in detail the role of each member of the surgical team (“Operating Nurse”, “Assistant 1”, “Assistant 2”, and the “Operating Surgeon”) using the surgical codes and the dedicated “MI Sagittal Split Osteotomy” surgical sequence (Table 5.1). The latter is mentioned on the “MI Sagittal Split surgical template bars” toward the “Operating Nurse” (Sect. “General Considerations Regarding the “MI Sagittal Split Osteotomy” Surgical Procedure”) in order to increase overall surgical efficiency and decrease patient morbidity. In this chapter, the “MI Sagittal Split” orthognathic surgical technique is explained toward the righthanded “Operating Surgeon” but could of course easily be modified toward the left-handed “Operating Surgeon”. An educational graphic video (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany), available on YouTube (https:// www.youtube.com/watch?v=CqOmWaKoOZM), has been made in close collaboration with highly skilled graphic engineers based on the combination of human cadaver pictures, initial synthetic skull pictures and personal designs (GS) that are not mentioned in this chapter. Note that throughout this chapter right and left are used in regard to the position of the right-handed “Operating Surgeon” performing a SSO at the right side of the mandible, sitting or standing at the right side of the patient’s head.

 tep 1—MI Soft Tissue Approach S to the Sagittal Split Osteotomy of the Mandible The MI approach toward the right sagittal split osteotomy (SSO) starts by placing a silicone bite block by the “Operating Surgeon” on the left side between the dental arches to ensure maximal bite opening and a tongue depressor which will be held by “Assistant 1” in order to give the “Operating Surgeon” the ideal access to perform surgical Steps 1–8 (Table 5.2). Two soft tissue retractors are then placed by “Assistant 2”, a slightly curved soft tissue retractor (RT1)  with his right hand and a larger soft tissue retractor (RT2) more posteriorly with his left hand to stretch the right buccal soft tissues (Fig.  5.3a) in order to facilitate the buccal incision by the “Operating Surgeon”. Meanwhile, “Assistant 1” holds the tongue depressor with his right hand and performs aspiration with his left hand. The “Operating Surgeon”, holding an anatomical forceps in his left hand, incises the oral mucosa with a #15 scalpel, starting approximately 10 mm behind and slightly divergent to the second molar at the level of the outer oblique line of the mandibular ramus (Fig. 5.3a, b). When reaching the distal side of the second molar, the “Operating Surgeon” changes the scalpel inclination (Fig. 5.3c, d) and incises perpendicular on the mandibular buccal bone until the mesial side of the first molar. The approximate length of the incision is 20 mm at a distance of 6–7 mm from the marginal gingiva (Fig. 5.4).

 tep 2—MI Access Toward the Buccal S Corticotomy of the Horizontal Mandibular Ramus After the incision, the “Operating Surgeon” identifies the antegonial notch by extraoral palpation and performs a strictly subperiosteal sliding dissection toward the antegonial notch using the large side of the sharp double-sided raspatorium  (MI1) (Figs.  5.5a and 5.6a–c). During this maneuver, he retracts the soft tissues laterally with a blunt double-sided elevator (MI2) in his left hand (Figs. 5.6a and 5.7b).

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Fig. 5.3  The MI soft tissue approach to the sagittal split osteotomy (SSO) of the mandible (Step 1) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a, b) and a synthetic skull (c, d).

Note the change of the #15 scalpel which is orientated 90 degrees to the bone once it reaches the distal side of the second molar toward the mesial side of the first molar. Note that “MI Chin“ (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Trick

When the sharp MI1 raspatorium reaches the antegonial notch, the “Operating Surgeon” turns the it approximately 45 degrees to the right (Fig.  5.6d) to create a narrow subperiosteal soft tissue pocket in order to facilitate the insertion of the small Md1 channel retractor at the lower mandibular border.

Tip

After the small Md1 channel retractor is positioned in the buccal subperiosteal tunnel, the “Operating Surgeon” rotates it approximately 45 degrees to the left (Fig.  5.5c) in order to identify and visualize the antegonial notch

Fig. 5.4  The MI soft tissue approach to the sagittal split osteotomy (SSO) of the mandible (Step 1) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands). Note that only a small incision is required. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

At this step, “Assistant 1” inclines the patient’s head slightly to the left side using the tongue depressor in his left hand and takes care of the aspiration with his right hand. “Assistant 2” meanwhile keeps holding the slightly curved RT1 soft tissue retractor with his right hand and the larger RT2 soft tissue retractor with his left hand. Once the strict subperiosteal buccal tunnel is created, the “Operating Surgeon” inserts a small channel retractor (Md1) toward the mandibular lower border at the level of the antegonial notch (Figs. 5.5b, c, 5.7a, d, 5.8a, b, and 5.9). Simultaneously, “Assistant 2” removes the RT1 retractor and returns it to the “Operating Nurse”.

 tep 3—MI Buccal Corticotomy S of the Horizontal Mandibular Ramus Once the buccal subperiosteal tunnel has been created and the Md1 channel retractor has been put in place (Step 2, Sect. “Step 2—MI Access Toward the Buccal Corticotomy of the Horizontal Mandibular Ramus”), the “Operating Surgeon” holds the Md1 channel retractor with his left hand and keeps his middle finger in close contact with the lower mandibular border at the level of the antegonial notch to protect the soft tissues. Simultaneously he receives the motor handpiece with a medium Lindemann burr (or the reciprocating saw) from the “Operating Nurse”. Consecutively, he performs an oblique buccal corticotomy into the spongiosa starting at the antegonial notch toward the region between the first and second lower molars (Figs.  5.10a–d, 5.11a–c, 5.12, and 5.13). At this stage, “Assistant 1” is still holding the tongue depressor and slightly inclines the patient’s head to the left while taking care of the aspiration with his right hand. “Assistant 2” meanwhile continues to hold the RT2 retractor with his left hand and also

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Fig. 5.5  MI access toward the buccal corticotomy of the right horizontal mandibular ramus (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics,

KLS Martin, Tuttlingen, Germany) (a–c). Note how the “Operating Surgeon” performs a 45-degree turn to the left with the small Md1 channel retractor to identify the right antegonial notch

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Fig. 5.6  MI access toward the buccal corticotomy of the right horizontal mandibular ramus (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a–d). Note how the “Operating Surgeon” performs a 45-degree turn to the right with the

large part of the sharp double-sided MI1 raspatorium to create a MI subperiosteal pocket. Note that “MI Chin” (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.7  MI access toward the buccal corticotomy of the right horizontal mandibular ramus (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a) and human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands (b-d). Note how the small Md1 channel retractor is slipped in the subperiosteal tunnel and positioned just in front of the antegonial notch. Note that “MI Chin” (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed (a). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.8  Positioning of the small Md1 channel retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, b). Note that during surgery the small Md1 channel retractor will be positioned in the subperiosteal plane underneath the vascular and nervous

structures in direct contact with the mandibular border (just in front of the anterior insertion of the masseter muscle) in order to prevent lesions of the marginal branch of the facial nerve and the facial artery and vein. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

5  Minimally Invasive (MI) Sagittal Split Osteotomy

Fig. 5.9  Positioning of the small Md1 channel retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) is shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands). Note the

helps to incline the patient’s head slightly to the left with his right hand.

Attention!

In order to decrease patient morbidity, it is essential that the course of inferior alveolar nerve (IAN) in the mandibular canal is assessed preoperatively during virtual surgical planning on the cone-beam (CBCT) or multi-slice (MSCT) computed tomography coronal slices. In this regard, special care must be taken when it is positioned in the buccal outer cortex to avoid injury of the IAN during the buccal and inferior border mandibular corticotomy.

Attention!

To avoid a “mandibular border bad split”, it is crucial to ensure that the buccal corticotomy (using the Lindemann burr or reciprocating saw) comprises also the lower mandibular border cortex.

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antegonial notch and the small Md1 channel retractor being positioned at the lower mandibular border. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

Tip

For mandibular advancements bigger than 10mm, the buccal corticotomy should be inclined more anteriorly e.g. toward the middle of the first lower molar, in order to increase the bony contact surface between the proximal and distal mandibular segments

Step 4—MI Retromolar Degloving Once the buccal corticotomy (Step 3, Sect. “Step 3—MI Buccal Corticotomy of the Horizontal Mandibular Ramus”) has been completed, the “Operating Surgeon” offers the small Md1 channel retractor to “Assistant 2”, who holds it with his right hand and inclines it posteriorly to avoid laceration of the small intraoral wound. At this stage, “Assistant 1” is still holding the tongue depressor and slightly inclines the patient’s head to the left while taking care of the aspiration with his right hand. The “Operating Surgeon” now retracts the retromolar soft tissues with the curved part of the blunt double-sided MI2 elevator in order to initiate retromolar degloving in a strict subperiosteal plane with the large side of the sharp

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Fig. 5.10  The MI buccal corticotomy of the right horizontal mandibular ramus (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a–c) and on a human cadaver (Department of

Anatomy and Embryology, University of Maastricht, the Netherlands) (d). Note the angulation of the Lindemann burr (a, b) and buccal corticotomy (c, d). Note that according to surgeon’s preferences, a reciprocating saw can also be used. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.11  The MI buccal corticotomy of the right horizontal mandibular ramus (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a–c). Note the change of inclination of the Lindemann burr (a, b) and how the Md1 channel retractor is positioned

at the antegonial notch level at the lower mandibular border (a-c). Note that according to surgeon’s preferences, a reciprocating saw can also be used (c). Note that “MI Chin“ (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.12  Positioning of the small Md1  channel retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) and the angulation of the Lindemann burr are shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University

of Maastricht, the Netherlands). Note the inclination of the Lindemann burr from the antegonial notch toward the region between the first and second lower molars. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

MI1 raspatorium (Figs. 5.14a and 5.15b). The “Operating Nurse” consecutively gives the “Operating Surgeon” a V-shaped elevator (MI4), with which he degloves in a single and continuous sliding movement the retromolar soft tissues toward the vertical mandibular ramus up to the insertion of the temporalis muscle (Figs.  5.14b–d and 5.15a, c). The “Operating Surgeon” then inserts a vertical mandibular ramus retractor (Md2) in the space that he previously created with the V-shaped MI4 elevator (Fig. 5.15d) and handles it to “Assistant 2”, who has given back the RT2 retractor to the “Operating Nurse” and takes over the vertical mandibular ramus Md2 retractor with his left

hand. The Md2’s intelligent handgrip (Chap. 2, Sect. “The Rationale Behind the “Intelligent Handgrip””) is kept horizontally by “Assistant 2” and slightly outside to ensure a stable position and proper retraction of the retromolar soft tissues.

Tip Retromolar degloving should be performed atraumatically and in a strict subperiosteal plane to avoid bleeding that would compromise the next steps

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then removes the blunt double-sided MI2 elevator, takes over the sharp MI1 raspatorium with his left hand and inserts a second small Md1 channel retractor in the lingual subperiosteal tunnel with his right hand (Figs.  5.16b, d, 5.17d, and 5.18). Simultaneously, “Assistant 1” removes the tongue depressor and takes over the lingually positioned small Md1 ­channel retractor from the “Operating Surgeon” with his left hand.

Tips

Fig. 5.13  Positioning of the small Md1 channel retractor, the large RT2 retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany), and the angulation of the Lindemann burr are shown in a “transparency view” after overlay of the human cadaver skull picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull picture. Note the inclination of the Lindemann burr from the antegonial notch toward the region between the first and second lower molars. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 5—MI Access toward the Lingual S Corticotomy of the Vertical Mandibular Ramus Once retromolar degloving (Step 4, Sect. “Step 4—MI Retromolar Degloving”) has been accomplished, the “Operating Surgeon” gently retracts the retromolar soft tissues lingually with the blunt double-sided MI2 elevator (straight or curved side) in his left hand and identifies the lingual retromolar subperiosteal plane with the small side of the sharp MI1 raspatorium in his right hand (Figs. 5.16a and 5.17a). At this stage, “Assistant 1” is still holding the tongue depressor and slightly inclines the patient’s head to the left while taking care of aspiration with his right hand. The “Operating Surgeon” now creates a strict lingual subperiosteal tunnel by sliding the large side of the sharp MI1 raspatorium approximately 3–5 mm above the lingula parallel to the lower occlusal plane toward the posterior border of the vertical mandibular ramus (Figs. 5.16c and 5.17b, c). He

In most of the cases, the lingula can be identified approximately 10mm above the lower occlusal plane. However, in order to decrease patient morbidity, the level of entrance of the inferior alveolar nerve (IAN) at the lingula should be assessed preoperatively during 3D virtual surgical planning on the 3D “surface” or “volumed” rendered images (See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.) If the inner part of the vertical mandibular ramus is concave and the IAN cannot be visualized directly, the surgeon may use a L-shaped blunt nerve locator to identify the lingula

Attention!

In the MI access toward the lingual corticotomy, special care must be taken in case the medial part of the vertical mandibular ramus is concave, in order to make sure that the small Md1 channel retractor is positioned strictly underneath the periosteum in direct contact with the bony surface to avoid bleeding in the next step.

Tip

The lingual small Md1 channel retractor must be placed parallel with the lower occlusal plane above the lingula until the posterior border of the vertical mandibular ramus in order to properly protect the IAN and soft tissues (Fig. 5.18).

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Fig. 5.14  MI retromolar degloving at the right mandible (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a–c) and a graphic illustration (L1® MI Orthognathics,

KLS Martin, Tuttlingen, Germany) (d). Note that the small Md1 channel retractor is preferably kept in place during retromolar degloving but inclined more backward (d) in order to allow appropriate access and avoid soft tissue laceration. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.15  MI retromolar degloving at the right mandible (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a) and  a

synthetic skull (b–d). Note that the small Md1 channel retractor is kept in place during retromolar degloving but inclined more backward in order to allow appropriate access and avoid soft tissue laceration. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 6—MI Lingual Corticotomy of the Vertical S Mandibular Ramus

vertical ramus with a 45-degree inclination just above the lingula to protect the IAN neurovascular bundle and surrounding soft tissues. Simultaneously, he receives the motor handpiece with a “pine-tree burr” from the “Operating Nurse” in his right hand. At this stage, “Assistant 1” slightly inclines the patient’s head to the right with his left hand and takes care of the aspiration with his right hand. Meanwhile, “Assistant 2” keeps the vertical mandibular ramus Md2 retractor with his left

Once the lingual subperiosteal tunnel has been created and the second small Md1 channel retractor has been placed in the correct position (Step 5, Sect. “Step 5—MI Access Toward the Lingual Corticotomy of the Vertical Mandibular Ramus”), the “Operating Surgeon” holds it with his left hand in close contact with the mandibular

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Fig. 5.16  MI access toward the lingual corticotomy of the right vertical mandibular ramus (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, b) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen,

Germany) (c, d). Note that in this step the first small Md1 channel retractor is preferably kept in place in the buccal subperiosteal tunnel while the lingual subperiosteal tunnel is created and a second small Md1 channel retractor is  positioned in it. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

hand and the buccal small Md1 channel retractor with his right hand in the same position. Subsequently, the “Operating Surgeon” uses the “pine-­ tree burr” (Fig. 5.19a, b) to initiate the lingual corticotomy just above the lingula parallel to the lower occlusal plane which allows better visualization and control. He then uses a long Lindemann burr (Fig. 5.20a–d, 5.21a, and 5.22a, b) to

perform the lingual corticotomy until the posterior border of the mandibular ramus or just behind the lingula according to the surgeon’s preference. In cases where there is no clear spongiosa in between both the inner and the outer cortexes above the lingula, the reciprocating saw is used. The saw can also be used to perform the entire lingual corticotomy, depending on the surgeon’s personal preference (Fig. 5.21b).

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Fig. 5.17  MI access toward the lingual corticotomy of the right vertical mandibular ramus (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a–d). Note that in this step

the first small Md1 channel retractor is kept in place in the buccal subperiosteal tunnel while the lingual subperiosteal tunnel is made and the second small Md1 channel retractor is put in place. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Trick

Attention!

3D virtual planning allows the surgeon to modify both the buccal and lingual corticotomies to avoid/decrese flaring and potential bony overlapping of the proximal and distal segments (See Swennen G.R.J. 3D Virtual Treatment Planning of Orthognathic Surgery. A Step-by-Step Approach for Orthodontists and Surgeons. Springer; 2017.)

The lingual corticotomy must go through the inner cortex of the vertical mandibular ramus behind the lingula (Spix spine) in order to avoid a condylar bad split

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Fig. 5.18  Positioning of the second small Md1 channel retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) at the lingual side of the right mandibular vertical ramus above the lingula (Spix spine) is shown on an anatomical dissection human cadaver specimen

a

Fig. 5.19  MI lingual corticotomy of the vertical mandibular ramus (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen,

(Department of Anatomy and Embryology, University of Maastricht, the Netherlands). Note how the small Md1 channel retractor protects the inferior alveolar nerve (IAN) and vascular bundle. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

b

Germany) (a) and a synthetic skull (b). Note that the lingual corticotomy is initiated by the use of a “pine-tree burr” parallel to the lower occlusal plane. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.20  MI lingual corticotomy of the vertical mandibular ramus (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a, b) and on a human cadaver (Department of Anatomy and

Embryology, University of Maastricht, the Netherlands) (c, d). Note the 45-degree inclination of the small Md1 channel retractor toward the mandibular vertical ramus just above the lingula. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 7—MI Completion of the Sagittal Split S Osteotomy

split osteotomy (SSO). At this stage, “Assistant 1” takes over the lingual small Md1 channel retractor with his left hand and still has the aspiration device in his right hand. Meanwhile, “Assistant 2” remains keeping the vertical mandibular Md2 ramus retractor with his left hand and the buccal small Md1 channel retractor with his right hand at the same place.

Once the lingual corticotomy of the vertical mandibular ramus has been performed (Step 6, Sect. “Step 6— MI Lingual Corticotomy of the Vertical Mandibular Ramus”), the “Operating Surgeon” needs to complete the sagittal

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Fig. 5.21  MI lingual corticotomy of the vertical mandibular ramus (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a, b). Note the particular inclinations of both small Md1

a

Fig. 5.22  MI lingual corticotomy of the vertical mandibular ramus (Step 6) and positioning of the second small Md1 channel retractor (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on an anatomical dissection human cadaver specimen (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a) and a “transparency view” after overlay of the human cadaver skull

b

channel retractors positioned in the buccal and lingual subperiosteal tunnels. Note that according to surgeon’s preferences, a reciprocating saw can also be used (b). Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

b

picture on the synthetic skull picture (b). Note how the lingually positioned small Md1 channel retractor protects the neurovascular bundle of the inferior alveolar nerve (IAN) at the lingula’s (Spix spine) level and the soft tissues at the posterior region of the vertical mandibular ramus. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.23  MI completion of the sagittal split osteotomy (SSO) (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a, c, d) and on a human cadaver (Department of Anatomy

and Embryology, University of Maastricht, the Netherlands) (b). Note the marking of the holes with a Lindemann burr along the buccal cortex between the lingual and buccal corticotomies. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

The “Operating Surgeon” now marks small reference holes along the buccal mandibular cortex in between the lingual and buccal corticotomies with a short Lindemann burr (Fig. 5.23a, b). This not only helps to guide the connecting corticotomy, but also gives the “Operating Surgeon” a valuable feedback regarding the bone quality in this particular

anatomical region, allowing him to foresee any difficulties in order to avoid potential complications in the following steps. The “Operating Surgeon” subsequently connects the reference holes starting from the lingual to the buccal corticotomy along the buccal cortex with a short Lindemann burr (Fig.  5.23c, d). At this moment, the

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Fig. 5.24  MI completion of the sagittal split osteotomy (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a), a human cadaver (Department of Anatomy and Embryology, University

of Maastricht, the Netherlands) (b) and a synthetic skull (c). Note the additional mandibular support with the Md1 channel retractor while OS4 is used to initiate the lingual osteotomy. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

“Operating Surgeon” can use (if needed) the blunt double-sided MI2 elevator with his left hand to retract and protect the retromolar and buccal gingival soft tissues, while he performs the connecting corticotomy with his right hand. The “Operating Surgeon” then supports the mandible at the level of the right mandibular gonial angle with his left

hand while he places a thin 4  mm osteotome (OS4) at the upper level of the lingual corticotomy (Fig. 5.24a–c). Both assistants hold their MI instruments in the same position while the “Operating Nurse” performs gentle taps with the metallic side of the mallet  (BI-TAP) until the “Operating Surgeon” feels that the lingual osteotomy has been initiated behind the lingula.

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Fig. 5.25  MI completion of the sagittal split osteotomy (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a), a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (b) and a synthetic skull (c). Note that

the mandible border at the level of the gonial angle is supported by “Assistant 2” who simultaneously holds the buccal small Md1 channel retractor with his right hand (c) while the “Operating Surgeon” uses the blunt wedge OS5 osteotome to further develop the sagittal split osteotomy (SSO). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

In order to complete the right SSO, the “Operating Surgeon” now takes the blunt wedge osteotome (OS5) and the BI-TAP mallet with his left and right hand, respectively. He positions the blunt OS5 wedge osteotome in the middle of the buccal connecting corticotomy at a level where there is tooth support (Fig. 5.25a–c) and performs a single relative

strong tap. At this time, it is crucial that the right lower mandibular border is supported by “Assistant 2” with his right hand that simultaneously holds the buccal small Md1 channel retractor. Once an initial opening of the osteotomy is noticed, the “Operating Surgeon” inserts the blunt OS5 wedge osteotome more anteriorly at the level of the buccal

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corticotomy and performs another tap (or taps) to complete the osteotomy in this region. Finally, he places and taps the blunt OS5 wedge osteotome more posteriorly at the level of the lingual corticotomy as a wedge. Tip

It is crucial to “double-check” the connection between the buccal, lingual, and interconnecting corticotomy lines at both the anterior and the posterior corners with the short Lindemann burr (or reciprocating saw) to make sure that there is no cortical bone left in between before the blunt wedge OS5 osteotome is used.

tome. Subsequently, the “Operating Surgeon” rotates simultaneously the blunt wedge OS5 and sharp OS6 osteotomes counterclockwise to mobilize the mandibular segments (Fig. 5.26b–d). Once the right SSO is completed and the IAN is properly identified and handled, the wound is extensively rinsed by the “Operating Surgeon” with saline (NaCl) solution. Potential bone particles are removed and a gauze impregnated with Exacyl® (tranexamic acid 500 mg/5 ml, Sanofi, Diegem, Belgium) is inserted into the wound. The MI instruments and the silicone bite block are removed and the left SSO can be performed by repeating Steps 1–8.

Attention! Attention!

The initiation of the SSO with the blunt wedge OS5 osteotome placed in the connecting corticotomy needs to be performed in the middle or anterior region, where there is tooth support to avoid a retromolar fracture.

 tep 8—MI Mobilization of the Mandibular S Segments after Sagittal Split Osteotomy After completion of the MI sagittal split osteotomy (SSO) (Step 7, Sect. “Step 7—MI Completion of the Sagittal Split Osteotomy”), mobilization of the mandibular segments needs to be performed. The “Operating Surgeon” keeps the blunt wedge OS5 osteotome with his left hand in its “wedged” position at the level of the lingual corticotomy and receives in his right hand a 8-mm sharp osteotome (OS6) from the “Operating Nurse”. At this stage, “Assistant 1” is still holding the lingual small Md1 channel retractor with his left hand and the aspiration device with his right hand. “Assistant 2” remains to keep the vertical mandibular ramus Md2 retractor with his left hand while with his right hand he performs a 45-degree turn of the buccal small Md1 channel retractor to the right. This maneuver allows the “Operating Surgeon” to insert the sharp OS6 osteotome with his right hand until the inferior part of the buccal corticotomy to further release and mobilize the right proximal mandibular segment at the level of the right lower mandibular border (Fig. 5.26a-c). The “Operating Surgeon” is now using the blunt wedge OS5 and sharp OS6 osteotomes simultaneously. With the sharp OS6 osteotome, he performs a mild counterclockwise (CCW) rotational force with his right hand to verify if the lower mandibular border is well released and the IAN is not crossing toward the buccal plate. In case the latter would happen, he releases the IAN with the small part of the double-­ sided MI1 raspatorium or with the small 4 mm OS4 osteo-

The initial counterclockwise (CCW) rotational force performed by the “Operating Surgeon” with the sharp OS6 osteotome at the lower mandibular border must be directed to the distal mandibular segment in order to avoid a bad split of the buccal cortex of the lower mandibular border. The “Operating Surgeon” may morever not apply any addtional force on the distal segment in the back with the blunt wedge OS5 osteotome during the this maneuver.

 tep 9—“Trivector Seating” of the Mandibular S Proximal Segment Once both MI sagittal split osteotomies (SSOs) have been completed, the “Operating Nurse” gives “Assistant 2” two cheek retractors that are placed bilaterally into the mouth to retract the soft tissues laterally. The “Operating Surgeon” now guides the distal segment of the mandible into the 3D virtual planned intermediate or final occlusion with the intermediate or final (or no) splint, respectively. While he holds it in place with his both hands, “Assistant 1” performs intermaxillary fixation (IMF) with 0.4 mm orthodontic steel wire-­ loops in the front and at the left most posterior region. The “Operating Surgeon” completes the IMF by placing a third wire-loop on the right most posterior region, while “Assistant 1” now supports the mandible into the planned occlusion with his left hand and performs the aspiration with his right hand. After IMF has been performed in the desired occlusion, “Assistant 2” positions the patient’s head in the neutral position toward trivector seating of the right mandibular proximal segment. The “Operating Surgeon” now retracts the soft tissues of the right cheek and lower lip with the RT2 retractor, positions the vertical mandibular ramus Md2 retractor in the wound at the retromolar level and handles it to “Assistant 2”, who takes it with his left hand. He removes the gauze impregnated with Exacyl® (tranexamic acid 500  mg/5  ml,

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Fig. 5.26  MI mobilization of the mandibular segments after sagittal split osteotomy (SSO) (Step 8) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a), a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

(b), and a synthetic skull (c, d). Note the mandibular support with the buccal small Md1 channel retractor while the sharp OS6 osteotome is used to complete the SSO at the lower mandibular border and to mobilize the mandibular segments. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Sanofi, Diegem, Belgium), rinses the wound once again with saline (NaCl) solution, positions the RT2 retractor into the wound and handles it to “Assistant 2”, who takes it with his right hand. “Assistant 1” is meanwhile taking care of the aspiration with his right hand.

The “Operating Surgeon” now positions the right proximal segment in centric relation (CR) following the “trivector seating” technique [3] using the V-shaped MI4 elevator and a bone repositioning forceps (Md3) in his right and left hands, respectively. After “bivector seating”

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Fig. 5.27  “Trivector seating” of the right mandibular proximal segment (Step 9) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, b) and graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (c, d). Note that

after bivector seating of the right proximal segment with the bone repositioning Md3 forceps and the V-shaped MI4 elevator (a, c), trivector seating is performed by inserting a dedicated MI spacer (Md4–9) (b, d) in the osteotomy gap to prevent condylar torque by a potential “Yaw” movement of the right proximal segment, if necessary. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

of the proximal ­segment in CR with the condyle in the superior-posterior region of the glenoid fossa with the V-shaped MI4 elevator (Fig.  5.27a, c), the “Operating Surgeon” needs to identify if there are any lateral or rotational forces that could alter the condyle’s 3D position

laterally or medially in the glenoid fossa in order to avoid condylar torque. Using the combination of the bone repositioning Md3 forceps and the V-shaped MI4 elevator, the “Operating Surgeon” assesses the lateral alignment of the buccal plates of the right proximal and distal mandibular

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Fig. 5.28  “Trivector seating” of the right mandibular proximal segment (Step 9) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (a) and a synthetic skull (b–d). Note that after bivector seating of the right proximal segment with the bone repositioning Md3 for-

ceps and the V-shaped MI4 elevator, trivector seating is performed and a dedicated MI spacer (Md4–9) can be inserted in the osteotomy gap to prevent condylar torque by a potential “Yaw” movement of the right proximal segment, if necessary. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

segments (Fig.  5.27a, c) and is able to remove potential premature bony contacts that could cause an outside lateral flaring of the right proximal segment. On the contrary, in case an inside lateral flaring of the right proximal segment could occur, the “Operating Surgeon” asks the

“Operating Nurse” for a MI spacer [3] (Md4–Md9, width range: 0.5–3.0 mm) and gently places the appropriate MI spacer into the SSO with the holding forceps  (BI3) (Figs. 5.27b, d and 5.28a–d) prior to rigid fixation of the right proximal to the distal mandibular segment (Step 10,

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Sect. “Step 10—MI Rigid Fixation of the Sagittal Split Osteotomy”). Tip

The “Operating Surgeon” can also use Md4-9 MI spacers to increase unilateral or bilateral transverse gonial angle projection according to the individualized 3D virtual treatment plan of the patient.

Tip

In order to achieve a stable and reproducible postoperative occlusion, it is crucial to adjust the patient’s head position during trivector seating and subsequent rigid fixation of the mandibular segments in slight flexion (Step 10, Sect. “Step 10—MI Rigid Fixation of the Sagittal Split Osteotomy”) and certainly avoid extension of the patient’s head.

 tep 10—MI Rigid Fixation of the Sagittal Split S Osteotomy Once trivector seating and positioning of the proximal mandibular segment(s) have been performed and secured with the bone repositioning Md3 forceps (Step 9, Sect. “Step 9—“Trivector Seating” of the Mandibular Proximal Segment”), the “Operating Surgeon” needs to perform passive rigid fixation of the proximal segment(s) (BSSO vs USSO) toward the distal mandibular segment. At this stage, “Assistant 2” inclines the patient’s head to the left with his left hand while he supports the right gonial angle with his right hand making sure that the occlusion remains stable and does not open in the posterior region. Meanwhile, “Assistant 1” remains taking care of the aspiration with his right hand and helps to support the inclined head position with his left hand. The “Operating Surgeon” is now able to perform passive rigid fixation of the right proximal segment toward the distal mandibular segment by using bi-cortical screws (Fig. 5.29a– c, 5.30a–d, 5.31a–d, and 5.32a, b), mini-plate osteosynthesis (Fig. 5.29d, 5.32c, d) or a combination of both, according to surgeon’s preference. In the author’s operating routine, rigid fixation is performed by placing three 2.0 bi-cortical (9 mm–15 mm) screws (mostly two of 13 mm and one of 11 mm more posteriorly) at each side by placing the most anterior bi-cortical screw first. To drill and place the bi-cortical screws, the “Operating Surgeon” stands up and positions the RT2 retractor inside the wound perpendicularly to the buccal cortex of the right proximal segment to guide the direction of both drilling and screw

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insertion. After placement of the second bi-cortical screw (Figs. 5.30c and 5.31c), the “Operating Surgeon” releases the bone repositioning Md3 forceps. In case a MI spacer (Md4– 9) was used, he removes it and handles the bone repositioning Md3 forceps to “Assistant 1” in order to retract the retromolar soft tissues prior to inserting the third and most posterior bicortical screw (9  mm or 11  mm). Finally, the “Operating Surgeon” verifies the stability of the rigid fixation of the right proximal segment to the distal segment with the V-shaped MI4 elevator. The three bi-­cortical screws can be positioned in a linear or triangular configuration. The MI instruments are removed and after trivector seating of the left proximal fragment (Step 9, Sect. “Step 9—“Trivector Seating” of the Mandibular  Proximal Segment”), MI rigid fixation of the left SSO can be performed in the same way as described above. Once this is done, cheek retractors are placed by “Assistant 2”, abundant rinsing with saline (NaCl) solution and aspiration is performed by “Assistant 1”, while the “Operating Surgeon” removes the posterior wire-loops with a cutting plier. After verifying the head position and posture, the “Operating Surgeon”, removes the last remaining wire-loop in the frontal region and verifies the occlusion prior to wound closure. To start suturing the right side, the “Operating Surgeon” places a small tongue depressor in between the dental arches and handles it to “Assistant 1”, who takes it with his right hand and takes care of the aspiration with his left hand. Meanwhile, “Assistant 2” is holding one RT1 retractor with his right hand more anteriorly and a RT2 retractor with his left hand more posteriorly to retract the soft tissues of the lower lip and the  right cheek, respectively. After another abundant rinsing with saline (NaCl) solution, the “Operating Surgeon” performs a one-layer closure of the wound with a Vicryl 3.0 rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) running suture starting anteriorly. Finally, he applies fibrin glue (Tisseel®, Baxter, Deerfield, IL, USA) into the wound through one of the spaces of the running suture. After mandibular advancement, in case an osteotomy gap equal or larger than 10 mm is created, the “Operating Surgeon” grafts the gap with particulate human lyophilized bone from the local bone bank. In these cases, the fibrin glue is applied over the bone graft before suturing. Afterward, to close the left side, “Assistant 1” takes over the RT1 retractor with his left hand and uses it to retract the lower lip, keeping the aspiration device on the other hand. “Assistant 2” moves the RT2 to the left side, exactly in the same position as the contralateral side, and holds the tongue depressor downward with his right hand. At the end of the entire “MI Sagittal Split Osteotomy” surgical procedure, after abundant rinsing with saline (NaCl) solution of the oral cavity and aspiration of the airway, the patient’s face is cleaned and a steroid ointment (Elocom® 0.1%, NV Schering-Plough Labo, Heist-op-den-Berg, Belgium) is applied on both lips. Finally, a cooling face mask

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Fig. 5.29  MI rigid fixation of the right sagittal split osteotomy (SSO) (Step 10) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a–d). Note the almost 90-degree position of the RT2 retractor toward the mandibular buccal cortex which allows appropriate guidance for drilling and screwing of the bi-cortical screws (L1® 2.0, KLS Martin, Tuttlingen, Germany) by the “Operating

Surgeon”. Note that during rigid fixation, the right mandibular proximal segment is absolutely passive and in centric relation (CR) with or without a spacer after trivector seating to avoid any torque of the condyle (a–c). Also note that using the MI approach, besides using 2 or mostly 3 bi-cortical screws, rigid fixation with a mini-plate using mono-­cortical screws can be safely performed. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 5.30  MI rigid fixation of the right sagittal split osteotomy (SSO) (Step 10) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on graphic illustrations (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

(a–d). Note that after placement of the first (or two) bi-­cortical screws, the bone repositioning Md3 forceps is opened but kept in place by “Assistant 1” to provide space for the insertion of a third bi-cortical screw while the spacer is removed using the long BI3 clamp (c)

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Fig. 5.31  MI rigid fixation of the right sagittal split osteotomy (SSO) (Step 10) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a–d). Note the almost 90-degree position of the RT2 retractor toward the mandibular buccal cortex to allow appropriate guidance for drilling and screwing of the bi-cortical screws (L1® 2.0, KLS Martin, Tuttlingen, Germany) by the “Operating Surgeon”. Note that

during rigid fixation, the right mandibular proximal segment is absolutely passive and in centric relation (CR) with or without an MI spacer after trivector seating to avoid any torque of the condyle. Also note that “MI Chin” (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

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Fig. 5.32  MI rigid fixation of the right sagittal split osteotomy (SSO) (Step 10) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a–d). Note the positioning of a third bi-cortical screw (a, b), or alternative rigid fixation with one (c) or two mini-plates using mono-cortical screws (L1® 2.0, KLS Martin, Tuttlingen, Germany)

using the same MI approach principles. In case of double mini-plate fixation the MI approach needs to be somewhat extended. Also note that “MI Chin“ (Chap. 3) and “MI Le Fort I” (Chap. 4) osteotomies were already performed. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

5  Minimally Invasive (MI) Sagittal Split Osteotomy

(Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/ Allgäu, Germany) is adapted without any tension on the skin for postoperative thermo-therapy (Chap. 8), which is continued for 1 week.

Tip

If a posterior bone contact is identified between the mandibular proximal and distal segments during trivector seating which should not be removed (e.g., in cases where the buccal cortices are well aligned or additional transversal projection of the gonial angle needs to be avoided), a MI spacer (Md4-9) can be placed in the most anterior region to avoid lateral torque of the condyle during rigid fixation with mono-­ cortical plates or bi-cortical screws. Moreover, in such a case the first bi-cortical screw should be placed in the most posterior region.

Trick

The RT2 retractor facilitates both the drilling, inserting and screwing of bi-cortical screws. The “Operating Surgeon” therefore must keep the RT2 as perpendicular as possible to the buccal cortex and may not change its inclination in order to keep the same vector. Moreover, the “Operating Surgeon” keeps his right ring finger on the RT2 to control and limit the depth of drilling while passing both the buccal and lingual cortexes.

Limits of the “MI Sagittal Osteotomy” Surgical Technique

Surgical experience The “10 Step-by-Step” surgical procedure described in this chapter and the accompanying graphic video are valuable for “in-depth” study of the MI technique (https:// www.youtube.com/watch?v=CqOmWaKoOZM).

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Dedicated phantom, cadaver or live surgery courses are recommended. Following the described MI orthognathic principles in this chapter, every orthognathic surgeon should be able to master the “MI Sagittal Split Osteotomy” after his individual “learning curve”. Large CCW mandibular advancements (e.g., in Obstructive  Sleep  Apnea (OSA) patients) that would need two plates at both sides and release of the masseter-­pterygoid medial muscle sling can be done following the same principles but would need a larger incision with more subperiosteal degloving and release of the muscle sling. Important mandibular asymmetries that would need additional mandibular contouring by bony resection or augmentation with bone grafts or patient-­ specific implants (PSIs) can be done following the same principles but would need a larger incision with more subperiosteal degloving or the combination with a “MI Chin Osteotomy” approach (Chap. 3) to properly address the mandibular asymmetry. For cases like this, intra-operative Cone-Beam CT (IO-CBCT) is recommended “Vertical ramus, or inverted L-condylectomy”. 

References 1. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017. 2. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 3. Swennen GRJ. Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi. org/10.1016/j.cxom.2020.05.009.

6

Minimally Invasive (MI) Maxillary Expansion Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola

Step-by-step standardization of minimally invasive (MI) orthognathic surgical techniques increases surgical efficiency and decreases patient morbidity. In this chapter, an innovative systematized “10 step-by-step approach” toward surgical assisted maxillary expansion following a “MI philosophy and mindset” is outlined in detail. General considerations regarding the preparation of the patient, instrumentation table, and operating room toward MI maxillary expansion are well described. Dedicated newly developed MI orthognathic surgical instruments allow to optimize the vascular blood supply and decrease interstitial edema and swelling after a MI maxillary expansion procedure which enhances postoperative fast recovery of the patient. Moreover, the introduction of MI orthognathic surgical codes, MI orthognathic surgical sequences, and MI orthognathic sequence template bars create a common language among the surgical team (“Operating Surgeon”, “Surgical Assistants”, and “Operating Nurse”) which increases surgical efficiency and additionally decreases patient morbidity. Furthermore, systematization of storage of the MI orthognathic instruments and MI surgical sequence template bars allows to optimize their gathering, cleaning, and sterilization process toward a more time-efficient and cost-effective clinical routine. Every single step of the MI approach toward the MI expansion surgical procedure is illustrated in detail by high-quality graphic G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected]

illustrations and pictures made on synthetic skulls and human cadavers. Finally, the limits of the described MI surgical technique toward maxillary expansion are summarized.

 eneral Considerations Regarding the “MI G Maxillary Expansion” Surgical Procedure In this chapter (Sect.“The “10 Step-by-Step MI Maxillary Expansion” Surgical Technique ”), a “10 Step-by-Step” surgical technique (see Table 6.2) to perform a surgical maxillary expansion in a systematized minimally invasive (MI) way will be described in detail. Surgical maxillary expansion, also called surgically assisted rapid palatal expansion (SARPE), is a well-­ established orthodontic-surgical procedure to correct maxillary transversal skeletal discrepancies. It is also considered a pre-surgical step toward future maxillary osteotomies to avoid the need for segmentation. This surgical technique is based on well-known distraction osteogenesis (DO) principles. It is only performed when the intermaxillary suture is fused and cannot be widened by conventional orthodontic expansion techniques anymore. Once the skeletal relationships of the jaws have been assessed and the need for a SARPE has been identified, a bone-borne, teeth-borne, or hybrid teeth/bone-borne appliance can be installed depending on the orthodontic-surgical team’s preference. Especially in case a bone-borne distraction appliance is chosen its anteroposterior position on the hard palate needs to be defined (Step 10, Sect “Step 10—Placement and / or Activation of a Maxillary Expansion Apparatus (Bone-­ Borne, Teeth-Borne or Hybrid Teeth/Bone-Borne)”) and also the potential need for pterygomaxillary (PTM) disjunction or septum release (Step 9, Sect. “Step 9—MI PTM Dysjunction / Septum Release if Required”) needs to be assessed. The limits of the presented “MI Maxillary Expansion” surgical technique, however, are outlined at the end of this chapter.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_6

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Based on the background of MI surgery in other surgical fields (Chap. 1) and supported by evidence-based medicine [1] a new innovative concept and rationale was developed toward “MI Orthognathic Surgery” (Chap. 2) in order to reduce overall patient morbidity by the combination of increasing surgical efficiency and decreasing surgical trauma through minimized degloving and compression of the soft tissue envelope. In specific regard toward “MI Maxillary Expansion”, the following general considerations need to be taken into account by the surgical team: 1. Organization of the surgical instrumentation table by the “Operating Nurse” (Sect. ““MI Maxillary Expansion” Instruments and “MI Maxillary Expansion” Surgery Instrumentation Table Organization”) 2. Preparation of the Patient in the Operating Room by the “Operating Surgeon”, “Assistant 1” and “Assistant 2” (Sect. “Patient and Operating room Preparation Toward the “MI Maxillary Expansion” Surgical Procedure”)

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“ MI Maxillary Expansion” Instruments and “MI Maxillary Expansion” Surgical Instrumentation Table Organization In order to improve the efficiency of the overall surgical team during an “MI Maxillary Expansion”, “MI Maxillary Expansion surgical sequence template bars” were developed to indicate in a systematic order the required MI coded instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) [2] (Chap. 2). The “Operating Nurse” places the three dedicated “MI Maxillary Expansion surgical sequence template bars” on top of the surgical instrumentation table (Fig. 6.1) which allows a fast, easy, and standardized organization of the relevant MI orthognathic instruments not only at the initiation but also during the entire surgical procedure. Moreover, the “Operating Nurse” is able to follow and knows at any moment which “MI Maxillary Expansion” orthognathic instrument is needed by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” to smoothly perform the “MI Maxillary Expansion”.

Fig. 6.1  MI orthognathic instruments used to perform “MI Maxillary Expansion” systematically organized on the surgical instrumentation table by the “Operating Nurse” (graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

6  Minimally Invasive (MI) Maxillary Expansion Table 6.1 “Surgical Codes” and “Surgical Sequence” for the “Minimally Invasive (MI) Maxillary Expansion” orthognathic surgical procedure MI Maxillary Expansion NS MI1 Mx2R/Mx2L RT3 MI2 Mx3 OS2 OS3 RT3 OS4 OS6 (OS7) (RT2) (NS) nose speculum; (MI) minimally invasive; (Mx) maxilla; (RT) retractor; (OS) Osteotome (From Swennen [2]; with permission)

The “Surgical Codes” and “Surgical Sequence” toward the “MI Maxillary Expansion” are mentioned in Table 6.1.

 atient and Operating Room Preparation P Toward the “MI Maxillary Expansion” Surgical Procedure To perform a “MI Maxillary Expansion”, the patient is placed in a supine position on the operating table by the “Anesthesiologic team” in close collaboration with the “Operating Surgeon”, who personally positions the patient’s head using a dedicated head support (Chap. 8) in a position that allows extension of the head in order to facilitate an easier placement of a bone-borne expansion device (Step 10, Sect. “Step 10—Placement and / or Activation of a Maxillary Expansion Apparatus (Bone-Borne, Teeth-Borne or Hybrid Teeth/Bone-Borne)”), if needed. After orotracheal intubation by the anesthesiologist and correct positioning of the tube in the midline in close contact to the patient’s chin and thorax (Chap. 8), local anesthesia (Xylocaine® 1% with adrenaline 1:200.000) is administered by “Assistant 2” in both nasal nostrils, in the maxillary vestibulum through the superficial mucosal and deep subperiosteal plane, and at the hard palate (between the premolars or in between the second premolar and first molar, depending on the type of the desired expansion, (see Step 10, Sect. “Step 10—Placement and / or Activation of a Maxillary Expansion Apparatus (Bone-Borne, Teeth-Borne or Hybrid Teeth/Bone-­Borne)”) for localized vasoconstriction and hemostasis. Additionally, two gazes impregnated with cocaine (Cocaine HCL 2% with Adrenaline 10 ppm, AZ Sint-Jan pharmacy, Bruges, Belgium) are placed in both nostrils for additional local vasoconstriction. “Assistant 2” also positions the two operating reflector lights (most ideally L.E.D.) in an ideal position above the patient—one straight above the head and the second above the legs with a 45-degree inclination angle toward the patient’s face.

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Meanwhile “Assistant 1” is scrubbing in order to start disinfection of the patient’s head and surgical draping immediately once the patient is intubated in order not to lose valuable time. Antisepsis of the face and both nostrils is performed by “Assistant 1” with a cutaneous disinfectant solution (Hibidil® 50  mg/100  ml chlorhexidine digluconate cutaneous solution, Hälsa Pharma GmbH, Münster, Germany) followed by disinfection of the mouth with a rinsing solution (Hextril® (1 mg/ml hexetidine mouth rinsing, Famar Orléans, Orléans, France) once all sterile drapes have been applied. A steroidal ointment is applied on both the upper and the lower lips (Elocom®, 0.1% mometasone furoate cream, ­Schering-­Plough Labo NV, Heistop-den-Berg, Belgium) by one of the assistant surgeons. Intravenous (IV) antibiotics (2  g amoxicillin clavulanic acid 2000  mg/200  mg intravenous injection, Augmentin®, GlaxoSmithKline, Singapore) are administered by the anesthesiologist only once in a single dose. In case of penicillin allergy, clindamycin (Clindamycin Sandoz® 600  mg/4  ml intravenous injection, Sandoz Canada Inc. Boucherville, QC, Canada) is administered by intravenous injection in a single dose. Corticosteroids are given in a single high dose (250  mg methylprednisolone intravenous injection, Solu-­ Medrol®, Pfizer Manufacturing, Puurs, Belgium) at the start of the surgery and repeated postoperatively at the recovery unit (80  mg methylprednisolone intramuscular injection, Depo-Medrol®, Pfizer Manufacturing, Puurs, Belgium). Tranexamic acid (500 mg/5 ml tranexamic acid intravenous injection, Exacyl®, Sanofi, Gentilly, France) is administered 1  g directly IV after induction and another 1  g in the 1-L NaCl drip infusion at initiation of the surgery unless contraindications. The anesthesiologic management is furthermore explained in Chap. 8. In case removal of lower (impacted or not) and upper (not impacted) wisdom teeth is indicated, these are always simultaneously removed. Impacted upper wisdom teeth, however, are left in place since their simultaneous removal could lead to asymmetric widening of the maxilla by uncontrolled weakening of its posterior region. These can easily be removed simultaneously with the removal of the maxillary expansion device under local anesthesia after 4 months of retention. To perform a “MI Maxillary Expansion”, the right-handed “Operating Surgeon” is positioned in front of the patient’s head (sitting or standing) while “Assistant 1” and “Assistant 2” are placed aside, on the right and left sides, respectively (Fig. 6.2). The “Operating Nurse” is ideally positioned at the right side of the patient’s thorax and “Assistant 1”, while the anesthesiologist is positioned at the left side of the patient’s feet (Fig. 6.2).

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Fig. 6.2  Positioning of the “Operating Surgeon”, surgical “Assistant 1”, surgical “Assistant 2”, “Operating Nurse”, and anesthesiologist are shown in the operating room (graphic illustrations from L1® MI Orthognathics,

KLS Martin, Tuttlingen, Germany): overview (a) and view from the “Operating Surgeon” sitting (or standing) position at the head of the patient (b) during the “MI Maxillary Expansion” surgical procedure

 he “10 Step-by-Step MI Maxillary T Expansion” Surgical Technique

Table 6.2  The “10 Step-by-Step MI Maxillary Expansion” Surgical Technique

The “10 Step-by-Step” surgical technique (Table 6.2) to perform a surgical maxillary expansion in a systematized minimally invasive (MI) way has initially been described concisely and accordingly illustrated on cadaver pictures [2]. In this chapter, the surgical technique has been elaborated in much more detail toward the overall surgical team using the combination of human cadaver, synthetic skull pictures, and high-professional illustration graphics. Special attention was taken to describe in detail the role of each member of the surgical team (“Operating Nurse”, “Assistant 1”, “Assistant 2”, and the “Operating Surgeon”) using the surgical codes and the dedicated “MI Maxillary Expansion surgical sequence template bars” (Table 6.1). The latter is mentioned on the “MI Maxillary Expansion surgical template bars” toward the “Operating Nurse” (Sect. “General Considerations Regarding the “MI Maxillary Expansion” Surgical Procedure”) in order to increase overall surgical efficiency and decrease patient morbidity. In this chapter, the “MI Maxillary Expansion” orthognathic surgical technique is explained toward the right-handed “Operating Surgeon” but could of course easily be modified toward the left-handed “Operating Surgeon”. Note that throughout this chapter right and left are used in regard to the position of the “Operating Surgeon” sitting or standing at the head of the patient and looking toward the patient’s body along the facial midline.

“Step 1” “Step 2” “Step 3” “Step 4” “Step 5” “Step 6” “Step 7” “Step 8” “Step 9” “Step 10”

MI endonasal approach to the Le Fort I corticotomy MI exposure of the hemimaxilla by subperiosteal tunnelling MI subperiosteal dissection of the inner part of the lateral nasal wall MI Le fort I corticotomy MI osteotomy of the medial and lateral maxillary pillars MI intraoral approach toward the midline Le fort I osteotomy Marking the skeletal maxillary midline toward the upper dental midline MI maxillary midline osteotomy and mobilization MI PTM dysjunction/septum release if required Placement and/or activation of a maxillary expansion apparatus (bone-borne, teeth-borne, or hybrid teeth/ bone-borne)

(From Swennen [2]; with permission)

 tep 1—MI Endonasal Approach to the Le Fort S I Corticotomy The MI approach toward “Maxillary Expansion” starts with the Le Fort I corticotomy, which is performed through an endonasal approach in five consecutive steps (Steps 1–5, Sect. “Step 1—MI Endonasal Approach to the Le Fort I Corticotomy”, “Step 2—MI Exposure of the Hemimaxilla by Subperiosteal Tunnelling”, “Step 3—MI Subperiosteal Dissection of the Inner Part of the Lateral Nasal Wall”, “Step

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Fig. 6.3  MI endonasal approach to the right Le Fort I corticotomy (Step 1) and positioning of the short NS nasal speculum (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, c), a graphic illustration (L1® MI

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (d). Note the passive insertion of the short NS nasal speculum inside the right nostril. Clinical pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

4—MI Le Fort I Corticotomy”, and “Step 5—MI Osteotomy of the Medial and Lateral Maxillary Pillars”) at both sides. With his left hand, the “Operating Surgeon” inserts a short nasal speculum (NS) in the right nostril (Fig. 6.3a–d) and opens it horizontally, while gently pushing the right nostril laterally (Fig. 6.4a, b). He then makes a 5-mm incision

through the nasal mucosa and periosteum directly to the right paranasal bone using a #15 scalpel with his right hand. This incision is made horizontally at the level of the Le Fort I corticotomy, slightly lateral to the piriform rim and parallel to the upper occlusal plane from medial to lateral (Fig. 6.5a–c).

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Fig. 6.4  MI endonasal approach to the right Le Fort I corticotomy (Step 1) and positioning of the short NS nasal speculum (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University

of Maastricht, the Netherlands) (a) and a synthetic skull (b). Note how the short NS nasal speculum retracts the soft tissues of the right nostril in a gentle way. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

During this step, “Assistant 2” keeps the small surgical field nicely dry using a fine aspiration device. Later, when “Step 1” is repeated on the left side, aspiration is performed by “Assistant 1”.

 tep 2—MI Exposure of the Hemimaxilla by S Subperiosteal Tunnelling

Trick

The “Operating Surgeon” first inserts the short NS nasal speculum completely “closed” in the nostril and then gradually opens it while pulling it back, in order to retract the soft tissues of the ipsilateral nostril.

Attention!

During the incision it is important that the “Operating Surgeon” makes sure that the short NS nasal speculum does not slip away in order to avoid a laceration of the nostril wound.

Once the MI endonasal incision (Step 1, Sect. “Step 1—MI Endonasal Approach to the Le Fort I Corticotomy”) has been made, MI exposure of the hemimaxilla by subperiosteal tunnelling is performed. The “Operating Surgeon” starts with minimal degloving of the right medial pillar of the maxilla in a strict subperiosteal plane by using first the small (Fig. 6.6a, b) and then the large (Fig. 6.6c) part of the sharp double-sided raspatorium (MI1) that he holds with his right hand. The right-handed “Operating Surgeon” now moves himself into a slightly two-third left position in relation to the patient’s head, while he removes the short NS nasal speculum from the right nostril with his left hand and keeps the large side of the sharp MI1 raspatorium in close contact with the right paranasal bone. He then creates, with the MI1 raspatorium in his right hand, by a single sliding movement, a strict subperiosteal tunnel toward the right crista infra-­

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Fig. 6.5  MI endonasal approach to the right Le Fort I corticotomy (Step 1) and positioning of the short NS nasal speculum (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a synthetic skull (b) and a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

(c). Note the small horizontal incision at the Le Fort I level, slightly lateral to the piriform rim and parallel to the upper occlusal plane. Also note how the short NS nasal speculum protects the soft tissues of the right nostril during the incision with the #15 scalpel. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 6.6  MI exposure of the right hemimaxilla by subperiosteal tunnelling (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University

of Maastricht, the Netherlands) (a, c) and a  synthetic skull (b). Note that minimally invasive dissection is performed first with the small and then the large part of the sharp MI1 double-sided raspatorium. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

zygomatica (CIZ) (Fig. 6.7a–d) and turns the MI1 raspatorium 45-degrees to create a small subperiosteal pocket. “Assistant 2” repositions the operating light into the direction of the right subperiosteal tunnel using his right hand and then continues to aspirate the small surgical field with a fine aspiration device. The “Operating Surgeon” then inserts a curved soft tissue retractor specially designed for the right side (Mx2R) into the

right subperiosteal tunnel toward the posterior part of the right CIZ (Fig. 6.8a–c) and offers it to “Assistant 1” who takes it with his left hand. A small soft tissue retractor (RT3) is then placed inside the right nostril and held by “Assistant 2” with his right hand to retract the soft tissues medially (Fig. 6.8a–c) toward MI subperiosteal dissection of the inner part of the lateral nasal wall (Step 3, Sect.  “Step 3—MI Subperiosteal Dissection of the Inner Part of the Lateral Nasal Wall”).

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Fig. 6.7  MI exposure of the right hemimaxilla by subperiosteal tunnelling (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI

Later, when “Step 2” is repeated on the left side, a curved soft tissue retractor that adapts to the left CIZ (Mx2L)  is inserted - instead of the curved MX2R soft tissue retractor and held by “Assistant 2”. The aspiration and insertion of the small RT3 soft tissue retractor are then performed by “Assistant 1”.

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and synthetic skull (c, d). Note how the right-handed “Operating Surgeon” places his left middle finger in the right upper vestibulum at the level of the right crista infra-zygomatica (CIZ) to guide the subperiosteal tunnelling. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Trick

At the level of the CIZ, the “Operating Surgeon” makes a 45-degree turn with the large side of the sharp double-­ sided MI1 raspatorium in order to create space to insert the flexible curved Mx2R or Mx2L soft tissue retractors.

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Fig. 6.8  MI exposure of the right hemimaxilla by subperiosteal tunnelling (Step 2) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic

Attention!

To check the angulation and protect the soft tissues while creating the subperiosteal tunnel toward the crista infra-zygomatica (CIZ), the “Operating Surgeon” uses his index and middle fingers intraorally in the upper vestibulum.

skull (c). Note the minimal required incision to perform the strict subperiosteal tunnelling and insertion of the flexible curved Mx2R soft tissue retractor. Note also that the RT3 retractor is already in place inside the right nostril to retract the soft tissues medially. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 3—MI Subperiosteal Dissection S of the Inner Part of the Lateral Nasal Wall Once MI exposure of the hemimaxilla by subperiosteal tunnelling (Step 2, Sect. “Step 2—MI Exposure of the Hemimaxilla by Subperiosteal Tunnelling”) has been performed, MI subperiosteal dissection of the inner part of the lateral nasal wall is managed. Therefore, “Assistant 2” con-

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Fig. 6.9  MI subperiosteal dissection of the inner part of the right lateral nasal wall (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, c), a synthetic skull (b) and  a graphic illustration (L1® MI Orthognathics, KLS Martin,

Tuttlingen, Germany) (d). Note the use of the sharp MI1 raspatorium and the blunt MI2 elevator for the subperiosteal dissection of the inner part of the lateral nasal wall and the retraction of the right nostril with the small RT3 soft tissue retractor. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

tinues to hold the small RT3 soft tissue retractor inside the right nostril with his right hand, while “Assistant 1” continues to hold the flexible curved Mx2R soft tissue retractor gently in place, behind the right CIZ, with his left hand. The “Operating Surgeon” now retracts the nasal soft tissues medially with the curved part of the blunt double-sided elevator  (MI2) with his left hand (Fig.  6.9a, b) in order to

perform strict subperiosteal dissection of the inner part of the right lateral nasal wall using first the small and then the large part of the sharp double-sided MI1 raspatorium (Fig. 6.9a, b). While retracting the nasal soft tissues medially with the curved part of the blunt double-sided MI2 elevator inside the small wound, the “Operating Surgeon” gently inserts a thin malleable soft tissue retractor (Mx3)  between the nasal

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Fig. 6.10  MI exposure of the right hemimaxilla and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown in a “transparency view” after overlay of the human cadaver picture (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) on the synthetic skull pic-

ture. Note the position of the flexible curved Mx2R and Mx3 soft tissue retractors to protect the soft tissues from the Lindeman burr during the Le Fort I corticotomy (Step 5). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

mucosa and the inner surface of the right lateral nasal wall (Figs. 6.9c, d and 6.10). Consecutively, he attaches the long intelligent handgrip (Chap. 2, Sect. “The Rationale Behind the “Intelligent Handgrip””) of thin malleable Mx3 soft tissue retractor with a mosquito forceps to the surgical drapes around the patient’s head on the contralateral side. Meanwhile, “Assistant 2” continues to perform fine aspira-

tion and removes the small RT3 soft tissue retractor once the thin malleable Mx3 soft tissue retractor is in place. Later, when “Step 3” is repeated on the left side, the small RT3 soft tissue retractor is inserted and removed by “Assistant 1” who also then performs the fine aspiration. The flexible curved Mx2L soft tissue retractor is intermittently held by “Assistant 2”.

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Step 4—MI Le Fort I Corticotomy Once MI subperiosteal dissection of the inner part of the lateral nasal wall (Step 3, Sect. “Step 3—MI Subperiosteal Dissection of the Inner Part of the Lateral Nasal Wall”) has been done, the MI Le Fort I corticotomy is performed. Care must be taken to protect the roots of the teeth and soft tissues, including the infraorbital nerve (V2), at this stage using the flexible curved Mx2R/L and malleable Mx3 soft tissue retractors. The “Operating Surgeon” takes over the curved Mx2R soft tissue retractor from “Assistant 1” with his left hand, verifies its correct position, and pushes it with his left middle finger in contact to the right CIZ. “Assistant 1” then supports the patient’s head position and inclines it medially with his right hand to help the “Operating Surgeon” who initiates the Le Fort I corticotomy by drilling with a medium Lindeman burr from lateral (Fig. 6.11a) to medial (Fig. 6.11b). During drilling, he handles over again the curved Mx2R soft tissue retractor to “Assistant 1” and takes the malleable Mx3 soft tissue retractor in his left hand to protect the nasal mucosa when he continues the Le Fort I corticotomy into the lateral nasal wall (Fig. 6.12a, b), similarly to the “MI Le Fort I Osteotomy” surgical procedure (Chap. 4, Sect. “Step 6—MI Le Fort I Corticotomy”).

a

Fig. 6.11  Right MI Le Fort I corticotomy (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

Later, when “Step 4” is repeated on the left side, Assistant 2″ holds the curved Mx2L soft tissue retractor intermittently and Assistant 1″ performs fine aspiration.

Attention!

During the posterior Le Fort I corticotomy, the “Operating Surgeon” holds the curved Mx2R/L soft tissue retractors, while during the anterior Le Fort I corticotomy he holds the malleable Mx3 soft tissue retractor, in order to control and prevent lesions of the roots of the teeth or soft tissues during drilling.

Tip

When the “Operating Surgeon” takes over the curved Mx2R (or Mx2L) soft tissue retractor during the drilling procedure, “Assistants 1 and 2” intermittently support the patient’s head in a medially inclined and stable position.

b

(a) and a synthetic skull (b). Note how the flexible curved Mx2R and malleable Mx3 soft tissue retractors protect the soft tissues toward the Le Fort I corticotomy during drilling with the Lindemann burr. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 6.12  Right MI Le Fort I corticotomy (Step 4) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands)

 tep 5—MI Osteotomy of the Medial S and Lateral Maxillary Pillars After the MI Le Fort I corticotomy (Step 4, Sect. “Step 4— MI Le Fort I Corticotomy”), MI osteotomies of the medial and lateral maxillary pillars are performed until the level of the medial pterygoid plates. The “Operating Surgeon” supports the flexible malleable Mx3 soft tissue retractor with his left hand, while he first inserts a straight osteotome (OS2) with a blunt protection in the Le Fort I corticotomy at the level of the right medial maxillary pillar (Fig.  6.13a–c). Consecutively, he instructs “Assistant 2” to perform intermittent tapping with the metal part of the BI-TAP mallet on the straight OS2 osteotome with his right hand. “Assistant 2” meanwhile performs fine aspiration with his left hand, while “Assistant 1” gently holds the curved Mx2R soft tissue retractor in the right subperiosteal tunnel with his right hand and supports the patient’s head in the neutral position. The “tapping” action is performed until a dull sound is heard, indicating that the medial pterygoid plate has been reached. Consecutively, the “Operating Surgeon” removes the straight OS2 osteotome and takes over the curved Mx2R soft tissue retractor from “Assistant 1” with his left hand. “Assistant 1” now inclines and supports the patient’s head slightly medially with his right hand. The “Operating Surgeon” then inserts the angled osteotome (OS3) that

G. R.J. Swennen et al.

b

(a) and a  graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b). Note the medially inclined position of the patient’s head. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

also has a blunt protection, through the subperiosteal tunnel into the Le Fort I corticotomy at the level of the right CIZ (Fig. 6.14a–c). Once he has verified, the correct position of the curved Mx2R soft tissue retractor, he pushes it with his left middle finger in close contact to the right CIZ and instructs “Assistant 2” to perform the intermittent tapping with the metal part of the BI-TAP mallet. Since unlike the medial pillar, the lateral maxillary pillar is not straight, the “Operating Surgeon” must gradually slightly modify the inclination of the angled OS3 osteotome during tapping in order to control that the angled OS3 osteotome remains at the bony level and follows the Le Fort I corticotomy toward the medial pterygoid plate, similarly to the “MI Le Fort I Osteotomy” surgical procedure (Chap. 4, Sect“Step 7—MI osteotomy of the medial and lateral maxillary pillars”). Once the osteotomies of the medial and lateral maxillary pillars have been performed on the right side, the “Operating Surgeon” inserts a sterile gauze impregnated with Exacyl® (500 mg/5 ml tranexamic acid injectable solution) inside the wound and performs Steps 1–5 on the left side. When “Step 5” is performed on the left side, “Assistant 2” holds the curved Mx2L soft tissue retractor intermittently and “Assistant 1” performs fine aspiration with his left hand and intermittent tapping with the BI-TAP mallet with his right hand. Finally, another sterile gauze impregnated with Exacyl® (500 mg/5 ml tranexamic acid injectable solution) is inserted inside the left wound by the “Operating Surgeon”.

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Fig. 6.13  MI osteotomy of the right medial maxillary pillar (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the insertion and inclination of the straight OS2 osteotome with its blunt protection at the right medial maxillary pillar. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Attention!

Tip

During the MI osteotomy of the lateral maxillary pillars, the “Operating Surgeon” holds the curved Mx2R / Mx2L soft tissue retractors in close contact to the CIZ with is middle finger to protect the soft tissues and to avoid bleeding.

To control the osteotomy of the medial and lateral maxillary pillars toward the medial pterygoid plates and to stop the tapping in time, the Operating Surgeon” clearly instructs the “Assistant” or “Operating Nurse” to perform single, consecutive taps with small pauses in between.

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Fig. 6.14  MI osteotomy of the right lateral maxillary pillar (Step 5) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and synthetic

Attention!

Controlling direction, strength, and deepness of the osteotomy of the medial and lateral maxillary pillars is crucial to prevent complications, especially bleeding, similar to the “MI Le Fort I Osteotomy” surgical procedure (Chap. 4, Sect. “Step 7—MI osteotomy of the medial and lateral maxillary pillars”).

skull (c). Note the insertion and inclination of the angled OS3 osteotome with its blunt protection (b) at the right lateral maxillary pillar. Also note that on the synthetic skull the angle OS3 osteotome was not placed in the corticotomy in order to better show its inclination. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

 tep 6—MI Intraoral Approach toward S the Midline Le Fort I Osteotomy Once the MI osteotomy of the medial and lateral maxillary pillars (Step 5, Sect. “Step 5—MI Osteotomy of the Medial and Lateral Maxillary Pillars”) has been performed, the MI approach toward maxillary expansion continues by an intraoral approach to address the intermaxillary suture in the next three consecutive steps (Steps 6–8, Sects. “Step 6—MI

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Fig. 6.15  MI intraoral approach toward the midline Le Fort I osteotomy (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c). Note the small vertical incision made at the maxillary midline directly to the bone. Also note the standard tube for orotracheal intubation (a) and an alternative more flexible one (c). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Intraoral Approach Toward the Midline Le Fort I Osteotomy”, “Step 7—Marking the Skeletal Maxillary Midline toward the Upper Dental Midline”, and “Step 8—MI Maxillary Midline Osteotomy and Mobilization”). First, two small RT3 soft tissue retractors are placed by “Assistant 1” and “Assistant 2” inside the upper vestibulum, with their left and right hands, respectively, to gently retract the soft tissues of the upper lip in the midline. The “Operating

Surgeon” then makes a small vertical incision of ­approximately 10  mm using a #15 scalpel in the midline along the upper buccal frenulum. This incision is made through the mucosa and the periosteum directly on the bone (Fig. 6.15a–c). Consecutively, the “Operating Surgeon” performs strict and minimal subperiosteal degloving of the alveolar mucoperiosteum between the upper central incisors and below the

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Fig. 6.16  MI intraoral approach toward the midline Le Fort I osteotomy (Step 6) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University

of Maastricht, the Netherlands) (a) and a synthetic skull (b). Note the insertion and positioning of the two small RT3 soft tissue retractors on the bone perpendicular to the MI vertical incision. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Anterior Nasal Spine (ANS), using the small part of the double-­sided sharp MI1 raspatorium. He then instructs both “Assistants 1 and 2” to insert the small RT3 soft tissue retractors inside the small wound strictly in the subperiosteal plane on the bone (Fig. 6.16a, b). At this stage, fine aspiration is performed by “Assistant 1”.

(Fig. 6.17a, b. Once he has clearly marked the intermaxillary suture, he deepens it with the same MI orthognathic instrument (Fig. 6.17c, d) to allow a stable positioning of a small and straight osteotome (OS4) in the next step (Step 8, Sect“Step 8—MI Maxillary Midline Osteotomy and Mobilization”). “Assistants 1 and 2” continue to gently retract the soft tissues with the small RT3 soft tissue retractors placed on the bone in the small wound, while “Assistant 1” performs fine aspiration of the surgical field.

Attention!

The small RT3 soft tissue retractors are placed by “Assistants 1 and 2” subperiosteally in the small wound on the bone, perpendicular to the vertical midline incision, in order to perform a  gentle horizontal lateral retraction of the soft tissues and avoid lacerations.

 tep 7—Marking the Skeletal Maxillary S Midline toward the Upper Dental Midline Once the MI intraoral approach toward the midline Le Fort I osteotomy (Step 6, Sect. “Step 6—MI Intraoral Approach toward the Midline Le Fort I Osteotomy”) has been performed, the skeletal maxillary midline toward the upper dental midline is marked. The skeletal maxillary midline is marked at this stage by the “Operating Surgeon” who at first identifies the vertical intermaxillary midline suture using the small part of the sharp double-sided MI1 raspatorium with his right hand

Trick

Identifying and deepening the anterior vertical intermaxillary midline suture with the small part of the sharp double-sided MI1 raspatorium eliminates the need for a burr or piezosurgery device, thus avoiding potential damage to the incisors’ roots.

 tep 8—MI Maxillary Midline Osteotomy S and Mobilization Once the anterior vertical intermaxillary midline suture has been clearly marked (Step 7, Sect. “Step 7—Marking the Skeletal Maxillary Midline toward the Upper Dental Midline”), the maxillary midline osteotomy is initiated ante-

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Fig. 6.17  Marking the skeletal maxillary midline toward the upper dental midline (Step 7) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, c), a synthetic skull (b)

and a  graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (d). Note that the small part of the sharp double-­ sided MI1 raspatorium is used to identify the anterior vertical intermaxillary midline suture without the use of a burr or a piezo device. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

riorly and continued posteriorly as a green-stick fracture, followed by its mobilization. While “Assistants 1 and 2” continue to gently retract the soft tissues with the small RT3 soft tissue retractors placed on the bone in the small wound, the “Operating Surgeon” places his left middle finger intra-orally at the anterior region of the hard palate. He then inserts with his right hand the thin straight OS4 osteotome with a 45-degree angle into the pre-

viously deepened anterior vertical intermaxillary suture at the dentoalveolar ridge in between the two upper central incisors (Fig. 6.18a–d). On the instructions of the “Operating Surgeon”, “Assistant 2” now performs single taps on the thin straight OS4 osteotome using the metal part of the BI-TAP mallet with his right hand, while “Assistant 1” performs fine aspiration. After a few taps, when the dentoalveolar bone is fully osteotomized and separation between the upper central

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Fig. 6.18  MI maxillary midline osteotomy (Step 8) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a  synthetic skull (c, d). Note that the

inclination of the thin straight OS4 osteotome is initially slightly more downward and then more upward while the “Operating Surgeon” palpates the hard palate with his left middle finger to control the direction of the maxillary midline osteotomy. Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

incisors is visible, the “Operating Surgeon” changes the inclination of the thin straight OS4 osteotome to be perpendicular to the skeletal bone and the tapping action is continued in a similar way under finger control at the anterior hard palate.

In order to complete the midline osteotomy toward the posterior maxilla, the “Operating Surgeon” inserts an 8-mm sharp osteotome (OS6) in the anterior midline osteotomy parallel to the hard palate (Fig. 6.19a, b). At this stage, the “Operating Surgeon” instructs “Assistant 2” to perform

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a

Fig. 6.19  MI maxillary midline osteotomy, mobilization (Step 8), and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

s­ ingle intermittent strong taps with the silicone part of the BI-TAP mallet, until a green-stick fracture is created in the maxillary midline all the way to the posterior hard palate. The” Operating Surgeon” now mobilizes both hemimaxilla by twisting the sharp OS6 osteotome 45-degree clockwise (CW) and counterclockwise (CCW) inside the anterior maxillary osteotomy and verifies their symmetric mobilization. Once Steps 1–8 are completed, the endonasal gauzes are removed from both nostrils and, after extensive rinsing, one-­ layer closure of the intraoral and endonasal small mucosal wounds is performed using a running Vicryl 5.0 rapid® (Ethicon, Johnson and Johnson, Somerville, NJ, USA) suture. The intraoral incision is closed by the “Operating Surgeon” from the bottom to the top, while “Assistants 1 and 2” gently retract the soft tissues of the upper lip holding the small RT3 soft tissue retractors placed in the upper vestibulum with their left and right hands, respectively. Finally, the “Operating Surgeon” closes the right endonasal incision from medial to lateral while “Assistant 1” is performing fine aspiration with his right hand and gentle retraction of the right nostril laterally with one small RT3 soft tissue retractor with his left hand. Another similar running endonasal mucosal suture is then performed in the left nostril, while “Assistants 1 and 2” switch their roles.

b

the Netherlands) (a) and graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b). Note that the direction of the sharp OS6 osteotome is parallel to the hard palate. Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

Tip

If the patient has already orthodontic braces, the upper arch-wire is cut in between the central upper incisors prior to the midline split and mobilization of the maxillary segments (Fig.  6.18b–d), unless “sliding orthodontic mechanics” is used.

Attention!

During the entire “Step 8”, middle finger control on the hard palate by the “Operating Surgeon” is crucial to prevent different types of complications, such as laceration of the palatal mucosa, incorrect maxillary midline split or bleeding.

Trick

Symmetric mobilization of the hemimaxilla is important to prevent asymmetric maxillary expansion, and needs to be verified by the “Operating Surgeon” by twisting the OS6 osteotome 45-degrees in both directions (CW and CCW).

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 tep 9—MI PTM Dysjunction/Septum Release S if Required Once the maxillary midline osteotomy and mobilization (Step 8, Sect. “Step 8—MI Maxillary Midline Osteotomy and Mobilization”) have been performed, MI Pterygomaxillary (PTM) dysjunction and/or septum release can be performed if required. In case of “V-shaped” maxillary constriction without posterior cross-bite, PTM dysjunction is not required since the PTM suture will act as a rotation point. However, in case of “U-shaped” maxillary constriction, with posterior cross-bite or in case a teeth-borne expansion apparatus is used (Step 10, Sect. “Step 10—Placement and/or Activation of a Maxillary Expansion Apparatus (Bone-Borne, Teeth-Borne or Hybrid Teeth/BoneBorne)”), weakening of the PTM sutures by a PTM dysjunction osteotomy is required, which can be performed transmucosaly. First, “Assistant 1” retracts the soft tissues of the right cheek laterally by using a large soft tissue retractor (RT2) with his left hand. Consecutively, the “Operating Surgeon” places his left middle finger at the palatal mucosa behind the second molar and inserts a 10-mm curved osteotome (OS7) behind the maxillary tuberosity at the level of the PTM suture (Fig. 6.20a, b). “Assistant 1” now removes the large RT2 soft tissue retractor and performs single taps on the curved OS7 osteotome with the metal part of the BI-TAP mallet when requested by the “Operating Surgeon”, who guides the transmucosal osteotomy under control with his left middle finger. The same procedure is then performed on the left side by the “Operating Surgeon” with the help of “Assistant 2”. a

Fig. 6.20  MI PTM dysjunction (Step 9) and positioning of the MI orthognathic instrument OS7 (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of

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The nasal septum is not released unless unilateral expansion is required. In that case, the “Operating Surgeon” inserts the septum osteotome (OS1) through the small vertical incision above the ANS to release it in the same manner as in the “MI Le Fort I Osteotomy” surgical procedure (Chap. 4, Sect. “Step 4—Degloving of the Nasal Floor and Septum Release”). Attention!

During PTM dysjunction it is crucial that the “Operating Surgeon” guides the angulation of the curved OS7 osteotome under palpation with his middle finger on the palatal mucosa to control the direction and depth of the osteotomy in order to avoid bleeding.

 tep 10—Placement and/or Activation S of a Maxillary Expansion Apparatus (Bone-­ Borne, Teeth-Borne, or Hybrid Teeth/ Bone-Borne) In this final step of the “MI Maxillary Expansion” surgical procedure, a maxillary expansion apparatus is activated. This can be a teeth-borne (hyrax expander device) or hybrid teeth/ bone-borne (hybrid hyrax expander device) apparatus previously placed by the orthodontist, where the latter one is fixed with micro-screws to the palatal bone, or a bone-borne transversal distraction device. b

Anatomy and Embryology, University of Maastricht, the Netherlands) (a) and a  synthetic skull (b). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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a

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Fig. 6.21  Placement of a bone-borne maxillary expansion apparatus (KLS Martin, Tuttlingen, Germany) (Step 10) is shown on a synthetic skull (a–c). Note the level of the triangular excision at bony level with the #15 scalpel in case of a “V-shaped” (blue) and “U-shaped” (gray) maxillary constriction (a, b). A dummy can be used to assess the size

and the symmetric position of the bone-borne maxillary expansion apparatus in regard to the bony maxilla (c). Note how the dummy is held by the “Operating Surgeon” with the long BI3 clamp (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Clinical pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Once all previous MI orthognathic steps (Steps 1–9, Sects. “Step 1—MI Endonasal Approach to the Le Fort I Corticotomy”, “Step 2—MI Exposure of the Hemimaxilla by Subperiosteal Tunnelling”, “Step 3—MI Subperiosteal Dissection of the Inner Part of the Lateral Nasal Wall”, “Step 4—MI Le Fort I Corticotomy”, “Step 5—MI Osteotomy of the Medial and Lateral Maxillary Pillars”, “Step 6—MI Intraoral Approach toward the Midline Le Fort I Osteotomy”, “Step 7—Marking the Skeletal Maxillary Midline toward the Upper Dental Midline”, “Step 8—MI Maxillary Midline Osteotomy and Mobilization”, and “Step 9—MI PTM Dysjunction/Septum Release if Required”) have been com-

pleted, maximal activation of the maxillary expansion device should be immediately performed at the end of the surgery. From the age of 15 years, it is the authors’ preference to place a bone-borne maxillary expansion apparatus in this final step. In case of a “V-shaped” maxillary constriction without posterior cross-bite, the bone-borne distraction apparatus is positioned at the level of the premolars while in case of a “U-shaped” maxillary constriction it should be installed between the second premolars and first molars (Fig. 6.21a, b). To facilitate the placement of the bone-borne distraction device (Fig. 6.22a, b), the “Operating Surgeon” positions the

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Fig. 6.22  Placement of a bone-borne maxillary expansion apparatus (KLS Martin, Tuttlingen, Germany) (Step 10) is shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a), a graphic illustration (L1® MI

Orthognathics, KLS Martin, Tuttlingen, Germany) (b) and a synthetic skull (c, d). Note the downward activation movement (b, c) and the blocking screw at the left side of the maxillary expansion apparatus (d). Clinical picture made by ©Valérie Swennen-Boehlen. All rights reserved

6  Minimally Invasive (MI) Maxillary Expansion

patients’ head in maximal extension and places a large tongue depressor in the midline of the oral cavity in order to retract both the tongue and the oral tube downward. “Assistant 2” then takes it with his left hand and supports the extended head position with his right hand. “Assistant 1” meanwhile takes care of fine aspiration with his right hand and helps to support the patient’s head with his left hand. At the next stage, the “Operating Surgeon” takes a dummy (Fig. 6.21c) with the long clamp (BI3) and inserts it into the palate to estimate the size of the bone-borne distraction device. The right-handed “Operating Surgeon” then performs a triangular mucoperiosteal incision directly to the bone with his right hand using the #15 scalpel parallel to the upper occlusal plane at a distance of approximately 5–7 mm of the left palatal alveolar ridge. The mucoperiosteal incision can be placed further forward or backward depending on the type of maxillary constriction (Fig. 6.21a). He then excises the mucoperiosteal soft tissues inside the triangle with mosquito forceps and performs some minor degloving with the small part of the sharp double-sided MI1 raspatorium in order to create a small subperiosteal pocket to slip in the abutment plate of the bone-borne distraction device. Afterward, the “Operating Surgeon” performs hemostasis using a bipolar electrosurgical unit while “Assistant 1” still takes care of fine aspiration. On the contralateral side, the “Operating Surgeon” performs a similar triangular mucoperiosteal excision and prepares a subperiosteal pocket with his left hand at the right palatal side (Fig.  6.21b) while “Assistant 1” supports the head in the extended position. Meanwhile, “Assistant 2” takes care of fine aspiration and retracts the tongue and oral tube downward with the tongue depressor with his right and left hands, respectively. The” Operating Surgeon” now first inserts the left abutment plate of the bone-borne distraction device with the long BI3 clamp into the left subperiosteal pocket using the small part of the double-side MI1 raspatorium with his left and right hands, respectively. He then removes the BI3 clamp and keeps the bone-borne distraction device in position with his left index finger while he inserts the right abutment plate into the right subperiosteal pocket using the small part of the doublesided MI1 raspatorium in his right hand. Once the right abutment plate is in the correct position, the “Operating Surgeon” fixates it with a 7-mm (2.0) screw with the screwdriver in his left hand while he holds the bone-borne distraction device stable with his right index finger. Meanwhile, “Assistant 2” takes care of fine aspiration with his right hand and holds down the tongue depressor with his left hand, and “Assistant 1” supports the patient’s head in the extended position.

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With his left hand, the “Operating Surgeon” then places a dental probe in the fixation hole of the left abutment plate to position the bone-borne distraction device in the correct three-dimensional position and slightly activates it with a dedicated activation key (Fig.  6.22c), using his right hand, until the spikes on the left abutment plate get some bony grip. Using the small part of the double-sided MI1 raspatorium, he is still able to perform some minor modifications in the position of the bone-borne distraction device with his right hand. Once correctly in place, the “Operating Surgeon” supports its position with his left index finger and fixates the abutment plate with another 7 mm screw (2.0) with his right hand. Finally, at the end of the “MI Maxillary Expansion” procedure, the bone-borne distraction device is activated under full tension until minimal separation is observed between the upper central incisors and then blocked with the blocking screw (Fig. 6.22c, d). Abundant rinsing with saline (NaCl) solution and aspiration of the mouth and airways is performed and chlorhexidine gel (Corsodyl® gel 1.0% 10  mg/g chlorhexidine digluconate, GlaxoSmithKline, Amersfoort, the Netherlands) is applied at the gingiva around the distraction device and between the two upper central incisors. The patient’s face is then cleaned with saline (NaCl) solution and a steroid ointment (Elocom® 0.1% mometasone furoate cream, Schering-­Plough Labo NV, Heist-op-denBerg, Belgium) is applied on both lips. In both nostrils, halve of nasal packing with a ventilation tube (Merocel® Nasal Pack, Medtronic Xomed, Minneapolis, Minnesota, USA) impregnated with an antibiotic-­ steroid ointment (Terra-Cortril® 30  mg/g oxytetracycline and 10  mg/g hydrocortisone ointment, Pfizer Laboratories, New  York, USA) is inserted. Finally, before the patient leaves the operating room, cold packs or a cooling mask (Hilotherm® Hilotherm GmbH, Argenbühl-Eisenharz/Allgäu, Germany) are placed for postoperative thermo-therapy.

Trick

The right-handed “Operating Surgeon” should support the bone-borne distraction device with his right index finger when he fixates the right abutment plate with a 7-mm screw (2.0) and the screwdriver in his left hand to make sure the distractor will not slip away. The “Operating Surgeon” then change hands and performs the same procedure on the left side.

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Tip

To prevent asymmetric expansion of the maxilla, the “Operating Surgeon” needs to position the bone-borne distraction device symmetrically in regard to the bony maxilla and not toward the dental maxillary arch, which can be asymmetric in relation to the palate and the dental arch.

Limits of the “MI Maxillary Expansion” Surgical Technique

Surgical experience The “10 Step-by-Step” surgical procedure described in this chapter is valuable for “in-depth” study of the MI technique, which is challenging in the beginning of the “learning curve”. Dedicated phantom, cadaver or live-surgery courses are recommended. Following the described MI orthognathic principles in this chapter, every orthognathic surgeon should be

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able to master the “MI Maxillary Expansion” Surgical Technique after his individual “learning curve”.  IV Sedation The described technique is not advocated under IV sedation since the nasal airway cannot be controlled. Previous maxillary orthognathic surgery The described technique is not possible in case plate removal is indicated after previous orthognathic surgery.

References 1. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 2. Swennen GRJ. Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi. org/10.1016/j.cxom.2020.05.009.

7

Minimally Invasive (MI) Mandible Constriction/Expansion Gwen R.J. Swennen, Yves Weinberg, and Fernando de O. Andriola

Step-by-step standardization of minimally invasive (MI) orthognathic surgical techniques increases surgical efficiency and decreases patient morbidity. In this chapter, an innovative systematized “5 step-by-step approach” toward mandible constriction or expansion following a “MI philosophy and mindset” is outlined in detail. General considerations regarding the preparation of the patient, instrumentation table, and operating room toward MI mandible constriction or expansion are well described. Dedicated new developed MI orthognathic surgical instruments allow to optimize the vascular blood supply and decrease of interstitial edema and swelling after mandible constriction or expansion which enhances postoperative fast recovery of the patient. Moreover, the introduction of the MI orthognathic surgical codes and MI orthognathic surgical sequences creates a common language among the surgical team ("Operating Surgeon", "Surgical Assistants", and "Operating Nurse") which increases surgical efficiency and additionally decreases patient morbidity. Furthermore, systematization of storage of the MI orthognathic instruments allows to optimize their gathering, cleaning, and sterilization process toward a more time-efficient and cost-effective clinical routine. Every single step of the MI approach toward the mandible constriction

G. R.J. Swennen (*) Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected] Y. Weinberg Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected]

or expansion surgical procedure is illustrated in detail by high-quality graphic illustrations and pictures made on synthetic skulls and human cadavers. Finally, the limits of the described MI surgical technique toward maxillary expansion are summarized.

 eneral Considerations Regarding the “MI G Mandible Constriction/Expansion” Surgical Procedure In this chapter (Sect. “The “5 Step-by-Step MI Mandible Constriction/Expansion” Surgical Technique”), a “5 Step-­ by-­Step” surgical technique (see Table  7.2) to perform a mandible constriction or expansion in the midline in a systematized minimally invasive (MI) way will be described in detail. Based on the background of MI surgery in other surgical fields (Chap. 1) and supported by evidence-based medicine [1] an innovative concept and rationale was developed toward “MI Orthognathic Surgery” (Chap. 2) in order to reduce overall patient’s morbidity by the combination of increasing surgical efficiency and decreasing surgical trauma through minimized degloving and compression of the surrounding soft tissue envelope. In specific regard toward the “MI Mandible Constriction / Expansion” surgical procedure, the following general considerations need to be taken into account by the surgical team: 1. Organization of the surgical instrumentation table by the “Operating Nurse” (Sect. ““MI Mandible Constriction/ Expansion” Instruments and Surgery Instrumentation Table Organization”). 2. Preparation of the patient in the operating room by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” (Sect. “Patient and Operating Room Preparation Toward the “MI Mandible Constriction / Expansion” Surgical Procedure”).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_7

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Fig. 7.1  MI orthognathic instruments used to perform the “MI Mandible Constriction/Expansion” systematically organized on the surgical instrumentation table by the “Operating Nurse” (graphic illustration from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany)

“ MI Mandible Constriction/Expansion” Instruments and Surgical Instrumentation Table Organization In order to improve the efficiency of the overall surgical team during a “MI Mandible Constriction or Expansion” surgical procedure, “MI Mandible Constriction / Expansion surgical sequence template bars” were developed to indicate in a systematic order the required MI coded instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) [2] (Chap. 2). The “Operating Nurse” places the three dedicated “MI Mandible Constriction / Expansion surgical sequence template bars” on top of the surgical operating table (Fig.  7.1) which allows a fast, easy, and standardized organization of the relevant MI orthognathic instruments not only at the initiation but also during the entire surgical procedure. Moreover, the “Operating Nurse” is able to follow and knows at any moment which “MI Mandible Constriction/Expansion” orthognathic instrument is needed by the “Operating Surgeon”, “Assistant 1”, and “Assistant 2” to smoothly perform the “MI Mandible Constriction / Expansion” surgical procedure. The “Surgical Codes” and “Surgical Sequence” toward the “MI Mandible Constriction / Expansion” surgical procedure are mentioned in Table 7.1.

 atient and Operating Room Preparation P toward the “MI Mandible Constriction/ Expansion” Surgical Procedure To perform a “MI Mandible Constriction/Expansion” surgical procedure, the patient is placed in a supine position on the operating table by the “Anesthesiologic team” in close

Table 7.1  “Surgical Codes” and “Surgical Sequence” for the “Minimally Invasive (MI) Mandible Constriction/Expansion” orthognathic surgical procedure MI Mandible Constriction/Expansion HK1 RT1 RT1 MI1 RT3 RT3 MI2 OS4 BI-TAP OS6 (HK) hook; (RT) retractor; (MI) minimally invasive; (OS) osteotome; (BI) basic instrument From Swennen [2]; with permission

collaboration with the “Operating Surgeon”, who personally positions the patient’s head with a dedicated head support (Chap. 8) in a “neutral horizontal position” in a way that head extension is avoided during the surgical procedure similar as in the “MI Chin Osteotomy” (Chap. 3), “MI Le Fort I Osteotomy” (Chap. 4), and “MI Sagittal Split Osteotomy” (Chap. 5) surgical procedures. The “MI Mandible Constriction” surgical procedure is less common in the daily clinical orthognathic routine but in case it is required it can be combined with a “MI Sagittal Split Osteotomy” (Chap. 5) surgical procedure under general anesthesia after nasotracheal intubation by the anesthesiologist. The “MI Mandible Expansion” surgical procedure can be performed alone under local/general anesthesia or IV sedation, but can also be combined with a “MI Le Fort I Expansion” surgical procedure (Chap. 6) in case of bimaxillary transverse constriction. Local anesthesia (Xylocaine® 1% with adrenaline 1:200.000) is administered by “Assistant 2” both in the superficial mucosal and deep subperiosteal plane in the chin midline for localized vasoconstriction and hemostasis. “Assistant 2” positions an operating reflector light (most ideally L.E.D.) in an ideal position straight above the patient’s head. Meanwhile “Assistant 1” is scrubbing in order to start disinfection of the patient’s head and surgical draping immedi-

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Fig. 7.2  Positioning of the “Operating Surgeon”, surgical “Assistant 1”, surgical “Assistant 2”, “Operating Nurse”, and anesthesiologist are shown in the operating room (graphic illustrations from L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany): overview (a) and

view from the “Operating Surgeon” sitting (or standing) position at the head of the patient (b) during the “MI Mandible Constriction/ Expansion” surgical procedure

ately once the patient is intubated in order not to lose valuable time if the surgery is performed under general anesthesia. Antisepsis of the face is performed by “Assistant 1” with Hibidil® (50 mg/100 ml chlorhexidine digluconate cutaneous solution, Hälsa Pharma GmbH, Münster, Germany) and consecutively disinfection of the mouth with Hextril® (1 mg/ml hexetidine mouth rinsing, Famar Orléans, Orléans, France) once all sterile drapes have been applied. A steroidal ointment is applied on both the upper and lower lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-den-Berg, Belgium) by one of the assistant surgeons. Intravenous (IV) antibiotics (2  g amoxicillin clavulanic acid 2000  mg/200  mg intravenous injection, Augmentin®, GlaxoSmithKline, Singapore) are administered only once in a single dose. In case of penicillin allergy, 600  mg of clindamycin (Clindamycin Sandoz® 600  mg/4  ml intravenous injection, Sandoz Canada Inc. Boucherville, QC, Canada) is administered by intravenous injection in a single dose. Corticosteroids are not administered in case of an isolate “MI Mandible Constriction/Expansion” surgical procedure is performed. To perform a “MI Mandibular Constriction/Expansion” surgical procedure, the right-handed “Operating Surgeon” is positioned in front of the patient’s head (sitting or standing) while “Assistant 1” and “Assistant 2” are placed aside, on the right and left sides, respectively (Fig.  7.2). This particular

position allows the “Operating Surgeon” to have the most ideal view on the chin midline during the “MI Mandibular Constriction / Expansion” surgical procedure. The “Operating Nurse” is ideally positioned at the right side of the patient’s thorax and “Assistant 1” while the anesthesiologist is positioned at the left side of the patient’s feet (Fig. 7.2).

 he “5 Step-by-Step MI Mandible T Constriction/Expansion” Surgical Technique The “5 Step-by-Step” surgical technique (Table 7.2) to perform a mandible constriction or expansion in a systematized minimally invasive (MI) way has initially been described concisely and accordingly illustrated on cadaver pictures [2]. In this chapter, the surgical technique has been elaborated in much more detail toward the overall surgical team using the combination of a human cadaver, synthetic skull pictures, and high-professional illustration graphics. Special attention was taken to describe in detail the role of each member of the surgical team (“Operating Nurse”,  “Assistant 1”, “Assistant 2”, and the “Operating Surgeon”) using the surgical codes and the dedicated “MI Mandible Constriction/ Expansion surgical sequence template bars” (Table 7.1). The latter is mentioned on the “MI Mandible Constriction/ Expansion surgical template bars” toward the “Operating Nurse” (Sect. “General Considerations Regarding the “MI

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154 Table 7.2  The “5 Step-by-Step MI Mandible Constriction/Expansion” Surgical Technique “Step 1” “Step 2” “Step 3” “Step 4” “Step 5”

MI soft tissue approach to the chin MI access and exposure of the bony chin Marking the skeletal chin midline toward the lower dental midline MI chin midline osteotomy and mobilization MI repositioning and rigid fixation of the chin/placement of a mandibular transverse expansion device

From Swennen [2]; with permission

Mandible Constriction/Expansion” Surgical Procedure”) in order to increase overall surgical efficiency and decrease patient morbidity. In this chapter the “MI Mandible Constriction/Expansion” orthognathic surgical technique is explained toward the right-handed “Operating Surgeon” but could of course easily be modified toward the left-handed “Operating Surgeon”. Note that throughout this chapter right and left are used in regard to the position of the “Operating Surgeon” sitting or standing at the head of the patient and looking toward the patient’s body along the facial midline.

Step 1—MI Soft Tissue Approach to the Chin The MI approach toward a mandibular midline osteotomy for mandibular constriction or expansion starts in a similar way as “Step 1” of the “MI Chin Osteotomy” (Chap. 3). The “Operating Surgeon” gently places a delicate soft tissue double hook (HK1) in the midline of the lower lip mucosa at approximately 10 mm of its border and offers the soft tissue HK1 double hook to “Assistant 2”, who takes it with his left hand. With his other hand, “Assistant 2” holds a slightly curved soft tissue retractor (RT1) to retract the labial soft tissues of the lower lip at the left side of the patient’s head. At the same time, “Assistant 1” is holding the aspiration device with his right hand and another soft tissue retractor (RT1) with his left hand. Similar to the “MI Chin Osteotomy” (Chap. 3), the “Operating Surgeon” sits at the head of the patient, being able to control the symmetrical positioning of both RT1 retractors (Fig. 7.3a) which is crucial toward the correct orientation of the mucosal incision. The “Operating Surgeon” now performs a 10-mm vertical incision using a #15 scalpel in the mucosa of the lower lip (Fig. 7.3b). The incision starts approximately 10 mm below the transition between the wet and dry vermilion and goes through the mucosa of the lower lip and periosteum straight

to the bone in between the mentalis muscles (Figs. 7.3c, d). Meanwhile “Assistant 1” is taking care of the aspiration with his right hand.

 tep 2—MI Access and Exposure S of the Bony Chin Once the small vertical midline incision is made through the mucosa and the deep layers of the chin (Step 1, Sect. “Step 1—MI Soft Tissue Approach to the Chin”), the “Operating Surgeon” performs a strict limited subperiosteal degloving of the chin midline region using firstly the small part and then the larger part of the sharp double-sided raspatorium (MI1) while supporting the chin himself with his left hand. Consecutively “Assistant 1” and “Assistant 2” place two small soft tissue retractors (RT3) on the bone to gently retract the soft tissues (Fig.  7.4a–c) laterally and hold these with their left and right hands, respectively. Meanwhile “Assistant 1” continues to take care of the aspiration with his right hand and “Assistant 2” is supporting the chin with his left hand to keep it in the horizontal plane. Attention!

During the entire “MI Mandible Constriction/ Expansion” surgical procedure, special care must be taken, by both “Assistant 1” and “Assistant 2”, to retract the soft tissues strictly “ad minima” in order to avoid tearing and lacerating the mucosa and the mentalis muscles.

 tep 3—Marking the Skeletal Chin Midline S toward the Lower Dental Midline Once the MI access and exposure of the bony chin (Step 2, Sect. “Step 2—MI Access and Exposure of the Bony Chin”) has been performed, the midline of the chin needs to be marked toward the lower dental midline. The “Operating Surgeon” protects the mucosal soft tissues and gingiva with the curved part of the blunt double-­ sided raspatorium (MI2) in the midline while “Assistant 1” and “Assistant 2” continue to gently retract the soft tissues to the sides with the small RT3 retractors with their left and right hands, respectively.

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Fig. 7.3  The MI soft tissue approach to the chin (Step 1) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands) (a–c) and a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (d). Note the small 10 mm vertical incision through the mucosa and periosteum. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 7.4  The MI access, exposure of the bony chin (Step 2), and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht,

the Netherlands) (a), a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b), and a  synthetic skull (c). Note the retraction of the soft tissues by the small RT3 soft tissue retractors. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

The “Operating Surgeon” now firstly creates some vertical landmarks toward the lower dental midline using a fine short 1 mm Lindemann burr (Fig. 7.5a–c) and secondly connects them starting from below (Fig. 7.6a–c). As an alternative, a piezoelectric ultrasonic device can be used. Meanwhile “Assistant 1” continues to take care of the aspiration with his right hand and “Assistant 2” continues to support the chin with his left hand to keep it in the horizontal plane.

 tep 4—MI Chin Midline Osteotomy S and Mobilization Once the chin midline toward the lower dental midline is marked (Step 3, Sect. “Step 3—Marking the Skeletal Chin Midline toward the Lower Dental Midline”), the chin midline osteotomy can be performed. The “Operating Surgeon” places his left middle finger into the floor of the mouth from inside toward the mandibu-

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Fig. 7.5  Marking the skeletal chin midline toward the lower dental midline (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a, c) and a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (b).

Note that the right-handed “Operating Surgeon” holds the blunt MI2 double-sided raspatorium with his left hand in order to protect the soft tissues with its curved side when marking the chin midline toward the lower dental midline using a fine short 1 mm Lindemann burr. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

lar symphysis in order to protect the soft tissues, while “Assistant 2” is supporting the chin with his left hand. Meanwhile, the soft tissues remain gently retracted laterally by two small RT3 soft tissue retractors placed on the bone by “Assistant 1” and “Assistant 2” with their left and right hands, respectively. The “Operating Surgeon” then performs, under finger control, the chin midline vertical osteotomy

with a fine short 1  mm Lindemann burr or piezoelectric device. Subsequently, he inserts a thin osteotome (OS4) in the chin dentoalveolar midline region with his right hand, inclines it upward (Fig.  7.7a, c) and asks “Assistant 1” to gently tap with the metal part of the mallet (BI-TAP) until the midline split slightly opens in the chin dentoalveolar midline region.

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Fig. 7.6  Marking the skeletal chin midline toward the lower dental midline (Step 3) and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown

on a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (a) and a synthetic skull (b, c). Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Afterward, the “Operating Surgeon” inserts an 8  mm sharp osteotome (OS6) in the chin skeletal midline region, inclines it downward to the chin symphysis and asks “Assistant 1” to gently tap with the silicone part of the BI-TAP mallet, which is in most cases sufficient to complete the chin midline osteotomy (Fig. 7.7b, d). It is important that at this stage “Assistant 2” supports well the chin with its left hand while “Assistant 1” still takes care of the aspiration with his right hand.

In case the chin midline osteotomy is not entirely completed yet, the “Operating Surgeon” inserts the 8-mm sharp OS6 osteotome at the level of the incomplete split and turns it 45 degrees to the right or left to completely mobilize it. As an alternative, the midline chin osteotomy can be performed by a piezoelectric ultrasonic device, especially when a bony wedge ostectomy in the chin midline needs to be performed toward mandibular constriction.

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Fig. 7.7  MI chin midline osteotomy, mobilization (Step 4), and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a, b), a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (c) and a graphic illustration

(L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (d). Note that the 8-mm OS6 osteotome can be inclined more downward (b) or upward (d) depending on the bony resistance that still needs to be released. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Tip

Attention!

In case of a dentoalveolar skeletal discrepancy of the mandible, the “Operating Surgeon” can include a horizontal step in the vertical chin midline osteotomy design.

It is important that the “Operating Surgeon” makes sure that the chin midline osteotomy goes until its inferior border and throughout the entire mandibular symphysis.

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 tep 5—MI Repositioning and Rigid Fixation S of the Chin/Placement of a Mandibular Transverse Expansion Device Once the chin midline osteotomy has been performed (Step 4, Sect. “Step 4—MI Chin Midline Osteotomy and Mobilization”), the “Operating Surgeon” will place a passive rigid fixation or a transverse expansion device. At this stage, both “Assistant 1” and “Assistant 2” remain gently retracting the soft tissues laterally with the two small RT3 soft tissue retractors placed on the bone, while “Assistant 1” continues to take care of the aspiration and “Assistant 2” supports the chin as in the previous steps (Steps 2, 3, and 4, Sects. “Step 2—MI Access and Exposure of the Bony Chin”, “Step 3—Marking the Skeletal Chin Midline toward the Lower Dental Midline”, and “Step 4—MI Chin Midline Osteotomy and Mobilization”). In case of a “MI Mandible Constriction” surgical procedure, the “Operating Surgeon” now performs passive rigid fixation of the chin midline osteotomy in the 3D virtual planned position after removal of potential bony interferences. With his left hand, the “Operating Surgeon” places a straight linear two-hole plate (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) on the buccal cortex of the mandible in a horizontal position using a clamp (BI3) (Fig.  7.8a), and consecutively drills and inserts two 7  mm (2.0) screws to fix it (Fig. 7.8b–d). In case of a “MI Mandible Expansion” surgical procedure, prior to wound closure, the “Operating Surgeon” acti-

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vates a teeth-borne mandibular expansion device that was previously installed by the orthodontist or installs a hybrid teeth/bone- or bone-borne (Fig.  7.9) mandibular transverse expansion device. Toward final wound closure, “Assistant 1” and “Assistant 2” now remove the small RT3 soft tissue retractors out of the wound and gently retract the labial soft tissues of the lower lip with two curved RT1 soft tissue retractors with their left and right hands, respectively. Meanwhile, “Assistant 1” takes care of the aspiration with his right hand, while “Assistant 2” continues to support the chin with his left hand. After abundant rinsing with saline (NaCl) solution of the surgical wound, the “Operating Surgeon” performs a one-layer closure of the soft tissues using a Vicryl 4.0 non-rapid® (Ethicon, Johnson and Johnson, Somerville, New Jersey, USA) running suture without tension. At the end of the “MI Mandible Constriction/Expansion” surgical procedure, after abundant rinsing with saline (NaCl) solution and aspiration of the airway, orthodontic wax is applied at the lower braces from canine to canine to protect the mucosal chin wound. After cleaning the patient’s face, a chin compression bandage is applied using 10  mm suture strips followed by application of a steroid ointment (Elocom® 0.1%, NV Schering-Plough Labo, Heist-op-den-Berg, Belgium) on the lower and upper lips and adaptation of a cold pack or cooling face mask (Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/ Allgäu, Germany) for postoperative thermo-therapy for 2 days (Chap. 8).

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Fig. 7.8  MI repositioning, rigid fixation of the chin in the midline (Step 5), and positioning of the MI orthognathic instruments (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) are shown on a synthetic skull (a, b), a human cadaver (Department of Anatomy and Embryology, University of Maastricht, the Netherlands) (c), and

a graphic illustration (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) (d). Note the easy use of the tap on the linear two-hole straight plate toward both positioning and fixation (a). Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Dedicated phantom, cadaver, or live surgery courses are recommended. Following the described MI orthognathic principles in this chapter, every orthognathic surgeon should be able to master the “MI Mandible Constriction/ Expansion” surgical technique after his individual “learning curve”. Anesthesia For experienced and well-trained surgical teams, the isolate “MI Mandible Expansion” can be perfectly performed under local anesthesia. Otherwise, it is better to initially perform it under general anesthesia or IV sedation.

References Fig. 7.9  Placement of a mandibular transverse bone-borne expansion device (KLS Martin, Tuttlingen, Germany) (Step 5) is shown on a synthetic skull. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

Limits of the “MI Mandible Constriction/Expansion” Surgical Technique

Surgical experience The “5 Step-by-Step” surgical procedure described in this chapter is valuable for “in-depth” study of the MI technique.

1. AlAsseri N, Swennen G. Minimally invasive orthognathic surgery: a systematic review. Int J Oral Maxillofac Surg. 2018;47:1299–310. https://doi.org/10.1016/j.ijom.2018.04.017. 2. Swennen GRJ. Surgical efficiency and minimizing patient morbidity by using a novel surgical algorithm in orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am. 2020;28:95–109. https://doi. org/10.1016/j.cxom.2020.05.009.

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Conditions Toward Minimally Invasive (MI) Orthognathic Surgery Yves Weinberg, Fernando de O. Andriola, and Gwen R.J. Swennen

Similar to conventional planning of orthognathic surgery which has been well established in the past, clinical experience and dedicated individual involvement of the “Operating Surgeon” in every detail of both the planning and the surgical process remain essential, although overall conditions in the era of 3D virtual treatment planning and minimally invasive (MI) orthognathic surgery are of major clinical importance. Important overall conditions toward MI orthognathic surgery in order to increase patient’s postoperative comfort and experience, enhance fast recovery and decrease patient morbidity consist of:

Germany) has been created by 3D printing the bony structures, facial soft tissue mask, and underlying mucoperiosteum based on the Cone-Beam CT (CBCT) and STL scanning data of a true patient of the editor of this atlas (GS). The patient, who is anonymized, has a Class III maxillofacial deformity and mild mandibular asymmetry to the left. Moreover, the phantom model is actually used in both onsite and online courses toward teaching and training MI orthognathic surgical techniques to both junior and experienced surgeons as well as surgical nurses.

1. Preoperative considerations toward “MI Orthognathic Surgery” (Sect. “Preoperative Considerations toward “MI Orthognathic Surgery””) 2. Perioperative considerations toward “MI Orthognathic Surgery” (Sect. “Perioperative Considerations Toward “MI Orthognathic Surgery””) 3. Postoperative considerations toward “MI Orthognathic Surgery” (Sect. “Postoperative considerations toward “MI Orthognathic Surgery””)

 reoperative Considerations toward “MI P Orthognathic Surgery”

For didactic illustration purposes, clinical pictures of a phantom model are used throughout this chapter. The phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen,

Orthognathic Surgical Workup

Y. Weinberg (*) Oral and Maxillofacial Surgery Division of Surgery, Barzilai University Medical Center, Ashkelon, Israel e-mail: [email protected] F. de O. Andriola Department of Oral and Maxillofacial Surgery, Hospital São Lucas, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil e-mail: [email protected] G. R.J. Swennen Division of Maxillofacial Surgery, Department of Surgery, AZ Sint-Jan Brugge-Oostende AV, Belgium, Bruges, Belgium e-mail: [email protected]

Preoperative considerations toward “MI Orthognathic Surgery” are related to the “Orthognathic Surgical Workup” (Sect. “Orthognathic Surgical Workup”) and clinical individualized “3D Virtual Surgical Planning (3D-VSP)” (Sect. “3D “Virtual Surgical Planning” (3D-VSP)”).

Once the orthodontic-surgical preparation has proceeded well, the orthodontist refers the patient back to the “Operating Surgeon” with actual physical dental models (3D printed or plaster dental casts) approximately 3–4  months prior to the potential operation date for reevaluation, eventual additional presurgical orthodontic recommendations, and final planning. Adequate preoperative orthodontic preparation is highly essential to the success of MI orthognathic surgical procedures. The orthognathic surgical workup takes place at approximately 3 weeks before patient’s surgery and consist of: (1) conventional orthognathic intraoral measurements (such as overbite and overjet) as well as extraoral clinical examination including anthropometric  static measurements (Figs. 8.1 and 8.2), dynamic evaluation (Fig. 8.3a, b), mirror test (Fig. 8.3c, d) and TMJ examination; (2) intraoral scan-

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. R.J. Swennen (ed.), Minimally Invasive (MI) Orthognathic Surgery, https://doi.org/10.1007/978-3-031-38012-9_8

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a

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Fig. 8.1  Didactic illustrations show some direct anthropometric static measurements by the use of a commercially available caliper on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany): (a) intercanthal width; (b) nasal base width; (c) anterior inferior facial

height; and (d) total anterior facial height. Note that the Bell proportion is often used in clinical planning as the proportion of the anterior inferior facial height toward the total anterior facial height to plan the vertical chin position. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 8.2 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show: (b) measurement of incisal exposure in rest and upper incisal midline toward the nasophiltrum; (a) measurement of upper incisal crown length; (c) chin

midline evaluation toward the lower dental midline; and (d) evaluation of the upper occlusal plane inclination in the frontal view. Note the use of a dental probe and face-bow appliance for clinical evaluation in rest. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 8.3  Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show the impact of mandibular autorotation (a, b) and mirror test (c, d) on the soft tissues in the right profile. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

ning (Fig. 8.4a, b), or all-in-one impression of both dental arches (Fig. 8.4c, d) or conventional separate registration of each of them; (3) wax bite registration in centric relation (CR) with first tooth contact (Fig.  8.5); (4) standardized clinical 2D photographs and 3D photograph imaging using a smartphone-­ based application (Fig.  8.6); (5) vertical CBCT scanning of the patient (seated or standing) looking into a mirror with the wax bite correctly placed in CR without distortion of lip morphology and posture; and (6) finally

thorough information on all practical aspects of the forthcoming surgical intervention and postoperative period is given to the patient and his relatives before the informed medical consent is signed. Based on the STL files of the upper and lower dental arches, 3D models are made by 3D printing for individual analysis (including space analysis, arch length, transverse width discrepancies, and position of the teeth within their respective dental arch) and toward final occlusal definition in the 3D-VPS

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a

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Fig. 8.4 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show intraoral scanning (Primescan®, Dentsply Sirona, Charlotte, USA) (a, b) and “all-in-­

one” impression (c, d) of the upper and lower dental arches. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

(Sect. “3D “Virtual Surgical Planning” (3D-­VSP)” ). The final occlusion (non-segmented or segmented) is always defined on the 3D printed models with or without occlusal grinding or segmentation toward the most optimal stable occlusion. In case it is not possible to obtain a satisfactory stable occlusion the patient needs to be sent back to the orthodontist for further adjustments, since instability of the final occlusion may increase the risk of relapse, lead to the need for revision surgery, and could compromise the initial MI treatment plan.

During the surgical orthodontic workup, standardized 2D clinical photographs of the patient are taken at first in a sitting position by an experienced and trained nurse. Extraoral pictures are taken in rest and during spontaneous smiling in the frontal view, left and right profile, and two-third profile views followed by intraoral views (frontal, left, and right) with cheek retractors in place. Finally, additional extraoral pictures are made in a standing position while the patient is looking into a mirror in the right and left profile views with a

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Fig. 8.5 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show wax bite registration (bite registration sheet wax, Almore International, Hickory,

USA) in centric relation (CR) (a, b) and additional trimming of the wax bite to avoid distortion of lip posture and morphology (c, d). Pictures made by ©Valérie Swennen-Boehlen. All rights reserved.

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In the daily clinical routine, surgical hooks or Kobayashis are mostly placed by the orthodontist after the surgical orthodontic workup for intraoperative intermaxillary fixation (IMF) and postoperative inter-arch elastic guidance.

3D “Virtual Surgical Planning” (3D-VSP)

Fig. 8.6 Didactic illustration on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) shows extraoral 3D face scanning with a smartphone-based application. Picture made by ©Valérie Swennen-Boehlen. All rights reserved

vertical cord to capture the true vertical natural head posture (NHP). Objects such as earrings or glasses need to be removed during standardized 2D clinical photography and also during consecutive 3D photography image acquisition using a smartphone-based application (Fig. 8.6).

Prior to clinically focused 3D-VSP, the 3D virtual model of the patient needs to be thoroughly verified using a “3D Virtual Step-by-Step Quality Control Checklist”  template (Fig. 8.7) in order to avoid errors in the individual surgical planning process of the patient. Once all data have been checked, individualized clinical focused planning is performed using a standardized “10 Step-by-Step” Individualized 3D Virtual Treatment Planning Protocol (Fig.  8.8) with the IPS Case Designer® (KLS Martin, Tuttlingen, Germany) software developed by the editor of this atlas (GS) in close collaboration with the engineers. It is essential that during the above-mentioned clinical focused 3D virtual planning process, all surgical relevant details are recorded by the “Operating Surgeon” on a “3D Virtual Treatment Planning OR” template (Fig. 8.9) toward optimal transfer of all clinically relevant details during the final actual surgery. In the week prior to the operation date, the patient has an appointment with the “Operating Surgeon” and “Surgical Assistants” to discuss the individualized “3D-VSP” and to check the 3D-printed intermediate and/or final splints.

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170 Fig. 8.7  “3D Virtual Step-by-Step Quality Control Checklist” template. (From Swennen [1])

“3D Virtual Step-by-Step Quality Control Checklist” Template (1) Verificaton of the Overall Augmented Model (AUM) of the patient by the clinician  

Accuracy of Registration of the upper dental arch Accuracy of Registration of the lower dental arch

This is verified by evaluation of multiplanar orthogonal slices at molar, canine and incisal level and correlation with clinical photographs.

 

Quality of the 3D rendering of the bone Quality of the 3D rendering of the soft tissues

(2) Verificaton of the condyle (CR) position in the AUM of the patient by the clinician  

Right condyle well seated in CR Left condyle well seated in CR

This is verified by evaluation of sagittal and coronal sices.

(3) Verificaton of the overall soft tissue quality of the AUM of the patient by the clinician     

Absence of eyebrow distortion (> fixation band during CBCT scanning) Absence of lip distortion (> wax bite) Lips in repose Mentalis muscle relaxed Absence of chin distortion (> chin support during CBCT scanning)

This is verified by correlation with clinical photographs and the clinical examination.

(4) Verificaton of the PHP of the patient by the clinician  

In the frontal plane towards the NHP+ In the profile plane towards the TVP

This is verified by corrleation with clinical photographs and the clinical examination *be always aware of the potential of a modified habitual NHP

(5) Verificaton of the final virtual occlusion by the clinician    

Dental midline Angle class i canine relationship Angle class i molar relationship Abscence of “yaw” at molar level

3D Virtual Planning of Orthognathic Surgery. Swennen GRJ, © Springer 2016 Addendum Template. Prof. Gwen Swennen and Dr. Martin Gaboury, Maxillofacial and facial Plastic Surgery.

Fig. 8.8  “Step-by-Step” Individualized 3D Virtual Treatment Planning (3D-VSP) protocol according to Swennen. (From Swennen [1])

Step 1 – Maxillary occlusal cant evaluation/correction (“Roll”) Step 2 – Upper dental midline evaluation/correction Step 3 – Overall evaluation of facial asymmetry after virtual occlusal definition Step 4 – Evaluation/correction of flaring (”Yaw”) Step 5 – Upper vertical incisal position evaluation/correction Step 6 – Upper sagittal incisal position evaluation/correction Step 7 – Profile evaluation/occlusal plane correction (“Pitch”) Step 8 – 3D chin position evaluation/correction (“Roll”, “Yaw” and “Pitch”) Step 9 – Patient communication of the “individualized 3 D virtual treatment plan” Step 10 – Final adjustments of the “individualized 3D virtual treatment plan”

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8  Conditions Toward Minimally Invasive (MI) Orthognathic Surgery Fig. 8.9  “3D Virtual Treatment Planning OR “template. (From Swennen [1])

 erioperative Considerations toward “MI P Orthognathic Surgery” Perioperative considerations toward “MI Orthognathic Surgery” are related to the surgical anesthesiologic team approach (Sect. “Surgical-Anesthesiologic Team Approach ”), operating room preparation (Sect. “Operating Room Preparation”), MI orthognathic instruments and surgical instrumentation table organization (Sect. “MI Orthognathic Instruments and Surgical Instrumentation Table Organization”), patient preparation (Sect. “Patient Preparation”), and hypotensive anesthesia and medication (Sect. “Hypotensive Anesthesia and Medication”).

Surgical-Anesthesiologic Team Approach A well-trained operating team is a significant advantage for performing good standardized and sequenced MI orthognathic procedures, as well as reducing operating time and patient morbidity. Nevertheless, good communication and briefing of the team before each surgery is highly recommended. Each team member (“Operating Surgeon”, “Surgical Assistants”, “Operating Nurse”, “Anesthesiologist”, and “Anesthesiology Nurse”) must be aware of which MI orthognathic surgical procedure and in which sequence they will be performed, in order to do the necessary preparations following the individual recommendations for each patient by the “Operating Surgeon”.

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“Patient and Operating Room Preparation Toward the “MI Maxillary Expansion” Surgical Procedure”), and “MI As described in Sect. “3D “Virtual Surgical Planning” (3D-­ Mandible Constriction / Expansion” (Chap. 7, Sect. “Patient VSP)” of this chapter, individualized clinical focused and Operating Room Preparation Toward the “MI Mandible 3D-VSP toward MI orthognathic surgery is essential to Constriction / Expansion” Surgical Procedure”). anticipate and prevent potential perioperative problems and to be aware of potential pitfalls. It is therefore important, before starting the intervention, to prepare the operating MI Orthognathic Instruments and Surgical room with all relevant patient data. The “Operating Surgeon” Instrumentation Table Organization and “Surgical Assistants” need to be able to visualize and have access at any moment to: (1) the “3D Virtual Treatment During the team preparation and briefing stage (Sect. Planning OR” template [1] (Fig. 8.9); (2) the clinical pictures “Surgical-Anesthesiologic Team Approach”), the sequence of the patient taken at the orthognathic surgical workup of the orthognathic procedure is communicated to the (Sect. “Orthognathic Surgical Workup”); (3) 3D images of “Operating Nurse” who will now, after scrubbing, prepare the patient’s individualized 3D-VSP in all views; (4) a the surgical instrumentation table according to the first MI DICOM viewer to scroll in real time through the axial, coro- orthognathic surgical procedure. By the use of the different nal, and sagittal slices which also allows surface rendering specific “MI surgical sequence template bars”, which indiby thresholding; (5) the 3D printed dental models of the cate in a systematic order the required MI coded instruments, patient; (6) Intermediate and/or final surgical splints; and (7) this can be performed in an easy, standardized, and time-­ guides and patient-specific implants (PSIs) if applicable. efficient manner as described in Chap. 2. The specific surgiPrior to sterile draping, the wax bite needs to be checked on cal instrumentation table organization for each MI the patient as well as the surgical splints which are afterward orthognathic surgical procedure has been illustrated in the put on the surgical instrumentation table in a disinfection dedicated chapters toward the “MI Chin Osteotomy” (Chap. solution (Hibidil® (50 mg/100 ml chlorhexidine digluconate 3, Fig. 3.1), “MI Le Fort I Osteotomy” (Chap. 4, Fig. 4.1), cutaneous solution, Hälsa Pharma GmbH, Münster, “MI Sagittal Split Osteotomy” (Fig. 5.1), “MI Maxillary Germany). Expansion” (Chap. 6, Fig. 6.1), and “MI Mandible The operating theatre is then organized in a systematized Constriction / Expansion” (Chap. 7, Fig.7.1). Once the MI way so that each team member can work independently and orthognathic instruments have been  organized, the comfortably, while maintaining good means of communica- “Operating Nurse” prepares the required osteosynthesis systion. The operating bed is placed in the middle of the room. tem and some additional basic instruments (such as a needle The anesthesia unit is positioned toward the patient’s legs on holder, forceps, scissors, cheek retractors, wire cutter, and the left side while the electrosurgery device, motor, aspira- osteosynthesis plate bender) on top of the instrumentation tion unit, and endoscopic units (optionally) are placed toward table. In case of combined MI orthognathic surgical procethe patient’s thorax, on the same side. A space should be left dures, the “Operating Nurse” replaces the “MI surgical between these units and the patient’s bed, especially near the sequence template bars” and positions the required MI head to allow the operating team to be comfortably installed orthognathic instrument toward the next procedure during during surgery (sitting or standing). The “Operating Nurse” suturing. positions the surgical instrumentation table toward the right side of the patient’s thorax. If the procedure is performed with the “Operating Surgeon” and “Surgical Assistants” in a Patient Preparation seated position, three chairs should be placed around the patient’s head, one in front, one on the right side, and one on The patient is placed in a supine position on the operating the left side. The specific operating room preparation for bed by the “Anesthesiologist” and “Anesthesiology Nurse”. each MI orthognathic surgical procedure has been described Once the patient has been intubated, they take care that the in the dedicated chapters toward the “MI Chin Osteotomy” nasotracheal tube (or orotracheal tube in case of “MI (Chap. 3, Sect. “Patient and Operating Room Preparation Maxillary Expansion”) is well fixed without compression Toward the “MI Chin Osteotomy” Surgical Procedure”), on the nasal tip and forehead. A protecting lubricating ster“MI Le Fort I Osteotomy” (Chap. 4, Sect. “Patient and ile gel (Oculotect 0,4  ml, Polyvidonum 50  mg/ml) is Operating Room Preparation Toward the “MI Le Fort I placed in both eyes which are then closed and covered by Osteotomy” Surgical Procedure”), “MI Sagittal Split a eyebarr protector (Eye cornea protectors, Eyebarr™). Osteotomy” (Chap. 5, Sect. “Patient and Operating Room Prior to sterile draping, the head is correctly positioned on Preparation Toward the “MI Sagittal Split” Surgical the headrest (Fig.  8.10) by the “Operating Surgeon” or Procedure”), “MI Maxillary Expansion” (Chap. 6, Sect. “Surgical Assistant”.  Meanwhile, the “Operating Nurse”

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a

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Fig. 8.10  Didactic illustration of different head positions of a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) in the headrest: (a) in the “neutral horizontal position” extension of the head should be strictly restricted; (b) head positioned too much in extension; (c) head in a lower position that allows hyperextension with

easier access to the palate (e.g., in order to place a palatal distraction device in the “MI Maxillary Expansion” procedure) and (d) head positioned too much in flexion. Pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

and the other “Surgical Assistant” are scrubbing. In most MI orthognathic surgical procedures such as the “MI Chin Osteotomy” (Chap. 3), “MI Le Fort I Osteotomy” (Chap. 4), “MI Sagittal Split Osteotomy” (Chap. 5), and MI Mandible Constriction/Expansion” (Chap. 7) the patient’s head is placed in a “neutral horizontal position” in the headrest (Fig.  8.10a, b), which allows changes of head

posture to both sides but strictly avoids extension. During “MI Maxillary Expansion” (Chap. 6), the head is positioned more downward allowing hyperextension (Fig. 8.10c), in order to facilitate the maxillary expansion device installation. Local anesthesia (Xylocaine 1% with adrenaline 1:200.000) is then administered by the “Operating Surgeon”

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or “Assistant 1” into the mucosa and subperiosteal plane of the first MI orthognathic surgical site. Besides the fact that it reduces postoperative pain and decreases the physiological stress response during orthognathic surgery, its main objective is to contribute to hemostasis, as the adrenaline (vasoconstrictor) reduces bleeding during surgery. In order to use its full potential, it should be applied at least 10  minutes before the first incision. In the next step, disinfection of the face, sterile draping, and intraoral rinsing of the patient are performed. Antisepsis of the face (and of the nostrils in case of “MI Maxillary Expansion”) is performed using Hibidil® (50  mg/100  ml chlorhexidine digluconate cutaneous solution, Hälsa Pharma GmbH, Münster, Germany). Sterile drapes are then applied, starting with the correct positioning and securing of the tube on the drape around the patient’s head. In cases where a nasotracheal intubation is performed, a clamp should be passively attached between the tube and the drape to avoid accidental extubation during the procedure and to avoid compression on the tip of the nose. Consecutively, disinfection of the mouth is carried out with Hextril® (1 mg/ml hexetidine mouth rinsing, Famar Orléans, Orléans, France). Two operating reflector lights (most ideally L.E.D) are positioned in an ideal position above the patient—one straight above the head and the second above the legs with a 45-degree inclination angle toward the patient’s face. Finally, a steroidal ointment is applied on the upper and lower lips (Elocom®, 0.1% mometasone furoate cream, Schering-Plough Labo NV, Heist-op-den-Berg, Belgium). Occlusal grinding is performed if necessary and the surgical splints (intermediate and/or final) are checked on the patient for final adjustments by the “Surgical Assistants”.

Hypotensive Anesthesia and Medication Good communication and cooperation with the “Anesthesiologist” and “Anesthesiology Nurse” is imperative before, during and after each MI orthognathic surgical procedure. Perioperatively, the position of the anesthesiologic unit and team as well as the position of the tube and fixation must be coordinated to create a comfortable access to the surgical site. MI orthognathic techniques, which are based on reducing the size of the incisions and limiting periosteal degloving, must imperatively be performed in a strictly controlled hemostatic environment. It can be otherwise very difficult and not safe to apply these techniques when the “Operating Surgeon” needs to struggle to control bleeding. In addition, bleeding management reduces the need for blood transfu-

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sions and associated morbidities (nausea, vomiting, weakness, transfusion reactions, etc.). In this sense, the “Anesthesiologist” has two main tools to help surgeons keeping the surgical site dry and visualize it clearly: (1) hypotensive anesthesia and (2) pharmacotherapy. Hypotensive anesthesia is widely accepted as a means of reducing intraoperative blood loss, thereby decreasing the need for blood transfusion [2, 3]. During MI orthognathic surgery it can be provided by inhalational anesthetics, intravenous (IV) agents, hypotensive drugs, or a combination of these. The target “Mean Arterial Pressure” (MAP) or “Systolic Blood Pressure” (SBP) when performing MI orthognathic surgery may vary between patients. In healthy and young patients, these are respectively 55 (MAP) and 75 (SBP), but in other patients, the MAP is rather targeted to 65. This can be achieved by different means, one of them is the administration of IV hypnotic drugs in combination with opioids, such as Propoven® (20  mg/ml Propofol 2% emulsion for injection, Fresenius Kabi, Schelle, Belgium) and Remifentanyl® (Remifentanil 1,2, or 5  mg, powder for injection, Pfizer, Capelle aan den Ijssel, Netherlands). However, although the use of total IV anesthesia with Propofol and Remifentanil may reduce the incidence of postoperative nausea and vomiting (PONV) (Sect. “Pain, Nausea and Vomiting Management”), it may also create difficulties in maintaining the desired stable hypotension. Accordingly, additional hypotensive drugs, such as Nicardipine (calcium channel blockers), Labetalol (beta blocker), and/or Urapidil (sympatholytic antihypertensive drugs) may be required, resulting in increased morbidity, particularly in elderly patients. In 2016, Lin et al. [4] published a comparison of different hypotensive anesthesia techniques during orthognathic surgery and they compared intraoperative blood loss, the quality of the surgical field, and PONV. They concluded that a better surgical field quality and less intraoperative blood loss could be achieved during orthognathic surgery when an inhaled agent, such as Sevorane® (Sevoflurane, liquid for inhalation, Abbvie, Wavre, Belgium), is used as the predominant maintenance agent. A balanced anesthesia approach incorporating a properly dosed inhaled agent (Sevoflurane) in combination with IV agent (Propofol) and opioids (Remifentanil) is most commonly used in MI orthognathic surgery in order to keep the blood pressure stable during the entire surgical procedure and considered to be an important safety factor. To reduce bleeding and associated comorbidities, another very efficient tool is the administration of antifibrinolytic agents such as Exacyl® (500 mg/5 ml tranexamic acid intravenous injection, Sanofi, Gentilly, France) after patient induction. This medication is routinely administered as a dose of 1 g via intravenous push and an additional

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1 g diluted in the 1 L NaCl drip infusion at initiation of the surgery unless contraindications. In 2019, Zhao et  al. [5] published a systematic review and meta-analyses of randomized controlled trials confirming the reduction of blood loss during orthognathic surgery with the use of tranexamic acid. Another complication that must be avoided during and after surgery is infection of the surgical site and therefore, IV antibiotics are administered by the anesthesiologist only once in “single shot”. Amoxiclav® (2  g Amoxicillin/ Clavulanic acid, intravenous, Sandoz GmbH, Kundl, Austria) is routinely administered 2  g IV before surgery but it is replaced by 600  mg Clindamycin® (600  mg Clindamycin, intravenous, Fresenius Kabi, Schelle, Belgium) in Penicillin allergic patients. In cases where bone grafting or liposculpture is performed, antibiotic treatment is continued for 1 week after surgery. Corticosteroids are administered intravenously as a single high dose (Solu-Medrol®, 250  mg methylprednisolone, Pfizer Manufacturing, Puurs, Belgium) by the “Anesthesiologist” at the initiation of surgery for antiemetic and edema reduction purposes. Swelling control is crucial for securing the airways and improving the patient’s overall recovery. It is repeated after surgery in the recovery unit, once, by administrating intramuscular (IM) Depot-Medrol® (Methylprednisolone 80  mg, Pfizer Manufacturing, Puurs, Belgium). a

Fig. 8.11 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show abundant rinsing with saline (NaCl) solution of the patient’s face (a) and intraoral

 ostoperative Considerations toward “MI P Orthognathic Surgery” Postoperative considerations toward “MI Orthognathic Surgery” include patient and wound care (Sect. “Patient and Wound Care”), pain, nausea, and vomiting management (Sect.  “Pain, Nausea and Vomiting Management”), dietary support (Sect. “Dietary Support”), thermo-therapy (Sect. “Thermo-Therapy”), manual lymphatic drainage (MLD) (Sect. “Manual Lymphatic Drainage (MLD)”), and patient follow-up (Sect. “Patient Follow-Up”).

Patient and Wound Care In the immediate postoperative period, infection prophylaxis and airway management is a major concern. At the end of each MI orthognathic surgical procedure, abundant cleaning of the patient’s face (Fig. 8.11a) and intense rinsing of the oral cavity (Fig. 8.11b) with saline (NaCl) solution is performed in combination with meticulous aspiration of the oral cavity and nasopharyngeal airway. In “MI Maxillary Expansion” (Chap. 6) and “MI Mandible Constriction / Expansion” (Chap. 7) procedures, topical application of chlorhexidine gel is performed at the level of the abutment plates in case a maxillary bone-borne expansion device is placed (Fig. 8.12a) and in between the central incisors (Fig. 8.12b). b

rinsing (b) at the end of the surgical procedure. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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Fig. 8.12  Didactic illustrations on a synthetic skull show topical application of chlorhexidine gel: (a) at the abutment plates of a bone-borne maxillary expansion apparatus (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) and (b) in between the lower incisors after insta-

lation of a bone-borne mandibular expansion apparatus (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany). Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

Prior to extubating the patient by the “Anesthesiologist”, inter-arch guiding elastics are placed to guide the patient’s final and new occlusion (Fig. 8.13) for the first week until the patient is seen after 1 one week by the “Operating Surgeon” for follow-up (Sect. “Patient Follow-Up”). The inter-arch guiding elastics are typically placed laterally along the perioperative jaw movements with an additional elastic in the frontal region to avoid immediate postoperative tongue interposition (Fig. 8.13a).

Consecutively, the patient’s face is cleaned with saline (NaCl) solution, dried and after application of an ether solution at the nasolabial and labiomental regions, suture strips are placed to properly define the new nasolabial angle and/or plica labio-mentalis, to prevent dead space and to apply postoperative compression for one week after surgery. In case of a “MI Le Fort I Osteotomy”, small 5 mm suture strips are applied at the level of the subnasale landmark to define the nasolabial angle (Fig. 8.14). In case of a “MI Chin Osteotomy”, small 5  mm suture strips are applied to define the new plica labio-mentalis (Fig.  8.15a) or large 10  mm suture strips (Fig.  8.15c) to stretch it in regard to the patient’s individualized treatment plan. Subsequently, an overlying chin compression bandage is applied using large 10 mm suture strips (Fig. 8.15b, d). Finally, a steroid ointment (Elocom ® 0.1%, NV Schering-­ Plough Labo, Heist-op-den-Berg, Belgium) is applied on both lips to reduce postoperative swelling (Fig. 8.16a).

Tip

Inter-arch guiding elastics are placed prior to extubating of the patient to guide the final new occlusion. In case of an Anterior Open Bite (AOB) deformity, the front elastic is placed on additional skeletal anchorage in the alveolar region of the upper and lower dental midlines. After applying inter-arch guiding elastics, orthodontic wax is placed on the orthodontic braces from canine to canine at the lower (Fig. 8.13c) and/or upper dental arch in case of a “MI Chin Osteotomy” or “MI Le Fort I Osteotomy”, respectively, in order to protect the mucosa and to enhance postoperative comfort.

Pain, Nausea, and Vomiting Management In addition to the measures described in this chapter to reduce pain after MI orthognathic surgery such as MI surgical techniques, local anesthesia prior to surgery (Sect.

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Fig. 8.13  Didactic illustrations on a synthetic skull show application of postoperative guiding elastics: (a) guiding elastics in a class II configuration with an additional front elastic; (b) guiding front elastic placed over additional skeletal anchorage in the lower dental arch with a 9-mm (2.0) screw (KLS Martin, Tuttlingen, Germany) and (c) appli-

cation of orthodontic wax on the skeletal anchorage and orthodontic lower braces from canine to canine after a “MI Chin Osteotomy” to protect the lower oral mucosa. Pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

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Fig. 8.14 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show the application of suture strips to define the nasolabial angle after a “MI Le Fort I Osteotomy: (a) without suture strips and (b) with small 5 mm suture

strips. Note that the application of small 5 mm suture strips for 1 week intends to immobilize the upper lip which is important for pain relief after paranasal cross suturing. Pictures made by ©Valérie Swennen-­ Boehlen. All rights reserved

“Patient Preparation”), IV pain medication (Sect. “Hypotensive Anesthesia and Medication”), and additional postoperative considerations such as thermo-therapy (Sect.  “Thermo-Therapy”) and manual lymphatic drainage (Sect. “Manual Lymphatic Drainage (MLD)”, analgesics are routinely prescribed during the postoperative period. In the recovery unit, opioids are used with precaution because of their emetic effect and in the first days after surgery IV 1 g Paracetamol® (10  mg/ml Paracetamol, Fresenius Kabi, Schelle, Belgium) and IM 10  mg Taradyl® (10  mg/1  ml Ketorolac Tromethamine, Atnahs Pharma, Copenhagen, Denmark) are mainly used, unless contraindicated. Then, per os (PO) paracetamol and ibuprofen are prescribed for the first 5 days. Postoperative nausea and vomiting (PONV) is a common complication after oral and maxillofacial surgery and a high incidence is described in the literature, especially after orthognathic surgery [6, 7]. This can be very unpleasant for patients, leading to a longer hospital stay and decreased patient satisfaction. It is frequently associated with general anesthesia, blood loss during surgery, pain, and reduced systolic blood pressure during the recovery period [7]. By reducing these risk factors, mainly operating time and pain,

MI orthognathic surgical techniques can have a major beneficial impact on PONV. Nausea and vomiting are commonly associated with the emetic properties of the inhaled anesthetics agents and the opioids administered during surgery. A balanced anesthesia approach (Sect. “Hypotensive Anesthesia and Medication”) combining an intravenous (IV) agent such as Propoven® (20  mg/ml Propofol 2% emulsion for injection, Fresenius Kabi, Schelle, Belgium) can then reduce their incidence. Corticosteroids and antiemetic agents may also be used, while pain, which can trigger PONV by itself, should be treated as quickly as possible in the postoperative care setting. Blood loss during surgery is another factor that can impact PONV since ingested blood in the stomach and a decrease in systolic blood pressure can create nausea and vomiting. MI orthognathic surgical techniques (Chap. 2, Sect. “Step-by-­ Step Standardization of “MI Orthognathic Surgical Techniques” to Increase Surgical Efficiency”) are crucial to minimize blood loss during surgery. Throat packs can be used to prevent blood, saliva, or other surgical debris from entering the pharynx, esophagus or airways, and prevent PONV. However, due to the life-threatening risk of forget-

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Fig. 8.15 Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show the application of suture strips after a “MI Chin Osteotomy”: (a) small 5 mm suture strips to define the plica labio-mentalis; (b) with additional large 10 mm suture strips as a compression bandage; (c) a large 10 mm suture strip

to stretch the plica labio-mentalis; and (d) with additional large 10 mm suture strips as a compression bandage. Note the application of small 5 mm suture strips at the nasolabial angle after a simultaneous “MI Le Fort I Osteotomy”. Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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ting these before extubation, they are not systematically used by all surgeons. Hence, suction of ingested blood out of the esophagus and stomach by the “Anaesthesiologist” prior to patient extubation is of major importance. Adequate perioperative administration of IV fluids may also reduce PONV by minimizing the reduction in systolic blood pressure expected after blood loss.

Dietary Support During the first week of the recovery period, MI orthognathic patients are limited to a strict liquid diet to minimize pain, mucosal wound trauma, and occlusal forces. Afterward, a soft diet is applied for another 5 weeks. A healthy and balanced diet is an important factor in reducing morbidity in surgical cases [8], especially in orthognathic patients who present unique nutritional challenges. Previous studies have suggested that patients undergoing orthognathic surgery with or without subsequent inter-arch elastics (especially intermaxillary fixation, IMF) [9, 10] are at risk for malnutrition and weight loss that can lead to impaired bone and wound healing [11]. Individualized dietary supplementation regimens, based on high caloric and protein intakes [12, 13], are then necessary and must be provided to all orthognathic patients in coordination with a nutritionist/dietician. Additionally, postoperative weight loss should be monitored. From a preoperative perspective, the presurgical nutritional status of patients should be assessed and treated

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accordingly. Close dietary and psychological support is necessary for patients with a Body Mass Index (BMI) classified as “underweight” [9]. The surgery itself not only affects the physical ability to eat but also impacts the patient’s mood and appetite. It is therefore important to minimize the overall trauma to the patients by preparing them for surgery, reducing operating time, pain, interstitial edema, and soft tissue swelling. The entire MI philosophy (Chaps. 1 and 2) and MI orthognathic surgical techniques (Chaps. 3, 4, 5, 6, and 7) are in this context crucial for the patients’ recovery.

Thermo-Therapy Immediately after surgery, a cold therapy is performed and applied to the patient’s face using cold packs in “MI Maxillary Expansion” (Chap. 6) and “MI Mandible Constriction / Expansion” (Chap. 7) procedures or by the use of a cooling face mask (Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/Allgäu, Germany) (Fig. 8.16). In “MI Chin Osteotomy” (Chap. 3), “MI Le Fort I Osteotomy” (Chap. 4), and “MI Sagittal Split Osteotomy” (Chap. 5) procedures, a cooling face mask (Hilotherm®, Hilotherm GmbH, Argenbühl-Eisenharz/Allgäu, Germany) (Fig. 8.16) is always applied during hospital stay and is continued for 1 week at home. Although the literature has shown that MI orthognathic surgery is associated with less pain, less swelling, fewer complications, and shorter hospital stay (Chap. 1), other con-

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Fig. 8.16  Didactic illustrations on a phantom model (L1® MI Orthognathics, KLS Martin, Tuttlingen, Germany) show (a) the application of a steroidal ointment(a) and Hilotherm® cooling face mask and (a, b). Pictures made by ©Valérie Swennen-Boehlen. All rights reserved

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siderations described in this chapter are of paramount importance to enhance patient postoperative recovery. The beneficial effects of localized cold treatment on postoperative edema are known and well described in the literature. Additional effects of cold therapy are reduced pain, less postoperative bleeding or hematomas, and improved mouth opening [14]. The use of cold packs is a more conventional mean of cooling and consists of two packs placed on each hemiface of the patient with a bandage without pressure and replaced every few hours. In the circulating water-cooling system, the “cuff” of a thermoplastic polyurethane cooling mask is connected to a Hilotherm® device that ejects cooled water inside. The mask is applied directly to the skin, without an intermediate layer, and covers the lower and middle thirds of the face, while the cooled water circulates continuously inside. The water temperature can vary between 10 and 30 °C and is usually set at 16 °C. In 2011, Rana et al. [14] performed a 3D evaluation of postoperative soft tissue swelling using the two different cooling methods following orthognathic surgery and concluded that the Hilotherm® significantly reduced swelling and length of the hospital stay in comparison to the conventional cooling method. Also, postoperative pain was significantly lower in patients treated with Hilotherm® and mouth opening was significantly better. It is important that the Hilotherm® cooling face mask is applied and fitted to the skin, without tension or compression on the lips, when the patient is still on the operation bed before transfer to the recovery unit.

the swelling peak or the patients’ perception of pain and swelling, an overall improvement in swelling was measured objectively in this study by using clinical videos and photographs. In an attempt to assess swelling and the rate of improvement using MLD after orthognathic surgery by more precise and objective means, Van de Velde et  al. [18] performed in 2020 a study with superimposition of 3D photographic images. Although no statistical significance was found, a tendency was observed for improved recovery regarding facial soft tissue swelling measurements and patients’ reports on pain and swelling. MLD techniques rely primarily on manual hand movements to stretch the skin in a specific direction and to influence changes in interstitial pressure [18]. The main objective is to promote lymphatic drainage without increasing capillary filtration and hyperemia. Slow movements are performed repeatedly, with varying pressures (depending on the underlying tissues) and include a brief resting phase to allow the skin to return to its normal position. It is advocated to perform a first series of three treatments in the week prior to the MI orthognathic surgery, and a second series of approximately six treatments during the week after discharge from the hospital.

Manual Lymphatic Drainage (MLD) In order to further reduce postoperative pain, edema or associated morbidities, patients are referred to a physiotherapist for “Manual Lymphatic Drainage (MLD)” a few days before and after MI orthognathic surgery. MLD is an additional tool to control soft tissue swelling after surgery aiming to improve lymphatic circulation and drainage. Reducing swelling is important for improving the perception of patients after orthognathic surgery, allowing them to return to normal activities as quickly as possible. In addition, it is crucial to secure the airways, reduce the risk of infection and improve pain control. While the pain and nausea usually resolve within the first few days after surgery, facial soft tissue swelling can take much longer to disappear, up to 6 months or even a year. MLD has been shown to be effective in reducing edema in breast cancer patients [15] and after wisdom teeth extractions [16]. In 2017, Yeadu et  al. [17] found a significantly faster and better disappearance of swelling when MLD was performed after orthognathic surgery. While it did not change

Patient Follow-Up In the first 1–2 hours after surgery, patients are closely monitored at the recovery unit and then transferred to the “one-­ day” or “short-stay” surgical department after all discharge criteria have been fulfilled: (1) autonomic airways and adequate gas exchange with correct oxygen saturation; (2) appropriate level of consciousness; (3) stable blood pressure, heart rate, and body temperature; (4) normal electrocardiogram and (5) good pain and PONV control. Afterward, in the surgical department, normal fluid balance of urine output and electrolytes is verified and further control of pain, PONV, and swelling is performed as described in this chapter to prevent complications. The treatment is of course always adapted to the specific needs of each patient. At discharge from the hospital, all postsurgical recommendations are given to the patient regarding pain control, mouth/nose rinsing, medication, nutrition, management of inter-arch elastics (if applicable), thermo-therapy, and MLD.  In case specific problems occurred during surgery or postoperatively, these are addressed to the patient. A digital orthopantomogram (OPG) X-ray is routinely performed at the outpatient clinic prior to discharge of the patient in “MI Chin Osteotomy” (Chap. 3), “MI Le Fort I Osteotomy” (Chap. 4), and “MI Sagittal Split Osteotomy” (Chap. 5) procedures, but not in case of a “MI Maxillary Expansion” (Chap. 6) or “MI Mandibular Constriction / Expansion” (Chap. 7) procedure, unless an unexpected problem occurred. Last but not least,

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patients are clearly informed when, who, and where to contact in case of a postoperative problem or emergency. After approximately 1 and 3 weeks, the patient is seen at the outpatient clinic by the “Operating Surgeon” who personally verifies the process of wound healing and decrease of soft tissue swelling, sensibility, occlusion, and TMJ.  Recommendations are given toward further wound care, nutrition, management of inter-arch elastics, and lip exercises. A postoperative CBCT is taken at the outpatient clinic at approximately 4–6 weeks after surgery and clinical evaluation and further recommendations by the “Operating Surgeon” are given prior to referring the patient back to the orthodontist for postsurgical orthodontic finishing and retention. Finally, the “Operating Surgeon” personally reevaluates the patient after braces removal by the orthodontist at approximately 6  months after surgery and 1  year later for adequate clinical and radiological long-term follow-up.

References 1. Swennen GRJ. 3D virtual treatment planning of orthognathic surgery: a step-by-step approach for orthodontists and surgeons. Springer; 2017. 2. Precious DS, Splinter W, Bosco D. Induced hypotensive anesthesia for adolescent orthognathic surgery patients. J Oral Maxillofac Surg. 1996;54:680–3. https://doi.org/10.1016/s0278-­2391(96)90679-­5. 3. Praveen K, Narayanan V, Muthusekhar MR, Baig MF. Hypotensive anaesthesia and blood loss in orthognathic surgery: a clinical study. Br J Oral Maxillofac Surg. 2001;39:138–40. https://doi. org/10.1054/bjom.2000.0593. 4. Lin S, Chen C, Yao CF, Chen YA, Chen YR. Comparison of different hypotensive anaesthesia techniques in orthognathic surgery with regard to intraoperative blood loss, quality of the surgical field, and postoperative nausea and vomiting. Int J Oral Maxillofac Surg. 2016 Dec;45(12):1526–30. https://doi.org/10.1016/j.ijom.2016.09.005. 5. Zhao H, Liu S, Wu Z, Zhao H, Ma CJ.  Comprehensive assessment of tranexamic acid during orthognathic surgery: a systematic review and meta-analysis of randomized, controlled trials. Craniomaxillofac Surg. 2019 Apr;47(4):592–601. https://doi. org/10.1016/j.jcms.2019.01.021. 6. Silva AC, O’Ryan F, Poor DB. Postoperative nausea and vomiting (PONV) after orthognathic surgery: a retrospective study and litera-

Y. Weinberg et al. ture review. J Oral Maxillofac Surg. 2006;54:1385–97. https://doi. org/10.1016/j.joms.2006.05.024. 7. Dobbeleir M, De Coster J, Coucke W, Politis C. Postoperative nausea and vomiting after oral and maxillofacial surgery: a prospective study. Int J Oral Maxillofac Surg. 2018 Jun;47(6):721–5. https:// doi.org/10.1016/j.ijom.2017.11.018. 8. Fearon KC, Luff R.  The nutritional management of surgical patients: enhanced recovery after surgery. Proc Nutr Soc. 2003 Nov;62(4):807–11. https://doi.org/10.1079/PNS2003299. 9. Hammond D, Williams RW, Juj K, O’Connell S, Isherwood G, Hammond N. Weight loss in orthognathic surgery: a clinical study. J Orthod. 2015 Sep;42(3):220–8. https://doi.org/10.1179/1465313 314Y.0000000130. 10. Ruslin M, Dekker H, Tuinzing DB, Forouzanfar T. Assessing the need for a protocol in monitoring weight loss and nutritional status in orthognathic surgery based on patients experiences. J Clin Exp Dent. 2017 Feb;9(2):e272–5. https://doi.org/10.4317/jced.53354. 11. Chidyllo SA, Chidyllo R. Nutritional evaluation prior to oral and maxillofacial surgery. N Y State Dent J. 1989;55:38–40. 12. Kendell BD, Fonseca RJ, Lee M.  Postoperative nutritional supplementation for the orthognathic surgery patient. J Oral Maxillofac Surg. 1982 Apr;40(4):205–13. https://doi. org/10.1016/0278-­2391(82)90312-­3. 13. Olejko TD, Fonseca RJ.  Preoperative nutritional supplementation for the orthognathic surgery patient. J Oral Maxillofac Surg. 1984 Sep;42(9):573–7. https://doi.org/10.1016/0278-­2391(84)90087-­9. 14. Rana M, Gellrich NC, Joos U, Piffkó J, Kater W. 3D evaluation of postoperative swelling using two different cooling methods following orthognathic surgery: a randomised observer blind prospective pilot study. Int J Oral Maxillofac Surg. 2011 Jul;40(7):690–6. https://doi.org/10.1016/j.ijom.2011.02.015. 15. Hamner JB, Fleming MD. Lymphedema therapy reduces the volume of edema and pain in patients with breast cancer. Ann Surg Oncol. 2007;14:1904–8. https://doi.org/10.1245/s10434-­006-­9332-­1. 16. Szolnoky G, Szendi-Horvath K, Seres L, Boda K, Kemeny L. Manual lymph drainage efficiently reduces postoperative facial swelling and discomfort after removal of impacted third molars. J Lymphol. 2007;40:138–42. 17. Yaedu RYF, Mello MAB, Tucunduva RA, da Silveira JSZ, Takahashi M, Valente ACB.  Postoperative orthognathic surgery edema assessment with and without manual lymphatic drainage. J Craniofac Surg. 2017;28:1816–20. https://doi.org/10.1097/ SCS.0000000000003850. 18. Van de Velde FEG, Ortega-Castrillon A, Thierens LAM, Claes P, De Pauw GAM.  The effect of manual lymphatic drainage on patient recovery after orthognathic surgery  – a qualitative and 3-dimentional facial analysis. Oral Surg Oral Med Oral Pathol Oral Radiol. 2020 Nov;130(5):478–85. https://doi.org/10.1016/j. oooo.2020.05.017.