Thoracic Outlet Syndrome [2 ed.] 9783030550721, 9783030550738

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Thoracic Outlet Syndrome Karl A. Illig Robert W. Thompson Julie Ann Freischlag Dean M. Donahue Sheldon E. Jordan Ying Wei Lum Hugh A. Gelabert Editors Second Edition

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Thoracic Outlet Syndrome

Karl A. Illig  •  Robert W. Thompson Julie Ann Freischlag  •  Dean M. Donahue Sheldon E. Jordan  •  Ying Wei Lum Hugh A. Gelabert Editors

Thoracic Outlet Syndrome Second Edition

Editors Karl A. Illig Vascular Surgeon Charleston, SC USA Julie Ann Freischlag Wake Forest Baptist Health Wake Forest School of Medicine Atrium Health Department of Vascular and Endovascular Surgery Winston-Salem, NC USA Sheldon E. Jordan Neurological Associates The Interventional Group Santa Monica, CA USA Hugh A. Gelabert UCLA Medical Center Los Angeles, CA USA

Robert W. Thompson Center for Thoracic Outlet Syndrome and Section of Vascular Surgery Washington University School of Medicine and Barnes-Jewish Hospital Saint Louis, MO USA Dean M. Donahue Department of Thoracic Surgery Massachusetts General Hospital Department of Thoracic Surgery Boston, MA USA Ying Wei Lum Division of Vascular Surgery and Endovascular Therapy Johns Hopkins School of Medicine Baltimore, MD USA

ISBN 978-3-030-55072-1    ISBN 978-3-030-55073-8 (eBook) https://doi.org/10.1007/978-3-030-55073-8 © Springer Nature Switzerland AG 2013, 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Is this the reason that humans replaced the dinosaurs? A picture of a T. Rex skeleton. Notice the huge cervical ribs, along with the atrophic arms. Perhaps dinosaurs suffered from severe neurogenic (and perhaps arterial) TOS, to the point where their arms atrophied away. They eventually became unable to feed themselves, and wasted away, allowing mammals to thrive. We thus have thoracic outlet syndrome to thank for our very existence! (Image purchased from 123RF website: https://www.123rf.com/ checkout-v2/creditcard/finalized_creds.php)

Preface

The world of thoracic outlet syndrome has been surprisingly busy since the first edition of this textbook was published in 2013. A unifying theme in this regard is a push toward objectivity. Stemming from the Consortium for Outcomes Research and Education on Thoracic Outlet Syndrome (CORE-TOS) meeting in St. Louis in 2009 and subsequently via the Society for Vascular Surgery’s Thoracic Outlet Reporting Standards document of 2016, there has been a strong push toward making what we do much more standardized and thus comparable. Encouragingly, most recent manuscripts report relatively objective outcome measures, rather than simply noting “improvement.” This edition hopefully reflects these changes and trends, with new editors (Drs. Lum and Gelabert), new chapters, and a broader range of contributors. There is emphasis always on objectivity, and new chapters reflect new knowledge and techniques. For example, greater emphasis is placed on, among other topics, rare nerve issues, the quadrilateral space, postoperative complications, and the roles of botox and scalene muscle blockade for diagnosis. In addition, the state of care in Great Britain and the Netherlands is discussed in detail, along with work on delving into the specifics of QuickDASH and CBSQ, quantification of the EAST, and a closer look at thoracoscopic rib resection. The same stumbling block, of course, remains as always—recognition of TOS as an entity by all who do not specialize in it, and timely recognition and referral to those of us who do. It remains relatively common to hear of insurance companies denying benefits to such patients, as “no objective diagnostic tests are performed,” and all of us see, almost weekly, young healthy patients vii

Preface

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with swollen arms treated with anticoagulation alone and patients with clear neurogenic TOS arriving with four years’ worth of medical records accumulated before the diagnosis was ever considered. There is no easy fix for this problem, but hopefully those who read and use this textbook (Figure; patient has given her permission to use) will continue to spread the word and thus improve care for these suffering patients. Charleston, SC St. Louis, MO Winston-Salem, NC Boston, MA Santa Monica, CA Baltimore, MD Los Angeles, CA

Karl A. Illig Robert W. Thompson Julie Ann Freischlag Dean M. Donahue Sheldon E. Jordan Ying Wei Lum Hugh A. Gelabert

Contents

1 Introduction��������������������������������������������������������������������������������������   1 Robert W. Thompson Part I Background and Basic Principles 2 A Brief History of the Thoracic Outlet Compression Syndromes����������������������������������������������������������������������������������������   7 Herbert I. Machleder 3 Embryology of the Thoracic Outlet������������������������������������������������  17 R. Shane Tubbs and Mohammadali M. Shoja 4 Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs������������������������������������  23 Frietson Galis, Pauline C. Schut, Titia E. Cohen-­Overbeek, and Clara M. A. ten Broek 5 Anatomy of the Thoracic Outlet and Related Structures������������  37 Richard J. Sanders and Stephen J. Annest 6 TOS: Clinical Incidence and Scope of the Problem����������������������  45 Karl A. Illig and Eduardo Rodriguez-Zoppi Part II Neurogenic TOS: General Principles and Diagnosis 7 Pathology and Pathophysiology of NTOS��������������������������������������  53 Richard J. Sanders and Dean M. Donahue 8 NTOS for the Primary Care Team: When to Consider the Diagnosis? ����������������������������������������������������������������������������������������  61 Karl A. Illig and Dean M. Donahue 9 Diagnosis of Neurogenic Thoracic Outlet Syndrome: 2016 Consensus Guidelines and Other Strategies����������������������������������  67 Robert W. Thompson 10 Differential Diagnosis in Patients with Possible NTOS����������������  99 M. Libby Weaver, Sheldon E. Jordan, and Margaret W. Arnold

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11 Increasing Objectivity in the Diagnosis of NTOS: The Standardized EAST-Meter������������������������������������������������������ 109 Niels Pesser, Sander Boidin, Marc R. H. M. van Sambeek, Bart F. L. van Nuenen, and Joep A. W. Teijink 12 A Closer Look at QuickDASH and CBSQ: What Do they Tell us?���������������������������������������������������������������������� 117 Karl A. Illig and Kathryn Cline 13 Scalene Test Blocks in Patients with Possible Neurogenic TOS ������������������������������������������������������������������������������ 125 Sheldon E. Jordan 14 Electrophysiological Assessment and Nerve Function in NTOS���������������������������������������������������������������������������� 131 Bennett I. Machanic 15 Pectoralis Minor Syndrome������������������������������������������������������������ 137 Robert W. Thompson 16 Double Crush Syndrome ���������������������������������������������������������������� 145 John M. Felder 17 Unusual Nerve Entrapments and Neuropathic Syndromes of the Neck and Shoulder�������������������������������������������� 153 Andrea Trescot 18 Cross-Sectional Imaging in Thoracic Outlet Syndrome�������������� 169 Daniel R. Ludwig, Sanjeev Bhalla, and Constantine A. Raptis 19 Ergonomic, Postural Issues, and Repetitive Stress Issues in NTOS���������������������������������������������������������������������� 185 Cassandra Pate, Lindsay Eichaker, and Jeanne A. Earley 20 Psychiatric and Psychologic Issues in NTOS�������������������������������� 193 Sarah Buday and Stephen L. Ristvedt Part III Neurogenic TOS: Treatment 21 Pathways of Care and Treatment Options for Patients with Neurogenic TOS���������������������������������������������������������������������� 201 Robert W. Thompson, J. Westley Ohman, Jeanne A. Earley, and Karen M. Henderson 22 Physical Therapy as Primary Treatment for Neurogenic TOS ������������������������������������������������������������������������ 211 John Hisamoto 23 Chiropractic and Nontraditional Treatment of NTOS ���������������� 229 Robert J. Trager 24 Anesthesia for Thoracic Outlet Decompression���������������������������� 241 Qianjin Liu and Ivan Kangrga 25 Regional Anesthesia for Thoracic Outlet Decompression������������ 249 Barbara Versyck, Renee van den Broek, and Joep Teijink

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26 Surgical Techniques: Operative Decompression Using the Transaxillary Approach for NTOS ������������������������������������������������ 257 Renganaden Sooppan, Rebecca Sorber, and Ying Wei Lum 27 Surgical Techniques: Operative Decompression Using the Supraclavicular Approach for Neurogenic Thoracic Outlet Syndrome ���������������������������������������� 265 Robert W. Thompson and J. Westley Ohman 28 Surgical Techniques: Operative Decompression Using Thoracoscopic Approach for Neurogenic Thoracic Outlet Syndrome������������������������������������������������������������������������������������������ 287 Kareem Ibrahim and Bryan M. Burt 29 Surgical Techniques: Pectoralis Minor Tenotomy for NTOS������������������������������������������������������������������������ 295 Chandu Vemuri and Robert W. Thompson 30 Surgical Techniques: Dorsal Cervico-Thoracic Sympathectomy�������������������������������������������������������������������������������� 303 Bryan F. Meyers and Robert W. Thompson 31 Botulinim Toxin Injection and Advanced Interventional Techniques for NTOS and Cervical Brachial Syndrome������������� 311 Sheldon E. Jordan 32 NTOS in the Competitive Athlete �������������������������������������������������� 317 Gregory J. Pearl 33 Neurogenic TOS in Children���������������������������������������������������������� 323 Jennifer Hong, Zarina S. Ali, Gregory G. Heuer, and Eric L. Zager 34 Recurrent and Residual Neurogenic Thoracic Outlet Syndrome������������������������������������������������������������������������������ 333 Stephen J. Annest, Barbara A. Melendez, and Richard J. Sanders Part IV Neurogenic TOS: Unanswered Questions 35 Controversies in Neurogenic Thoracic Outlet Syndrome (NTOS): What Testing Is Needed to Establish the Diagnosis?������������������������������������������������������������������ 343 Joshua Balderman and Kaj H. Johansen 36 Botulinum Toxin Injections for Neurogenic Thoracic Outlet Syndrome������������������������������������������������������������������������������������������ 347 Dean M. Donahue and Martin Torriani 37 What Do the Results of Conservative Therapy Tell Us About the Need for Surgery: Lack of Improvement Means Surgery Is Indicated������������������������������������������������������������ 353 J. Westley Ohman

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38 Point/Counterpoint: What Does the Result of Conservative Therapy Tell Us About the Need for Surgery? Improvement Means Surgery Is Indicated������������������������������������ 359 Anahita Dua and Jason T. Lee 39 Controversies in NTOS: Transaxillary or Supraclavicular First Rib Resection in NTOS? Arguments Pro and Con the Transaxillary Approach in Favor of Transaxillary First Rib Resection�������������������������������������������������� 365 Maria C. Gelabert 40 Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic Outlet Syndrome������������������������������������������������������������������������������ 375 Francis J. Caputo and Robert W. Thompson 41 Does the First Rib Always Need to Be Removed? ������������������������ 387 Richard J. Sanders and Stephen J. Annest 42 Controversies in NTOS: What Is the Evidence Supporting Brachial Plexus Neurolysis and Wrapping���������������� 391 Chetan Dargan and Karl A. Illig Part V Neurogenic TOS: Outcomes and Future Directions 43 Neurogenic TOS: Early Postoperative Care���������������������������������� 399 Karen M. Henderson, Farzana Najrabi, Marilynn N. Robinson, Katherine Kolster, and Robert W. Thompson 44 Perioperative Pain Management for Thoracic Outlet Syndrome Surgery �������������������������������������������������������������������������� 405 Chelsea Thomas and Kara Segna 45 Rehabilitation After First Rib Resection �������������������������������������� 415 Jeanne A. Earley and Cassandra Pate 46 Outcomes After Treatment of NTOS���������������������������������������������� 425 Rebecca Sorber and Ying Wei Lum 47 Management of Nerve Dysfunction after First Rib Resection ������������������������������������������������������������������������������������������ 435 Katherine Giuliano and Ying Wei Lum 48 Management of Coexisting Factors Complicating NTOS������������������������������������������������������������������������ 441 Sheldon E. Jordan 49 Treatment for Thoracic Outlet Syndrome: A UK Perspective���������������������������������������������������������������������������������������� 453 Frank C. T. Smith 50 Neurogenic TOS in the United Kingdom: A Consultant Orthopaedic Physiotherapist’s View���������������������������������������������� 461 Rob Patterson

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51 Diagnosis and Treatment of Thoracic Outlet Syndrome in The Netherlands�������������������������������������������������������� 467 Jens Goeteyn, Bart van Nuenen, Marc van Sambeek, and Joep Teijink 52 Research Directions in Neurogenic Thoracic Outlet Syndrome������������������������������������������������������������������������������ 477 Parth Shah Part VI Venous TOS: General Principles and Diagnosis 53 Anatomy and Pathophysiology of Venous Thoracic Outlet Syndrome������������������������������������������������������������������������������������������ 487 Christopher O. Audu, Chandu Vemuri, Harold C. Urschel Jr, J. Mark Pool, and Amit N. Patel 54 Diagnosis of VTOS: 2016 Consensus Guidelines�������������������������� 495 Karl A. Illig 55 Imaging in VTOS ���������������������������������������������������������������������������� 501 Michael J. Singh and Scott Chapman 56 VTOS for the PCP—When to Consider the Diagnosis���������������� 511 J. Eli Robins and Adam J. Doyle 57 Hypercoagulable Conditions and VTOS���������������������������������������� 517 Kendall Likes and Karl A. Illig 58 VTOS in the Competitive Athlete �������������������������������������������������� 523 Robert W. Thompson and Jason T. Lee 59 Thoracic Outlet Syndrome in Hemodialysis Patients������������������ 529 Eric K. Peden and Edward Andraos Part VII Venous TOS: Treatment 60 Differential Diagnosis, Decision-­Making, and Pathways of Care: Acute Thrombosis and Non-­thrombotic Positional Compression ������������������������������������������������������������������ 537 Maria C. Gelabert and Hugh A. Gelabert 61 Management of Chronic Venous Thoracic Outlet Syndrome������ 553 Dominique L. Tucker, Axel Sinclair Cooper, and Julie Ann Freischlag 62 Conservative (Non-Operative) Treatment of VTOS �������������������� 559 Kaj H. Johansen 63 Thrombolysis and Balloon Venoplasty for Subclavian Vein Thrombosis �������������������������������������������������������������������������������������� 565 Michael Darcy

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64 Surgical Techniques: Operative Decompression Using the Transaxillary Approach for Venous Thoracic Outlet Syndrome�������������������������������������������������������������� 577 Michael A. Mederos and Hugh A. Gelabert 65 Surgical Techniques: Operative Decompression Using the Infraclavicular Approach for VTOS with Intraoperative Venography�������������������������������������������������������������������������������������� 587 Matthew C. Smith and Darren B. Schneider 66 Surgical Techniques: Operative Decompression Using the Paraclavicular Approach for Venous Thoracic Outlet Syndrome������������������������������������������������������������������������������ 591 Robert W. Thompson and J. Westley Ohman 67 The Robotic Transthoracic Approach for Venous Thoracic Outlet Syndrome�������������������������������������������������������������� 617 Bryan M. Burt 68 Medial Claviculectomy for VTOS�������������������������������������������������� 621 Philip L. Auyang and Eric K. Peden 69 Advanced Surgical Techniques in Venous Thoracic Outlet Syndrome������������������������������������������������������������������������������������������ 627 Tanner I. Kim and Kristine C. Orion Part VIII Venous TOS: Unanswered Questions 70 Point/Counterpoint: Is Thrombolysis Always Required in Patients with Effort Thrombosis? ���������������������������� 637 Axel Sinclair Cooper, Dominique L. Tucker, and Julie Ann Freischlag 71 Management of Residual Stenosis after Thrombolysis���������������� 643 Robert J. Beaulieu and Chandu Vemuri 72 First Rib Resection Is Always Needed After Thrombolysis �������� 649 Chong Li, Gregory Westin, and Joanelle Lugo 73 Controversies in VTOS: Is Thrombolysis Alone Sufficient Treatment for VTOS?—YES���������������������������������������������������������� 655 Kaj H. Johansen 74 Controversies in Venous Thoracic Outlet Syndrome: Timing of First Rib Resection After Thrombolysis���������������������� 659 Michael R. Go and Patrick S. Vaccaro 75 Controversies in VTOS: What Is the Best Approach for VTOS? ���������������������������������������������������������������������� 665 Misty D. Humphries 76 Controversies in VTOS: What Is the Best Approach to the First Rib in VTOS? �������������������������������������������������������������� 669 Kevin R. Kniery, Louis M. Messina, and Darren B. Schneider

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77 Point/Counterpoint: Paraclavicular Decompression Is the Best Approach for Venous Thoracic Outlet Syndrome���������������� 675 Chandu Vemuri and Robert W. Thompson 78 Controversies in Venous Thoracic Outlet Syndrome: Is There a Role for Venous Stents? ������������������������������������������������ 683 Omar Zurkiya and Suvranu Ganguli Part IX Venous TOS: Outcomes and Future Directions 79 Venous TOS: Early Postoperative Care ���������������������������������������� 689 Karen M. Henderson, Marilynn N. Robinson, Katherine Kolster, Farzana Najrabi, and Robert W. Thompson 80 Controversies in VTOS: How Long Should Anticoagulation Be Used in VTOS? ���������������������������������������������� 699 Maria C. Gelabert and Hugh A. Gelabert 81 VTOS: Management of the Contralateral Side and Asymptomatic Compression���������������������������������������������������� 709 J. Eli Robins and Adam J. Doyle 82 Outcomes After Treatment of VTOS���������������������������������������������� 715 Gloria Y. Kim and Chandu Vemuri 83 Assessment and Treatment of Recurrent Venous Thoracic Outlet Syndrome�������������������������������������������������������������� 725 Robert W. Thompson Part X Arterial TOS: General Principles and Diagnosis 84 Anatomy and Pathophysiology of ATOS���������������������������������������� 739 Enjae Jung 85 Clinical Presentation and Patient Evaluation in ATOS���������������� 743 Akbarshakh Akhmerov, Robert W. Thompson, and Ali Azizzadeh 86 ATOS Consensus Guidelines���������������������������������������������������������� 751 Maria C. Gelabert and Hugh A. Gelabert 87 The Axillary Artery and Humeral Head in ATOS������������������������ 757 Olamide Alabi and Yazan Duwayri 88 Quadrilateral Space Syndrome������������������������������������������������������ 761 Arjun Jayaraj and Peter Gloviczki 89 Arterial Thoracic Outlet Syndrome in the Competitive Athlete������������������������������������������������������������������������� 771 J. Westley Ohman and Robert W. Thompson Part XI Arterial TOS: Treatment 90 Decision-Making and Pathways of Care for ATOS���������������������� 783 Ashley K. Vavra, William H. Pearce, and Mark K. Eskandari

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91 Surgical Techniques: Endovascular Intervention for Arterial Thoracic outlet Syndrome������������������������������������������ 789 Abdulhameed Aziz 92 Axillosubclavian Artery Repair and Reconstruction�������������������� 795 Jocelyn Beach and Francis J. Caputo 93 Upper Extremity Fasciotomy After Arterial Embolization���������� 803 Kathryn S. King, Michael A. Harrington, and David J. Smith 94 Quadrilateral Space Syndrome and Management of the Posterior Circumflex Humeral Artery�������������������������������� 811 G. J. Pearl and S. K. Hansen 95 Management of Digital Emboli, Vasospasm, and Ischemia �������� 817 Robert W. Thompson Part XII Arterial TOS: Outcomes and Future Directions 96 Outcomes After Treatment of Arterial Thoracic Outlet Syndrome������������������������������������������������������������������������������ 829 Gregory J. Pearl and Lauren Beliveau 97 Recurrent and Residual ATOS������������������������������������������������������� 835 Stephen J. Annest, Barbara A. Melendez, and Richard J. Sanders Part XIII Additional Topics Related to Thoracic Outlet Syndrome 98 Medicolegal Issues in TOS�������������������������������������������������������������� 845 Kevin J. Adrian 99 Disability and Workers’ Compensation Issues in TOS���������������� 851 Gary M. Franklin and Zach Gray 100 Special Considerations in the Elite High Profile Athlete�������������� 859 Gregory J. Pearl and Keith Meister 101 Combined and Secondary Forms of TOS�������������������������������������� 863 J. Westley Ohman 102 TOS: The Perspective of the Patient���������������������������������������������� 867 Karl A. Illig 103 Venous TOS: The Perspective of the Patient �������������������������������� 879 Ying Wei Lum 104 TOS, the Internet and Social Media���������������������������������������������� 885 Samantha J. Erdmann 105 Establishing a TOS-Focused Practice�������������������������������������������� 891 Karl A. Illig, Robert W. Thompson, Julie Ann Freischlag, Dean M. Donahue, Hugh A. Gelabert, and Ying Wei Lum Index���������������������������������������������������������������������������������������������������������� 899

Contents

1

Introduction Robert W. Thompson

Although problems eventually known as TOS were known since the mid-nineteenth century, the term “thoracic outlet syndrome” was coined by Peet and colleagues in 1956 [1]. Interest in this group of relatively rare but potentially debilitating conditions was heightened by the introduction of new surgical techniques for treatment in the 1960s, along with controversies over definitions, diagnosis, treatments, complications, and outcomes [2, 3]. This interest is reflected in a steady increase in publications related to TOS over the following decades, continuing to the current day (Fig. 1.1), while introduction and utilization of the term “disputed TOS” only served to emphasize the ongoing controversies [4, 5]. A valuable critique of the field was presented in a Cochrane systematic review published in 2010 (updated in 2014), which served as a critical “call to arms” for those interested in these conditions: “This review was complicated by a lack of generally accepted diagnostic criteria for the diagnosis of TOS… There is no evidence from RCTs [randomized clinical trials] for the use of… currently used treatments. There is a need for an agreed definition for the diagnosis of TOS, especially the disputed form, agreed outcome meaR. W. Thompson (*) Center for Thoracic Outlet Syndrome and Section of Vascular Surgery, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, MO, USA e-mail: [email protected]

sures, and high quality randomized trials that compare the outcome of interventions with no treatment and with each other” [6, 7]. In 2009, a number of leaders in the management of TOS formed the Consortium for Outcomes Research and Education on Thoracic Outlet Syndrome (CORE-TOS) to more rigorously address these concerns. An underlying theme of the CORE-TOS effort was to establish more standardized definitions, to increase the objectivity of the criteria by which physicians and therapists approach the diagnosis of all forms of TOS, and to more broadly apply formal measures by which to assess and compare the outcomes of treatment. The first edition of Thoracic Outlet Syndrome was a direct outgrowth of the initial CORE-TOS consensus conference meeting, held in St. Louis in 2009, and it represented the first comprehensive multidisciplinary textbook in the field [8]. Its success undoubtedly reflects the persistent need for a definitive resource on this topic in the medical literature. Landmarks in this effort were the development of consensus-based clinical diagnostic criteria for neurogenic TOS by the CORE-TOS group and development of a reporting standards document for all forms of thoracic outlet syndrome, published by the Society for Vascular Surgery (SVS) in 2016, reiterating the strong urgency toward making what we do more standardized and thereby comparable for the conduct of clinical research studies [9]. For example, the SVS

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_1

1

R. W. Thompson

2 100 Annual Number of Articles Published on “Thoracic Cutlet Syndrome” 1956 - 2019 (n = 2802) 2009 Consensus Conference

90

Number of Publications

80

First Edition

70 60 50 40 30 20

2019

2015

2010

2005

2000

1995

1990

1985

1980

1975

1970

1965

1960

0

1956

10

Year of Publication

Fig. 1.1 Annual number of articles published on TOS.  Publications listed in the National Library of Medicine PubMed database (pubmed.ncbi.nlm.nih.gov) using the search term “thoracic outlet syndrome” are shown, for each year from 1956 to 2019, with a total of

2802 articles. The 2009 consensus conference of the Consortium for Outcomes Research and Education on Thoracic Outlet Syndrome (CORE-TOS) and the 2013 publication of the first edition of Thoracic Outlet Syndrome are highlighted

Table 1.1  Recent PubMed publications for various conditions Search term Thoracic Outlet Syndrome Ehlers–Danlos Syndrome Complex Regional Pain Syndrome Carpal Tunnel Syndrome Fibromyalgia Aortic Aneurysm

2015 82 155 268 409 684 3284

2016 81 157 266 448 685 3262

2017 85 171 248 492 690 3322

2018 98 196 244 479 644 3367

2019 75 252 245 481 697 3423

Average 84.2 186.2 254.2 461.8 680.0 3331.6

Publications listed in the National Library of Medicine PubMed database for each of the search terms listed and the years cited were identified (pubmed.ncbi.nlm.nih.gov)

d­ocument describes four specific criteria (and only four) to be used in the diagnosis of neurogenic TOS, it mandates the use of the patientreported outcomes measures (PROMs), such as the Disabilities of the Arm, Shoulder, and Hand (DASH) and Cervical Brachial Symptoms Questionnaire (CBSQ) instruments, and it clearly draws the dividing line between neurogenic and arterial TOS.  The first publication utilizing the CORE-TOS and SVS reporting standards definitions of neurogenic TOS appeared in 2017, and most recent manuscripts report the use of objec-

tive, quantifiable outcome measures, rather than simply noting “improvement” [10–22]. Despite the impressive and steady increase in publications related to TOS, there remains much to improve upon. As shown in Table 1.1, articles published on TOS are dwarfed by the number of publications on other similar topics, such as Ehlers–Danlos syndrome, complex regional pain syndrome (CRPS), carpal tunnel syndrome, and fibromyalgia. Furthermore, in evaluating the nature of recent publications on TOS, it is also evident that case reports and small case series

1 Introduction

3

Table 1.2  Recent PubMed publications for thoracic outlet syndrome In English, Validated TOS Principal Topic of Article/Study Anatomy/Pathology Diagnosis/Treatment Type of Article/Study Case Report (n = 1–5) Descriptive Study (n > 5) Comparative Study (n > 5) Database Study Meta-Analysis Topical Review Systematic Review Guidelines/Standards Editorial/Letter/Opinion

2015 60

2016 55

2017 68

2018 68

2019 70

Total 321

36 (60%) 23 (38%)

31 (56%) 22 (40%)

30 (44%) 29 (43%)

25 (37%) 23 (34%)

21 (30%) 38 (54%)

143 (44%) 135 (42%)

24 (40%) 16 (27%) 1 (2%) 0 (0%) 0 (0%) 15 (25%) 1 (2%) 1 (2%) 2 (3%)

24 (44%) 8 (14%) 3 (5%) 0 (0%) 0 (0%) 17 (31%) 0 (0%) 1 (2%) 4 (7%)

26 (38%) 14 (21%) 2 (3%) 2 (3%) 1 (1%) 22 (32%) 2 (3%) 0 (0%) 3 (4%)

28 (41%) 13 (19%) 7 (10%) 1 (1%) 1 (1%) 12 (18%) 4 (6%) 0 (0%) 6 (9%)

25 (36%) 23 (33%) 12 (17%)a 1 (1%) 2 (3%) 6 (9%) 2 (3%) 0 (0%) 1 (1%)

127 (40%) 74 (23%) 25 (8%) 4 (1%) 4 (1%) 72 (22%) 9 (3%) 2 (1%) 16 (5%)

Publications listed in the National Library of Medicine PubMed database for each of the search terms listed and the years cited were identified (pubmed.ncbi.nlm.nih.gov). Articles written in English and verified to be focused on thoracic outlet syndrome (TOS) were selected. The individual abstracts were reviewed for each article to assess the principal topic and type of the publication, as tabulated for each year. aThe publication of 12 comparative studies or clinical trials in 2019 is highlighted [11–22]

still represent 40% of papers, with topical review articles making up another 22% (Table  1.2). In the past few years, we are beginning to see an increased number of larger-scale descriptive studies, more comparative studies and clinical trials, and even large database studies and meta-­ analyses [11–22]. This trend bodes well for the future growth of interest in TOS as a better defined group of conditions for which the modern tools of rigorous clinical research can be applied. Another sign of cohesion in the field is reflected by the prompt development of consensus guidelines for the evaluation and management of patients with TOS during the 2020 global COVID-19 pandemic [23].

References 1. Peet RM, Hendriksen JD, Anderson TP, Martin GM. Thoracic-outlet syndrome: evaluation of a therapeutic exercise program. Proc Staff Meet Mayo Clin. 1956;31(9):281–7. PMID: 13323047. 2. Roos DB.  Transaxillary approach for first rib resection to relieve thoracic outlet syndrome. Ann Surg. 1966;163(3):354–8. PMID: 5907559. 3. Roos DB. Congenital anomalies associated with thoracic outlet syndrome. anatomy, symptoms, diagnosis, and treatment. Am J Surg. 1976;132(6):771–8. PMID: 998867.

4. Roos DB.  Thoracic outlet syndrome is underdiagnosed. Muscle Nerve. 1999;22(1):126–9. PMID: 9883869. 5. Wilbourn AJ.  Thoracic outlet syndrome is overdiagnosed. Muscle Nerve. 1999;22(1):130–6. PMID: 9883870. 6. Povlsen B, Belzberg A, Hansson T, Dorsi M. Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2010;1:CD007218. PMID: 20091624. 7. Povlsen B, Hansson T, Povlsen SD.  Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2014;11:CD007218. PMID: 25427003. 8. Illig KA, Thompson RW, Freischlag JA, Donahue DM, Jordan SE, Edgelow PI, editors. Thoracic outlet syndrome. London: Springer Nature; 2013. 9. Illig KA, Donahue D, Duncan A, Freischlag J, Gelabert H, Johansen K, Jordan S, Sanders R, Thompson R. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. J Vasc Surg. 2016;64(3):e23–35. 10. Balderman J, Holzem K, Field BJ, Bottros MM, Abuirqeba AA, Vemuri C, Thompson RW. Associations between clinical diagnostic criteria and pretreatment patient-reported outcomes measures in a prospective observation cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2017;66(2):533–44. PMID: 28735950. 11. Beteck B, Shutze W, Richardson B, Shutze R, Tran K, Dao A, Ogola GO, Pearl G.  Comparison of athletes and nonathletes undergoing thoracic outlet decompression for neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2019;54:269–75. PMID: 30081158. 12. Maqbool T, Novak CB, Jackson T, Baltzer HL. Thirty-day outcomes following surgical decom-

4 pression of thoracic outlet syndrome. Hand (N Y). 2019;14(1):107–13. PMID: 30182746. 13. Henni S, Hersant J, Ammi M, Mortaki FE, Picquet J, Feuilloy M, Abraham P.  Microvascular response to the Roos test has excellent feasibility and good reliability in patients with suspected thoracic outlet syndrome. Front Physiol. 2019;10:136. (ecollection 2019). PMID: 30846945. 14. Balderman J, Abuirqeba AA, Eichaker L, Pate C, Earley JA, Bottros MM, Jayarajan SN, Thompson RW.  Physical therapy management, surgical treatment, and patient-reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2019;70(3):832–41. (epub Mar 7, 2019). PMID: 30852035. 15. Weaver ML, Hicks CW, Fritz J, Black JH 3rd, Lum YW.  Local anesthetic block of the anterior scalene muscle increases muscle height in patients with neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2019;59:28–35. (epub Apr 19, 2019). PMID: 31009716. 16. Golarz SR, White JM.  Anatomic variation of the phrenic nerve and brachial plexus encountered during 100 supraclavicular decompressions for neurogenic thoracic outlet syndrome with associated postoperative neurologic complications. Ann Vasc Surg. 2020;62:70–5. (epub Jun 14, 2019). PMID: 31207398. 17. Rached R, Hsing W, Rached C.  Evaluation of the efficacy of ropivacaine injection in the anterior and middle scalene muscles guided by ultrasonography in the treatment of thoracic outlet syndrome. Rev Assoc Med Bras. 2019;65(7):982–7. PMID: 31389509. 18. Madden N, Calligaro KD, Dougherty MJ, Maloni K, Troutman DA.  Evolving strategies for the management of venous thoracic outlet syndrome. J Vasc Surg

R. W. Thompson Venous Lymphat Disord. 2019;7(6):839–44. (epub Aug 27, 2019). PMID: 31471278. 19. Dua A, Rothenberg KA, Gologorsky RC, Deslarzes-­ Dubuis C, Lee JT.  Long-term quality of life comparison between supraclavicular and infraclavicular rib resection in patients with vTOS. Ann Vasc Surg. 2020;62:128–32. (epub Aug 30, 2019). PMID: 31476427. 20. Bozzay JD, Walker PF, Ronaldi AE, Patel JA, Koelling EE, White PW, Rasmussen TE, Golarz SR, White JM.  Infraclavicular thoracic outlet decompression compared to supraclavicular thoracic outlet decompression for the management of venous thoracic outlet syndrome. Ann Vasc Surg. 2020;65:90–9. (epub Oct 31, 2019). PMID: 31678546. 21. Brownie ER, Abuirqeba AA, Ohman JW, Rubin BG, Thompson RW. False-negative upper extremity ultrasound in the initial evaluation of patients with suspected subclavian vein thrombosis due to thoracic outlet syndrome (Paget-Schroetter syndrome). J Vasc Surg Venous Lymphat Disord. 2020;8(1):118–26. (epub Nov 13, 2019). PMID: 31732483. 22. Donahue DM, Godoy IRB, Gupta R, Donahue JA, Torriani M. Sonographically guided botulinum toxin injections in patients with neurogenic thoracic outlet syndrome: correlation with surgical outcomes. Skeletal Radiol. 2020;49(5):715–22. (epub Dec 5, 2019). PMID: 31807876. 23. Ohman JW, Annest SJ, Azizzadeh A, Burt BM, Caputo FJ, Chan C, Donahue DM, Freischlag JA, Gelabert HA, Humphries MD, Illig KA, Lee JT, Lum YW, Meyer RD, Pearl GJ, Ransom EF, Sanders RJ, Teijink JAW, Vaccaro PS, van Sambeek MRHM, Vemuri C, Thompson RW. Evaluation and treatment of thoracic outlet syndrome during the global pandemic due to SARS-CoV-2 and COVID-19. J Vasc Surg. 2020;72(3):790–8. PMID: 32497747.

Part I Background and Basic Principles

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A Brief History of the Thoracic Outlet Compression Syndromes Herbert I. Machleder

Abstract

The history of the Thoracic Outlet Compression syndromes has evolved over the past 150 years, from the first well documented case in 1861 to series of patients now treated in modern prospective randomized trials. This evolution has been driven by clinical and basic research contributions from major university medical centers and private clinics around the globe. The three major manifestations of thoracic outlet syndrome (TOS)—arterial, venous, and neurogenic—were drawn together in a dramatic, tragic, and eventually transcendent series of events, summarized in a single clinical case by the great American neurologist William S. Fields in 1986. The complex developmental anatomy of this area, including a key evolutionary departure of primates from the rest of the mammals, created a complex situation that shrouded the thoracic outlet from clarity. The contributions from embryologists, anatomists, neurophysiologists, and neuropathologists, coupled with astute observations from generations of clinicians, now clearly define the issues surrounding this unique anatomic site.

H. I. Machleder (*) Department of Surgery, University of California, Los Angeles (UCLA), Los Angeles, CA, USA e-mail: [email protected]

In reviewing this historical sequence the reader encounters a fascinating account of a disorder that affects a diverse population, including musicians, athletes, industrial workers, data entry personnel, and many others with various vocations and avocations. This history also well illustrates the twists and turns of scientific discovery and clinical application that have encumbered our efforts to study, understand, and effectively alleviate a disorder that can range from a curious annoyance to major disability.

2.1

Prologue

It was sometime in winter of 1994 when a newspaper reporter came upon a tattered, homeless, and destitute man living in a crude cardboard shelter under a Houston bridge. How could this be—JR Richard, once one of the highest paid and most talented All-Star pitchers of the Houston Astros? A giant of a man both in size (6′8″) and accomplishment, brought low by an odd, poorly understood disorder [1]. It remained for another iconic figure to decipher the diagnosis, the Neurologist William Fields; referred to by his contemporaries as a physician who was a “giant” in the field of Neurology (whose members are not noted for hyperbole), and whose contributions were “monumental” [2].

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_2

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H. I. Machleder

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After examining Richard, and studying his case, Fields wrote, in his definitive style, “All shoulder girdle compression syndromes have one common feature, namely; compression of the brachial plexus, the subclavian artery, and subclavian vein, usually between the first rib and the clavicle. With elevation of the upper limb, there is a scissorlike approximation of the clavicle superiorly and the first rib inferiorly. Grouping the various conditions under the single heading of thoracic outlet syndrome should be considered in all neurologic and vascular complaints of the arm previously reported as scalenus anticus, hyperabduction, costoclavicuar, cervical rib, fractured clavicle, cervicobracial compression, pneumatic hammer, effort vein thrombosis, subcoracoid pectoralis minor, and first thoracic rib syndrome” [3]. As is often said in the vernacular, “…there you have it!” the essential history of Thoracic Outlet Compression Syndrome (TOS) in a paragraph. A group of seemingly inconsequential developmental and acquired abnormalities that can hide for a lifetime in obscurity, or, under certain conditions of occupational, recreational, or cumulative trauma, result in a syndrome of dramatic and unremitting disability.

2.2

Historical Evolution

The commonality of the often disparate abnormalities and complaints associated with TOS was not always so evident, but has been slowly worked out over years of experimental research and clinical observation (beginning more than a century before JR Richards’ case). This trajectory was laid out in a paper presented at a Festschrift for Charles Rob held in San Francisco California in 1993, “Thoracic Outlet Syndromes: new concepts from a century of discovery” [4]. The history of TOS as a medical diagnosis begins in 1861 on a rainy spring day in London, when “Charlotte D,” a 26  year-old servant woman, was admitted to St. Bartholomew’s Hospital with a painful, dysesthetic and somewhat ischemic left arm. The diagnosis of “cervical rib” was made, and surgical excision was

undertaken by Mr. Holmes Coot. The case was beautifully described less than 2  weeks later in the journal Lancet [5]. These earliest cases fascinated both physicians and surgeons, as they diagnosed and treated mostly young patients with painful pulsatile masses in their necks, often associated with a cool, painful, dysesthetic upper extremity. The presence of a cervical rib was diagnosed by physical examination, this being almost half a century before the discovery of X-rays. The technically challenging but by and large successful treatment, often dramatically so, drew the attention of clinics around the world. After Coote’s successful case, anomalous cervical rib and its syndrome were increasingly diagnosed, particularly after 1900 when recognition was facilitated by the growing use of radiographic imaging. A number of subsequent surgical reports appeared in the literature, and cervical rib excision became an accepted therapeutic approach when the rib was associated with upper-extremity neurovascular symptoms. Paradoxically, the symptom complex was becoming increasingly recognizable in the industrializing cities in England and Australia, but without a detectible bony abnormality. In 1912, T.  Wingate Todd reported a landmark clinical and anatomical study of a large number of men woman and children. He concluded that “symptoms of cervical rib” may be caused by an apparently normal first dorsal rib, and may be cured by its removal. His studies showed that there was a progressive and gradual descent of the shoulder girdle in advancing years such that the first and second thoracic nerves are gradually displaced and must travel upward until they have crossed the uppermost rib and then angulate downward to enter the arm. As a consequence of this configuration, any elevation of the rib or depression of the shoulder must stretch these lower connections with the brachial plexus. He also noted the resting and carrying positions that relieve and exacerbate this stretching [6]. In 1920 Stopford and Telford reported a group of patients seen in Manchester complaining of loss of grip strength, fatigue of the hand with

2  A Brief History of the Thoracic Outlet Compression Syndromes

exercise, weakness of the intrinsic muscles, loss of sensation in the distribution of the lower trunk of the brachial plexus, and vasomotor instability with episodes of cyanosis and coolness. They noted that after removal of the impinging portion of the first rib there was rapid resolution of the vasomotor and sensory changes and slow resolution of atrophic and motor changes [7]. This is, fascinatingly, quite a modern description of neurogenic TOS as reported now almost a full century later.

2.3

The Scalenectomy Era

Although the general anatomic region of the compressive abnormality had became quite evident, there was changing opinion about the key offending structure. Consequently, the disorder did not yet have a commonly accepted name! There was also considerable variation in opinion regarding the best mode of treatment, or surgical decompression. At the Mayo Clinic Adson, the Chief of the Neurosurgical Service, began to treat “cervical rib” patients by removing the anterior scalene muscle. He reasoned that the compression originated superiorly and compressed the neurovascular structures against the unyielding bony structure beneath, and thus that relief of the superior compression would solve the problem with limited morbidity [8]. The popularity of this operation grew, particularly as it was far safer than resection of a cervical rib. Naffziger, who was chief of Neurosurgery at the University of California and President of the American College of Surgeons, also considered the anterior scalene muscle to be the key to the neurovascular compressive abnormalities in patients with “Cervical Rib Syndrome,” even in the absence of an actual cervical rib, and thus first used the term “Scalenus Syndrome.” [9] The widespread interest in this subject is highlighted by Ochsner, Gage, and DeBakey publishing a description of the disorder in a landmark paper entitled “Scalenus anticus (Naffziger) syndrome,” giving credit to Naffziger (although Ochsner’s paper antedated Naffziger’s by 3 years!) [10].

9

The concept of dividing the scalene muscle flourished, albeit with both dramatic cures and less enthusiastically documented failures. In this period of time, before the widespread recognition of carpal tunnel syndrome, cervical disc disease and neuroforaminal compression, and other similar problems, the widespread application of scalenotomy was certain to lead to failures, particularly when applied to patients with predominantly upper plexus or median nerve distribution symptoms. The anatomic variations seen during surgery suggested that a careful look at the embryology of the area might provide some insight into the etiology and interrelation of the structural elements. Some of the most illuminating basic research was done in Paris and Berlin [11, 12]. Milliez and Poitevin working at the Museum of Man at the Sorbonne in Paris, demonstrated that the scalene muscle mass is differentiated into specific muscle groups by passage of the developing neurovascular bundle. The persistence of certain muscle inclusions in the brachial plexus as well as muscle groups that traverse various elements of the brachial plexus is related to the original mass of the scalene variously segmented by the passage of these developing structures as the limb bud develops. These investigators also emphasized that anomalies at the thoracic outlet rarely exist in isolation as there is interaction in development of the different elements. Cervical rib development, for example, is determined by the formation of the spinal nerve roots. The regression of the C5 through C7 ribs is occasioned by the rapid development of the enlarging roots of the brachial plexus in the region of the limb bud. In cases of a C7 rib, there is only a small neural contribution from the T1 nerve root. The inhibition of rib development at that level is lost or reduced, and the size of the cervical rib is then related to the extent of the contribution of this T1 root to the brachial plexus. When muscle histochemistry and fiber type analysis became available, these newer methods of muscle investigation were applied to the anterior scalene. The neuropathologist Anthony Verity recognized that in the post-traumatic situation there would be a gradual recruitment of

H. I. Machleder

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sustained contracting Type 1 fibers, corresponding to the clinical observation of increased muscle tone, tenderness, and consequent compression [13]. This clinical and ultrastructural evidence formed the basis for a number of non-surgical treatment protocols for symptomatic relief of the neurogenic disability, including targeted physical therapy and chemodenervation of the anterior scalene [14–16], although this is getting ahead of ourselves.

2.4

The Era of First Rib Resection

In 1962 O Theron Clagett delivered his Presidential address to the American Thoracic Society. Subsequently published in the Journal of Thoracic and Cardiovascular Surgery, it described the evolution of his understanding of the compressive process and his application of first rib resection to patients with TOS. The posterior thoracoplasty approach was a difficult operation (for both patient and surgeon) and there was consequently relatively limited further clinical application [17]. The paper was a milestone, however, in turning attention away from the scalene muscle and back to the first Thoracic rib. Renewed interest in first rib resection then followed a report in 1966 by David Roos, who reported a series of 15 patients treated by removal of the first thoracic rib from a transaxillary approach. The dramatic superiority of this technique was readily appreciated and became widely accepted [18]. Improved recognition of other problems that can be confused with TOS combined with a more effective operative approach to thoracic outlet compression led to demonstrably superior results in the treatment of patients with upper extremity neurogenic and neurovascular symptoms. Roos’s superb ability in communicating the critical elements in the clinical workup as well as the operative details proved to be one of the keys to widespread acceptance of this approach, and the transaxillary procedure became the standard operation for removal of the first thoracic rib by the early- to mid-1970s [19]. Unfortunately there remained a lack of familiarity with the complex developmental anomalies that occur in these patients leading to a definite

incidence of poor surgical results soon followed by medical malpractice litigation. This turn of events was highlighted by Andrew Dale, a thoracic Surgeon from Nashville [20]. At the time of his paper’s publication it was still the practice for journals to publish the full discussion that followed the paper’s oral presentation, which was most interesting (and three full journal pages long!). The lively and instructive debate that followed his talk sounds surprisingly modern and illustrates the differences of opinion and lack of consensus that existed in the beginning of the 1980s, and he concluded the printed discussion with a quote from John Homans; “I enjoyed the discussion of my paper, but I wish I had not learned so much from it” (20, p. 1445). The first good description of clinical anatomical observations was published by Roos in 1976, who described a constellation of abnormal bands and fibers that he had observed in the course of operative intervention [21]. Because of incomplete understanding of the embryology of the region at that time, Roos was able to identify the abnormalities only by number: Type I, Type II, etc. As research regarding the embryology and developmental anatomy of this area progressed, Makhoul was able to place all of the structural variations seen within a more comprehensive system [22]. As understanding of the various underlying anomalies developed it became apparent to many surgeons who had a focused interest in this entity, that simply removing the first rib was not the single best operation in all circumstances. Although removal of the rib would often lead to relief of symptoms, failure to identify and deal with other associated developmental abnormalities would often lead to recurrent (or residual) problems—first rib resection alone really only decompressed the soft tissue elements. Because of this the group at the University of California, Los Angeles (UCLA) have emphasized the fact that this operation, in general, should be considered thoracic outlet decompression [23]. Unfortunately for billing and coding reasons the term “first rib resection” had become firmly established by this point (and remains so), illustrating (in a negative sense) how evolving understanding can be encumbered by terminology!

2  A Brief History of the Thoracic Outlet Compression Syndromes

2.5

 he Concept of “Thoracic T Outlet Compression Syndrome”

By the 1950s the term “Thoracic Outlet Compression Syndrome” began to appear in the medical literature. The ‘Mayo Clinic Number’ of the 1946 Surgical Clinics of North America was devoted to a symposium on pain in the shoulder and arm. Eaton, the consultant in Neurology, described a group of disorders that he would 10 years later (in 1956) regularly refer to as the “thoracic outlet syndrome.” He began his description in this way, “Almost always the patient seeks relief from pain and paresthesias of the upper extremity…” [24]. In 1958 Rob and Standeven reported ten cases of arterial occlusion as a complication of what they termed, “thoracic outlet compression syndrome”, and thereby introduced the term to the surgical literature. They remarked at the often delayed diagnosis of thoracic outlet problems, suspecting that the subtle early manifestations of arterial compression were often masked by collateral formation. They further observed that, ‘three cases have been recorded in the literature in which proximal spread of arterial thrombosis had reached the bifurcation of the innominate artery and caused hemiplegia.’ It would be almost three decades later that J.R. Richard would suffer this identical consequence, on July 30, 1980, while pitching in the Houston Astrodome. The arterial complications of TOS (ATOS) seemed to find particular occurrence in “throwing athletes.” The variety of lesions, and the exceptional skill needed for both accurate identification and correction was well documented by Cormier, Yao, and Gelabert [25–27].

2.6

The Venous Abnormality

Although by 1980 compression of the axillosubclavian artery and brachial plexus in the thoracic outlet were well described, compression of the axillosubclavian vein (venous TOS; VTOS) was still an uncertain member of this syndrome. The phenomenon that had originally been described as the Paget-Schroetter Syndrome (based on the

11

first two case reports) was later routinely referred to as “spontaneous thrombosis of the axillosubclavian vein” or “effort thrombosis.” The first designation was perhaps most accurate, reflecting as it did an acknowledged lack of understanding regarding the etiology. The second designation, however, was an imaginary construction, that was actually quite fanciful. In its original form it posited that an extreme Valsalva maneuver (the “effort”) would increase pressure in the innominate and jugular-subclavian venous system enough to invert and tear the retro-­ clavicular valve of the subclavian vein, in turn setting up a nidus for inflammation, fibrosis and thrombosis. The few reported pathologic examinations of resected specimens showed an area of fibrosis, chronic thrombus, and thickening which could be construed as possibly substantiating the hypothesis (today, of course, the term “effort” is used to refer to the fact that most patients with this problem are young, fit athletes) [28]. Finally, there was no recognition at this time that nonocclusive intermittent compression could also occur as part of this problem [29]. The more accurate explanation (chronic, extrinsic compression by the structures that make up the costoclavicular junction) was developed around the time that thrombolytic therapy began to be used, by means of which the thrombosed vein could be rapidly cleared of thrombus and the underlying structural abnormality then demonstrated by positional venography. The earliest attempts at treatment using this new paradigm were published in a series of case reports by Zimmerman [30], Taylor [31], and Perler [32] in the 1980s. The institution of a comprehensive approach to the Paget-Schroetter Syndrome was applied to a reasonable cohort of patients beginning in 1985 and reported by Kunkel in the Archives of Surgery in 1989 [33]. The key at this stage was the careful exclusion of any of the other possible causes of venous thrombosis (which had become legion as a consequence of using the brachial veins for all type of access). The management strategy for true effort thrombosis was further refined and results as applied to a large, meticulously controlled group of patients were reported in the Journal of Vascular Surgery by the UCLA group in 1993 at which time the

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staged, multidisciplinary approach of thrombolysis followed by thoracic outlet decompression had become widely accepted [34].

H. I. Machleder

that however close we’ve gotten to the underlying “truth” of NTOS, at least we are now all using the same definition of it and treating the same group of patients. In addition, the recognition and engagement of a major medical society in pro2.7 Where Are We Today? spectively ensuring the integrity, transparency and comparability of reported results will place The 150  year history of the Thoracic Outlet TOS in a unique position of probity. The conseCompression Syndromes takes a circuitous quence of this disciplined structure will serve to course, with the rather erratic contributions from either validate or revise the major advances made many disciplines resulting in multiple directional in the previous decades, and may well serve to changes. The decade of 2010–2020, however, is encourage a new generation of academicians to proving to be a unique watershed epoch as the add their talents to the existing pool. Particularly sesquicentennial year of TOS history passes by. in the area of NTOS, increased participation of This decade encompasses some of the most dra- Neurologists is necessary. Those who have led in matic advances in diagnosis and therapy, as well the effort to better define NTOS have been as in our understanding of the true dimensions of inspired innovators with exceptional talents. this unique disorder. Energized by the uncertainties and complexities The landmark of this period in time is unques- of NTOS, rather than alienated or intimidated, tionably the Publication of the first Edition of they have made truly seminal contributions. “Thoracic Outlet Syndrome.” [35] The inaugural This current decade has also witnessed other edition of this the first comprehensive, multi-­ tradition-rending changes that mark it as unique. authored, multicenter, and multispecialty text- The interest in TOS as a subject of medical invesbook on the subject, has in a few short years tigation has been steadily increasing. This is parstimulated a renaissance of interest, a resurgence ticularly well documented by peer reviewed of high quality publications and renewed multi- publications in the medical literature. Over the specialty involvement. The first edition proved to past decade the number of articles focused on be singularly consequential in the development Thoracic Outlet Syndrome subjects and cited by of a more cohesive and accepted understanding the NCBI PubMed Bibliographic Index has gone of TOS and its components; ATOS, VTOS, and from 46 articles in 2008 to 68 articles in 2017 to NTOS. Perhaps for the first time there was also a 88 from January to August in 2018. The publicageneral acceptance of compelling evidence that tions are world-wide and include submissions diagnostic and therapeutic inconsistencies from the Basic Sciences in areas relevant to TOS needed to be addressed by; carefully controlled, studies. Some examples of this “return to basics” meticulously monitored, objectively assessed, come from refinements in the analysis of anaand transparently validated methods as could be tomic data [37] as well as, better estimates of the achieved in the arena of clinical constraints. And true incidence of the Cervical Rib abnormality since that time improvement in the publication of [38]. clinical studies has already become evident. Another change has been the marked consoliThe second landmark, a dramatic milestone dation of TOS practice in major medical centers, which definitively marks this as a new era, is the leading to the development of “centers of excelpublication of the “Society for Vascular Surgery lence.” The gravitation of patients to Vascular reporting standards: Thoracic outlet syndrome.” Surgery facilities has been occasioned partly by [36] This monumental document serves to stan- default, but increasingly by the highly successful dardize; terminology, nomenclature, and defini- management of the arterial and venous tions in addition to establishing consistent disabilities. reporting parameters with regard to all three With ATOS and VTOS the physical examinaforms of TOS. Critically important is the concept tion is relatively clear cut and unambiguous.

2  A Brief History of the Thoracic Outlet Compression Syndromes

Non-invasive and catheter based diagnostic modalities are highly accurate and refined, and the therapeutic protocols have made major advances that have contributed to excellent results. It is almost routine to witness those patients undergoing extraordinarily safe and effective procedures for complex ATOS and VTOS return to normal function without residual disability. There was obviously the optimistic anticipation that this developing expertise could be applied to NTOS. This major commitment of Vascular Surgical departments to education, training and surgical management of these disorders has also left its mark on this new period. The change is highlighted in records of the American College of Surgeons National Surgical Quality Improvement Program database. In the decade through to 2014, 1431 patients are identified who had first or cervical rib resection for TOS; 83% for Neurogenic (NTOS), 3% for Arterial (ATOS) and 12% for Venous (VTOS), 90% of procedures were performed by vascular surgeons. As an indication of the truly dramatic improvement in skill and break from the past, the incidence of operative nerve injury was 0.3% (four patients) [39]. Perhaps more objective evidence of the impact of this impressive emphasis on formal education and training can be found in the annals of jurisprudence. Recounting a rather sobering tale of the past is the report by Andrew Dale, a very talented surgeon and an eminent member of the Thoracic and Vascular Societies. In 1982 Dale, reported the increasingly high incidence of malpractice cases arising from rib resection for TOS, and a rather astonishing recognition that this diagnosis resulted, at the time, in the most frequent malpractice action against Thoracic Surgeons in the U.S. [20]. This has clearly and dramatically changed. Looking at actions against Vascular Surgeons in a comprehensive legal data base in the more recent 15 year period, there were 135 cases where a vascular surgeon was the defendant in a malpractice action. The procedures in litigation, in order of frequency were almost exclusively vascular intervention; peripheral 14.8%, carotid 11.85%, aortic 11.1%, trauma 9.63%, dialysis access 8.15% and venous 5.93%.

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The authors concluded that although TOS was commonly believed to be among the most frequent procedures leading to litigation, the reality is that Rib Resection has become one of the safest surgical procedures performed by vascular surgeons and is rarely a source of litigation [40]. This is no coincidental or accidental occurrence, but the result of a confluence of dedicated pedagogical efforts in these recent decades. The consolidation of practice and assumption of major responsibility by Vascular Surgical programs has led to TOS surgical training being placed in American Board recognized and regulated training programs. Diagnosis and management are a part of the regular curriculum, with expert supervision, graded responsibility, and exceptionally rigid maintenance of quality improvement practices. The thought and preparation for the two “landmark” events detailed above have played a major role in instituting these important changes. Another consequence of this “consolidation of practice” has been the opportunity to study large groups of patients suffering from each of the three forms of TOS. In the past, it was difficult to chart their progress, response to therapy, and long term outcomes based on the major studies available. These often proved to be inadequate to measure results of therapy or decide on long term trends from anecdotal experiences, and retrospective analysis of often inadequately selected groups of dissimilar patients. As an example of this dramatic advancement of our basic information, we have a study of cervical rib treatment in a series reported by Gelabert. This comprises a group of 873 consecutive patients treated at one institution by a standardized approach, and by a team dedicated to the study and treatment of this disorder [41]. As another example, we consider a prospective study of 538 TOS patients treated over a 10  year period; with carefully designed protocols, a predetermined operative approach by a dedicated team, then evaluation by standardized testing modalities, and with results subject to robust statistical analysis [42]. The Neurosurgical group, at Dartmouth-Hitchcock Medical Center, has added to the data base by reporting follow-up results in Pediatric TOS patients [43].

H. I. Machleder

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In addition to traditional formats of study, the group at Washington University led by Thompson has embarked on a truly innovative clinical approach with the identification of diagnostic markers that may serve to predict treatment ­outcomes. They have masterfully designed a prospective study which must have required an almost herculean effort of patient and physician involvement to accomplish in the clinical setting. The study has succeeded in its endeavor to match patient’s predetermined and specific perceptions of their pain and disability against well established and accepted clinical diagnostic criteria in a design, for the first time, to enable a reasoned prediction of treatment outcomes [44]. New treatment modalities are also a feature of this unique era. After being pioneered by Jordan and Ahn the role and efficacy of temporary chemo-denervation and muscle paralysis has been further investigated by Donahue and Boston colleagues for its role in the treatment of a host of musculoskeletal disorders including thoracic outlet compression syndrome [45, 46]. It would then suffice to say that this new era of clinical research has seen a turn towards protocol driven and patient directed approaches to TOS management [47, 48]. As a consequence, many large systematic reviews and meta-analyses that include classic studies from earlier periods, are now largely irrelevant [49]. This even includes recent reviews that are otherwise carefully controlled and intelligently analyzed [50]. One final characteristic will be mentioned, that is and will be, defining this new age. The management of poorly defined chronic pain syndromes is becoming exceedingly difficult, with a change in the social and political climate. No longer is it considered good practice to keep patients free of pain with effective narcotic pharmaceutical analgesics. In the face of presumed; narcotic abuse, overuse, addiction and mortality this treatment strategy is now considered reprehensible. Governing professional and political entities once encouraged “pain management.” They chastised physicians for inadequate attention to maintaining patients with chronic musculoskeletal pain, free of symptoms. Now rather draconian measures are contemplated to discourage and ban

the use of narcotic analgesics. Even to the point of denying coverage to patients on public assistance programs [51]. Perhaps this can be likened to the German proverb of “throwing out the baby with the bathwater.” Although many sporadic reports document meritorius efforts to develop a robust electrophysiologic diagnosis of NTOS, these have yet to generate the benefits of a sustained research approach [52–57]. With the dawn of changes in treatment options, intellectually disturbing concepts such as “Cervico-Brachial Pain Syndrome,” a cover for the curious entity of “disputed TOS,” should give way to more sophisticated diagnostic approaches. Perhaps it may be the time for influential neurology Journals that deal with muscles and nerves to lay to rest the seemingly endless cogitation and polemic of “Disputed TOS,” now that the actual disputants have long since left the arena. Redirecting this impressive intellectual firepower to finding new means of diagnosing NTOS should insure the development of additional accuracy, before the suffering caused by this painful disorder further reflects our ineptitude and parochial bickering [58]. Where we are today in this neurologic diagnosis can perhaps be described by borrowing an analogy from Jurisprudence: Our concept of NTOS can be likened to Supreme Court Justice Potter Stewart’s famous determination of “Pornography” in a “freedom of speech” ruling that was before the Court. To paraphrase his words; we may not yet be able to precisely define NTOS in unambiguous scientific neurologic terminology… “However, we know it when we see it.” [59]

References 1. Keith Knomes. Resurrection: The J.R. Richard story. IMDB 2005, Director; Greg Carter. Production; Bellinger-BotheaX films. 2. Van Horn G, Grotta JC, William S, Fields MD. Texas medical center pioneer. Ann Neurol. 2004;56(2):314. 3. Fields WS, et  al. Thoracic outlet syndrome: review and reference to stroke in a major league pitcher. AJR Am J Roentgenol. 1986;7:73–8. 4. Machleder HI.  Thoracic outlet syndromes: new concepts from a century of discovery. Cardiovasc Surg. 1994;2(2):137–45. LCCN-Sn93002438 ISSN 0967–2109

2  A Brief History of the Thoracic Outlet Compression Syndromes 5. Coote H.  Exostosis of the left transverse process of the seventh cervical vertebrae, surrounded by blood vessels and nerves, successful removal. Lancet. 1861;1:350–1. 6. Todd TW.  The descent of the shoulder after birth: its significance in the production of pressure symptoms on the lowest brachial trunk. Anat Anz. 1912;41:385–95. 7. Stopford JSB, Telford ED. Compression of the lower trunk of the brachial plexus by a first dorsal rib. Br J Surg. 1919;7:168–77. 8. Adson AW, Coffey JR. Cervical rib, a method of anterior approach for relief of symptoms by division of the scalenus anticus. Ann Surg. 1927;85:839–53. 9. Naffziger HC, Grant WT.  Neuritis of the brachial plexus, mechanical in origin: the scalenus syndrome. Surg Gynecol Obstet. 1938;67:722–30. 10. Ochsner A, Gage M, DeBakey M.  Scalenus anticus (Naffziger syndrome). Am J Surg. 1935;28:669–95. 11. Milliez PY. Contribution A L’Etude De L’Ontogenese Des Muscles Scalenes (Reconstruction D’Un Embryon De 2.5 cm) June 28, 1991. Universite Paris 1 Pantheon-Sorbonne Musee De L’Homme, Museum D’Histoire Naturelle. 12. Lang J. Tropographische Anatomie de plexus brachialis und thoracic outlet Syndrom. Berlin: Walter de Gruyter; 1985. 13. Machleder HI, Moll F, Verity MA. The anterior scalene muscle in thoracic outlet compression syndrome: histochemical and morphometric studies. Arch Surg. 1986;121:1141–4. 14. Pascarelli EF, Hsu YP.  Understanding work-­ related upper extremity disorders. J Occup Rehabil. 2001;11(1):1–21. 15. Jordon SE, et  al. Diagnosis of thoracic outlet syndrome using electrophysiologically guided anterior scalene blocks. Ann Vasc Surg. 1998;12:260–4. 16. Jordon SE, et  al. Selective botulinum chemodenervation of the scalene muscles for treatment of neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2000;14:365–9. 17. Clagett OT.  Research and prosearch. J Thorac Cardiovasc Surg. 1962;44:153–66. 18. Roos DB.  Transaxillary approach for first rib resection to relieve thoracic outlet syndrome. Ann Surg. 1966;163:354–8. 19. Roos DB. Experience with first rib resection for thoracic outlet syndrome. Ann Surg. 1971;173:429–33. 20. Dale WA. Thoracic outlet compression syndrome: critique in 1982. Arch Surg. 1982;117:1437–45. 21. Roos DB.  Congenital anomalies associated with thoracic outlet syndrome. Am J Surg. 1976;132: 771–8. 22. Makhoul RG, et al. Developmental anomalies at the thoracic outlet: an analysis of 200 consecutive cases. J Vasc Surg. 1992;16:534–45. 23. Machleder HI.  Transaxillary operative management of thoracic outlet syndrome: current therapy in vascular surgery. 2nd ed. Philadelphia: B.C. Decker; 1991. isbn:1-55664-262-8.

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24. Eaton LM. Neurological causes of pain in the upper extremities; with particular reference to syndromes of protruded intervertebral disk in the cervical region and mechanical compression of the brachial plexus. Surg Clin North Am. 1946;4(6):810–32. 25. Cormier JM, et al. Arterial complications of the thoracic outlet syndrome: fifty-five operative cases. J Vasc Surg. 1989;9:778–87. 26. Durham JR, Yao JST, Pierce WH, et al. Arterial injuries in the thoracic outlet syndrome. J Vasc Surg. 1995;21:57–70. 27. Gelabert HA, et  al. Diagnosis and management of arterial compression at the thoracic outlet. Ann Vasc Surg. 1997;11:359–66. 28. Adams JT, DeWeese JA. “Effort” thrombosis of the axillary and subclavian veins. J Trauma. 1971;11:923–30. 29. Adams JT, DeWeese JA, Mahoney EB, Rob CG. Intermittent subclavian vein obstruction without thrombosis. Surgery. 1968;68:147–65. 30. Zimmerman R, Morl H, et  al. Urokinase ther apy of subclavian-axillary vein thrombosis. Klin Wochenschr. 1981;59:851–6. 31. Taylor LM, Mcallister WR, et  al. Thrombolytic therapy followed by first rib resection for spontaneous (“effort”) subclavian vein thrombosis. Am J Surg. 1985;149:644–7. 32. Perler BA, Mitchel SE.  Percutaneous transluminal angioplasty and transaxillary first rib resection: a multidisciplinary approach to the thoracic outlet compression syndrome. Am Surg. 1986;52:485–97. 33. Kunkel JM. Treatment of Paget-Schroetter syndrome: a staged, multidisciplinary approach. Arch Surg. 1989;124:1153–8. 34. Machleder HI. Evaluation of a new treatment strategy for Paget-Schroetter syndrome: spontaneous thrombosis of the axillary-subclavian vein. J Vasc Surg. 1993;17:305–17. 35. Illig KA, Thompson RW, Freischlag JA, Donahue DM, Jordan SE, Edgelow PI, editors. Thoracic outlet syndrome. London: Springer; 2013. 36. Illig KA, Donahue D, Duncan A, Freischlag J, Gelabert H, Johansen K, et  al. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. J Vasc Surg. 2016 Sep;64(3):e23–35. 37. Henry BM, Tomaszewski KA, Walocha JA. Methods of evidence-based anatomy: a guide to conducting systematic reviews and meta-analysis of anatomical studies. Ann Anat. 2016 Dec;205:16–21. 38. Bots J, Wijnaendts L, Delen S, Van Dongen S, Heikinheimo K, Galis F. Analysis of cervical ribs in a series of human fetuses. J Anat. 2011 Jun;219:403–9. 39. Rinehardt EK, Scarborough JE, Bennett KM. Current practice of thoracic outlet decompression surgery in the United States. J Vasc Surg. 2017;66:858–65. 40. Phair J, Trestman EB, Skripochnik E, Lipsitz EC, Koleilat I, Scher LA. Why do vascular surgeons get sued? analysis of claims and outcomes in malpractice litigation. Ann Vasc Surg. 2018 Aug;51:25–9. https:// doi.org/10.1016/j.avsg.2018.02.024.

16 41. Gelabert HA, Rignberg DA, O’Connell JB, Jabori S, Jimenez JC, Farley S.  Transaxillary decompression of thoracic outlet syndrome patients presenting with cervical ribs. J Vasc Surg. 2018 Apr;68(4):1143–9. https://doi.org/10.1016/jvs.2018.01.057. 42. Orando MS, Likes K, Mirza S, Freischlag JA. A decade of excellent outcomes after surgical i­ntervention in 538 patients with thoracic outlet syndrome. J Am Coll Surgeons. 2015 Jan;220(5):934–9. 43. Hong J, Pisapia JM, Ali ZS, Heuer AJ, Alexander E, Heuer GG, et  al. Long-term outcomes after surgical treatment of pediatric neurogenic thoracic outlet syndrome. J Neurosurg Pediatr. 2018 Jan;21(1):54–64. 44. Balderman J, Holzem BS, Field BJ, Bottros MM, Abuirqeba AA, Vemuri C, et al. Associations between clinical diagnostic criteria and pretreatment patient-­ reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2017;66:533–44. 45. Jordan SE, Ahn SS, Gelabert HA. Combining ultrasonography and electromyography for botulinum chemodenervation treatment of thoracic outlet syndrome: comparison with fluoroscopy and electromyography guidance. Pain Physician. 2007 Jul;10(4):541–6. 46. Godoy IR, Donahue DM, Torriani M.  Botulinum toxin injections in musculoskeletal disorders. Semin Musculoskelet Radiol. 2016 Nov;20(5):441–52. 47. Archie M, Rigberg D.  Vascular TOS—creating a protocol and sticking to it. Diagnostics (Basel). 2017 Jun;7(2):34. 48. Freischlag JA.  The art of caring in the treatment of thoracic outlet syndrome. Diagnostics (Basel). 2018 Jun;8(2):36.

H. I. Machleder 49. Povisen B, Hansson T.  Treatment for Thoracic Outlet Syndrome, Cochrane Database Syst Rev. 2014;26(11):CD007218. 50. Peek J, Vos CG, Unlu C, van de Pavoordt HD, van den Akker PJ, de JPM V. Outcome of surgical treatment for thoracic outlet syndrome: systematic review and meta-analysis. Ann Vasc Surg. 2017 Apr;40:303–26. 51. Oregon Overshoots on Opioids. (Headline). Wall Street Journal; Friday August 17, 2018. 52. Daube JR.  Nerve conduction studies in the thoracic outlet syndrome. Neurology. 1975;25:347–52. 53. Eisen A, et al. Application of F wave measurements in the differentiation of proximal and distal upper limb entrapments. Neurology. 1977;27:662–8. 54. Yiannikas C, Walsh JC.  Somatosensory evoked responses in the diagnosis of thoracic outlet syndrome. J Neurol Neurosurg Psychiatry. 1983;46:234–40. 55. Machleder HI, Moll F, Nuwer M, Jordan S. Somatosensory evoked potentials in the assessment of thoracic outlet compression syndrome. J Vasc Surg. 1987;6:177–84. 56. Haghighi SS, et al. Sensory and motor evoked potential findings in patient with thoracic outlet syndrome. Electromyogr Clin Neurophysiol. 2005;45(3):149–54. 57. Gilliat RW, et al. Wasting of the hand associated with a cervical rib or band. J Neurol Neurosurg Psychiatry. 1970;33:615–24. 58. Relman AS.  Editorial: responsibilities of author ship: where does the buck stop? N Engl J Med. 1984;310:1048–9. 59. Stewart P Justice. U.S. Supreme Court. Jacobellis v. Ohio, 378 U.S. 184 (1964).

3

Embryology of the Thoracic Outlet R. Shane Tubbs and Mohammadali M. Shoja

Abstract

The thoracic outlet is the area in the lower neck traversed by the brachial plexus and subclavian vessels between the thorax and axilla. This dynamic space is formed by the first thoracic vertebra, first rib, and manubrium of the sternum. The thoracic outlet changes in volume with the movement of the upper limbs, thorax, and neck, is occupied by scalene and prevertebral muscles and fibrous structures, and is limited by osseous structures—the clavicle, first rib, and cervical vertebrae and their transverse processes. During upper limb abduction, patients with thoracic outlet syndrome (TOS) have been found to decrease the space of the outlet more compared to healthy individuals.

The thoracic outlet (superior thoracic aperture) is the area in the lower neck traversed by the brachial plexus and subclavian vessels between the thorax and axilla. Osteologically, this dynamic space is formed by the first thoracic vertebra, first rib, and manubrium of the sternum (Fig.  3.1). The thoracic outlet changes in volume with the R. S. Tubbs (*) Tulane University School of Medicine, New Orleans, LA, USA e-mail: [email protected] M. M. Shoja Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

movement of the upper limbs, thorax, and neck, is occupied by scalene and prevertebral muscles and fibrous structures, and is limited by osseous structures—the clavicle, first rib, and cervical vertebrae and transverse processes. During upper limb abduction, patients with thoracic outlet syndrome (TOS) have been found to decrease the space of the outlet more compared to healthy individuals [1]. The embryogenesis of the thoracic outlet is a function of harmonious and timely growth of regional osseous, fibromuscular and neurovascular elements with the emerging upper limb bud. Any disturbance in the interaction or development of these elements affects spatial features of the outlet. From a morphological point of view, the thoracic outlet is a heterogeneous region with inter-individual variability and individuals with substantially distorted outlet contours or a crowded outlet are prone to develop TOS. In this chapter, the general aspects of the development of the thoracic outlet region are described followed by an overview of the embryology of common osseous and fibromuscular anomalies associated with TOS.

3.1

Neurovascular Development

The subclavian vessels and brachial plexus traverse the thoracic outlet. The left subclavian artery arises from the left seventh intersegmental

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_3

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R. S. Tubbs and M. M. Shoja

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Fig. 3.1  Left: lateral view of the thoracic outlet from the skeleton of a 30-week-old fetus. Notice the more horizontal nature of the manubrium (black arrow) as compared to

the adult and the increased concavity of the first rib (white arrow); Right: anterior view noting the right first rib (black arrow) and body of the T1 vetebra (asterisk)

artery and from proximal to distal, the right subclavian artery arises from the fourth aortic arch, right dorsal aorta (between the fourth and the seventh intersegmental arteries), and the right seventh intersegmental artery. The subclavian veins form from the fusion of venous tributaries from the upper limb bud and the ventral rami that will form the brachial plexus begin budding from the neural tube by the end of the first month of gestation and grow toward their respective slerotomes and myotomes [2]. The slerotome of the upper thoracic region gives rise to the first thoracic vertebra. Normally, only the costal processes of the thoracic vertebrae give rise to ribs with the first rib joining the manubrium, which in turn is formed from the upper mesenchymal condensations that make up the sternebrae [2]. If the costal elements of the seventh cervical vertebrae grow in a similar manner, an anomalous cervical rib forms.

3.2

Cervical Ribs

Anomalous elongation of the costal process of the seventh cervical vertebrae (cervical rib) (Fig. 3.2) has a wide range of frequency and has been reported to be present in 0.1–6.1% of otherwise healthy individuals [3–5]. Although such variability can perhaps suggest that different ethnic groups could be more susceptible to thoracic outlet abnormalities, the validity of this assertion remains to be determined. During the development of the cervical vertebrae, cartilaginous costal elements are incorporated into the anterior and posterior tubercles and the intertubercular lamella of the transverse processes [6]. The anterior tubercle and intertubercular lamella of C7 are ill developed [7]. The endochondral ossification of the C7 costal element with the growth zone located at its medial margin acts as a precursor to a supernumerary rib [8]. A separate,

3  Embryology of the Thoracic Outlet

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Fig. 3.3  Schematic drawing of the right brachial plexus as it is deflected superiorly (especially the lower trunk formed by C8 and T1 ventral rami) by an anomalous cervical rib

Fig. 3.2  Right neck from a cadaver found to harbor a cervical rib (arrow), which binds itself to the first rib (FR) via a fibrous band. Also note the middle (MS) and anterior scalene (AS) muscles and the lower trunk (LT) of the brachial plexus

ossified costal element of C7 has been seen in up to 63% of stillborn human fetuses and as early as 14 weeks of gestation [9]. The dramatic reduction in the incidence of cervical ribs in adult humans implies an age-related process of absorption of the ossified costal element into the transverse processes of cervical vertebrae [3]. Cervical ribs may cause both neurogenic (Fig. 3.3) and arterial TOS [10]. The length of a supernumerary rib is also a determinant of the severity of compression. As cited in Makhoul and Machleder, Lang noted that cervical ribs greater than 5.6  cm in length pass beneath the subclavian artery and are more likely compress it [11]. Familial forms of TOS have been reported with apophysomegaly of the C7 transverse process or formation of a cervical rib [12, 13]. An autosomal dominant inheritance has been suggested for such cases [14].

The mechanisms by which ossification of the C7 costal element and extent of growth and persistence of a cervical rib are directed have yet to be understood. Prenatal exposure to various toxic substances (e.g. valproic acid, retinoic acid, nitrous oxide, methanol) and disturbances in early organogenesis induce formation of cervical rib in some animals [15, 16]. An early attempt to understand the appearance of a cervical rib was made by Todd [17]. He attested that nerve and vessels at the thoracic outlet are the main limiting factors for the formation and size of cervical ribs. He distinguished several types of cervical ribs; some terminated behind the nerve trunk, some between the nerve and artery and others between the artery and vein, possibly indicating that the nerve, artery or vein, respectively, limits the growth of the cervical rib during embryogenesis. Jones (as cited in Adson and Coffey [18]) suggested that with the outgrowing upper limb bud, the developing nerve trunks tend to course more or less obliquely. As the embryonic nerve trunk is proportionally larger than the ribs, the conflict between the obliquely oriented nerve and rib is in favor of the former, ultimately impeding the growth of the cervical rib.

R. S. Tubbs and M. M. Shoja

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Embryogenetics: Abnormalities in Hox gene expression affect the development of the thoracic outlet [19]. HOX genes are a cluster of homeobox-­ containing genes expressed along the anteroposterior axis of the developing skeleton which determine the segmental fate of the vertebral column [20, 21]. It has been postulated that formation of cervical ribs represent an error in HOX gene expression and thus the segmental identity of cervical and thoracic vertebrae [19, 22]. Alterations in homeotic transformation of the axial skeleton are often associated with fatal congenital malformations and are strongly ­ selected against during development [23]. However, minor abnormalities such as formation of cervical ribs may escape this negative selection and persists through postnatal life.

3.3

Scalene Muscles

The scalene muscles occupy much of the thoracic outlet. Embryologically, the scalene muscles are derived from hypaxial mesoderm of the hypomere of somital myotomes in much the same way as the intercostal muscles. While derivatives of the thoracic hypaxial mesoderm connect ribs, those of the lower cervical mesoderm extend from the transverse processes of cervical vertebrae to the upper ribs. Other local mesodermal components regress or transform into loose connective tissue or occasionally dense fibrous or ectopic/supernumerary muscular slips. Interestingly, in one series, single or multiple developmental anomalies were found in the thoracic outlet region in two thirds of surgical patients with TOS [11]. Developmental anomalies associated with TOS are classified into fibromuscular or osseous abnormalities [24, 25], and it is not uncommon to find a combination of both in a single patient [24]. Osseous abnormalities (e.g. cervical rib, abnormal first rib, or elongated C7 transverse process) are less common than fibromuscular anomalies, but are more likely to induce significant compressive symptoms or vascular TOS [26, 27]. Molecular aspects of these abnormalities (formation of dense fibrous or ectopic/supernumerary muscular strips) remain to be fully

explored. It is known that precursor cells giving rise to hypaxial muscles undergo migration and myogenesis under the influence of various signals from dorsal ectoderm, lateral mesoderm and the developing limb buds [28, 29]. Congenital Anomalies of the Scalene Muscles: Congenital anomalies of the scalene muscles ranging from supernumerary muscle slips to muscle contraction and fibrosis account for a significant proportion of TOS cases. In one series, more than half of TOS patients without a cervical rib or other osseous abnormality had a scalene muscle anomaly crowding the interscalenic triangle [30]. Comments regarding the ontogeny of the scalene muscles are rarely found in the literature. Machelder [10] cited Millez and Poitevin who mentioned two relevant hypotheses: First, by the eighth week of gestation (2.5 cm embryo), a common scalene muscle mass develops and later separates into distinct muscle groups by traversing neurovascular bundles. As a consequence of segmentation defects, the scalenic mass may give rise to supernumerary muscle slips, e.g. scalenus minimus. Ectopic mesenchymal masses may transform into an anomalous muscle. One hypothesis is that supernumerary scalene muscles are remnants of the mesodermal mass, which normally regresses during embryogenesis. More than ten fibromuscular anomalies of the thoracic outlet have been described in the literature. These anomalies may lead to compression of the brachial plexus anterior and/or posterior to the C5-T1 nerve trunks [26]. Anomalies posterior to the brachial plexus are more likely to cause symptomatic TOS [26]. Females have a predilection to combined anterior and posterior anomalies causing V-shaped impingement of the brachial plexus [26]. The most common anomaly is a ligamentous band that extends from the neck of the first rib to the inner surface of the first rib just behind the distal insertion of the anterior scalene muscle onto the scalenic tubercle (called by some an “outlet band”). Roos found this anomaly in 146 (61%) out of 241 operations for TOS [25]. The scalenus minimus and scalenus pleuralis muscles are well described and extend from C7 and/or rarely C6 transverse processes to the inner border of the first rib or the suprapleural fascia of

3  Embryology of the Thoracic Outlet Table 3.1  Roos’ classification of fibromuscular anomalies associated with neurogenic TOS Involvement of upper and middle trunks of brachial plexus A muscle strip that passes between C5 and C7, and connects the anterior and middle scalene muscles (interscalenic muscle) An anomalous anterior scalene that is mixed with the middle scalene muscle superiorly and traverses between C5 anteriorly and C6-T1 posteriorly An anterior scalene muscle with attachments to the epineurium of the upper trunk of brachial the plexus A fused anterior-middle scalenic muscle mass through which the brachial plexus traverses A vertical fibrous mass parallel to the vertebral column and anterior to the origin of the brachial plexus Scalenus minimus muscle (see text) A fibromuscular connection between the anterior and middle scalene muscles in the mid-portion of the inter-scalenic triangle Involvement of lower trunk of brachial plexus A fibrous band connecting the tip of an incomplete cervical rib to the mid-shaft of the first rib A fibrous band connecting an elongated C7 transverse process to the upper surface of the first rib A fibrous band connecting the neck of the first rib to the mid-shaft An anomalous middle scalene muscle with an anterior extension of the distal insertion over the first rib Scalenus minimus muscle (see text) Scalenus pleuralis muscle (see text) A fibromuscular band extending anteriorly from the lower portion of the middle scalene muscle beneath the lower trunk and subclavian vessels and attaching to the costal cartilage and sternum A fibromuscular band extending anteriorly from the anterior scalene beneath the subclavian vein and attaching to the subclavius muscle and costoclavicular joint A fibromuscular band along the posterior inner surface of the first rib A fibromuscular band along the inner surface of the first rib from the rib neck to the sternum Based on data from reference [36] Note that other fibromuscular anomalies may exist that do not fit into the Roos classification, e.g. a fibrous band extending from the T1 vertebra to the inner surface of the first rib separating T1 from the C8 nerve root [32], a band from the C7 transverse process to the middle scalene separating the C8-T1 nerve root and subclavian artery from the C5–C7 nerve roots [32], a muscular slip from the anterior scalene muscle attaching to the first rib between the subclavian artery and brachial plexus [26], etc.

Sibson, respectively [31]. The scalenus minimus muscle is found in 15–88% of thoracic outlets [32, 33]. This muscle passes between the subcla-

21

vian artery anteriorly and the brachial plexus posteriorly, is occasionally replaced by a fibrous band or ligament, usually has attachment to Sibson’s fascia, and can lead to irritation of the lower part of the brachial plexus [33, 34]. An anomalous distal insertion of the scalenus minimus onto the scalene tubercle of the first rib causes elevation and compression of the subclavian artery [35]. It should be noted that many ­clinicians simply describe any muscle fibers that pass between the trunks of the brachial plexus as the scalenus minimus. Finally, a fibrotic band running from C7 to the first rib can be labeled as either a “middle scalene band” or simply as a non-ossified cervical rib. In up to approximately 50% of TOS patients without osseous anomalies, the distal insertion of the scalene medius is extended anteriorly behind the scalenus anterior muscle. A common distal insertion of the anterior and middle scalene muscles, or overlapping distal insertions, referred to as intercostalization of the scalene muscle has been described [11]. Table 3.1 summarizes fibromuscular congenital anomalies associated with neurogenic TOS.

References 1. Smedby O, Rostad H, Klaastad O, Lilleås F, Tillung T, Fosse E.  Functional imaging of the thoracic outlet syndrome in an open MR scanner. Eur Radiol. 2000;10:597–600. 2. Larsen WJ, Sherman LS, Potter SS.  Human embryology. 3rd ed. Philadelphia: Churchhill Livingstone; 2001. 3. Chernoff N, Rogers JM. Supernumerary ribs in developmental toxicity bioassays and in human populations: incidence and biological significance. J Toxicol Environ Health B Crit Rev. 2004;7:437–49. 4. Merks JH, Smets AM, Van Rijn RR, Kobes J, Caron HN, Maas M, et  al. Prevalence of rib anomalies in normal Caucasian children and childhood cancer patients. Eur J Med Genet. 2005;48:113–29. 5. Brewin J, Hill M, Ellis H.  The prevalence of cervical ribs in a London population. Clin Anat. 2009;22:331–6. 6. Cave AJE. The morphology of the mammalian cervical pleurapophysis. J Zool. 1975;177:377–93. 7. O’Rahilly R, Müller F, Meyer DB.  The human vertebral column at the end of the embryonic period proper. 2. The occipitocervical region. J Anat. 1983;136:181–95.

22 8. Meyer DB.  The appearance of ‘cervical ribs’ during early human fetal development. Anat Rec. 1978;190:481. 9. McNally E, Sandin B, Wilkins RA.  The ossification of the costal element of the seventh cervical vertebra with particular reference to cervical ribs. J Anat. 1990;170:125–9. 10. Machleder HI.  Thoracic outlet syndrome. In: White RA, Hollier LH, editors. Vascular surgery: basic science and clinical correlations. 2nd ed. Malden: Blackwell Publishing; 2005. p. 146–61. 11. Makhoul RG, Machleder HI. Developmental anomalies at the thoracic outlet: an analysis of 200 consecutive cases. J Vasc Surg. 1992;16:534–42. 12. Weston WJ.  Genetically determined cervical ribs; a family study. Br J Radiol. 1956;29:455–6. 13. Boles JM, Missoum A, Mocquard Y, Bastard J, Bellet M, Huu N, et  al. A familial case of thoracic outlet syndrome. Clinical, radiological study with treatment [French]. Sem Hop. 1981;57:1172–6. 14. Schapera J. Autosomal dominant inheritance of cervical ribs. Clin Genet. 1987;31:386–8. 15. Rengasamy P, Padmanabhan RR. Experimental studies on cervical and lumbar ribs in mouse embryos. Congenit Anom (Kyoto). 2004;44:156–71. 16. Steigenga MJ, Helmerhorst FM, de Koning J, Tijssen AM, Ruinard SA, Galis F.  Evolutionary conserved structures as indicators of medical risks: increased incidence of cervical ribs after ovarian hyperstimulation in mice. J Anim Biol. 2006;56:63–8. 17. Todd TW. “Cervical Rib”: Factors controlling its presence and its size. Its bearing on the morphology and development of the shoulder. J Anat Physiol. 1912;46:244–88. 18. Adson AW, Coffey JR. Cervical rib: a method of anterior approach for relief of symptoms by division of the scalenus anticus. Ann Surg. 1927;85:839–57. 19. Galis F.  Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes, and cancer. J Exp Zool. 1999;285:19–26. 20. Burke AC, Nelson CE, Morgan BA, Tabin C.  Hox genes and the evolution of vertebrate axial morphology. Development. 1995;121:333–46. 21. Ferrier DE, Holland PW.  Ancient origin of the Hox gene cluster. Nat Rev Genet. 2001;2:33–8. 22. Horan GS, Kovàcs EN, Behringer RR, Featherstone MS.  Mutations in paralogous Hox genes result in overlapping homeotic transformations of the axial skeleton: evidence for unique and redundant function. Dev Biol. 1995;169:359–72.

R. S. Tubbs and M. M. Shoja 23. Galis F, Van Dooren TJ, Feuth JD, Metz JA, Witkam A, Ruinard S, et  al. Extreme selection in humans against homeotic transformations of cervical vertebrae. Evolution. 2006;60:2643–54. 24. Roos DB.  Pathophysiology of congenital anoma lies in thoracic outlet syndrome. Acta Chir Belg. 1980;79:353–61. 25. Roos DB. Congenital anomalies associated with thoracic outlet syndrome: anatomy, symptoms, diagnosis, and treatment. Am J Surg. 1976;132:771–8. 26. Redenbach DM, Nelems B.  A comparative study of structures comprising the thoracic outlet in 250 human cadavers and 72 surgical cases of thoracic outlet syndrome. Eur J Cardiothorac Surg. 1998;13:353–60. 27. Sanders RJ, Hammond SL. Management of cervical ribs and anomalous first ribs causing neurogenic thoracic outlet syndrome. J Vasc Surg. 2002;36:51–6. 28. Krüger M, Mennerich D, Fees S, Schäfer R, Mundlos S, Braun T.  Sonic hedgehog is a survival factor for hypaxial muscles during mouse development. Development. 2001;128:743–52. 29. Ordahl CP, Williams BA, Denetclaw W. Determination and morphogenesis in myogenic progenitor cells: an experimental embryological approach. Curr Top Dev Biol. 2000;48:319–67. 30. Thomas GI, Jones TW, Stavney LS, Manhas DR.  The middle scalene muscle and its contribution to the thoracic outlet syndrome. Am J Surg. 1983;145:589–92. 31. Bergman RA, Afifi AK, Miyauchi R. Illustrated encyclopedia of human anatomic variation: opus I: muscular system: alphabetical listing of muscles. 2011. http://www.anatomyatlases.org/AnatomicVariants/ MuscularSystem/Text/S/04Scalenus.shtml. Accessed 15 Apr 2011. 32. Juvonen T, Satta J, Laitala P, Luukkonen K, Nissinen J. Anomalies at the thoracic outlet are frequent in the general population. Am J Surg. 1995;170:33–7. 33. Chen D, Fang Y, Li J, Gu Y.  Anatomical study and clinical observation of thoracic outlet syndrome [Chinese]. Zhonghua Wai Ke Za Zhi. 1998;36:661–3. 34. Stott CF. A note on the scalenus minimus muscle. J Anat. 1928;62:359–61. 35. Boyd GI.  Abnormality of subclavian artery associated with presence of the scalenus minimus. J Anat. 1934;68:280–1. 36. Brantigan CO, Roos DB. Etiology of neurogenic thoracic outlet syndrome. Hand Clin. 2004;20:17–22.

4

Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs Frietson Galis, Pauline C. Schut, Titia E. Cohen-­Overbeek, and Clara M. A. ten Broek

Abstract

Ribs on the seventh cervical vertebra, so-­ called cervical ribs, imply a change of the highly conserved number of cervical vertebrae in mammals from seven to six. Cervical ribs are rare in the general population, but they are common in deceased fetuses and infants. There is strong, often prenatal, selection against individuals with cervical ribs and as such, cervical ribs can be seen as marker of a disturbed early embryogenesis which may include congenital abnormalities of all organ systems. The almost unavoidable association with many different abnormalities appears to be due to the high global interactivity during the embryonic patterning of the cervical vertebrae. This strong interactivity can also explain the large heterogeneity of genetic and environmental causes of cervical ribs. In other mammals cervical ribs are also associated with abnormalities. Exceptionally the slow sloths and manatees can tolerate some of these norF. Galis (*) · C. M. A. ten Broek Naturalis Biodiversity Center, Leiden, The Netherlands e-mail: [email protected] P. C. Schut · T. E. Cohen-Overbeek Department of Obstetrics and Gynecology, Division of Obstetrics and Prenatal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands

mally deleterious side-effects, which has apparently allowed them to evolve an abnormal cervical vertebral number. In long-necked reptiles and birds, there is no constraint on changes of the number of cervical vertebrae.

Critical Take-Home Messages  1. Cervical ribs are an exception to the highly conserved number of seven cervical vertebrae in mammals. They are common in miscarriages but rare in the healthy general population (~50% vs ~1%). 2. Cervical ribs in deceased fetuses and infants are often associated with multiple and major congenital abnormalities and in pediatric patients with specific cancers. 3. Cervical ribs are caused by a wide variety of genetic or environmental disturbances of the early head-to-tail patterning of the embryo. 4. The interactivity of the early head-to-tail patterning is probably the cause of the frequent and variable side-effects. 5. There is a strong selection against changes of the number of cervical vertebrae in mammals. Cervical ribs are ribs on the seventh, normally ribless, vertebra (Figs. 4.1 and 4.2). They are the result of a partial or full (homeotic) transformation of the seventh cervical vertebra into a thoracic rib-bearing vertebra, which results from a change in the expression of Hox genes during

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_4

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a

b

c

Fig. 4.1 (a) Vertebral column and sternum of a 24 year old woman. The seventh vertebra has bilaterally rudimentary cervical ribs, on the right one with an articulation with the transverse process, on the left one that is fused with the transverse process, also called an apophysomegaly. The 19th vertebra has bilaterally rudimentary ribs, on the left longer than on the right. The 24th vertebra is a transitional lumbosacral vertebra, more sacral than lumbar in character. (b) Vertebral column and sternum of an 80  year old woman. The seventh vertebra has two short cervical ribs that are fused with the transverse processes. The 19th vertebra has rudimentary ribs. There are only

four lumbar vertebrae, the normally fifth one has been transformed into a sacral vertebra. Note that the sacrum has six vertebrae. (c) Vertebral column and sternum of a 29 year old man. The first thoracic vertebra has rudimentary ribs. The 20th vertebra has bilateral large ribs (lumbar ribs). The 25th vertebra is lumbar (a lumbarization of the first sacral vertebra). The fourth rib is abnormally enlarged on the right, the sternum is asymmetric and the fourth cervical vertebra is anomalous in shape. Note that in all three vertebral columns, there are, partial or full, homeotic transformations at the cervicothoracic, thoracolumbar and lumbosacral boundary. (From Fischel 1906)

early development. The number of cervical vertebrae is remarkably constant in mammals. Even giraffes with their long necks have seven cervical vertebrae, unlike long-necked birds and reptiles which always have a large number of cervical vertebrae, allowing for longer and more flexible necks (Fig. 4.2). In the giraffe, the neck is quite stiff, because of the relatively few and extremely long vertebrae and as a consequence, considerable force is necessary to lift it. Despite the long vertebrae the neck is still too short to reach the ground, unless the front legs are spread wide apart, making it vulnerable for predators when

drinking (Fig. 4.3). Although the number of cervical vertebrae in mammals is most often constant, the other vertebral regions of mammals are variable in number, with bottlenose whales having nine thoracic vertebrae and elephants 19–21 and anteaters having 2–3 lumbar vertebrae and Indri lemurs 8–9 [2, 3]. Despite the constancy of the number of cervical vertebrae in mammals, cervical ribs, which change this number, are quite common in certain circumstances. For example, in deceased fetuses and infants the prevalence is particularly high (33–63% [1, 4–6]), much higher than in the gen-

4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs

a

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Fig. 4.2  Cleared and stained fetuses with different vertebral patterns. (a) A fetus of ±12 weeks. The seventh cervical vertebra has on the left a rib, but not on the right. Rudimentary 12th right thoracic rib. (b) A fetus of ±13 weeks old. The seventh vertebra has bilateral cervical ribs and an absent (left) and a rudimentary (right) 12th

thoracic rib. (c) a fetus of CR. (c) A fetus of ±13 weeks old with a normal vertebral pattern. Note that at these stages cervical ribs can not yet be detected in standard radiographs, which is possible from approx. 14 weeks onwards [1] (From Bots et  al. 2011, Collection, Institute of Dentistry, University of Turku, Finland)

eral population (1% or less, [4, 5, 7, 8]). The striking disparity between fetal and adult incidence has led to two hypotheses. The first h­ ypothesis is that most of the cervical ribs, in particular the small ones, disappear after birth by fusing with the transverse process of the seventh vertebra [1, 9, 10]. The second hypothesis is that the frequency of cervical ribs is high in deceased fetuses and infants, but not in those that stay alive and, hence, most cervical ribs do not disappear [4–6].

after birth. Nonetheless is it quite likely that when tiny rib ossification centers of cervical ribs fuse with the transverse process they may not be detectable at a later stage. The enlarged transverse processes will not always project beyond those of the first thoracic vertebra, which is usually the diagnostic criterion for such small fused cervical ribs (also called apophysomegalies, [8, 11]). In this sense, the tiniest cervical ribs will, thus, disappear. However, the majority of cervical ribs that can be detected on radiographs, do not seem to disappear postnatally. Three arguments support this hypothesis. Firstly, the frequency of cervical ribs detected in radiographs of deceased fetuses and infants does not decline with age and there is no significant difference between fetuses and infants

4.1

 ervical Ribs Do Not C Disappear

There is no empirical support for the first hypothesis, stating that most cervical ribs disappear

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Fig. 4.3  The long neck of the giraffe has only seven vertebrae, which makes it rather stiff, such that lifting it costs considerable force. Despite the long vertebrae, the neck is not long enough to reach the ground, unless the front legs are spread wide apart, an awkward position that makes the

giraffe vulnerable to predators. A large number of vertebrae contributes to make a long and flexible neck in flamingoes. (a) and (c) reproduced from Owen (1866). (b) From Evans (1900). (d) Drawing by Erik-Jan Bosch (Naturalis)

(Fig. 4.4b), [4, 5, 12]. Disappearance of cervical ribs in yet older children is unlikely, given the advanced stage of ossification during the last gestational stages and in infants (Fig. 4.5). In the first year, responses of the first rib to the adjacent presence of cervical ribs or ligaments projecting from it can already been seen (Fig.  4.5c). Additionally, the incidence of cervical ribs does

not appear to be lower in adults than in children in the general population [8, 13] vs [7], or in comparisons of patient populations (mainly infectious and pulmonary diseases, [5, 6]). The second argument is that at least half of the cervical ribs in deceased fetuses and infants ­co-­occur with other, homeotic transformations that do not disappear with age, i.e. rudimentary or

4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs

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Fig. 4.4 (a) Schematic representation of a regular vertebral pattern (R) on the right side and on the left with shifts of the cervicothoracic (CT), thoracolumbar (TL) and lumbosacral (LS) boundary (pattern CT  +  TL  +  LS). (b–e) Vertebral patterns are indicated with R for regular (light green shade) and with shifts of specific boundaries: LS, TL, TL + LS (darker green shades), CT, CT + LS, CT + TL, CT + TL + LS (blue shades). All blue shades indicate vertebral patterns with cervical ribs and vertebral patterns without cervical ribs have different shades of green. See (a) for an explanation. (b) Frequencies of vertebral patterns for deceased fetuses and infants with different ages at death (excluding those prematurely terminated for medical reasons) in comparison with the overall pattern and that for those without anomalies. Age groups: abortions (up to 22 weeks old), fetal deaths (>22 weeks), neonatal mortality (early, 0–6 days and late, 7–27 days), post-neonatal infant mortality (27 days–1 year). There is no significant relationship with age and, hence, no decrease in the number of cervical ribs over time. (c) Frequencies of vertebral patterns for fetuses and infants with different aneuploidies, Tris 13, 18, 21, Turner and Klinefelter syndrome. The frequency of a normal vertebral pattern is highest in the subgroup with Klinefelter syndrome, in agreement with the highest sur-

Fetal Mortality

Early Neon. Mort

Late Neon & Infant

vival for this group. Turner syndrome is virtually always accompanied by cervical ribs and, additionally, for Tris 13 and 18 the majority also has cervical ribs. (d) Frequencies of vertebral patterns for deceased foetuses and infants with different numbers of affected organ systems. The group with no anomalies (No Anom), has the highest prevalence of regular patterns, followed by the no malformations (No Mal) malformations group. The group with more than three affected organ systems has the largest frequency of cervical ribs and of the most abnormal vertebral pattern (CT + TL + LS). (e) Frequencies of vertebral patterns for deceased foetuses and infants with malformations of different organ systems. Malformations are indicated for the different organ systems: MS Muscular System, NS Nervous System, UG Urogenital System, CV Cardiovascular System, BP Bronchopulmonary System, LD Limb Defects, VBW Ventral Body Wall Defects, DS Digestive System, SK Skeletal Malformations, CF Craniofacial Malformations, No Mal No Malformations. The group with no anomalies (No Anom), has the highest incidence of regular patterns and the lowest incidence of cervical ribs and the groups with skeletal and craniofacial malformations have the lowest incidence of regular patterns and the highest incidence of cervical ribs. Data ref. [4, 5, 12]

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c 100%

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4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs

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Fig. 4.4 (continued)

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Fig. 4.5  Radiographs showing cervical ribs in deceased full term foetuses and an infant. (a) Fetus that died at ±39 weeks, with bilaterally small cervical ribs that clearly protrude beyond the first transverse process of the first thoracic vertebra. (b) Fetus that died at ±40 weeks with bilaterally cervical ribs, on the left much larger than on the

right. (c) Infant that died 5 months old (SID) with bilaterally small cervical ribs. Note the bilateral bulges on the first thoracic ribs that are most likely in response to the nearby presence of cervical ribs or ligaments projecting from it. Radiographs: Institute of Pathology, Division Photography, Free University Medical Center, Amsterdam

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absent twelfth ribs, a missing fifth lumbar vertebra, or a transitional lumbosacral vertebra (Fig. 4.4, cf. light blue bars for single cervical ribs with darker blue bars, cervical ribs co-­occurring with other homeotic transformations). Interestingly, the co-occuring shifts at vertebral boundaries are virtually always in the same direction, either rostrad shifts or, more rarely, caudad (see Fig.  4.1) [14, 15]). Transformations of vertebrae in the middle of a region are more difficult to detect on radiographs, as the differences are only subtle. However, detailed observations on human skeletons by [15, 16] have shown that cervical ribs are often associated with partial homeotic transformations of several adjacent cervical and thoracic vertebrae, for instance larger first thoracic ribs. The third argument supporting the hypothesis that cervical ribs do not disappear, is the strong association of cervical ribs in deceased fetuses and infants with multiple and major congenital abnormalities and in children with specific embryonal tumors, see below [4, 5, 11, 17–19]. These major abnormalities indicate a disturbed early embryogenesis, which is likely to have played a role in the causation of the early deaths. I.e. cervical ribs are not common in all fetuses, but only in those that die. As ultrasound was not available yet, earlier research was only conducted on deceased fetuses, which involves a selection bias.

4.2

 Plethora of Coexisting A Malformations

Cervical ribs appear to be associated with a multitude of coexisting malformations. In deceased human fetuses and infants, they were found to be associated with abnormalities of all organ systems, including cardiovascular, nervous, bronchopulmonary, digestive system, craniofacial, skeletal and urogenital abnormalities (Fig. 4.4c) [4, 5, 12]. The strongest association was found with segmentation defects, such as fused vertebrae, which, almost without exception, co-occur with cervical ribs [4]. Particularly strong associations were also found with neural crest-related, left-right, midline and skeletal defects. Examples are cleft lip/palate, anal

atresia, neural tube defects, bilateral kidney agenesis, horseshoe kidney, aberrant arteria subclavian dextra, ­ventricular septum defect, oligo/polydactyly, ventral body wall defects, bleeding disorders [5, 12]. Importantly, the more organ systems were affected in individuals, the higher the chance of cervical ribs and of the most disturbed vertebral patterns [4]. In contrast, when no anomalies were detected (also excluding infections, metabolic diseases, tumors or bleeding disorders), the majority of individuals had no cervical ribs (76%) and a normal vertebral pattern (Fig. 4.4d). As mentioned above, a high prevalence of cervical ribs is found in children with specific pediatric malignancies, including neuroblastoma, brain tumors and acute lymphoblastic leukemia, ranging from 12–33% [11, 17], see also [18, 19]. The associated congenital abnormalities and embryonal tumors are unlikely to be directly caused by cervical ribs, but presumably result from a common disturbance of early organogenesis. Cervical ribs can have direct effects, as discussed in this handbook, by pressure on nerves or arteries, which is called the thoracic outlet syndrome (TOS). TOS occurs after birth and usually only in adults. It appears to be positively associated with vigorous activity of the arms, such as in athletes and can lead to serious degenerative symptoms of the arm (this volume). Absent or rudimentary ribs on the first thoracic vertebra, the other way to change the number of cervical vertebrae, are rare, but they are also associated with major congenital abnormalities in deceased fetuses and infants and with TOS [5]. The pressure on nerves and arteries is often caused by anomalous fibrous or muscular bands (cervical bands) that tend to run from a cervical rib or an apophysomegaly to the first rib [20, 21]. The anomalous bands may be due to a slight mismatch between the shift of the head-to-tail patterning of the vertebral colum (i.e. cervical rib) and associated shifts of the neighbouring tissues [3, 4]. This may also explain the variability in the patterns of the brachial plexus that are associated with cervical ribs [3, 20]. An alternative or additional explanation for anomalous fibrous bands may be that they are part of the original cervical rib Anlage, that did not chondrify and ossify, but,

4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs

instead became ligamentous. Brent et  al. [22] showed that axial tendons and cartilage originate from a common pool of bipotent progenitors in the sclerotome, with chondrification suppressing tendon formation. If chondrification somehow does not happen, tendons are formed. This would explain the usual attachment of the fibrous bands to the distal part of the cervical ribs, or enlarged transverse processes (apophysomegaly, [21]). Distally the fibrous bands tend to be attached to the first ribs [15, 21]. This hypothesis would also explain that sometimes fibrous bands run all the way from the cervical, or rudimentary first rib, to the sternum (e.g. Fig. 7f in a manatee in ref. [3] and Fig. 1 of a horse in ref. [23]). Cervical ribs, like other rostral ribs, have the tendency to distally fuse with bone, normally with the sternum. However, when the sternum is too far away, as in the case of rudimentary ribs, they fuse with the adjacent rib, and in the case of the smallest of cervical ribs, with the transverse process of the vertebra (forming an apophysomegaly). Fibrous cervical bands may do the same.

31

netic processes that are going on at that time, such as division and migration of cells, cell shape changes, segmentation (somitogenesis), and the active maintenance of left-right symmetry of the somites from which the vertebrae develop (e.g. [24–26, 27–29]). The strong coupling between early head-to-tail patterning of the vertebral column and the active preservation of left-right symmetry of the somites can be easily seen in the marked asymmetry that often characterizes cervical ribs, rudimentary 12th and lumbar ribs and transitional lumbosacral vertebra (Figs. 4.1, 4.2, and 4.5).

4.4

Heterogeneity of Genetic and Environmental Causes for Cervical Ribs

The strong global interactivity in the embryo can not only explain the many congenital abnormalities that co-occur with cervical ribs, but also the large heterogeneity of genetic and environmental causes of cervical ribs. Many different genetic abnormalities can disrupt the patterning of early 4.3 Why Do Cervical Ribs organogenesis and lead to the induction of cervical ribs [5, 12, 30–32]. The strongest association Co-Occur with So Many is found with Turner syndrome which is virtually Abnormalities? always accompanied by cervical ribs in deceased The determination of the identity of cervical ver- fetuses and infants (Fig.  4.4e) [5, 30]. Further tebrae occurs during the highly interactive and strong associations were found with single gene, vulnerable early organogenesis stage. This deter- large deleterious CNVs [12] and most aneuploimination process forms part of the early head-to-­ dies (Fig. 4.4e) [5, 30, 32]. tail patterning of the mesoderm and is mediated Teratological experiments on mice and rats by the Hox genes (e.g. [24]). This is also the stage have shown that a wide variety of disturbances, when teratological treatments can induce cervical including heat shock, boric acid, valproic acid, ribs in rodents [5]. It is the intense global interac- salicylate and retinoic acid, can lead to shifts in tivity and the lack of modularity in the embryo the expression of Hox genes in the somatic mesothat are probably the cause of the many coexist- derm and concomitantly to the development of ing malformations. Teratology experiments have cervical ribs [33]. Shifts of the cervicothoracic shown that it is difficult to induce changes at this boundary are induced by earlier treatments than stage, without simultaneously inducing other more caudal shifts (e.g. [34]). Hence, when mulchanges. The interactivity and lack of modularity tiple regions of the vertebral column are affected results from the strong coordination between the by transformations (Figs. 4.1 and 4.2), the disturpatterning of the three body axes in the three bance of early development has presumably germ layers e.g. [25, 26]. The interactivity is fur- lasted for a longer time and concomitantly, the ther enhanced by the strong coupling between development of more organ systems is affected axial patterning and most, if not all, morphoge- (Fig. 4.4). Therefore, the timing and duration of

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the disruption of the patterning matters more than the specific nature of the disruption.

4.5

Evolutionary Selection Against Cervical Ribs and Exceptional Mammals

Cervical ribs are rarely found in the general population, both in humans and in other mammals. The majority of human individuals with a cervical rib is estimated to die before the age of 1 year (~90%, [5]). In contrast, the incidence of cervical ribs is quite high in inbred populations of dogs, minipigs and in declining woolly mammoth and woolly rhino populations shortly before their extinction in the Late Pleistocene ([36, 37], see also [38] on an isolated human population). As described above, the strong selection is often not directly against the presence of cervical ribs, but against the associated malformations: i.e. the multitude of deleterious coexisting problems dramatically limits the chances of individuals with cervical ribs to develop into viable adults [4, 5]. In addition, when individuals with a cervical rib survive the prenatal period and childhood with its risks for embryonal tumors, there may still be strong selection against cervical ribs when they cause TOS. This will be disadvantageous in most mammals and in humans also, at least in prehistoric times when athletic performance was more important. For similar reasons, in fast and agile mammals, domesticated dogs and inbred wolves transitional lumbosacral vertebrae are associated with biomechanical problems including pressure on blood vessels and nerves of the sacral plexus [39, 40]. In this respect it is interesting that the only mammals that do have an abnormal number of cervical vertebrae are arguably the least active ones, i.e. sloths and manatees [3]. TOS will not be a problem in these species that hardly move and when they do so, they move slowly. Adult sloths and manatees frequently have skeletal abnormalities that in deceased fetuses and infants are commonly associated with cervical ribs (e.g. fused cervical vertebrae) and this apparently poses no major problem. Finally, regarding cancer risks, their extremely low metabolic rates

probably mitigate the risk for embryonal tumors [3]. Whales and dolphins are also exceptional in that they frequently have cervical ribs ([41]). This may be due to the limited use of their front limbs; their surprisingly low cancer rates and their tolerance for skeletal abnormalities [42], the latter of which is presumably due to the supporting effect of water.

4.6

 hy Can Birds and Reptiles W Have Long Necks?

Birds and many reptiles have long necks with many cervical vertebrae. The number of cervical vertebrae is highly variable in birds, with 12  in pigeons and up to 25  in swans [43]. Note, that even in the shortest necks, the number of vertebrae is considerably larger than that in mammals. In reptiles, the number of vertebrae can also be highly variable. However, this is mainly the case in reptiles with long necks (e.g. many dinosaurs), whereas the number is quite constant in families with eight or fewer cervical vertebrae, such as crocodiles, turtles, geckos and many other lizards [44]. When cervical numbers are large, the cervicothoracic boundary is determined at a later, less interactive, stage compared with mammals and more short-necked reptiles [4]. This should weaken the constraint, because the expectation is that changes of the number are associated with fewer side-effects, as is the case for shifts of the thoracolumbar and lumbosacral boundary in humans [4, 5]. In agreement with this, the largest variability in number is found in birds and reptiles with the longest necks (e.g. swans can have 21–25 vertebrae [43]). Interestingly, once reptiles lose their limbs and sternum, as in snakes and limbless lizards, the constraint on the number of cervical vertebrae also weakens and they usually end up with fewer cervical vertebrae [44]. Possibly this is because TOS cannot play a role anymore when the limbs are lost. An additional factor for a weaker constraint in reptiles in general may be the usually lower mobility (less TOS) and lower metabolic rates (lower cancer risks). In birds metabolic rates are high, as in mammals, but cancer risk appears to be drastically lower,

4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs

presumably because they have a much lower level of oxidative damage than mammals [18]. Hence, the constraint on changes in mammals is, thus, less exceptional than it seems, it is just somewhat stronger than in short-necked reptiles with limbs, presumably because of a combination of the generally greater mobility and higher metabolic rates.

4.7

 ervical Ribs Are Common C and Need More Study

Cervical ribs are exceptionally common, as they are found in ∼50% of deceased fetuses and infants. Assuming that ~15% of clinically recognized pregnancies ends in a miscarriage [45] and approximately half of these have cervical ribs, almost 8% of all human conceptions experiences a disturbed early organogenesis and develops cervical ribs. This makes cervical ribs one of the most common congenital abnormalities. It is not clear why cervical ribs are so common in humans. The early organogenesis stage during which cervical ribs are induced is highly vulnerable, as described above, but many more abnormalities are induced during this stage, such as extra digits, segmentation defects, neural tube defects, conotruncal defects, cyclopia, which are all less prevalent. In agreement with the high prevalence of cervical ribs in humans, several studies on rodents show that cervical ribs are the most sensitive endpoint of toxicity for specific treatments during early organogenesis [46]. Possibly, the central organizing role of the presomitic mesoderm, from which the vertebrae will develop, is causally involved in the frequent inductions of cervical ribs. Part of the explanation may be that other common, more serious abnormalities, are associated with yet earlier prenatal deaths, before their presence can be detected. The extraordinary prevalence of cervical ribs in deceased fetuses and infants deserves more scrutiny, in particular in the light of the high percentage of unexplained still births (17–66%) and the current strong ambition to lower perinatal mortality [47]. It may be useful to recognize

33

that the percentage of cervical ribs in perinatal mortality is as high as in the earlier occurring abortions or in the later infant mortality, which indicates frequent disturbances of early embryogenesis in perinatal mortality, as ~80% has a disturbed vertebral pattern, of which ~60% has cervical ribs (Fig. 4.4b, see also [5]). Hence, to lower avoidable perinatal mortality, improving conditions around conception and during early pregnancy might be more critical, than the usual suggestions for improving perinatal care, at least in high-income countries. In low-income countries this may be rather different, given the often regrettably sparse availability of perinatal care. Finally, the association of cervical ribs with pediatric cancers suggests that early detection of cervical ribs might help in earlier detection of embryonal tumors. Hence, cervical ribs do not only deserve attention because they can be the cause of TOS, but also because of the associated earlier arising problems. To this aim, it might be useful to collect data on possible associations of TOS with stillbirths, embryonal tumors, genetic and congenital abnormalities in patients with cervical ribs and their family members.

References 1. McNally E, Sandin B, Wilkins RA.  The ossification of the costal element of the seventh cervical vertebra with particular reference to cervical ribs. J Anat. 1990;170:125–9. 2. Narita Y, Kuratani S.  Evolution of the vertebral formulae in mammals: a perspective on developmental constraints. J Exp Zool B Mol Dev Evol. 2005;304(2):91–106. 3. Varela-Lasheras I, Bakker AJ, van der Mije SD, Metz JA, van Alphen J, Galis F. Breaking evolutionary and pleiotropic constraints in mammals: on sloths, manatees and homeotic mutations. EvoDevo. 2011;2(1):11. 4. ten Broek CM, Bakker AJ, Varela-Lasheras I, Bugiani M, Van Dongen S, Galis F. Evo-devo of the human vertebral column: on homeotic transformations, pathologies and prenatal selection. Evol Biol. 2012;39(4):456–71. 5. Galis F, Van Dooren TJM, Feuth JD, Metz JAJ, Witkam A, Ruinard S, et  al. Extreme selection in humans against homeotic transformations of cervical vertebrae. Evolution. 2006;60(12):2643–54.

34 6. Schut PC, Cohen-Overbeek TE, Galis F, Ten Broek CMA, Steegers EA, Eggink AJ.  Adverse fetal and neonatal outcome and an abnormal vertebral pattern: a systematic review. Obstet Gynecol Surv. 2016;71(12):741–50. 7. Menarguez Carretero AL. M. CM. A radiologic study and the morphologic types of cervical ribs in the female. Enferm Torax. 1967;16:285–308. 8. Kerley P.  The normal spine and pelvis. In: Shanks S, Kerley P, editors. A textbook of X-ray diagnosis by British authors. 6 bones, joints and soft tissues. London: HK Lewis; 1971. 9. Todd TW. The relations of the thoracic operculum considered in reference to the anatomy of cervical ribs of surgical importance. J Anat Physiol. 1911;45(Pt 3):293. 10. Chernoff N, Rogers JM. Supernumerary ribs in developmental toxicity bioassays and in human populations: incidence and biological significance. J Toxicol Env Heal B. 2004;7(6):437–49. 11. Merks JH, Smets AM, Van Rijn RR, Kobes J, Caron HN, Maas M, et  al. Prevalence of rib anomalies in normal Caucasian children and childhood cancer patients. Eur J Med Genet. 2005;48(2):113–29. 12. Schut PC, Brosens E, Van Dooren TJM, Galis F, Ten Broek CMA, Steegers EA, et al. Exploring copy number variants in decreased fetuses and neonates with abnormal vertebral patterns and cervical ribs. Birth Defects Res 2020;144:105027. 13. Etter L.  Osseous abnormalities of the thoracic cage seen in forty thousand consecutive chest photoroentgenograms. Am J Roentgenol. 1944;81:359–63. 14. Kühne K.  Die Vererbung der Variationen der menschlichen Wirbelsäule. Z Morphol Anthropol. 1932;H.1/2:1–221. 15. Fischel A. Untersuchungen über die Wirbelsäule und den Brustkorb des Menschen. Anatomische Hefte. 1906;31(3):462–588. 16. Oostra RJ, Hennekam RC, de Rooij L, Moorman AF.  Malformations of the axial skeleton in museum Vrolik I: homeotic transformations and numerical anomalies. Am J Med Genet A. 2005;134(3): 268–81. 17. Schumacher R, Mai A, Gutjahr P. Association of rib anomalies and malignancy in childhood. Eur J Pediatr. 1992;151(6):432–4. 18. Galis F, Metz JA.  Anti-cancer selection as a source of developmental and evolutionary constraints. BioEssays. 2003;25(11):1035–9. 19. Galis F.  Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes, and cancer. J Exp Zool. 1999;285(1):19–26. 20. Redenbach DM, Nelems B.  A comparative study of structures comprising the thoracic outlet in 250 human cadavers and 72 surgical cases of thoracic outlet syndrome. Eur J Cardiothorac Surg. 1998;13: 353–60. 21. Roos DB. Congenital anomalies associated with thoracic outlet syndrome. Anatomy, symptoms, diagnosis, and treatment. Am J Surg. 1976;132:771–8.

F. Galis et al. 22. Brent AE, Braun T, Tabin CJ.  Genetic analysis of interactions between the somitic muscle, cartilage and tendon cell lineages during mouse development. Development. 2005;132:515–38. 23. Bradley OC. On a case of rudimentary first thoracic rib in a horse. J Anat Physiol. 1901;36:54–62. 24. Mallo M, Wellik DM, Deschamps J. Hox genes and regional patterning of the vertebrate body plan. Dev Biol. 2010;344(1):7–15. 25. Vermot J, Pourquié O.  Retinoic acid coordinates somitogenesis and left-right patterning in vertebrate embryos. Nature. 2005;435:215–20. 26. Diez del Corral R, Olivera-Martinez I, Goriely A, Gale E, Maden M, Storey K.  Opposing FGF and retinoid pathways control ventral neural pattern, neuronal differentiation, and segmentation during body axis extension. Neuron. 2003;40(1):65–79. 27. Yang X, Dormann D, Muensterberg AE, Weijer CJ.  Cell movement patterns during gastrulation in the chick are controlled by positive and negative chemotaxis mediated by FGF4 and FGF8. Dev Cell. 2002;3:425–37. 28. Galis F, Metz JA.  Testing the vulnerability of the phylotypic stage: on modularity and evolutionary conservation. J Exp Zool. 2001 Aug 15;291(2):195–204. 29. Krebs LT, Iwai N, Nonaka S, Welsh IC, Lan Y, Jiang R, et  al. Notch signaling regulates left–right asymmetry determination by inducing nodal expression. Genes Dev. 2003;17(10):1207–12. 30. Keeling JW, Kjaer I. Cervical ribs: useful marker of monosomy X in fetal hydrops. Pediatr Dev Pathol. 1999;2(2):119–23. 31. Schut PC, Ten Broek CMA, Cohen-Overbeek TE, Bugiani M, Steegers EAP, Eggink AJ, et al. Increased prevalence of abnormal vertebral patterning in fetuses and neonates with trisomy 21. J Matern Fetal Neonatal Med. 2018;32:1–7. 32. Furtado LV, Thaker HM, Erickson LK, Shirts BH, Opitz JM.  Cervical ribs are more prevalent in stillborn fetuses than in live-born infants and are strongly associated with fetal aneuploidy. Pediatr Dev Pathol. 2011;14(6):431–7. 33. Wéry N, Narotsky MG, Pacico N, Kavlock RJ, Picard JJ, Gofflot F.  Defects in cervical vertebrae in boric acid-exposed rat embryos are associated with anterior shifts of Hox gene expression domains. Birth Defects Res A Clin Mol Teratol. 2003;67(1):59–67. 34. Rengasamy P, Padmanabhan RR. Experimental studies on cervical and lumbar ribs in mouse embryos. Congenit Anom (Kyoto). 2004;44:156–71. 35. Connely LE, Rogers JM.  Methanol causes posteriorization of cervical vertebrae in mice. Teratology. 1197;55:138–44. 36. Brocal J, De Decker S, José-López R, Manzanilla EG, Penderis J, Stalin C, et al. C7 vertebra homeotic transformation in domestic dogs–are pug dogs breaking mammalian evolutionary constraints? J Anat. 2018;233(2):255–65.

4  Evolutionary and Developmental Issues of Cervical Ribs/Evolutionary Issues of Cervical Ribs 37. Van der Geer AE. High incidence of cervical ribs indicates vulnerable condition in late Pleistocene woolly rhinoceroses. PeerJ. 2017;5:e3684. 38. Palma A, Carini F.  Variazioni dell’apofisi trasversa della settima vertebra cervicale: studio anatomo-­ radiologico su una popolazione “segregata”. Arch Ital Anat Embriol. 1990;95:11–6. 39. Galis F, Carrier DR, van Alphen J, van der Mije SD, Van Dooren TJM, Metz JAJ, et al. Fast running restricts evolutionary change of the vertebral column in mammals. Proc Natl Acad Sci. 2014;111(31):11401–6. 40. Damur-Djuric N, Steffen F, Hässig M, Morgan J, Flückiger M.  Lumbosacral transitional vertebrae in dogs: classification, prevalence, and association with sacroiliac morphology. Vet Radiol Ultrasound. 2006;47(1):32–8. 41. Slijper EJ.  Die Cetaceen: Vergleichend-Anatomisch und Systematisch. The Netherlands: Martinus Nijhoff, ‘s Gravenhage; 1962. 42. Nagy J, Victor E, Cropper J.  Why don’t all whales have cancer? A novel hypothesis resolving Peto’s paradox. J Integr Comp Biol. 2007;47:317–28.

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43. Woolfenden GE.  Postcranial osteology of the waterfowl. Bull Florida State Museum Biol Sci. 1961;6:1–129. 44. Hofstetter R, Gasc J.  Vertebrae and ribs of modern reptiles. In: Gans C, AdA B, Parsons TS, editors. Biology of the reptilia, vol. 1. London and New York: Academic; 1969. p. 202–310. 45. Forbes LS.  The evolutionary biology of spon taneous abortion in humans. Trends Ecol Evol. 1997;12(11):446–50. 46. Rogers JM, Mole ML, Chernoff N, Barbee BD, Turner CI, Logsdon TR, et  al. The developmental toxicity of inhaled methanol in the CD-1 mouse, with quantitative dose—response modeling for estimation of benchmark doses. Teratology. 1993;47(3):175–88. 47. Basu MN, Johnsen IBG, Wehberg S, Sørensen RG, Barington T, Nørgård BM.  Causes of death among full term stillbirths and early neonatal deaths in the region of southern Denmark. J Perinat Med. 2018;46(2):197–202.

5

Anatomy of the Thoracic Outlet and Related Structures Richard J. Sanders and Stephen J. Annest

Abstract

The anatomy of the thoracic outlet area is contained in three anatomical spaces: The scalene triangle, above the clavicle; the pectoralis minor space below the clavicle; and the costoclavicular space immediately underneath the clavicle. The nerves and artery run through the scalene triangle, while the vein lies in the costoclavicular space, anterior to the anterior scalene muscle. In descending from the scalene triangle to the pectoralis minor space, the nerve roots of the brachial plexus rearrange themselves into trunks, divisions, cords, and branches. The dorsal scapular and long thoracic nerves arise from the C5 and C6 nerve roots near the emergence of the roots from the cervical spine and before entering the scalene triangle; the phrenic nerve usually runs medial to the scalene triangle, but in some patients lies

R. J. Sanders (*) Emeritus Clinical Professor of Surgery, University of Colorado Medical School, Aurora, CO, USA e-mail: [email protected] S. J. Annest Department of Vascular Surgery, St. Joseph’s Hospital, Vascular Institute of the Rockies, Denver, CO, USA

directly over the nerve roots and trunks; and the sympathetic nerve chain runs over the transverse processes of the cervical spine medial to the thoracic outlet. The chain is not seen during the dissection but can be injured when electric current from a cautery is used too near the cervical spine.

Critical Take Home Points  1. Among TOS patients, about 90% have neurogenic TOS; less than 1% have arterial TOS. 2. Neurogenic TOS is felt to be caused by pathology of the anterior scalene (classic NTOS) and/or pectoralis minor (Neurologic Pectoralis Minor Syndrome) muscles. 3. Surgery for venous TOS requires removal of the anterior portion of first rib; scalenectomy is of no use. 4. Arterial TOS usually is due to a cervical or anomalous first rib. 5. Significant occipital headaches and neck pain often result from scalene muscle pathology.

5.1

Introduction

Knowledge of anatomy is essential to understanding the thoracic outlet syndromes (TOS). By definition, neurogenic TOS (NTOS) is the presence of hand and arm pain, paresthesia, and

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_5

37

R. J. Sanders and S. J. Annest

38

weakness due to compression of the neurovascular bundle in the thoracic outlet area. While initially the scalene triangle was the focus of pathology in TOS, recent studies indicate that more than half of the patients thought to have TOS also have associated pectoralis minor compression, and in some patients this is the only diagnosis [1]. Finally, it is important to recognize that the large majority of patients with anatomic abnormalities are asymptomatic unless an environmental factor is also present— in other words, the mere presence of an abnormality does not mean it must be treated. Like many medical conditions, both an anatomic predisposition plus an environmental stressor are usually necessary for symptoms and pathology to exist.

a

5.2

Anatomical Spaces

There are three anatomical spaces in the thoracic outlet area (Fig. 5.1a): The scalene triangle lying above the clavicle (Fig.  5.1b); the pectoralis minor space, below the clavicle (Fig. 5.1c); and the costoclavicular space between clavicle and first rib. The neurovascular bundle, consisting of subclavian artery, vein, and brachial plexus, travels from the scalene triangle into the costoclavicular space and then through the pectoralis minor space. In this journey there is very little change in the vessels or the nerves (Fig. 5.2), and as a result the symptoms of nerve or vessel compression are about the same for each of the three spaces. The scalene triangle, unlike the other two spaces, contains only the subclavian artery and

b Middle scalene muscle

Scalene triangle Costoclavicular space

Anterior scalene muscle

Brachial plexus

Phrenic nerve

Long thoracic nerve Pectoralis minor space

c

Subclavian artery and brachial plexus

Clavicle

Subclavian artery

Subclavius muscle Costoclavicular ligament 1st rib

Anterior scalene muscle

Fig. 5.1  Three spaces. (a) Anatomy showing the three spaces. (b) Scalene triangle with phrenic nerve passing from lateral to medial as it crosses anterior scalene muscle and long thoracic nerve exiting the middle scalene mus-

Subclavian vein

cle. (c) Costoclavicular space. (Reprinted from Sanders and Haug [2] With permission from Lippincott Williams & Wilkins)

5  Anatomy of the Thoracic Outlet and Related Structures Fig. 5.2  Thoracic outlet and pectoralis minor areas. Left arm is down, at the side. Note the subclavian and axillary artery and vein are essentially the same vessels one above and one below the clavicle. Right arm is elevated. This raises the axillary neurovascular bundle against the pectoralis minor muscle. This can constrict the axillary artery causing loss of the radial pulse and hand pallor and also pressure on the nerves of the brachial plexus causing paresthesia in the hand

39 C2 C3 C4 C5

Scalene triangle

C6 C7 T1

Subcl A. & V.

T2 1

Nerves of the brachial plexus

2

Pec min M.

Clavicle Subclavian A. & brachial plexus

Subclavius muscle

Costoclavicular lig. 1st rib

Subclavian V.

Fig. 5.3  Costoclavicular Space. Between the clavicle above and first rib below, all structures in the thoracic outlet area are seen. Note the subclavian vein is surrounded by costoclavicular ligament medially, subclavius muscle

superiorly, anterior scalene muscle posteriorly, and first rib inferiorly. The subclavian vein is the structure most often compressed in this area and most often by costoclavicular ligament and/or subclavius muscle tendon

brachial plexus while the subclavian vein lies anterior to the triangle, anterior to the anterior scalene muscle. Clinically, there is a small but significant difference in the symptoms of nerve compression in the scalene triangle versus the pectoralis minor space. Compression in the scalene triangle is usually associated with occipital headaches and significant neck pain due to trauma to the scalene muscles, while headaches and neck pain are absent or minimal when compression is in the

other two spaces. When the arm is elevated, the neurovascular bundle rises against the pectoralis minor muscle which probably accounts for the onset of symptoms with the hyperextension maneuver (180° abduction) (Fig. 5.2) [3] and the elevated arm stress test (EAST or Roos test) [4]. The costoclavicular space is an area of potential compression in cases of clavicular fractures and subclavian vein obstruction, but it does not seem to be as important in neurogenic or arterial TOS (Fig. 5.3).

R. J. Sanders and S. J. Annest

40 Fig. 5.4 Bilateral cervical ribs. On the right, the cervical rib inserts on the second rib. The right first rib is absent. On the left, the cervical rib inserts on the first rib

C2 C3 C4 C5 C6 C7

Cervical Rib

Ant. scalene m. Cervical rib

T1

Subclavian a. T2

1

1st Rib

2nd Rib

2nd Rib 2

5.3

Cervical Ribs

Cervical ribs arise from the seventh cervical vertebral body (C7). Complete ribs insert on the first rib (or the second rib, when the first rib is absent) (Fig. 5.4).

5.4

Ligaments and Bands

A variety of ligaments and bands attached to the first rib have been identified and classified [5]. These structures are present in about two-thirds of the normal population [6]. Since they are so common they are regarded as predisposing factors of NTOS rather than causative factors.

5.5

Nerves

In addition to the five nerve roots and their branches comprising the brachial plexus, other nerves also lie in the thoracic outlet area and are of extreme surgical importance. These include the phrenic, long thoracic, dorsal scapular, sec-

ond intercostobrachial cutaneous, and supraclavicular nerves, along with the cervical sympathetic chain. Brachial Plexus (BP): The plexus arises from nerve roots C5 to C8 plus T1. The five nerve roots and the lower, middle, and upper trunks lie in the scalene triangle. The anterior and posterior divisions and cords form at the level of the costoclavicular space. By the time the BP reaches the pectoral space the cords and branches have formed (Fig. 5.5). Phrenic nerve: The phrenic nerve arises from branches of C3, C4, and C5. The C3 and C4 branches unite cephalad to the thoracic outlet area. As the combined two branches descend they cross the anterior scalene muscle (ASM) from lateral to medial (Fig.  5.1b). The C5 branch usually joins C3 and C4 near the spot where these two branches begin crossing the ASM, but the exact place where C5 joins them is quite variable. In some patients the C5 branch runs separately over ASM and may join the other two branches in the chest, and in a few patients (13%) the C5 branch remains separate all the way to the diaphragm (when this occurs the C5 branch is called the accessory phrenic

5  Anatomy of the Thoracic Outlet and Related Structures

41 Posterior root ganglion Post. ramus

Post. root

Ant. ramus

Ant. root

3 Trunks–upper, middle, & lower 3 Anterior divisions—upper, middle, & lower

5 C. 6 C. 7 C.

5 Anterior rami

8 C. 1 Th.

3 Posterior divisions 3 Cords

Radial nerve

Median nerve

Muscule- Circumflex Ulnar cutaneous (Axillary) nerve nerve nerve

5 Terminal branches

Fig. 5.5  Brachial plexus. Above the clavicle where the scalene triangle lies, the plexus is present as five nerve roots (C5 through T1) forming three trunks. Just below the clavicle in the costoclavicular space the trunks are starting

to form divisions. Where the plexus travels through the pectoralis minor space the cords and branches appear. (Reprinted from Grant [7]. With permission from Lippencott Williams & Wilkins

nerve) [8]. When performing supraclavicular scalenectomy it is important to identify the phrenic nerve (and any accessory phrenic nerves) before dissecting the ASM to recognize and avoid injuring them. The phrenic n runs on the medial side of ASM in 84% of necks but remains on the lateral side in 16% [8]. It is the nerves on the lateral side that are most at risk as they must be carefully protected during the dissection. Long thoracic nerve: The long thoracic nerve is formed by branches of C5, C6, and C7 with the C6 branch being the largest and most important. C5 and C6 branches arise cephalad to the scalene muscles and travel through the belly of middle scalene muscle (MSM) where they unite forming a single nerve. As the single nerve descends it exits the MSM, crosses the lateral edge of first rib (Fig. 5.1b), picks up the C7 branch, and eventually innervates the serratus anterior muscle. The C7 branch arises from the posterior aspect of C7, 2–4 cm below the top of ASM. It is a small branch

which descends below the clavicle before it joins C5 and C6. However, in a minority of patients the C7 branch unites with the other two branches in the belly of MSM. When performing middle scalenotomy or scalenectomy it is vital to dissect a few fibers at a time until the long thoracic branches are identified and preserved. In the axilla, the long thoracic nerve lies on the superficial surface of the posterior scalene muscle. In transaxillary rib removal, injury to the long thoracic nerve is avoided by dissecting the first rib inside the anterior border of the posterior scalene muscle. The nerve is protected by placing a retractor between the posterior scalene muscle and the first rib. Dorsal scapular nerve: The dorsal scapular nerve is the first branch arising from the C5 nerve root. It usually arises close to the C5 branch of the long thoracic nerve and the two branches descend a short distance together until the dorsal scapular nerve separates in the cephalic part of the MSM exiting through the lateral edge of that

R. J. Sanders and S. J. Annest

42

muscle and descending to innervate the rhomboid muscles and a portion of the levator scapulae muscle. Unlike the long thoracic nerve branches, the dorsal scapular nerve is only on the superior-lateral edge of MSM dissections; it is usually not seen and easy to avoid. Cervical sympathetic nerve chain: The cervical sympathetic nerve chain lies on the anterior surface of the cervical transverse processes, and is not seen when performing supraclavicular scalenectomy. However, when cautery is used to control bleeding from the MSM at the transverse process of scalene muscle origins, the electric current of the cautery can reach the sympathetic nerve chain causing a Horner’s syndrome. The Horner’s may heal itself after a few months, but in some patients it is permanent. This can be avoided surgically by not dividing the scalenes on the transverse processes, instead staying at least a few mm away.

5.6

Subclavian and Axillary Vessels

The axillary artery and vein are continuations of subclavian vessels as they move laterally beneath the pectoralis minor muscle (PMM). Each vessel has a few small branches, but functionally the axillary and subclavian arteries are regarded as a single large vessel traversing the thoracic outlet (the same is true of their accompanying veins). Only the subclavian artery lies in the scalene triFig. 5.6 Relationship of subclavian vein between clavicle and first rib. Subclavian vein can easily be compressed by costoclavicular ligament, subclavius tendon, or anterior scalene muscle. (Reprinted from Sanders and Haug [2]. P236. With permission from Lippincott Williams & Wilkins)

angle while the subclavian vein lies anterior to the triangle, anterior to the ASM. The portion of subclavian artery deep to the ASM has branches which vary between patients. These include the vertebral, internal mammary, thyrocervical trunk, and dorsal scapular artery. The most frequently encountered branch during supraclavicular dissection, is the dorsal scapular artery. This artery usually courses between trunks of the BP and traverses the belly of MSM. When visualized at its origin from the subclavian artery, it is best ligated at this point. The axillary artery begins at the lateral border of the first rib and extends to the teres major muscle. It has three sections, medial to, under, and lateral to the PMM. One branch lies in the first portion—the superior thoracic artery; two branches lie under the PMM—the thoracoacromial and lateral thoracic arteries; and three branches lie lateral to the PMM—the subscapular, anterior and posterior circumflex humoral arteries. It is the circumflex humoral branches that are of surgical significance as they are subject to aneurysm formation following repetitive stress injury from excessive, repetitive shoulder motion, such as pitching. The subclavian vein is bounded by the subclavius tendon above, first rib below, ASM laterally, and costoclavicular ligament medially (Fig. 5.6). When the vein lies a little too medial, it lies against the costoclavicular ligament which sets up conditions for venous intimal injury and subsequent thrombosis.

Anterior scalene muscle

Clavicle First rib Subclavian artery Subclavian vein Costoclavicular ligament

Subclavius muscle

5  Anatomy of the Thoracic Outlet and Related Structures

Anterior scalene muscle

Internal jugular vein Phrenic nerve Innominate vein

Subclavian vein

43

Another important observation in decompressing the subpectoral space is the presence of the fascia beneath the coracobrachialis muscle. This fascia lies lateral to the clavipectoral fascia (or might be an extension of it) and forms a distinct connective tissue arch covering the axillary neurovascular bundle as it continues into the arm. This area cannot be incised unless a transaxillary approach is employed.

First rib

Fig. 5.7  Prevenous (anterior) phrenic nerve obstructing the subclavian vein. [Reprinted with permission from Sanders and Haug [2], p  237. With permission from Lippincott Williams & Wilkins]

Prevenous phrenic nerve: In over 90% of subjects the phrenic n descends into the chest posterior to the subclavian vein. However, in 5–7% of patients, the phrenic nerve lies superficial to the vein [9–11]. In this situation it can partially obstruct the vein, a situation which has twice been reported [12, 13] (Fig. 5.7).

5.7

 calene and Pectoralis Minor S Muscles

The ASM and MSM originate at the transverse processes of the cervical spine and insert on the first rib. Hyperextension neck injuries stretch and tear some of the muscle fibers which then heal, in part by forming scar tissue. The scarred, inelastic muscle replaces the normal soft muscle, which compresses the nerves causing the symptoms of NTOS by preventing normal stretching with movement. The PMM originates on the anterior surfaces of ribs 3–5 and inserts on the coracoid process of the scapula after passing over the top of the neurovascular bundle. When surgically dividing the PMM at the coracoid, removing 2 cm of the muscle will prevent the muscle end from attaching to the top of the neurovascular bundle. Because the lateral pectoral nerve to the pectoralis major muscle runs through PMM to reach the pectoralis major, care must be taken to avoid excising too much PMM to protect this nerve.

5.8

Thoracic Duct

In the left neck the thoracic duct lies just posterior and inferior to the clavicle in the scalene fat pad. In addition, a fine network of tiny lymph channels runs along the internal jugular vein. The lymph vessels are best avoided by being aware of the normal location of these structures. In supraclavicular TOS operations in the left neck, by avoiding dissection of the fat pad below the clavicle and by avoiding separating the fat pad from the internal jugular vein, lymph leaks are minimized. Following these guidelines will reduce lymphatic leaks, but will not totally eliminate them. In the right neck, lymphatics lie only along the internal jugular vein, and lymph leaks in the right neck are rare.

5.9

Distribution of Pathology

The scalene triangle has traditionally been thought to be the space involved in about 95% of patients with NTOS. Since recognizing the neurogenic pectoralis minor syndrome (NPMS) in 2004, more than 75% of patients we have seen for NTOS seem to have NPMS; 70% of these combined with NTOS (a double crush syndrome [14]) while the other 30% have NPMS alone (unpublished data RJS).

5.10 Conclusion “Anatomy of the thoracic outlet and related structures”—A thorough understanding and familiarity with the complex anatomy of the

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thoracic outlet is mandatory in order to perform safe and successful surgery for patients with entrapment of nerves of the brachial plexus, and in treating patients with entrapment of vascular structures. In order to minimize surgical complications, the supra and infraclavicular thoracic outlet has to become the surgeon’s “Briar Patch”.

References 1. Sanders RJ, Rao NM. The forgotten pectoralis minor syndrome: 100 operations for pectoralis minor syndrome alone or accompanied by neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2010;24:701–8. 2. Sanders RJ, Haug CE.  Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia, PA: JB Lippincott; 1991. p. 237. 3. Wright IS.  The neurovascular syndrome produced by hyperabduction of the arms. Am Heart J. 1945;29:1–19. 4. Roos DB, Owens JC. Thoracic outlet syndrome. Arch Surg. 1966;93:71–4.

R. J. Sanders and S. J. Annest 5. Roos DB. New concepts of thoracic outlet syndrome that explain etiology, symptoms, diagnosis, and treatment. Vasc Surg. 1979;13:313–21. 6. Juvonen T, Satta J, Laitala P, Luukkonen K, Nissinen J. Anomalies at the thoracic outlet are frequent in the general population. Am J Surg. 1995;170:33–7. 7. Grant JCB. An atlas of anatomy. Baltimore: Williams and Wilkins Co; 1947. p. p12. 8. Sanders RJ, Roos DB.  The surgical anatomy of the scalene triangle. Contemp Surg. 1989;35:11–6. 9. Schroeder WE, Green FR.  Phrenic nerve injuries; report of a case. Anatomical and experimental researches, and critical review of the literature. Am J Med Sci. 1902;123:196–220. 10. Hovelacque A, Monod O, Evrard H, Beuzart J. Etude anatomique du nerf phrenique pre-veineux. Ann D’Anatomie Path. 1936;13:518–22. 11. Hughes ESR. Venous obstruction in the upper extremity. Brit J Surg. 1948;36:155–63. 12. Jackson NJ, Nanson EM. Intermittent subclavian vein obstruction. Brit J Surg. 1961;49:303–6. 13. Sanders RJ, Haug CE.  Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia: JB Lippincott; 1991. p. 237. 14. Upton ARM, McComas AJ.  The double crush in nerve-entrapment syndromes. Lancet. 1973;2:359–62.

6

TOS: Clinical Incidence and Scope of the Problem Karl A. Illig and Eduardo Rodriguez-Zoppi

Abstract

Thoracic outlet syndrome (TOS) has been recognized since the nineteenth century, and the “modern” area of treatment, especially for NTOS, dates from at least the 1970s. Despite this, however, the incidence of this syndrome is almost completely unknown. Several factors contribute to this, including the very subjective nature of the problem and resultant lack of consensus as to diagnosis, poor physician knowledge and thus recognition, and the very fuzzy line between physiologic brachial plexus compression and the true syndrome. Several authors have “reported” incidences, but such reports either rely on very old, suspect data, are analyses of operative cases only, or represent nothing more than opinion. In addition, basic mathematics illustrate the very poor face validity of estimates such as “3–80 per 1000 people.” We prospectively tracked 526 patients with possible TOS referred to our center over a 47 month period, and found that approximately 82% were referred for NTOS.  Of these, 83% had moderate to high

K. A. Illig (*) Dialysis Access Institute, The Regional Medical Center, Orangeburg, SC, USA e-mail: [email protected] E. Rodriguez-Zoppi Memorial Regional Hospital, Hollywood, FL, USA

suspicion; subtracting the 17% who did not have NTOS the ratio of “probable” NTOS:VTOS was 80:20 and the rate of those undergoing thoracic outlet decompression was 75:25 (ATOS being sporadic). Using population estimates, we estimate the incidence of NTOS to be approximately 3 per 100,000 people per year, and VTOS to be approximately 1 per 100,000 people per year.

Critical Take-Home Points  1. Based on actual diagnosis, the percentages of probable NTOS and VTOS seem to be about 80:20, with ATOS being only sporadic. 2. Based on who undergoes thoracic outlet decompression, the percentages seem to be about 75:25. 3. The incidence of NTOS is around 3 cases per 100,000 people, while that of VTOS is around 1 cases per 100,000 people. 4. TOS in general occurs at rates similar to Amyotrophic Lateral Sclerosis and Cystic Fibrosis, to use two examples of “common” rare diseases.

6.1

Introduction

Thoracic outlet syndrome (TOS) refers to a group of compressive problems that occur at the thoracic outlet or just beyond. While over-

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lap exists, three separate types of thoracic outlet syndrome are described: compression of the nerves (brachial plexus) at the scalene triangle and/or retropectoral space produces neurogenic thoracic outlet syndrome (NTOS), compression of the vein at the anterior costoclavicular junction produces venous thoracic outlet syndrome (VTOS), and compression of the artery by the first or cervical rib leading to organic damage to it produces arterial thoracic outlet syndrome (ATOS) [1]. In addition, patients with ipsilateral arteriovenous access can develop a form of VTOS, likely because of the high flow created through the vulnerable vein in this situation [2]. TOS has been recognized since the nineteenth century, and the “modern” area of treatment, especially for NTOS, dates from at least the 1970s. Despite this, however, the incidence and prevalence of these syndromes are almost completely unknown. Several factors contribute to this, including the very subjective nature of the problem and resultant lack of consensus as to diagnosis, poor physician knowledge and thus recognition, and the very fuzzy line between physiologic brachial plexus compression and the true syndrome. Several authors have attempted to determine incidence and prevalence, and identify the ratio between each disorder, but such reports either rely on very old, suspect data and opinion [3] or are analyses of operative cases only [4, 5]. Three caveats should be kept in mind when reading this chapter. First, true ATOS, as defined by the SVS reporting standards document, is sporadic, making up only 1–2% of cases, and will be ignored when dealing with ratios below. Second, most of this work is derived from a manuscript in press in Annals of Vascular Surgery [6], to which the reader is referred to for complete data, methods, and references. Finally, this chapter is a discussion of incidence only. Based on numerous factors (including poor treatment or provider unwillingness to treat), we do not feel prevalence is currently analyzable.

6.2

What Data Exist?

It has been surprisingly difficult to determine the actual incidence of TOS, especially NTOS. First, diagnostic criteria have been difficult to determine, so much so that the existence of NTOS has been disputed in the past [7, 8]. Secondly, virtually all reports describe outcomes of those actually treated, and do not discuss this topic based on initial referrals. For example, two recent studies documented the “rates” of NTOS:VTOS to be 97:3 [4] and 83:12 [5]. These papers, however, were both based on samples only (NIS and NSQIP, respectively), and, obviously, both based on operations only. Others quote rates of NTOS to be between 95 and 99% (Table 6.1, with our results below added), although these are often opinion based or derived from specialty centers with atypical referral patterns. A number that has been extensively quoted is “3–80 per 1000 people” (for example, in the first sentence of the preface of the first edition of this book [13] as well as Chap. 4 in the same text [14]). It is difficult to track down the source of this quote. Huang and Zager [3] reference competing editorials by Roos [7] and Wilbourne [8], who only touch on this question. Jones [15] says that “several articles report an incidence of 3–80/1000” but references only an article from Turkey [16], which in turn lists this estimate without reference. Urschel, in an old textbook chapter [9] referenced in Wilbourne’s editorial, apparently says that up to 8% of the population has “TOS.” Similarly, in a seminal but also old chapter, Roos describes the incidence of TOS as being between 0.3 and 2% of the population aged Table 6.1  Percentages of patients “with NTOS” from various sources [6] Source [ref] Urschel [9] Roos [7, 10] Sanders [11] (extension of Roos) Hopkins [12] Current experience

% 99 97 >95

Comment Poorly attributed, potentially just opinion based

95 82

Prospectively recorded

6  TOS: Clinical Incidence and Scope of the Problem

25–40 [10]. The US Census estimates that approximately 20% of the current population (of 325,719,178 people) lies within this age range— 65,143,835 people. Even the lower range of this—0.3%—yields a total number of 195,431 patients in the US with TOS, and if 8%, 27,000,000 people in the US would have TOS! Even as an estimate of prevalence, this number does not seem to coincide with reality. It is clear that this is an excellent example of a number essentially created out of thin air that has taken on a life of its own based on repeated citation. A second question of interest is that of the various rates of the different subtypes of TOS. Again, these numbers are widely disputed, and are again usually based on “common wisdom” or numbers passed down for decades without critical examination. In particular, the proportion of patients who present with NTOS (as opposed to being operated upon) is quite high, although may have been overestimated in the past. For example, Urschel feels that 99% of patients with TOS have NTOS [16], Roos feels that this number is 97% [6], and the current group in Denver states that “over 95% of [our] TOS procedures were done for NTOS (15).” In a major analysis of the Hopkins experience (N = 538), the percentage discussed (without attribution) in the introduction for NTOS was 95% [12]. It must be pointed out, of course, that this number will vary according to the interests of the center, and will likely be lower if the center has a significant interest in venous TOS or higher if the center is comprised of neurosurgeons, for example. What of those actually operated upon? In the NIS report referenced above, 97% of rib resections were performed for NTOS and 3% for venous [4], although it is difficult to know how accurate the diagnoses were. Similarly, in the NSQIP report, the respective numbers were found to be 83 and 13%, respectively [5]. In the Hopkins experience (N = 538), the proportions of operations performed were 52 and 44%, respectively [12]. In what has to be the largest series in the world, Urschel, a thoracic surgeon, reviewed 3129 of his group’s 5102 operations [17], describ-

47

ing 2210 operations for primary NTOS, 625 for VTOS, and 294 (perhaps high, based on outdated definitions) for ATOS, which ends up being a ratio of 71% for NTOS, 20% for VTOS, and 9% for ATOS, respectively.

6.3

 he University of South T Florida Experience

This chapter’s senior author has had a longstanding interest in TOS, and moved to the University of South Florida in 2011. At approximately this point, he became involved in the Society for Vascular Surgery’s Reporting Standards Committee on TOS [1], and as a result evolved a fairly objective pathway for the diagnosis and treatment of these patients. Being frustrated with the subjective and inconsistent data surrounding this issue, beginning in July of 2014 we (with the assistance of the second author, a Fellow in the USF vascular surgery program from 2014 to 2016) established a prospective database of all patients referred to our group with the express goal of answering these fundamental questions, fully described in an upcoming manuscript [6]. From July 2014 to May 18, 2018 (when the senior author left the University of South Florida), a time span of 47 months, a total of 526 patients were referred to our institution with a diagnosis of possible TOS.  Of these, 82% were referred with symptoms suggestive of NTOS, 16% with symptoms suggestive of VTOS (82:16), and 10 (2%) with findings and/or symptoms suggestive of true ATOS (as described by the SVS consensus document). 31 patients (6%) presented with clear overlapping symptoms of more than one type— 15 with primary VTOS along with fixed distal neurologic symptoms, 12 with primarily NTOS along with positional swelling or history of axillosubclavian thrombosis, and four with primary NTOS along with objective subclavian arterial pathology. Of course, not all patients referred for a problem actually have it. Virtually all patients referred

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for VTOS do have subclavian vein pathology, and eight of the ten patients referred for ATOS have objective subclavian artery pathology (the other two had early evidence of poor blood flow, but symptoms judged due to NTOS). However, based on criterial published by the consensus committee, only 84% of patients referred for NTOS were felt to have high (54%) or moderate (30%) suspicion of actually having it. Therefore, when only those with moderate or high suspicion of the various forms of the condition were counted, the ratio (excluding the 2–3% rate of ATOS) changes to 80:20 (Table 6.2). Finally, not all patients with a positive diagnosis will need an operation. Virtually all of those with acute VTOS and ATOS will need surgery. The numbers of those with subacute and chronic VTOS will vary by symptom status and degree of aggressiveness of the treating center, while the number of those undergoing NTOS will vary widely based on numerous factors, but is definitely less than either of the other two factors. When analyzed, our numbers now change to 75:25 (Table 6.2). Incidence estimates: To estimate overall incidence, we made the following estimates (based on community practices, discussions at local/ regional meetings, patient information, and so on): First, we estimated that we saw 90% of patients with NTOS, 75% of those with VTOS, and 50% of those with ATOS (this low number based on poor recognition) in our metropolitan statistical area (MSA). This was 2,783,469  in 2010 and was estimated at 3,142,663 in 2018; for purposes of this analysis we’ll assume a rough number of 3,000,000. Based on zip codes, the number of those with NTOS, VTOS, and ATOS, Table 6.2  Relative incidence of subtypes based on category derived from the USF experience [6]

Based on initial referral Based on moderate to high suspicion Based on surgical therapy

NTOS (%) 82 80

VTOS (%) 16 19

ATOS (%) 2 2

73

25

3

USF University of South Florida, NTOS neurogenic thoracic outlet syndrome, VTOS venous thoracic outlet syndrome, ATOS arterial thoracic outlet syndrome

respectively, who lived in our MSA and were seen by us over the 4-year period was 305, 58, and 7, respectively, yielding yearly rates of 76, 15, and 2 per year. Adjusted according to the estimates above, the absolute yearly incidence in our MSA (seen by any surgeon) was thus 84, 20, and 4, respectively. The incidence per 100,000 patients thus ends up being 3 patients with NTOS per 100,000 people per year, 1 patient with VTOS (half acute PSS) per 100,000 people per year, and 0.2 patients with ATOS per 100,000 people per year. TOS has been described as a “rare” disorder. Wikipedia cites the Rare Disease Act of 2002 in the US and definitions from Japan as defining a rare disease as one with an incidence of between 40 and 67 per 100,000 people [18]; based on this, TOS certainly qualifies. At a rate of 10/100,000 persons, where exactly does this fall on the scale of “rare” disorders? Amyotrophic Lateral Sclerosis (ALS), commonly known as Lou Gehrig’s disease, seems to be as common as NTOS, occurring with an incidence of 3.9 per 100,000 people [19]. By contrast, cystic fibrosis is much less common; approximately 1000 cases are diagnosed yearly, and the prevalence in the United States is about 30,000 [20]. Both diseases, it should be pointed out, are well-publicized and benefit from charitable foundations set up expressly for them.

6.4

Conclusions

It is clear that past estimates of incidence (or even if interpreted as prevalence) do not correspond to reality. Using prospective analysis of all patients referred to our tertiary TOS clinic, we believe that about 80% of those referred with NTOS and ATOS (and essentially all with VTOS) actually have the condition. Using population data and referral percentage estimates, we estimate the incidence of NTOS to be about 3 cases per 100,000 people per year, and that of VTOS to be about 1 case per 100,000 patients per year. While “rare,” these numbers yield 30 patients with NTOS and 10 patients with VTOS yearly in a population of 1  million patients, and compare

6  TOS: Clinical Incidence and Scope of the Problem

closely to the incidence of AML and Cystic Fibrosis. In any group treating vascular patients in any reasonably-sized metropolitan area, TOS must be taken seriously.

References 1. Illig KA, Donahue D, Duncan A, Freischlag J, Gelabert H, Johanson K, et  al. SVS reporting standards: thoracic outlet syndrome (executive summary). J Vasc Surg. 2016;64:797–802. 2. Glass C.  VTOS in the patient requiring chronic hemodialysis access. In: Illig KA, Thompson RW, Freischlag JA, Donahue DD, Jordan SE, Edgelow PI, editors. Thoracic outlet syndrome. London: Springer; 2013. p. 355–9. 3. Huang JH, Zager EL.  Thoracic outlet syndrome. Neurosurgery. 2004;55:897–902. 4. Lee JT, Dua MM, Chandra V, Hernandez-Boussard TM, Illig KA.  Surgery for thoracic outlet syndrome: a nationwide perspective. J Vasc Surg. 2011;53(17S):100S–1S. 5. Rinehardt EK, Scarborouth JE, Bennett KM. Current practice of thoracic outlet decompression surgery in the United States. J Vasc Surg. 2017;66:858–65. NSQIP 83:12:3 OR 6. Illig KA, Rodriguez-Zoppi E, Bland T, Muftah M, Jospitre E. The demographics of thoracic outlet syndrome. In press, Ann Vasc Surg. 7. Roos DB. The thoracic outlet syndrome is underrated. Arch Neurol. 1990;47:327–8. 8. Wilbourn A. The thoracic outlet syndrome is overdiagnosed. Arch Neurol. 1990;47:328–30. 9. Urschel HC, Razzuk MA. Thoracic outlet syndrome. In: Sabiston DC, Spencer FC, editors. Gibbon’s sur-

49 gery of the chest. Philadelphia: WB Saunders, Co; 1983. p. 437–52. 10. Roos D.  Review of thoracic outlet syndrome. In: Machleder HI, editor. Vascular diseases of the upper extremity. NY: Mt Kisko; 1989. p. 155–77. 11. Sanders RJ, Hammond SL, Rao NM.  Diagnosis of thoracic outlet syndrome. J Vasc Surg. 2007;46:601–4. 12. Orlando MS, Likes KC, Mirza S, Cao Y, Cohen A, Lum YW, et al. A decade of excellent outcomes after surgical intervention in 538 patients with thoracic outlet syndrome. J Am Coll Surg. 2015;220:934–9. 13. Illig KA, Thompson RW, Freischlag JA, Donahue DM, Jordan SE, Edgelow PI, editors. Thoracic outlet syndrome. London: Springer; 2013. 14. Lee JT, Jordan SE, Illig KA.  Clinical incidence and prevalence: basic data on the current scope of the problem. In: Illig KA, Thompson RW, Freischlag JA, Donahue DD, Jordan SE, Edgelow PI, editors. Thoracic outlet syndrome. London: Springer; 2013. p. 25–8. 15. Jones MR, Prabhaker A, Viswanath O.  Thoracic outlet syndrome: a comprehensive review of pathophysiology, diagnosis, and treatment. Pain Ther. 2019;8(1):5–18. 16. Citisli V.  Assessment of diagnosis and treatment of thoracic outlet syndrome, an important reason of pain in the upper extremity, based on literature. J Pain Relief. 2015;4:173. 17. Urschel H, Kourlis H Jr. Thoracic outlet syn drome: a 50-year experience at Baylor University medical Center. Proc (Baylor Univ Med Cent). 2007;20:125–35. 18. https://en.wikipedia.org/wiki/Rare_disease. Accessed 21 Sept 2019. 19. https://www.medscape.com/viewarticle/828861. Accessed 4 May 2020. 20. O’Sullivan BP, Freedman SD. Cystic fibrosis. Lancet. 2009;373:1891–904.

Part II Neurogenic TOS: General Principles and Diagnosis

7

Pathology and Pathophysiology of NTOS Richard J. Sanders and Dean M. Donahue

Abstract

Neurogenic TOS is usually due to a combination of predisposing factors and a hyperextension neck injury. Predisposing factors include cervical ribs, anomalous first ribs, an elongated transverse process of C7, a narrow scalene triangle, and various congenital bands and ligaments. The most common trauma is a whiplash injury, usually from a motor vehicle accident. The pathophysiology begins with trauma to the scalene muscles, causing tearing of muscle fibers and hemorrhage with subsequent replacement of the blood with microscopic scar tissue throughout the scalene muscles. The now tight muscles compress the nerve roots and trunks of the brachial plexus, subsequently causing the classic symptoms of extremity pain, paresthesia, and weakness. Further, the injured scalene muscles lead to neck pain and occipital headaches which are referred from the transverse process muscle origin.

R. J. Sanders (*) University of Colorado Medical School, Aurora, CO, USA e-mail: [email protected] D. M. Donahue Massachusetts General Hospital Department of Thoracic Surgery, Boston, MA, USA

Critical Take Home Messages  1. In most NTOS patients, objective pathology is due to scalene muscle scarring, not exclusively in the first rib. 2. We feel first rib resection is successful because the scalene muscles have been released. 3. Cervical ribs are only removed for symptoms. Most cervical ribs are asymptomatic. 4. Pectoralis Minor Syndrome (PMS) often accompanies NTOS with symptoms of pain in the arm, chest, and axilla plus paresthesia in the hand. PMS can exist alone.

7.1

Introduction

The usual etiology of neurogenic thoracic outlet syndrome (NTOS) is the combination of one or more predisposing anatomical variations or anomalies combined with a hyperextension neck injury. The eventual pathology created by this combination of factors is scarred scalene muscles which then compress the brachial plexus to produce symptoms.

7.2

Predisposing Factors

Relatively minor trauma is a part of life, but some people are more likely than others to develop symptoms of NTOS, probably because they have variations of what is considered normal anatomy.

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_7

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Such a predisposition doesn’t cause NTOS, rather it renders a person more likely to become symptomatic when a hyperextension neck injury occurs.

7.3

Scalene Muscle Variations Associated with NTOS

The width of the scalene triangle varies from 0.1 to 2.2  cm, averaging 1.1  cm [1]. In a cadaver study it was observed that 29% of scalene triangles were narrow compared to 39% in NTOS patients (Fig. 7.1) [2]. In the same study, interdigitating muscle fibers between the anterior (ASM) and middle scalene muscles (MSM) were found to be much more common in patients undergoing operation for NTOS—present in 50% of cases—than in control cadavers (23%), a difference that was highly significant [2]. The emergence of the C5 and C6 was found to be high in the apex of the scalene triangle in 80% of patients operated upon for NTOS as compared to only 40% of cadaver controls, again highly significant [2]. Finally, adherence of ASM to C5, C6, and C7 nerve roots was found to be more common in patients operated upon for NTOS as compared to cadaver controls, being present in 90% vs 29%, 91% vs 40%, and 62% vs 14%, respectively. Splitting of the ASM around C5 and C6 was found in 61% of NTOS patients vs 32% of controls and 72% of NTOS patients vs. 35% of controls, respectively. It should be noted that although this may reflect a causative factor, this high incidence of adherence could also be due to the original muscle trauma that caused the NTOS [2].

7.4

a

Scalene Muscle Variations that Do Not Correlate with NTOS

Congenital bands and ligaments have been classified into nine groups by Roos [3]. One or more of these are present in the majority of NTOS patients, but also in a high number of asymptomatic controls [4]. Because most of the

b

Fig. 7.1  Range of width of scalene triangle. (a) Usual width seen in cadavers. This is wider and nerves emerge a little lower than is seen in most NTOS patients. (b) Narrow tight triangle, the type seen in most NTOS patients. Nerves emerge higher and are in contact with muscle. Reprinted with permission from Sanders RJ, Roos DB.  The surgical anatomy of the scalene triangle. Contemporary Surgery 1989; 35:11–16

population has some such bands it is unlikely that these represent significant predisposing factors for NTOS.  In the cadaver study cited above, splitting of ASM around C5 and C6 was actually more common in cadavers (45%) than in patients operated upon for NTOS (21%) [2].

7  Pathology and Pathophysiology of NTOS

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Although this has been regarded by some as a predisposing factor, the data suggest the opposite. Finally, the presence of a scalene minimus muscle has been suggested as a predisposing factor for NTOS.  However, scalene minimus muscles have been found in as many 71% of (normal) cadavers [5].

7.5

 ervical Ribs, Anomalous C First Ribs, and Elongated Transverse Processes of C7

While the anatomy in NTOS is usually normal, abnormalities such as cervical ribs, anomalous first ribs, and elongated processes of C7 more often give rise to NTOS and only occasionally to ATOS. Cervical ribs arise from the transverse process of C7. Analysis of 12 studies found a prevalence of cervical ribs of 0–3% [6]. A review of 1352 digital chest radiographs noted the incidence of cervical ribs was 1.1% in females and 0.42% in males [7]. This confirmed an earlier study of cervical ribs in which the incidence was 0.7%; 70% women and 30% men [8]. However, the incidence of cervical ribs among patients operated upon for TOS is much higher, 4.5–8.5% [9, 10]. This indicates that the presence of a cervical rib makes an individual more likely to be a surgical candidate following neck trauma than people without cervical ribs. Most patients with cervical ribs remain asymptomatic throughout their lives. Patients with bilateral cervical ribs may develop unilateral symptoms. While symptoms can develop spontaneously, 80% of patients with cervical ribs who are operated upon, have a history of neck trauma, most often from whiplash injuries in motor vehicle accidents or from repetitive stress injury. In 1869 cervical ribs were classified into four groups [11]. However, from a clinical viewpoint, there are only two types: Complete or incomplete. About 30% of cervical ribs are complete. Complete ribs attach to the normal first rib either by a true joint or by fusion (Fig.  7.2) [12]. In some patients, the first rib is absent and the cervical rib attaches to the second rib. Incomplete

Fig. 7.2  Complete cervical rib with true joint with first rib. Rerprinted with permission from Sanders [12]

Fig. 7.3  Incomplete bilateral cervical ribs. (Reprinted with permission from Sanders RJ, Haug CE [13]. With permission from Lippincott Williams & Wilkins)

cervical ribs are 0.5–3  cm long and invariably have a very tight, thick band or ligament extending from the tip of the cervical rib to the first or the second rib (Fig. 7.3) [13]. Both complete and incomplete cervical ribs lie in the midst of the middle scalene muscle where their presence renders the scalene triangle tighter than triangles without cervical ribs. The embryology of cervical ribs and elongated C7 transverse processes is similar. In the developing embryo, lateral costal processes form along each vertebrae of the entire spine. In the thorax these processes continue to grow and become ribs, but in the remainder of the spine they fuse with the vertebrae and become transverse processes. In the neck, one theory states that developing cervical nerves block the progression of ribs from the cervical spine, but leave the transverse processes. In less than 1% of embryos, the C7 rib is not completely blocked resulting in development of a cervical rib. If the

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Fig. 7.4  CT scan with 3-dimensional reconstruction of a patient with symmetrical symptoms of TOS.  An incomplete cervical rib (open arrow) with an articulation to the transverse process of the C7 vertebrae is seen on the left. An elongated transverse process of the C7 vertebrae extending beyond the transverse process of the first thoracic vertebrae is seen on the right side (solid arrow). At surgery, dense tissue bands were found attaching each bone abnormality to the first thoracic rib

C7 cervical nerve is late in blocking rib development, a partial cervical rib or an elongated transverse process of C7 is the result. (Unpublished notes by Bradley Patten, author of Human Embryology in 1950). The incidence of elongated transverse processes of C7 is 3.4% in women and 1.1% in men [7]. Radiologic differentiation between a short cervical rib and an elongated transverse process of C7 can be difficult with plain x-rays. CT scans of the cervical spine may help reveal the ­articulating joint of a short cervical rib or lack of such a joint thereby identifying an elongated transverse process of C7 (Figs.  7.4 and 7.5). Clinically, the difference is primarily academic as both the short cervical rib and the elongated transverse process of C7 have a tight band or ligament running from the tip of the bone to the middle of the first rib. In each case, the ligament narrows the scalene triangle which increases the likelihood of pressure against the brachial plexus or subclavian artery. This is a predisposing factor in developing symptoms of Neurogenic or Arterial TOS. Anomalous first ribs have an incidence of 0.7% and are equally as common in men as

R. J. Sanders and D. M. Donahue

Fig. 7.5  Plain radiograph of the anterior cervical spine. This was initially interpreted as showing bilateral cervical ribs (open arrows), but a CT scan demonstrated that these bone projections originating from the C7 vertebrae were elongated transverse processes

women [8]. The difference in gender distribution between the cervical and anomalous first ribs has yet to be explained. Anomalous first ribs developed congenitally and are thinner, tend to lie more cephalad, and usually fuse to the second rib rather than the sternum as do normal first ribs. Seen on X-rays, anomalous first ribs are difficult to differentiate from cervical ribs. The best way to recognize them is to identify the T1 transverse process of the normal first rib on the contralateral side and see if the abnormal rib arises from the T1 or the C7 transverse process (Fig.  7.6) [12]. From a clinical viewpoint both cervical and anomalous first ribs act in the same way, and differentiation between the two is primarily of academic interest. Either can cause brachial plexus compression (NTOS) or subclavian artery compression (ATOS), although ATOS with aneurysms usually occur with complete cervical ribs only. We have also seen one case of venous obstruction by an anomalous first rib causing VTOS. Cervical and anomalous first ribs are usually predisposing causes of NTOS.  The majority of patients who posses them are asymptomatic. When symptoms of NTOS occur, it is usually following some type of hyperextension neck injury [9].

7  Pathology and Pathophysiology of NTOS

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Fig. 7.6 Anomalous right first rib. Note the normal second ribs bilaterally. Then note the normal left first rib and the anomalous right first rib both arising from transverse processes of T1. Reprinted with permission from Sanders

RJ. Thoracic outlet syndrome: General considerations; in Cronenwett JL, Johnston KW. Eds. Rutherford’s vascular surgery, 7th ed. Philadelphia, Saunders 2010 p. 1869

7.6

a few days to a several weeks later pain moves into the upper extremities and paresthesia develops in the fingers and hands. The microscopic pathology as noted in Fig.  7.7, is a significant increase in scar tissue spread diffusely throughout the scalene muscles. Putting together the history of an injury along with the pattern of symptom development and subsequent muscle pathology gives a plausible explanation for the pathophysiology: Following a neck injury the initial neck pain is due to two things: Cervical spine neck strain and tearing of the scalene muscle fibers. There is probably some muscle hemorrhage in the scalenes which causes muscle swelling and increased neck pain over the first few days. The symptoms of arm pain and paresthesia that develop in the first few days are due to swelling of the injured scalene muscles. If the muscle injury is mild so there is not much swelling, arm pain and paresthesia may not appear for a few weeks. This is because the later arm and hand symptoms are due to the healing process in the scalene muscles by which the intramuscular blood is absorbed and replaced by fibroblasts which later are replaced by collagen. This normal healing process results in scarred, tight muscles. Since normally the nerves roots of the brachial plexus are in contact with the scalenes, when the

Pathology

Study of scalene muscles of NTOS patients has revealed two types of significant changes. First, the incidence of scar tissue (or connective tissue) is three times greater in NTOS patients than in controls (36% vs 14.5%, p = 70% improvement compared to previous DASH score Good 45–70% improvement compared to previous DASH score Fair 25–45% improvement compared to previous DASH score Poor 50% of the evaluators. These features were then modified and/or consolidated during the feedback/discussion phase and additional features were added for more specificity. In the second round the consensus panel evaluated 242 features, of which 183 were considered to be of potential value by >50% of evaluators. In a third round, the list of diagnostic features was consolidated to 62 items that appeared to exhibit the greatest estimated diagnostic sensitivity, specificity, and accuracy. The expert panel next re-evaluated the series of items derived from the previous work with respect to the relative importance of each item in making a clinical diagnosis of neurogenic TOS, seeking to assess which items carried the greatest analytical strength as consensus-derived criteria. This approach was modeled after the survey construction and statistical analysis of Delphi-based survey results used by Graham and Wright, in their development of criteria for the diagnosis of carpal tunnel syndrome [120, 121]. The final list of items was then grouped and consolidated to establish terms that would reflect overlapping information from the similarly grouped items. These consolidated items indicated a series of 14 criteria in 5 categories that, taken together, would

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be expected to capture the most important features needed to establish a clinical diagnosis of neurogenic TOS. These items are summarized as the “CORE-TOS clinical criteria for the diagnosis of neurogenic TOS” shown in Fig. 9.7.

9.3.2 S  ociety for Vascular Surgery Reporting Standards During deliberations to develop new reporting standards for TOS, a special panel sponsored by the Society for Vascular Surgery (SVS) also addressed the diagnosis of neurogenic TOS [2]. Using the CORE-TOS diagnostic criteria as a starting point, the SVS panel gradually revised these criteria as based on the five categories into a more concise reconfigured form, based on evaluation of “central” and “peripheral” symptoms and examination findings (Table  9.4). Both sets of diagnostic criteria are based on initial exclusion of alternative diagnoses and supporting evidence from the patient history and physical examination; however, it is notable that unlike the CORE-TOS criteria, the SVS reporting standards criteria include a more prominent role for a positive response to “test injections” of the anterior scalene and/or pectoralis minor muscles, when properly performed in a suitably interpretable manner. Overall, the CORE-TOS criteria and SVS reporting standards criteria are considered to be similar and complementary, rather than opposed or competing, and clinicians and investigators are encouraged to utilize one or both sets of criteria in addressing the diagnosis of neurogenic TOS.

9.3.3 Application and Validation of Diagnostic Criteria Over the past 10 years, our TOS-focused specialized clinic has used the CORE-TOS clinical diagnostic criteria as part of our initial evaluation of patients with suspected neurogenic TOS, and we have found these criteria to be very effective in helping characterize and quantify the likelihood of diagnosis. To more formally evaluate

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CORE-TOS CLINICAL DIAGNOSTIC CRITERIA FOR NEUROGENIC THORACIC OUTLET SYNDROME Upper extremity symptoms which extend beyond the distribution of a single cervical nerve root or peripheral nerve, have been present for at least 12 weeks, have not been satisfactorily explained by another condition, AND Meet at least 1 criterion in at least 4 of following 5 categories: Principal Symptoms 1A: Pain in the neck, upper back, shoulder, arm and/or hand 1B: Numbness, paresthesias, and/or weakness in the arm, hand, or digits Symptom Chareacteristics 2A: Pain/paresthesias/weakness exacerbated by elevated arm positions 2B: Pain/paresthesias/weakness exacerbated by prolonged or repetitive arm/hand use, or by prolonged work on a keyboard or other repetitive strain tasks 2C: Pain/paresthesias radiate down the arm from the supraclavicular or infraclavicular spaces Clinical History 3A: Symptoms began after occupational, recreational, or accidental injury of the head, neck, or upper extremity, including repetitive upper extremity strain or overuse 3B: Previous ipsilateral calvicle or first rib fracture, or known cervical rib 3C: Previous cervical spine or ipsilateral peripheral nerve surgery without sustained improvement 30: Previous conservative or surgical treatment for ipsilateral TOS

Physical Examination 4A: Local tenderness on palpation over scalene triangle and/or subcoracoid space 4B: Arm/hand/digit paresthesias on palpation over scalene triangle and/or subcoracoid space 4C: Weak handgrip, intrinsic muscles or digit 5, or thenar/hypothenar atrophy Maximal Local Tenderness:

0

1+

Provocative Maneuvers 5A: Positive upper limb tension test (UL TT) 5B: Positive 3-minute elevated arm stress test (EAST)

2+

3+ EAST Seconds

Fig. 9.7  CORE-TOS clinical diagnostic criteria for neurogenic TOS. Office form depicting the CORE-TOS clinical diagnostic criteria for neurogenic TOS, including 14 separate items organized into 5 different categories. This form also includes information on the maximal degree of

local tenderness to palpation as determined by the examining physician, and the duration of time that the patient was able to continue the 3-min elevated arm stress test (EAST). Adapted from Balderman et  al. [93], with permission from Elsevier

and validate the utility of these criteria, we recently completed a prospective, observational, clinical cohort study that involved all patients referred over a 6-month period for evaluation for suspected neurogenic TOS [81, 93]. During the time period of this study there were 183 new patient referrals, with 150 (82%) meeting the CORE-TOS (and SVS reporting

standards) criteria for a diagnosis of neurogenic TOS (Fig.  9.8) [93]. The mean patient age was 37.1 ± 1.1 years (range, 12–66), 107 (71%) were women, 5 (3%) had a cervical rib and 15 (10%) had recurrent neurogenic TOS. Figure 9.9 shows that the most frequently positive diagnostic criteria were neck or upper extremity pain (99%), upper extremity or hand paresthesia (94%),

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88 Table 9.4  Society for vascular surgery reporting standards criteria for diagnosis of neurogenic TOS

Patients must meet at least three of the four following criteria for a diagnosis of neurogenic TOS 1. Local findings  History: Symptoms consistent with irritation or inflammation at the site of compression- scalene triangle in the case of NTOS and pectoralis insertion site in the case of NPMS- along with symptoms due to referred pain in the areas near the thoracic outlet. Patients may complain of pain in the chest wall, axilla, upper back, shoulder, trapezius region, neck, or head (including headache)  Examination: Pain on palpation of the affected areas as above 2. Peripheral findings  History: Arm or hand symptoms consistent with central nerve compression. Such symptoms can include numbness, pain, paresthesia, vasomotor changes, and weakness (with muscle wasting in extreme cases). These peripheral findings are often exacerbated by maneuvers that either narrow the thoracic outlet (lifting the arms overhead) or stretch the brachial plexus (dangling; often driving or walking/running)  Examination: Palpation of the affected area (scalene triangle or pectoralis minor insertion site) often reproduces the peripheral symptoms. Peripheral symptoms are often produced or worsened by provocative maneuvers that are believed to narrow the scalene triangle (EAST) or to stretch the brachial plexus (ULTT). 3. Absence of other reasonably likely diagnoses (cervical disc disease, shoulder disease, carpal tunnel syndrome, chronic regional pain syndrome, brachial neuritis) that might explain the majority of symptoms 4. In those who undergo it, the response to a properly performed test injection is positivea Adapted from Illig et al. [2], with permission from Elsevier EAST elevated arm stress test, NTOS neurogenic thoracic outlet syndrome, NPMS neurogenic pectoralis minor syndrome, ULTT upper limb tension test a Local anesthetic injection of the scalene and/or pectoralis minor muscles, preferably with imaging or electrophysiological guidance

symptom exacerbation by arm elevation (97%), localized supraclavicular or subcoracoid tenderness to palpation (96%), and a positive 3-min EAST (94%; with a mean duration 102 ± 5 seconds). The mean number of positive diagnostic criteria was 9.6 ± 0.1, and interestingly, this correlated with the degree of tenderness to palpation (Table 9.5) and the duration of EAST (Table 9.6), as well as with PROMs for pain severity, functional disability, depression, physical quality-of-­ life, and pain catastrophizing (all P  85–90% of patients with neurogenic TOS can expect substantial improvement in symptoms and function following supraclavicular decompression, with long-term recurrence rates less than 5% during follow-up. With expertise and experience, supraclavicular decompression offers the surgeon an excellent, versatile and safe approach in patients with neurogenic TOS and it has the flexibility to be applicable to all other forms of TOS and intraoperative contingencies. R. W. Thompson (*) · J. W. Ohman Center for Thoracic Outlet Syndrome, Section of Vascular Surgery, Department of Surgery, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, MO, USA e-mail: [email protected]

Critical Take-Home Points  1. Supraclavicular decompression for neuro genic thoracic outlet syndrome allows the surgeon to perform complete anterior and middle scalenectomy, thorough brachial plexus neurolysis, and first rib (and cervical rib) resection, as well as pectoralis minor tenotomy, within an easily visualized operative field. 2. Use of a consistent, step-wise procedure based on achieving a series of sequential “critical views” will allow the surgeon to follow an effective, thorough, flexible, and safe approach. 3. Supraclavicular decompression is associated with a number of potential complications, but the risk of intraoperative and early postoperative complications is very low, and outcomes studies indicate that >85–90% of patients can expect substantial improvement in symptoms and function with long-term recurrence rates less than 5%.

27.1 Introduction From a historical perspective, the operations initially developed for neurogenic thoracic outlet syndrome (TOS) employed the supraclavicular approach, including cervical rib resection, first rib resection, anterior scalenotomy, and scalenectomy [1–4]. Transaxillary first rib resection became widely used after its introduction by

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Roos in 1966, but its popularity diminished somewhat in the 1980s after reports of significant morbidity due to brachial plexus nerve injury [5–7]. Sanders and colleagues reintroduced the supraclavicular approach in 1979, initially for scalenectomy in recurrent neurogenic TOS after transaxillary first rib resection, followed by descriptions of combined transaxillary/supraclavicular approaches and more refined techniques for supraclavicular decompression in primary operations [8–13]. Subsequent reports emphasized the effectiveness of supraclavicular decompression for all forms of TOS, exemplified by several particularly large clinical series [14–16]. In this chapter, we present technical aspects of definitive surgical treatment for neurogenic TOS by the supraclavicular approach, with or without pectoralis minor tenotomy, based on 25  years of personal experience in a high-volume TOS practice (approximately 200–250 procedures per year). The techniques described are therefore built upon a broad background in dealing with this challenging area, and reflect ongoing conceptual updates and technical advances [17– 20]. Current technical aspects of transaxillary first rib resection are discussed elsewhere in this textbook (see Chap. 26), as are other procedures under preliminary investigation (see Chap. 28). The indications for surgical treatment of neurogenic TOS include (a) a sound clinical diagnosis, based on current reporting standards and validated diagnostic criteria; (b) substantial functional disability, with symptoms that interfere with daily activities and/or ability to work; and (c) an insufficient response to conservative management centered around a suitable treatment trial of TOS-specific physical therapy [20, 21]. Clinical and imaging evaluation may suggest variations in anatomy that can contribute to neurogenic symptoms, such as a cervical rib, scalene muscle anomalies or aberrant fibrofascial (“Roos”) bands, and physical examination should elicit the anatomical site(s) responsible for brachial plexus compression and irritation, distinguishing between the supraclavicular scalene triangle and/or the subcoracoid (pectoralis minor) spaces, in order to guide the most appropriate

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surgical approach (Fig.  27.1). When treating a patient with neurogenic TOS, it is widely acknowledged that the most critical anatomical structures are the anterior and middle scalene muscles, the brachial plexus, and the posterolateral aspect of the first rib. Many surgeons believe that to achieve the best and most durable results in thoracic outlet decompression, the scalene muscles should be entirely resected and fibrous scar tissue around the brachial plexus nerve roots should be fully excised; in addition, first rib resection is almost always advocated in current practice, to minimize the potential for recurrence, and pectoralis minor tenotomy should be considered where appropriate [22–26]. For these reasons, many favor the advantages of the supraclavicular approach to surgical treatment of neurogenic TOS (Table 27.1).

27.2 Surgical Technique Patient preparation: No special preoperative preparation is needed. We ask all patients to wash the surgical site (in this case, the shoulder and supraclavicular region) with a surgical detergent solution and sponge the night before surgery. The base of the neck is a very well-perfused and clean area, and postoperative infection in this site is extremely rare. We prescribe a scopolamine patch, to be applied behind the opposite ear the morning of surgery, to help alleviate postoperative nausea related to general anesthesia. The supraclavicular surgical site is marked in the preoperative holding area, being sure to include the subcoracoid space if concomitant pectoralis minor tenotomy is planned. Prophylactic antibiotics are administered within an hour of the planned procedure, and in some patients, a T1/T2 paravertebral anesthetic block is performed in the holding area before entering the room [27]. A detailed description of anesthesia for thoracic outlet decompression is provided elsewhere in this textbook (see Chap. 24). Instruments and patient positioning: In the operating room, the set-up includes a standardized instrument table including self-retaining retractors and emergency equipment (Fig. 27.2).

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Scalene Triangle Brachial Plexus

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Subclavian Artery and Vein Costoclavicular Space

Pectoralis Minor Space Pectoralis Minor Muscle

Scalene Triangle

Middle Scalene Muscle

Phrenic Nerve

Brachial Plexus

Anterior Scalene Muscle

Long Thoracic Nerve

Costoclavicular Space Pectoralis Minor Space

Subclavian Artery Subclavian Vein First Rib

Fig. 27.1  Anatomy of the thoracic outlet. Drawing illustrating the location and anatomy of the thoracic outlet, with emphasis on the supraclavicular scalene triangle and

the infraclavicular subcoracoid (pectoralis minor) space. Reproduced from Illig et  al. [21], with permission from Elsevier

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268 Table 27.1  Advantages of supraclavicular decompression for neurogenic TOS

• Allows complete removal of the anterior and middle scalene muscles, which cannot be accomplished by other surgical approaches • Permits full exposure of the entire brachial plexus by which to perform complete external neurolysis, which cannot be accomplished by other surgical approaches • Provides the best exposure of the posteriolateral first rib, from the level of the anterior scalene tubercle to the (T1) transverse process of the cervical spine •  Provides the best exposure of cervical ribs and other anomalous anatomic structures • Provides a great degree of safety in surgical treatment given the optimal anatomical exposure, potentially better than that achievable through alternative surgical approaches • Supine position provides easy access for inclusion of pectoralis minor tenotomy, at same time as the supraclavicular operation, both on the ipsilateral and contralateral sides • Ease of management of the pleural space and potential complications, including pneumothorax, hemothorax, and/or cervical lymph leak, as well as intraoperative bleeding • Low incidence of postoperative wound infection with cosmetically-favorable incisional healing and scar appearance •  Optimal exposure for reoperative surgical procedures regardless of initial approach. • Offers versatility to provide definitive treatment of all forms of TOS (including arterial and venous TOS) and to most effectively address unexpected anatomical abnormalities

The operation is performed under general endotracheal anesthesia with the patient in a semi-­ Fowler’s position, placing the legs flat and the upper body elevated about 30°. A small inflatable pillow is placed behind the shoulder blades and the neck is extended and turned to the opposite side (ROHO Thyroid Pillow, Moxi Enterprises, St. Louis, MO). The neck, chest, and affected upper extremity are prepped into the field, with the arm wrapped in sterile stockinette to permit free range of movement during the operation (Fig. 27.3a). This positioning provides excellent exposure to the supraclavicular region in a fashion that is comfortable for the surgeon and safe for the patient, and allows the surgeon to move between a position lateral to the shoulder or near the head, as the need for exposure dictates. Lower extremity sequential compression devices are used for thromboprophylaxis. Neuromuscular blocking agents are not used following the initial induction of anesthesia. Incision: A transverse incision is made in the supraclavicular fossa, parallel to and one or two fingerbreadths above the clavicle, with the medial end at the lateral edge of the sternocleidomastoid muscle and extending almost to the anterior edge of the trapezius muscle (Fig. 27.3). The platysma layer is entered and the clavicular head of the sternocleidomastoid muscle is retracted medially,

but not divided. Subplatysmal flaps are developed to expose the scalene fat pad. Mobilization of the scalene fat pad: One of the keys to simplifying the supraclavicular exposure is proper mobilization and lateral reflection of the scalene fat pad (Fig.  27.3d). This begins with detachment of the fat pad along the lateral edge of the internal jugular vein and the superior edge of the clavicle. Small blood vessels and lymphatic tissues are ligated and the thoracic duct, usually observed near the junction of the internal jugular and subclavian veins on the left side (a prominent accessory thoracic duct may also exist on the right side), may also be ligated and divided. The omohyoid muscle is routinely divided and excised. The scalene fat pad is progressively elevated in a medial to lateral direction, by gentle fingertip dissection over the surface of the underlying anterior scalene muscle, with the brachial plexus nerve roots becoming apparent along the lateral edge. The phrenic nerve is observed passing in a lateral to medial direction as it descends along the anterior scalene muscle surface. Gentle manipulation of the phrenic nerve produces a “dartle” (diaphragmatic startle) response, which can be confirmed by stimulation with a hand-held peripheral nerve stimulator (Vari-Stim III Nerve Locator, Medtronic, Minneapolis, MN) and documented by a transient alteration in the end-tidal

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a

b

d

Fig. 27.2  Instruments for supraclavicular decompression. Photograph of surgical instruments commonly used in supraclavicular thoracic outlet decompression. (a) Back table instrument set-up prior to operation. (b) Assembled Henley self-retaining wound retractor with three variable-length blades. (c) Disposable dual flexible-­ ring wound protector-retractor with plastic sheath (Alexis,

c

e

f

Applied Medical Resources Corporation, Rancho Santa Margarita, CA). (d) Disposable dual hinged-ring retractor system with elastic stay hooks (Lone Star, CooperSurgical, Inc., Trumbull, CT). (e) Suction catheters with removable tips are excluded from the operative field. (f) Emergency equipment including a hand-held sternal saw are kept available during all thoracic outlet operations

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a

b

c

d

Fig. 27.3  Patient positioning and surgical incisions. (a) The affected upper extremity is wrapped in stockinette and included in the sterile field that encompasses the neck, shoulder, and upper chest, to allow full range of motion and inspection of the hand, if necessary, during the course of the operation. (b) Planned incision sites for left supraclavicular decompression and pectoralis minor tenotomy. (c) The supraclavicular skin incision is made 1–2  cm above and parallel to the clavicle, extending from the lat-

eral edge of the sternocleidomastoid (SCM) muscle to the anterior edge of the trapezius (Trap) muscle. (d) The scalene fat pad is carefully dissected from its attachment to the internal jugular vein (IJV) and underlying structures, including the brachial plexus (BP), then mobilized toward the lateral aspect of the operative field where it is held in position by stay sutures to allow full exposure of the structures associated with the scalene triangle. Photo credits: Taylor D. Velleca, RN, BSN

CO2 waveform (Fig.  27.4). Following this the scalene fat pad is reflected further, until the middle scalene muscle and the long thoracic nerve

are also in view, and the scalene fat pad is then held in position with several silk retraction sutures. The resulting exposure represents the

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retaining retractor, with our current preference being a dual flexible ring self-retaining wound protector (Alexis, Applied Medical Resources Corporation, Rancho Santa Margarita, CA) (Fig. 27.5b) [28]. Anterior scalenectomy: Attention is next turned to the insertion of the anterior scalene muscle upon the first rib. The subclavian artery and brachial plexus are carefully mobilized until b a fingertip can be easily passed behind the muscle just above the first rib, thereby displacing the neurovascular structures posterolaterally. Blunt fingertip dissection is continued behind the muscle to its medial edge, taking care to avoid the phrenic nerve. Once the insertion of the anterior scalene muscle onto the first rib has been isolated under direct vision to protect the phrenic nerve, the subclavian artery, and the brachial plexus, it is sharply divided from the top of the bone with scissors (Fig.  27.6a) [29]. In this step we avoid use of the electrocautery, to minimize any risk of c thermal injury to adjacent structures, and find that any slight muscular bleeding from the muscle edge will stop spontaneously. The end of the divided anterior scalene is then elevated with forceps and attachments of the muscle to the underlying extrapleural fascia are sharply divided, to expose the subclavian artery and brachial plexus (Fig. 27.6b). Muscle fibers extending from the posterior aspect of the muscle often pass around the subclavian artery to form a tethering “subclavian sling” that should also be resected to fully release the artery. Any scalene minimus musFig. 27.4 Verification of phrenic nerve function. (a) Disposable hand-held battery-powered nerve stimulator cle fibers found to be present (passing between the (Vari-Stim III Nerve Locator, Medtronic, Minneapolis, roots of the brachial plexus) are divided as the MN) used during thoracic outlet decompression opera- anterior scalene muscle is mobilized. Blood vestions. (b) Operative photograph showing electrical stimusels that supply the muscle in this area can be easlation of the phrenic nerve on the surface of the anterior scalene muscle (ASM), following lateral rotation of the ily divided between ligatures, along with the scalene fat pad. (c) Anesthesia monitor tracings illustrat- branches of the thyrocervical trunk. As the anterior ing tidal volume (green line) and end-expiratory CO2 scalene muscle is lifted further, it is passed underconcentration (white line). The arrows indicate the tranneath and medial to the phrenic nerve (the “phrenic sient effects of phrenic nerve stimulation resulting in a diaphragmatic startle (“capnographic dartle”) response flip” maneuver), and the dissection is carried superiorly to the origin of the muscle on the C6 trans(arrows). Photo credit: Hope A. Waller, RN verse process, which is easily palpated in the upper aspect of the operative field as the apex of the “scafirst and most important of six “critical views” to lene triangle.” The anterior scalene muscle is then be sequentially obtained during supraclavicular divided with scissors from its origin on the transdecompression (Fig.  27.5 and Table  27.2) [18– verse process under direct vision and the entire 20]. The exposure is maintained with a self-­ muscle is removed, with a typical specimen a

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a

b Phrenic Nerve

Anterior Scalene Muscle

Long Thoracic Nerve

Jugular Vein

Middle Scalene Muscle Brachial Plexus Scalene Fat Pad (Reflected)

Sternocleidomastoid Muscle (Reflected)

Subclavian Artery

Fig. 27.5  Definitive exposure. (a) Operating room photograph demonstrating “critical view 1” during supraclavicular decompression, in which the following structures are visualized within the operative field: internal jugular vein, anterior scalene muscle, phrenic nerve, brachial plexus nerves, subclavian artery, middle scalene muscle, and long thoracic nerve. (b) Photograph demonstrating

the view obtained after placement of a dual flexible ring self-retaining wound retractor (Alexis, Applied Medical Resources Corporation, Rancho Santa Margarita, CA), to maintain and enhance exposure of the operative field during supraclavicular decompression. Panel A adapted from Duwayri et al. [18], with permission from Elsevier

Table 27.2  Six critical views to be obtained during supraclavicular decompression 1.

2.

3. 4.

5. 6.

View of the operative field after lateral reflection of the scalene fat pad, with visualization of the internal jugular vein, anterior scalene muscle, phrenic nerve, brachial plexus, subclavian artery, middle scalene muscle, and long thoracic nerve View of the lower part of the anterior scalene muscle where it attaches to the first rib, with space sufficient to allow a finger to pass behind the anterior scalene muscle and in front of the brachial plexus and subclavian artery, prior to division of the anterior scalene muscle insertion from the top of the first rib View of the upper part of the anterior scalene muscle at the level of the C6 transverse process, in relation to the C5 and C6 nerve roots, prior to division of the anterior scalene muscle origin View of the insertion of the middle scalene muscle on the first rib, with each of the five nerve roots of the brachial plexus and the subclavian artery retracted medially and the long thoracic nerve retracted laterally, prior to division of the middle scalene muscle insertion from the top of the lateral first rib View of the posterior neck of the first rib, with the T1 nerve root passing from underneath the rib to join the C8 nerve root to form the inferior trunk of the brachial plexus, prior to division of the posterior first rib View of the anterior portion of the first rib, with placement of the rib shears medial to the scalene tubercle, prior to division of the anterior first rib

weighing 5–10  g. Any minor bleeding from the edge of the divided muscle origin is controlled with small polypropylene sutures rather than electrocautery, given the proximity of the nerve roots. Any anomalous fibrofascial (“Roos”) bands may then be observed, typically passing in front of the lower brachial plexus nerve roots. These structures

are also resected as they are encountered to ensure thorough decompression and full nerve root mobility. Middle scalenectomy: At this point, the brachial plexus nerve roots are separated from the front edge of the middle scalene muscle by sharp and blunt fingertip dissection, to extend the expo-

27  Surgical Techniques: Operative Decompression Using the Supraclavicular Approach for Neurogenic… Middle scalene muscle

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Phrenic n.

Resected anterior scalene muscle

a

First rib

b

Scalene minimus muscle

Fig. 27.6  Anterior scalenectomy. (a) After the insertion of the anterior scalene muscle on the anterior first rib is circumferentially isolated by gentle fingertip dissection to protect the underlying subclavian artery and brachial plexus nerves, the muscle insertion is sharply divided with scissors, while observing and protecting the phrenic nerve. (b) The end of the divided anterior scalene muscle

is lifted and sharply dissected free of structures lying behind the muscle. The dissection is carried further to the origin of the anterior scalene muscle on the C6 transverse process, where it is sharply divided to excise the muscle specimen. Redrawn from Thompson [29], with permission from Springer Nature

sure deeper to the inner curve of the first rib and the extrapleural space. A small malleable retractor is placed between the brachial plexus nerves and the middle scalene muscle, and with gentle medial retraction of the brachial plexus, each nerve root from C5 to T1 is sequentially identified. The transverse cervical artery and vein are ligated and divided where they pass through the brachial plexus and middle scalene muscle, to avoid bleeding should these vessels be avulsed during retraction. The main landmark to note at this point is the long thoracic nerve, which exits the lateral aspect of the middle scalene muscle and courses inferiorly, and a second malleable retractor is placed lateral to the middle scalene muscle and first rib, to displace the long thoracic nerve posteriorly. The oblique attachment of the middle scalene muscle along the top of the posterolateral first rib is then fully exposed and the muscle insertion is divided from the

surface of the bone with a periosteal elevator or the electrocautery, until the first rib is cleanly exposed to a point parallel with the underlying T1 nerve root (Fig. 27.7). It is notable that if a cervical rib is present, it is typically exposed at this point in the dissection, since it arises in the anatomical plane of the middle scalene muscle. The bulk of the detached middle scalene muscle is then sharply excised while protecting the long thoracic nerve, with a typical specimen weight of 3–8 g. Any minor bleeding from the cut edge of the middle scalene muscle is controlled with figure-of-eight silk sutures, ­ rather than the electrocautery, to avoid thermal injury to the C8 nerve root or the long thoracic nerve. First rib resection: At this point, the remaining intercostal muscle attaching to the lateral edge of the first rib is separated from the bone with a periosteal elevator or the electrocautery (Fig. 27.7b). A right angle clamp is passed underneath the

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Long thoracic nerve

Middle scalene muscle

Division of intercostal muscles

C8 T1 Scalene tubercle

a

b

Division of posterior first rib

Protection of T1 Nerve Root

c

Smoothing end of posterior first rib

d

Fig. 27.7  Middle scalenectomy and division of the posterior first rib. (a) The middle scalene muscle is detached from the top of the posterolateral first rib and muscle lying in front of the long thoracic nerve is excised. (b) The intercostal muscles along the outer curve of the first rib are bluntly divided. (c) The posterior “neck” of the first rib is exposed with full visualization of the C8 and T1 nerve

roots, which are protected with a fingertip while the rib is divided with rib shears. (d) The posterior edge of the divided first rib is further remodeled with a Kerrison bone rongeur to achieve a smooth surface at the level of the costotransverse joint, medial to the T1 nerve root. Redrawn from Thompson [29], with permission from Springer Nature

posterior “neck” of the first rib and gently spread to detach additional intercostal tissues and extrapleural fascia. A modified Stille-Giertz rib cutter is inserted around the neck of the posterior first

rib, and after verifying that the C8 and T1 nerve roots are well protected with a fingertip, the bone is sharply divided (Fig. 27.7c). A Kerrison bone rongeur is then used to smooth the posterior cut

27  Surgical Techniques: Operative Decompression Using the Supraclavicular Approach for Neurogenic…

edge of the bone, to the level of the T1 costo-­ transverse joint space, or at least medial to the underlying T1 nerve root, and the end of the bone is sealed with bone wax (Fig. 27.7d). The free end of the divided posterior first rib is elevated, and blunt fingertip dissection is used to separate the remaining extrapleural fascia and intercostal muscle attached to the undersurface of the first rib, progressing anteriorly to the level of the scalene tubercle (the previous site of attachment of the anterior scalene muscle). No effort is made to avoid entering the pleura during first rib resection, as the open pleural space will allow better drainage of postoperative fluids away from the brachial plexus (which might otherwise promote perineural adhesions). To access the anterior first rib, the subclavian artery and brachial plexus are gently retracted posterolaterally. Using fingertip pressure to displace the posterior first rib downward (Fig. 27.8a), the surgeon opens the anterior costoclavicular space, and the clavicle and subclavian vein are elevated with a small Richardson retractor. The Stille-Giertz rib cutter is placed around the anterior first rib, immediately medial to the scalene tubercle, and the first rib is then divided under direct vision and the intact first rib specimen is extracted from the operative field (Fig.  27.8c). The remaining anterior end of the first rib is further remodeled to a smooth surface with a Kerrison bone rongeur, to a level well underneath the clavicle. Oxidized cellulose fabric (Surgicel, Ethicon, Inc., Somerville, NJ) is placed within the bed of the resected first rib as a topical hemostatic agent. Cervical rib resection: It is again noted that cervical ribs arise within the tissue plane of the middle scalene muscle, posterior to the brachial plexus and subclavian artery, and anterior to the long thoracic nerve [30]. While complete cervical ribs usually attach to the lateral first rib in the form of a true joint, incomplete cervical ribs typically have a ligamentous extension to the first rib. The posterior portion of a cervical rib is thereby first encountered during dissection of the middle scalene muscle and it is divided in a manner similar to the posterior first rib. When there is a true joint between a complete cervical rib and the first rib, the anterior portion of the cervical rib can be

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left attached while the first rib resection is completed, and the two removed together as a single specimen (Fig. 27.8d). Brachial plexus neurolysis: The final step in supraclavicular decompression is to fully mobilize each of the individual nerve roots contributing to the brachial plexus and to ensure that the brachial plexus itself is free of any investing muscle fibers and perineural fibrous scar tissue (“external neurolysis”) (Fig.  27.9). If there are muscle fibers that interdigitate between the nerve roots and trunks (e.g. a scalene minimus anomaly), these fibers should also be sharply debrided. Inspection of the most proximal aspect of the C8 and T1 nerve roots is especially important, as there is often a small fibrofascial band overlying these nerves that should be specifically sought out and resected. Each nerve root from C5 to T1 is meticulously dissected free of any adherent fibrous tissue that might impair mobility, persisting until all five nerve roots and three trunks are identified, fully mobilized, and well-cleaned throughout their course through the supraclavicular operative field. Pectoralis minor tenotomy: In most patients with neurogenic TOS we currently combine supraclavicular decompression with concomitant pectoralis minor tenotomy. To accomplish this, a short vertical incision is made in the deltopectoral groove, extending inferiorly from the level of the coracoid process. The deltoid and pectoralis major muscles are gently separated and the plane of dissection is carried medial to the cephalic vein into the axillary space. The lateral edge of the pectoralis major muscle is gently lifted with a small Deaver retractor, and the plane underneath the muscle is separated from the underlying fascia by blunt fingertip dissection where the pectoralis minor muscle can be easily identified. The fascia along the superior and inferior edges of the pectoralis minor muscle is entered and the muscle is circumferentially isolated near its insertion on the coracoid process, where it is encircled with umbilical tape or rubber tubing and elevated (Fig. 27.10). While the coracoid process is exposed with a small Richardson retractor, a finger is placed behind the muscle to prevent thermal injury to the n­ eurovascular structures,

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276 Downward digital pressure on posterior rib

Clavicle

Manubrium

First rib removed

Level of anterior rib resection

a Cervical rib Posterior Posterior

First rib

b

Anterior

First rib

c

Anterior

Fig. 27.8  Division of the anterior first rib and operative specimens. (a) The posterior end of the first rib is displaced downward by the finger of the surgeon to open the anterior costoclavicular space, and the anterior aspect of the first rib is exposed underneath he clavicle and subclavian vein. While retracting the subclavian artery and brachial plexus nerves posteriorly, a rib shears is placed across the anterior first rib, just medial to the scalene

tubercle, to divide the bone at the level indicated. (b) Typical operative specimen of the first rib after supraclavicular decompression. (c) Typical operative specimen of a complete cervical rib, which had formed a fibrous joint with the resected first rib, after supraclavicular decompression. Panel A redrawn from Thompson [29], with permission from Springer Nature

and the insertion of the pectoralis minor tendon is divided from the coracoid process with the electrocautery. After the pectoralis minor muscle has been divided, the medial-­lower edge will retract to release any compression of the neurovascular bundle. The remaining clavipec-

toral fascia is also incised at the level of the clavicle, along with any other anomalous fascial bands that might be present over the brachial plexus, but no further dissection of the brachial plexus nerves or the axillary vessels is performed.

27  Surgical Techniques: Operative Decompression Using the Supraclavicular Approach for Neurogenic…

a

b

Fig. 27.9  Brachial plexus neurolysis. Operating room photographs depicting brachial plexus neurolysis. (a) Dense fibrous scar tissue surrounding brachial plexus (BP) nerves before neurolysis. The adjacent subclavian artery is shown (SCA). (b) Sharp scissors dissection to excise scar tissue from outer surface of nerves (“external

Fig. 27.10  Pectoralis minor tenotomy. Operating room photograph showing isolation of the left pectoralis minor muscle through a deltopectoral groove incision, just prior to dividing the insertion of the muscle on the coracoid process. Adapted from Duwayri et al. [18], with permission from Elsevier

Wound closure: Prior to wound closure, two small perfusion catheters are placed from ­adjacent skin sites to lie within the operative field, next to the brachial plexus nerves and along the bed of the resected first rib. These catheters are connected to an elastomeric osmotic pump that has been pre-filled with 0.5% bupivacaine, to provide continuous perineural infusion of local anesthetic during the postoperative

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c

neurolysis”). (c) Neurolysis is considered to be complete when each component of the brachial plexus has been cleared of scar and fully mobilized, including C5 and C6 forming the upper trunk, C7 representing the middle trunk, and C8 and T1 forming the lower trunk

period (ON-Q Pain Relief System, Avanos, Alpharetta, GA) (Fig.  27.11) [31, 32]. A 19-French closed-suction silicon drain (Blake Drain, Ethicon, Inc., Somerville, NJ) is placed through a stab wound, positioned to pass behind the brachial plexus and into the upper posterior aspect of the pleural space, then connected to a fluid collection bulb reservoir. In an effort to limit the development of perineural scar tissue that might contribute to recurrent neurogenic TOS, we also place an absorbable polylactide film (SurgiWrap Bioresorbable Sheet, MAST Biosurgery, San Diego, CA) around the brachial plexus, which can be held in position by several fine absorbable sutures attached to the back of the scalene fat pad (Fig.  27.11c). This material also has the advantage that it provides a temporary physical barrier around the nerves for a longer period than alternative materials, being resistant to bioabsorption for up to 2–3 months. Once these steps have been taken, the scalene fat pad is placed back into its normal anatomic position and held in placed with several sutures, and the wounds are closed in two layers and dressed with steristrips (Fig. 27.11d). Following an average postoperative hospital stay of 3–4 days, the closed-suction drain is removed in the outpatient office (Fig. 27.12).

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a

c

Fig. 27.11  Anesthetic infusion catheters and surgical dressings. (a and b) Operating room photographs demonstrating scrub nurse placing local anesthetic (0.5% bupivacaine) into an osmotic pump (ON-Q Pain Relief System, Avanos, Alpharetta, GA) and placement of the continuous infusion catheters just prior to closure of the surgical wounds. The infusion catheters are positioned by the surgeon to lie along the path of the brachial plexus nerves. (c)

b

d

The brachial plexus is loosely wrapped with an absorbable polymer film (SurgiWrap Bioresorbable Sheet, MAST Biosurgery USA, Inc., San Diego, CA), intended to diminish the potential for perineural adhesions and recurrent neurogenic TOS. (d) Placement of surgical dressings upon completion of the operation. Photo credits: Kandyce K. Branham, RN, and Catrice Parke-Stacy, RN

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a

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b

Fig. 27.12  Removal of closed-suction drain. (a) Surgical dressings at outpatient office follow-up visit on postoperative day 5, just before removal of the closed-suction drain (Blake Drain, Ethicon, Inc., Somerville, NJ) placed at the

time of surgery. (b) Chest radiograph following removal of the closed-suction drain. The posterior extent of left first rib resection is indicated (arrow). Photo credit: Karen Henderson, RN

27.3 Potential Complications and Postoperative Care

Table 27.3  Potential complications of supraclavicular thoracic outlet decompression

Supraclavicular decompression for neurogenic TOS is accompanied by a number of potential complications, as listed in Table 27.3. The overall incidence of complications is less than 5% and the majority are temporary and readily managed; however, there remains the potential for significant concerns that may require reoperation or other interventions [33–35]. A comprehensive, protocol-driven approach to postoperative care remains an important component of treatment for neurogenic TOS, helping to optimize early outcomes, recovery and rehabilitation. A detailed description of early postoperative care and follow-­up is provided elsewhere in this textbook (see Chap. 43). The most serious intraoperative complication in any operation for TOS is rapid unexpected hemorrhage following injury to the subclavian artery or vein, coupled with delayed

Intraoperative hemorrhage Pneumothorax or air-leak Postoperative bleeding, localized hematoma, or hemothorax Wound infection (cellultitis or abcess) Pleural effusion (serosanguinous) Persistent lymph leak, chylothorax Brachial plexus nerve dysfunction (temporary or sustained) Phrenic nerve dysfunction (temporary or sustained) Long thoracic nerve dysfunction (temporary or sustained) Deep vein thrombosis, pulmonary embolism Subclavian or axillary artery thrombosis Adverse drug reactions, interactions, and medication side-effects Persistent pain, numbness, and/or paresthesias Diminished upper extremity range of motion, “frozen” shoulder Complex regional pain syndrome (CRPS) Persistent or recurrent neurogenic thoracic outlet syndrome

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recognition and inadequate resuscitation. This rarely described event can indeed be life-threatening and it usually occurs in the setting of unusually difficult anatomic exposure, unexpected pathology, surgical inexperience, and poor selection of operative approach. The operating surgeon must therefore remain ever-vigilant for signs of undue bleeding, and the operating room team prepared for rapid response to such an uncommon circumstance. Toward this end, it is notable that for all thoracic outlet decompression operations we keep resuscitative equipment and surgical instruments immediately available, including the routine availability of a sternal saw and retractors for the potential surgical management of catastrophic intrathoracic hemorrhage, even though in practice we have yet to experience such an unfortunate emergency event. The remaining risks of thoracic outlet decompression revolve around the potential for nerve or vascular injury that exist in any operation in this area, as well as operative inadequacies that may lead to persistent or recurrent problems. It is notable that in the approach described in this chapter, the possibility of pneumothorax is obviated by routine placement of the closed-suction drain into the opened pleural space, which also helps mitigate postoperative pleural effusion. Postoperative hemothorax and persistent lymph leak are usually managed expectantly, but when early reoperation is required this can also be readily accomplished through the supraclavicular incision. While the potential for serious nerve injury and/or postoperative neuropraxia is a significant concern in any operation for neurogenic TOS, the actual incidence of these complications is extremely low with use of a meticulous, systematic operative approach, and in current practice the risks associated with thoracic outlet decompression are very low [16, 36–50]. Nonetheless, it should be acknowledged that these procedures are technically demanding and accomplishing them with acceptably low complication rates

requires a considerable amount of training and experience.

27.4 Results In assessing the outcomes of surgery for neurogenic TOS, most authors describe patient-­ reported results divided into four categories: (1) excellent, with complete relief of all symptoms; (2) good, with relief of major symptoms but some persistent symptoms; (3) fair, with partial relief but persistence of some major symptoms; and (4) poor, with no improvement [14]. In general, patients having results considered in the excellent, good or fair categories will feel that the operation was worthwhile, whereas those in the poor category will feel that the operation was a failure. More recently, investigators have used semi-quantitative functional and patient-reported outcomes measures (PROMs), such as the Disabilities of the Arm, Shoulder and Hand (QuickDASH) survey and the SF-12 quality-of-­ life (QOL) assessment tool [51, 52]. Because the degree of improvement obtained in the first few months after surgery may diminish with time, the durability of successful outcomes has become another important measure of results, along with the proportion of patients eventually requiring reoperation for recurrent symptoms. Supraclavicular decompression became one of the more commonly performed operations for neurogenic TOS over the past several decades. In a collection of studies published from 1973 to 2001 encompassing 1222 operations, the results for supraclavicular decompression were good in 59–91% (mean 77%), fair in 5–33% (mean 15%), and poor in 3–18% (mean 8%) [20]. Hemple and colleagues reported a particularly large series of 770 operations in 637 patients in 1996, describing “excellent” or “good” results in 86% of cases [15]. Sanders presented one of the most comprehensive analyses of surgical results for neurogenic TOS, in which the life-table method was used to compare outcomes for different operative

27  Surgical Techniques: Operative Decompression Using the Supraclavicular Approach for Neurogenic…

procedures [8, 14, 16, 53]. In comparing patients that underwent transaxillary first rib resection (n  =  112), supraclavicular scalenectomy alone (n = 286), or supraclavicular scalenectomy with first rib resection (n = 249), he found no difference in the initial success rate between these three procedures (91, 93 and 93%, respectively). The percentage of patients with successful outcomes also declined over time with all three procedures, with the long-term success of supraclavicular scalenectomy and first rib resection appearing somewhat better at 10–15  years (71%) than the results for either scalenectomy alone (66%) or transaxillary first rib resection (64%), but there were no statistically significant differences between these operations. Further analysis indicated that certain preexisting clinical features may be associated with diminished success for operative treatment of neurogenic TOS, particularly work-related injury, longstanding symptoms, major depression, diffuse upper extremity symptoms, and lack of a response to anterior scalene muscle blocks. In another recent study, Axelrod and colleagues examined 170 patients who underwent supraclavicular decompression for neurogenic TOS between 1990 and 1999, with an average follow-up of 47 months [54]. They describe that 65% reported a substantial improvement in symptoms and 64% were satisfied with their operative outcome, but that 18% remained disabled. Using multivariate logistic regression models they found that preoperative factors associated with persistent self-reported disability included major depression (odds ratio 15.7; P  =  0.02), not being married (odds ration 7.9; P = 0.04), and less than a high school education (odds ration 8.1; P = 0.09).This study supported the conclusion that operative decompression is beneficial for most patients with neurogenic TOS but that psychological and social factors have a strong impact on individual patient outcome. More recently, our group conducted a retrospective review of 189 patients with disabling neurogenic TOS that underwent primary supraclavicular decompression by the techniques

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described in this chapter, to compare clinical characteristics and functional outcomes between adolescent patients (age  21 years, n = 154) [48]. Adolescent and adult patients were not significantly different with respect to gender (overall 72% female), bony anomalies (23%), previous injury (56%), co-existing pain disorders (11%), or positive response to a scalene muscle anesthetic block (96%), but compared to adults, adolescent patients had a significantly lower incidence of depression (11.4% vs. 41.6%), previous motor vehicle injury (6% vs. 20%), previous operations (11% vs. 30%), preoperative use of opiate medications (17% vs. 45%), and symptom duration greater than 2 years (24% vs. 50%). Mean hospital length of stay was lower in adolescent versus adult patients (4.4  ±  0.2 vs. 4.9  ±  0.1  days; P = 0.03), but the rate of postoperative complications was no different (overall 4.2%: one surgical site bleeding, two infected wound fluid collections, and five persistent lymph drainage). Both groups exhibited significant improvement in functional outcome measures at 3- and 6-months, particularly as measured by the QuickDASH survey, but adolescent patients had significantly better outcomes and lower long-term use of opiate medications compared to adults. This study illustrated that adolescent patients undergoing supraclavicular decompression for neurogenic TOS had more favorable preoperative characteristics and enhanced 3- and 6-month functional outcomes compared to adults, and emphasized that further studies are needed to delineate the age-­ dependent and independent factors that promote optimal surgical outcomes for this condition. Given that supraclavicular decompression for neurogenic TOS involves mobilization of the scalene fat pad and surgical dissection within the anterior neck, we have examined whether obesity might have an adverse influence on the technical conduct of surgery or on early postoperative complications, such as wound infection and persistent lymph drainage [49]. This study involved a series of 265 patients that underwent supraclavicular decompression for neurogenic TOS, with

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patients grouped according to six standard body mass index (BMI) categories: mean BMI was 27.2 ± 0.4 (range 16.8–49.9), with 7 underweight (3%), 95 normal (36%), 84 overweight (32%), 47 obese-I (18%), 15 obese-II (6%), and 17 obese-­ III (6%). There were no significant differences between the six BMI categories in the length of operation, intraoperative blood loss, amount of fluid administered, scalene muscle weight, or hospital length of stay, and no differences in the amount of lymphatic fluid production or drain duration. Six patients (2%) underwent early reoperation for control of a persistent lymph leak and there were 11 (4%) readmissions within 30 days of operation (all for unsatisfactory outpatient control of postoperative pain), but complications and hospital readmission rate were not associated with BMI.  The mean follow-up QuickDASH score was 41.6 ± 1.6, which compared favorably to the mean preoperative QuickDASH score of 59.1  ±  1.2 (P  0.05. Gelabert et.al. JVS 2018

Fig. 39.3  Outcomes of trans-axillary first rib resection. Results of transaxillary first and cervical rib resections for NTOS, Gelabert et al.

39  Controversies in NTOS: Transaxillary or Supraclavicular First Rib Resection in NTOS? Arguments… Table 39.1  Outcomes of trans-axillary first rib resection. Reported results of transaxillary first rib resection for NTOS in patients who underwent an anterior scalene muscle block, Machelder et al. Guided anterior scalene blocks surgical outcomes • 102 patients with Clinical Dx TOS • Positive ASMB 32 patients 30 (94%) improved • Positive ASMB 1 not improved = 5% false negative • Negative ASMB 6 patients 3 (50%) improved Jordan and Machleder. Annals of Vascular Surgery 1998 [13] Table 39.2  Outcomes of transaxillary first rib resection for NTOS in patients who underwent an anterior scalene muscle block, Orlando et al. Long-term outcomes of patients treated with TAFRR Neurogenic TOS n = 281 93% improved Venous TOS n = 225 97% improved Arterial TOS n = 24 100% improved Orlando et al. J AM Coll Surg 2015 [17] Table 39.3  Outcomes of trans-axillary first rib resection. Results of transaxillary first and cervical rib resections for NTOS, Gelabert et al. n = 70 H Pain score DASH score

All Initial 6.99* Final 1.34* Initial 60.39* Final 31.33*

Pain score: Somatic pain score (0–10) QD score: QUICK DASH (Disability Arm Shoulder Hand) Score (0–100) * Statistically significant P > 0.05 Gelabert et al. JVS 2018 [15]

context of a positive anterior scalene muscle block, we anticipate between 90 and 95% of patients will be significantly improved [13–15]. As other causes for thoracic outlet-like symptoms have been recognized, and patient selection is refined, then the number of TOS patients with persistent symptoms is reduced. Coincident diagnosis, which may affect the results of surgery have been better defined. The most common coincident diangosis include cervical spine disease, peripheral nerve compressions (carpal tunnel, cubital tunnel, Guyon tunnel, and radial tunnel), and pectoralis minor compression syn-

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drome. Patients with concurrent pain syndromes such as myofascial pain or fibromyalgia or CPRS will certainly not be expected to report complete resolution of symptoms with TAFRR or any form of TOS decompression.

39.2.4 An Advantage Less Frequently Employed One advantage of TAFRR is the ability to reach and perform an upper extremity dorsal sympathectomy. This operation was used in treatment of causalgia (CRPS) and chronic ischemia. Current pain management approaches discourage the use of sympathectomy, as it disrupts the continuity of the sympathetic fibers and renders useless many of the current treatment modalities (sympathetic blockade, dorsal column stimulators, nerve root stimulators).

39.3 Disadvantages of TAFRR 39.3.1 Most Physicians Are Not Familiar with the Anatomy The principal disadvantage of TAFRR is the lack of familiarity of most physicians with the anatomical concepts underlying this approach. Most students learn anatomy from an anterior-­posterior perspective. For this reason, most vascular surgeons have a rudimentary familiarity with supraclavicular approach as the anatomy is approached and displayed in a manner similar to that learned in medical school. Additionally most vascular surgeons have experience with carotid-­subclavian bypass reconstruction. This operation employs an approach similar to that of the supraclavicular decompression. Approaching the thoracic outlet from the axilla is not taught in medical school and thus is a perspective not familiar to most surgeons. The transaxillary approach to the thoracic outlet is via an oblique plane which follows a caudad to cephalad direction. This is not intuitive and requires close study.

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39.3.2 Teaching the Operation Is Difficult Prior to use of fiber-optic endoscopy, the opportunities to learn of the transaxillary approach to thoracic outlet decompression were quite limited. Because of the limitations of the incision (narrow aperture with significant depth) only the operating surgeon could see the dissection. The step-by step clearing and definition of the key anatomical elements was difficult to teach. Students and Fellows assisting in these cases could only glimpse the anatomy briefly and intermittently when the primary surgeon would pause the case for instruction. In our current practice, high definition video endoscopy is used routinely to assist in dissection [18]. This provides added perspective, and allows clear identification of key structures. Critical views are examined prior to transecting the rib at various stages, making the operation safer. At the same time, the high-­ definition endoscopy allows assistants and staff the opportunity to follow the operation as it unfolds. It allows teaching the anatomy, the operation, and the interrelation of structures.

39.3.3 Special Equipment Is Not Widely Available TAFRR is optimally done with special equipment which most hospitals do not have (Fig.  39.4). Retraction of the arm is a major element of the operation. Traditionally, this was done by a surgical assistant. Table mounted arm retractors allow for sterile positioning, retraction and resting of the in the course of the operation. These are not widely available as they originally were custom made and not well publicized. Currently they are commercially available and have been used in major centers with large TOS volumes. The advantage of a table mounted arm retractor is that the exposure is reliable and stable. The need to rest and re-position allows the conduct of the operation to proceed more rapidly and safely. Visualizing the anatomical structures at the depth of the incision is difficult without excellent lighting. This is a significant problem if one relies

M. C. Gelabert

only on operating room overhead lights. Fiber-­ optic lighted wound retractors are important in allowing bright, clear visualization of structures at the depth of the incision. These accomplish the retraction of tissues while simultaneously bringing light into the wound. The surgical instrumentation is unfamiliar to most vascular surgeons as it is derived from Orthopedic and Thoracic surgery. Some of it is specially developed for TAFRR: the Roos nerve root protector. Others are adapted for the operation: the Betheune rib shear, the box, Leksel, and Luer-Stile rongeurs, and the Lane bone forceps (Fig. 39.4b).

39.3.4 TAFRR Does Not Allow Complete Scalene Muscle Resection An important concern with TAFRR is the inability to resect the entire scalene muscle. At best, the lower 25% of the muscle can be resected. This may allow re-attachment of the transected muscle with development of recurrent symptoms. Several concerns may arise from this: in rare instances the upper portions of the scalene muscle may interdigitate between the roots or trunks of the brachial plexus. While the significance of these interdigitations is uncertain, they would not be amenable to resection via TAFRR. The ability to perform neurolysis is limited in TAFRR. The ability to clear fibrous bands from the upper portions of the brachial plexus is not possible. Neurolysis of the lower brachial plexus from T1 through C7 is possible, but reaching to C6 or C5 is beyond the scope of the TAFRR. Again, the importance of neurolysis of the upper brachial plexus is debatable. Of concern, the partially resected scalene muscles may re-attach and result in recurrent TOS.  The incidence of this occurrence is relatively low. In our practice, re-operation for scalene muscle re-attachment is relatively infrequent: about 10% of cases. On the balance we feel that the ability to avoid potential injuries inherent in a supraclavicular approach are offset by the relatively small number of patients who may ultimately require scalene muscle resection.

39  Controversies in NTOS: Transaxillary or Supraclavicular First Rib Resection in NTOS? Arguments…

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a

b A

B

C

D G

F E

H

Fig. 39.4  Arm holder, equipment. (a) The patient is positioned in a lateral position and the affected limb is held in intermittent abduction in a sterile arm holder. (b) Equipment used for transaxillary first rib resection. (A)

Alexander Haight periosteal elevator. (B) Luer-Stile rongeur. (C) Box rongeur. (D) Roos nerve root retractor. (E) Fiber optic lighted retractors. (F) Betheheune rib shear. (G) High-definition digital camera. (H) Endoscope

39.3.5 Misconceptions of TAFRR

lar approach. Our experience indicates that these are readily managed via TAFRR. Recently published experience with transaxillary resection of cervical ribs indicates that these may be safely resected via transaxillary approach [15]. In all cases, the fully formed cervical ribs have been successfully resected with excellent results.

Misconceptions regarding the ability to manage cervical ribs, fibrous bands, scaleneius minimis muscles via trans-axillary approach abound. Many authors assume cervical ribs and anatomical anomalies must be managed via supraclavicu-

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a

b

c

d

Fig. 39.5  C rib resected, fibrous band resected, sclaneemius minimis, intercostalizaiton. (a) Photo of first and cervical rib resected via a transaxillary approach. (b) Photo of a fibrous band resected from the end of a class 1 cervical rib onto the first rib. (c) Intra-operative photo showing a scalenenius minimis muscle. SCA  =  subclavian artery, BP  =  brachial plexus. (d) Intra-operative

photo demonstrating intercostalization between fibers of the anterior and middle scalene muscle. The curved lines highlight the direction of the fibers of the anterior scalene and middle scalene muscles. The arrow denotes the area of overlap of these fibers accounting for the “intercostalization”. SCA subclavian artery, BP brachial plexus

Similarly, cervical rib bands extending from a partial (class 1) rib to the first rib are readily resected. Additional tendinous or fibrous bands crossing the lower plexus are readily dissected and removed. Muscular variations such as ­scalenius minimis and intercostalization are also easily excised (Figs. 39.5 and 39.6).

39.3.6 Arterial Reconstruction Is Difficult Open arterial reconstruction requires a supra-­ clavicular or para-clavicular exposure and would be difficult to accomplish via a TAFRR. On the other hand, most patients presenting with ATOS

Fig. 39.6 Final appearance of decompression. Intra-­ operative photo of the final state following TAFRR. Note the bright white appearance of the articular cartilage of the T1 transverse process (arrow). SCV subclavian vein, SCA subclavian artery, BP brachial plexus

39  Controversies in NTOS: Transaxillary or Supraclavicular First Rib Resection in NTOS? Arguments…

can be effectively managed with endovascular techniques [19]. While endovascular reconstruction cannot be done via a transaxillary approach, the TAFRR sets the stage for endovascular reconstruction. In our practice, the two techniques are complimentary: TAFRR followed by angioplasty or stent grafting of the subclavian artery.

39.4 Conclusion It is certain that experience and familiarity with TOS decompression will result in reliable and successful outcomes—for either TAFRR or supraclavicular decompression. The transaxillary approach is simple and relatively rapid. It exposes the brachial plexus and its associated branches to minimal risk. The operation is characterized by low blood loss and short hospital stay. The surgical incision is discrete and the scar not readily visible—something which many patients appreciate. The operation does have drawbacks: Most surgeons are not very familiar with the anatomy; the necessary equipment is not widely available; concurrent arterial or venous bypass reconstruction requires re-positioning the patient and re-­prepping; the remnant of the anterior scalene may result in recurrent TOS symptoms in about 10–15% of patients. Despite these drawbacks, we find the TAFRR to be reliable, highly effective and popular with our patients. New technologies and techniques have improved on earlier results and are making the surgical procedure more accessible to vascular surgeons in training and in practice.

References 1. Cooper AP, Travers B. Surgical essays. London: Cox Longman. p. 1818. 2. Coote H.  Exostosis of the left transverse process of the seventh cervical vertebra, surrounded by blood vessels and nerves; successful removal. Lancet. 1861;i:360–1. 3. Halstead WS.  An experimental study of circumscribed dilatation of an artery immediately distal to

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a partially occluding band and its bearing on the dilation of the subclavian artery observed in certain cases of cervical rib. J Exp Med. 1916;24(3):271–86. 4. Murphy LB. Brachial neuritis caused by pressure of the first rib. Aust Med J. 1910;15:582–5. 5. Todd TW.  The descent of the shoulder after birth: its significance in the production of pressure symptoms on the lower brachial plexus trunks. Anat Anz. 1912;41:385–97. 6. Morley J. Brachial pressure neuritis due to a normal first thoracic rib: its diagnosis and treatment by excision of rib. Clin J. 1913;42:461–4. 7. Adson AW, Coffey JR. Cervical rib. A method of anterior approach for relief of symptoms by division of the scalenus anticus. Ann Surg. 1927;85(6):839–57. 8. Falconer MA, Li FWP. Resection of first rib in costoclavicular compression of brachial plexus. Lancet. 1962;279:59–63. 9. Clagget OT.  Presidential address: research and prosearch. J Thorac Cardiovasc Surg. 1962;44:153–66. 10. Roos DB.  Transaxillary approach for first rib resection to relieve thoracic outlet obstruction. Ann Surg. 1966;163(3):354–8. 11. Reilly LM.  Stoney RJ supraclavicular approach for thoracic outlet decompression. J Vasc Surg. 1988;8(3):329–34. 12. Sanders RJ, Pearce WH.  The treatment of thoracic outlet syndrome: a comparison of different operations. J Vasc Surg. 1989 Dec;10(6):626–34. 13. Jordan SE, Machleder HI. Diagnosis of thoracic outlet syndrome using electrophysiologically guided anterior scalene blocks. Ann Vasc Surg. 1998 May;12(3):260–4. 14. Rigberg DA, Gelabert H. The management of thoracic outlet syndrome in teenaged patients. Ann Vasc Surg. 2009 May-Jun;23(3):335–40. 15. Gelabert HA, Rigberg DA, O’Connell JB, Jabori S, Jimenez JC, Farley S.  Transaxillary decompression of thoracic outlet syndrome patients presenting with cervical ribs. J Vasc Surg. 2018 Oct;68(4):1143–9. 16. Roos DB.  Experience with first rib resection for thoracic outlet syndrome. Ann Surg. 1971 Mar;173(3):429–42. 17. Orlando MS, Likes KC, Mirza S, Cao Y, Cohen A, Lum YW, Reifsnyder T, Freischlag JA.  A decade of excellent outcomes after surgical intervention in 538 patients with thoracic outlet syndrome. J Am Coll Surg. 2015 May;220(5):934–9. 18. Chan YC, Gelabert HA.  High-definition video assisted transaxillary first rib resection for thoracic outlet syndrome. J Vasc Surg. 2013 Apr;57(4):1155–8. 19. Archie MM, Gelabert HA. Endovascular reconstruction of subclavian artery aneurysms in patients with arterial thoracic outlet syndrome. Ann Vasc Surg. 2019 May;57:10–5.

Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic Outlet Syndrome

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Francis J. Caputo and Robert W. Thompson

Abstract

In this point/counterpoint chapter, we present the view that supraclavicular decompression is the best approach for the surgical treatment of neurogenic thoracic outlet syndrome (TOS). This is based on consideration of the limitations and deficiencies of transaxillary first rib resection, as well as the advantages of supraclavicular decompression. Potential complications are discussed along with the results of treatment. We conclude that in the hands of surgeons with experience and expertise, supraclavicular decompression offers the most thorough, versatile and safe approach to the treatment of neurogenic TOS, and it has the flexibility to be applicable to all other forms of TOS and intraoperative contingencies.

F. J. Caputo Department of Vascular Surgery, The Cleveland Clinic and Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA R. W. Thompson (*) Center for Thoracic Outlet Syndrome, Section of Vascular Surgery, Department of Surgery, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, MO, USA e-mail: [email protected]

Critical Take-Home Points 1. Supraclavicular decompression for neuro genic thoracic outlet syndrome allows the surgeon to routinely perform complete anterior and middle scalenectomy, thorough brachial plexus neurolysis, and first rib (and cervical rib) resection, as well as pectoralis minor tenotomy, within an easily visualized operative field. 2. Use of a consistent, step-wise procedure for supraclavicular decompression (based on a series of sequential “critical views”) provides an effective, thorough, flexible, and safe approach to neurogenic TOS, with a very low risk of intraoperative and early postoperative complications. 3. Outcomes studies indicate that >85–90% of patients undergoing supraclavicular decompression for neurogenic TOS can expect a substantial improvement in symptoms and function, with long-term recurrence rates less than 5%. “We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.” —President John F. Kennedy, September 12, 1962

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_40

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40.1 Introduction In the spirit of taking on immense challenges and unresolved problems, we recognize that neurogenic thoracic outlet syndrome (TOS) is one of the most under-recognized, poorly understood, and mismanaged conditions in contemporary medicine. Patients with neurogenic TOS face enormous difficulties with longstanding unexplained symptoms that appear to be a mystery to physicians and specialists of all types, often with progressive disability despite negative results from various testing procedures and evaluations, and an inevitable sense that there is nothing that can be done to relieve symptoms or help regain a normal level of function. The optimal approaches to diagnosis of neurogenic TOS are nonetheless more clear today than they were two decades ago, as described in other sections of this textbook (see Chaps. 7–10), and approaches to effective treatment are now similarly more refined, safe, and increasingly understood, based on an accumulating foundation of clinical data and comparative evidence [1–3]. Despite these apparent advances, there remains a great deal more to be investigated and understood regarding the optimal surgical treatment for the various forms of TOS [4]. In this point/counterpoint chapter, we present the view that supraclavicular decompression is currently the best approach for the surgical treatment of neurogenic TOS, based on consideration of the limitations of transaxillary first rib resection and other procedures, as well as the recognized advantages of supraclavicular decompression. Potential complications are discussed along with the results of treatment, particularly where the two operative approaches have been directly compared. We conclude that in the hands of surgeons with experience and expertise, supraclavicular decompression currently offers the most thorough, versatile and safe approach to the treatment of neurogenic TOS, and it has the flexibility to be applicable to all other forms of TOS and intraoperative contingencies.

F. J. Caputo and R. W. Thompson

40.2 Indications and Goals of Surgical Treatment The indications for surgical treatment of neurogenic TOS include (a) a sound clinical diagnosis, based on current reporting standards and validated diagnostic criteria; (b) substantial functional disability, with symptoms that interfere with daily activities and/or ability to work; and (c) an insufficient response to conservative management, centered around a suitable treatment trial of TOS-specific physical therapy [5]. Clinical and imaging evaluation may suggest variations in anatomy that can contribute to neurogenic symptoms, such as a cervical rib, scalene muscle anomalies or aberrant fibro-fascial bands. Physical examination should elicit the anatomical site(s) responsible for brachial plexus compression and irritation, distinguishing between the supraclavicular scalene triangle and/or the subcoracoid (pectoralis minor) spaces, in order to guide the most appropriate surgical approach. Imagingguided local anesthetic blocks of the anterior scalene and/or pectoralis minor muscles are a useful adjunct, providing additional diagnostic and prognostic information about the likely responsiveness to surgical treatment, but are not used as the sole basis for clinical decision-making. When planning surgical treatment for a patient with neurogenic TOS, it is widely acknowledged that the most critical anatomical structures to be addressed during a decompression procedure are the anterior and middle scalene muscles, the posterolateral aspect of the first rib, any anomalous fibro-fascial bands that are encountered, and constricting postinflammatory scar tissue around the brachial plexus nerves. As a result, the most frequently performed operations involve resection of the first rib (and cervical rib if present), along with division or resection of the scalene muscles and any anomalous bands, and at least some degree of brachial plexus mobilization and external neurolysis. As the role played by the pectoralis minor muscle in brachial plexus compression has become better appreciated, the frequent need for decompression at this site has also become more emphasized.

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Surgeons that frequently perform operations for neurogenic TOS obtain excellent results with a low rate of complications, but most vascular and thoracic surgeons only rarely perform surgery for this condition. The typical surgeon thereby gains little experience with the spectrum of issues to be encountered with neurogenic TOS, may not have had the opportunity to develop technical expertise, and may have had only ­anecdotal exposure to the potential outcomes of treatment. Because neurogenic TOS is frequently associated with a high level of patient and family anxiety, most surgeons choose to refer patients to a local, regional, or national center of excellence, where high patient volumes have allowed development of individual and institutional expertise with all forms of TOS. This chapter is therefore focused on comparisons between the transaxillary and supraclavicular approaches to neurogenic TOS, as performed by surgeons with expertise and experience in the management of TOS, and may not be applicable to those with a casual or only passing interest in this problem.

fully expose the brachial plexus above the lower trunk (and C8 and T1 nerve roots). Resection of the first rib nonetheless allows sufficient decompression of the scalene triangle to markedly diminish brachial plexus compression, and surgeons that frequently perform this operation can obtain excellent results with a low rate of complications. It is notable that recent applications of transpleural video-thoracoscopic approaches, with or without the use of a robotic techniques, are similar to transaxillary first rib resection, both in concept and practice [24–27]. Such video-­ thoracoscopic operations are not yet proven to be as effective in the treatment of neurogenic TOS as transaxillary first rib resection and are thereby considered to be investigational; further evaluation is needed to determine if thoracoscopic approaches to TOS are any safer or more efficient than open procedures and their long-term effectiveness remains unknown.

40.3 T  ransaxillary First Rib Resection

Operations initially developed for neurogenic TOS employed the supraclavicular (anterior) approach, including cervical rib resection, first rib resection, anterior scalenotomy, and scalenectomy. Sanders and colleagues reintroduced the supraclavicular approach in 1979, initially for scalenectomy in recurrent neurogenic TOS, followed by descriptions of combined transaxillary/ supraclavicular approaches and more refined techniques for supraclavicular decompression in primary operations [28–33]. Subsequent reports emphasized the effectiveness of supraclavicular decompression for all forms of TOS, exemplified by several particularly large clinical series [34–36]. The principal advantage of the supraclavicular approach is unrestricted and comfortable exposure of the entire scalene triangle, all five nerve roots and three trunks of the brachial plexus, and the posterolateral first rib and cervical rib if present (Table 40.1) [37–39]. One of the keys to simplifying the supraclavicular exposure is proper

Transaxillary first rib resection became widely used after its introduction by Roos in 1966, [6, 7] but its broad popularity diminished somewhat in the 1980s after reports of significant morbidity due to brachial plexus nerve injury [8–12]. With more careful patient selection, surgeon experience, and improved surgical techniques, this operation has since become one of the most frequently employed in the treatment of neurogenic TOS, with successful approaches epitomized by the descriptions and contributions from Urschel, Machleder, Freischlag, Gelabert, and others (see Chap. 26 for a more complete description of specific techniques) [13–23]. Transaxillary first rib resection and scalenectomy typically involves partial resection of the first rib and division of its scalene muscle attachments. The extent of scalene muscle resection is limited and given the limited exposure obtained, it is not feasible to

40.4 Supraclavicular Decompression

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Table 40.1  Advantages of supraclavicular decompression for neurogenic TOS

Table 40.2  Critical views obtained during supraclavicular decompression

• Allows complete removal of the anterior and middle scalene muscles, which cannot be accomplished by other surgical approaches • Permits full exposure of the entire brachial plexus by which to perform complete external neurolysis, which cannot be accomplished by other surgical approaches • Provides the best exposure of the posteriolateral first rib, from the level of the anterior scalene tubercle to the (T1) transverse process of the cervical spine • Provides the best exposure of cervical ribs and other anomalous anatomic structures • Provides a great degree of safety in surgical treatment given the optimal anatomical exposure, potentially better than that achievable through alternative surgical approaches • Supine position provides easy access for inclusion of pectoralis minor tenotomy, at same time as the supraclavicular operation, both on the ipsilateral and contralateral sides • Ease of management of the pleural space and potential complications, including pneumothorax, hemothorax, and/or cervical lymph leak, as well as intraoperative bleeding • Low incidence of postoperative wound infection with cosmetically-favorable incisional healing and scar appearance • Optimal exposure for reoperative surgical procedures regardless of initial approach. • Offers versatility to provide definitive treatment of all forms of TOS (including arterial and venous TOS) and to most effectively address unexpected anatomical abnormalities

1. View of the operative field after lateral reflection of the scalene fat pad, with visualization of the internal jugular vein, anterior scalene muscle, phrenic nerve, brachial plexus, subclavian artery, middle scalene muscle, and long thoracic nerve 2. View of the lower part of the anterior scalene muscle where it attaches to the first rib, with space sufficient to allow a finger to pass behind the anterior scalene muscle and in front of the brachial plexus and subclavian artery, prior to division of the anterior scalene muscle insertion from the top of the first rib 3. View of the upper part of the anterior scalene muscle at the level of the C6 transverse process, in relation to the C5 and C6 nerve roots, prior to division of the anterior scalene muscle origin 4. View of the insertion of the middle scalene muscle on the first rib, with each of the five nerve roots of the brachial plexus and the subclavian artery retracted medially and the long thoracic nerve retracted laterally, prior to division of the middle scalene muscle insertion from the top of the lateral first rib 5. View of the posterior neck of the first rib, with the T1 nerve root passing from underneath the rib to join the C8 nerve root to form the inferior trunk of the brachial plexus, prior to division of the posterior first rib. 6. View of the anterior portion of the first rib, with placement of the rib shears medial to the scalene tubercle, prior to division of the anterior first rib

mobilization and lateral reflection of the scalene fat pad (see Chap. 27 for a detailed description of operative techniques). The resulting exposure represents the first and most important of six “critical views” to be sequentially obtained during supraclavicular decompression (Table 40.2), with the exposure readily maintained with a simple self-retaining retractor (Fig.  40.1). This approach thereby provides the operating surgeon and assistants with an easily visualized surgical field by which to perform complete anterior and middle scalenectomy, resection of any anomalous scalene musculature and fibro-fascial bands, extended brachial plexus neurolysis, and thorough resection of the first rib to its posterior junction with the transverse vertebral process. Supraclavicular exposure also makes resection of

any associated cervical ribs, whether partial or complete, relatively straightforward. The type of decompression attained with supraclavicular exposure is much more thorough than that achievable by transaxillary exposure, in which the operation is focused on resection of the first rib and division (but not resection) of the anterior and middle scalene muscles, and in which brachial plexus neurolysis is limited to the lower trunk and nerve roots (C8 and T1). A complete scalenectomy is therefore possible from the supraclavicular exposure, which will address any potential compression of the upper brachial plexus that cannot be observed from the transaxillary approach. Moreover, the ability to conduct complete brachial plexus neurolysis, and to wrap the entire neural bundle in an effort to limit potential perineural adhesions, is a unique advantage of the supraclavicular exposure [40, 41]. It is

40  Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic…

a

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b Phrenic Nerve

Anterior Scalene Muscle

Long Thoracic Nerve

Jugular Vein

Middle Scalene Muscle Brachial Plexus Scalene Fat Pad (Reflected)

Sternocleidomastoid Muscle (Reflected)

Subclavian Artery

Fig. 40.1  Supraclavicular Exposure for Thoracic Outlet Decompression. (a) Operating room photograph demonstrating “critical view 1” during supraclavicular decompression, in which the following structures are visualized within the operative field: internal jugular vein, anterior scalene muscle, phrenic nerve, brachial plexus nerves, subclavian

artery, middle scalene muscle, and long thoracic nerve. (b) Photograph demonstrating the view obtained after placement of a dual flexible ring self-­retaining wound retractor (Alexis, Applied Medical Resources Corporation, Rancho Santa Margarita, CA), to maintain and enhance exposure of the operative field during supraclavicular decompression

further noted that the supraclavicular approach is also applicable in patients with obesity and muscular body habitus, as we have found no difference in early or follow-up outcomes across the spectrum of body mass index, which is not likely the case for transaxillary operations [42]. A second advantage of supraclavicular decompression is that it facilitates concomitant pectoralis minor tenotomy, as the patient is positioned such that a deltopectoral approach to the subcoracoid space adds little to the operation. This has become increasingly important with better recognition of brachial plexus compression at the subcoracoid space, which is present in 75–85% of patients with neurogenic TOS [43]. While some surgeons prefer to conduct pectoralis minor tenotomy as a first procedure, reserving supraclavicular decompression for those with persistent symptoms, when indicated by preoperative clinical findings it has been our preference to conduct pectoralis minor tenotomy in combination with

supraclavicular decompression, rather than to stage these operations [43–46]. Supraclavicular decompression can also be easily adapted to address vascular forms of TOS that may occur in conjunction with neurogenic TOS. For example, some patients with symptoms of neurogenic TOS and a bony anomaly (e.g. a cervical rib) may present with evidence of subclavian artery dilatation or aneurysm formation, even in the absence of a thromboembolic complication [47]. In the event that arterial reconstruction is warranted, there are few alterations in the supraclavicular exposure needed in order to complete interposition bypass graft repair of the subclavian artery (see Chap. 92). For the treatment of venous TOS, supraclavicular decompression alone is insufficient, as it does not allow adequate resection of the anterior aspect of the first rib in the costoclavicular space. Nonetheless, the supraclavicular exposure forms the basis for paraclavicular decompression, which allows scalenectomy and complete first rib resection,

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along with direct subclavian vein reconstruction when needed (see Chap. 66) [48]. In contrast, vascular reconstructions are not considered feasible during transaxillary first rib resection, given the limited exposure and difficulty in obtaining adequate arterial or venous control. Another important advantage of the supraclavicular approach is the relative ease with which the operating surgeon can deal with unexpected findings or intraoperative complications, such as lymphatic disruption or vascular injuries. The most serious intraoperative complication in any operation for TOS is rapid unexpected hemorrhage following injury to the subclavian artery or subclavian vein, coupled with delayed recognition and inadequate resuscitation. This rarely described event can be life-threatening and it usually occurs in the setting of unusually difficult anatomic exposure, unexpected pathology, surgical inexperience, and poor selection of operative approach. Management of catastrophic intrathoracic hemorrhage would be exceptionally difficult when operating from the transaxillary approach, likely requiring anterolateral thoracotomy or rapid repositioning to allow supraclavicular exposure or median sternotomy. In contrast, surgical management of such potential complications can be more ready accomplished in the patient undergoing supraclavicular decompression, without the need for repositioning. The importance of conducting the most thorough decompression feasible during primary operations for neurogenic TOS is informed by experience in reoperations for patients with persistent or recurrent symptoms after a previous operation. For example, in a series of 39 reoperations conducted with the supraclavicular approach, Cheng and Stoney described reattachment of the previously divided anterior and/or middle scalene muscles in 29 (74%), untreated bony abnormalities in 26 (67%), and soft tissue anomalies or fibrous bands in 20 (51%) [49]. This led the authors to subsequently modify their practice toward supraclavicular decompression, for both primary and all reoperative procedures. AmbradChalela et al. reported a series of 17 patients with recurrent neurogenic TOS, with reoperative (supraclavicular) findings including brachial

F. J. Caputo and R. W. Thompson

plexus compression by reattached residual scalene muscles, incompletely resected or retained first ribs, ectopic fibrous bands, and the pectoralis minor tendon [50]. The authors concluded that complete excision of cervical or first ribs and subtotal excision (instead of simple division) of the scalene muscles would decrease the incidence of recurrent neurogenic TOS, and that pectoralis minor tenotomy should be considered part of any complete thoracic outlet decompression. Our experience with reoperations at Washington University parallels these observations. As shown in Table  40.3, in a series of 36 supraclavicular reexplorations following a previous transaxillary first rib resection, the most frequent findings were reattached anterior (97%) and middle (92%) scalene muscles, long posterior first rib remnants (75%), and the uniform presence of dense fibrous perineural scar tissue encasing the entire brachial plexus. These observations emphasize the value of complete scalenectomy and brachial plexus neurolysis in primary operations for neurogenic TOS, as achieved with the supraclavicular approach, which thereby addresses two of the principal causes of recurrent symptoms. Table 40.3  Operative findings during reoperative supraclavicular exploration Bony findings Complete first 2 (5%) rib retained Anterior first 4 (11%) rib remnant

Muscle findings Anterior scalene muscle remnant Anterior scalene muscle weight (gm) Posterior first 27 (75%) Middle scalene rib remnant muscle remnant Cervical rib 3 (8%) Middle scalene remnant muscle weight (gm) No rib 4 (11%) No muscle remnants remnants 0 (0%) No rib or muscle findings

35 (97%) 5.4 ± 0.4

33 (92%) 4.8 ± 0.4

0 (0%)

Patients were identified that had supraclavicular decompression for recurrent neurogenic TOS at Washington University in St. Louis, following a previous transaxillary first rib resection at another institution (n = 36, including four previous video-assisted thoracoscopic operations). For each item assessed, the data shown indicate the number of patients (%) for categorical variables or the mean ± SE for continuous measures

40  Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic…

It is of interest that “regrowth” of the first rib has often been cited as a potential cause of recurrent neurogenic TOS after transaxillary decompression, yet this finding appears to be particularly rare in reoperations after supraclavicular decompression [51, 52]. It is suspected that the type of regrowth described, seen almost exclusively after transaxillary operations, can be ascribed to regeneration and ossification of retained periosteum in the intercostal muscle bed and scattered ectopic calcification with a dense fibrous tissue response. First rib “regrowth” more typically represents a retained segment of the first rib after a previous incomplete resection [53]. Finally, it is evident that most vascular surgeons should be familiar and comfortable with supraclavicular approaches given the frequency with which they perform carotid-subclavian bypass operations. It is acknowledged that the specific techniques needed to undertake effective thoracic outlet decompression require further training, exposure, and experience than typically acquired in conducting vascular reconstructions, but should be well within the scope of vascular surgery experience. In contrast, other than TOS there are no indications for transaxillary approaches in vascular surgery and only few in thoracic surgery, so in the absence of specific training in select programs, most surgeons are unfamiliar and inexperienced with these ­operations and the somewhat difficult exposure that is required.

40.5 Potential Complications and Results The potential complications of thoracic outlet decompression are essentially the same regardless of operative approach (Table 40.4). In expert hands the incidence of early and follow-up complications is very low (less than 5%), as evident in large clinical series and database studies [54– 58]. The potential for complications nonetheless remains a significant concern, especially when operations for TOS are performed on an infrequent basis in a low-volume clinical setting, as these procedures are technically demanding and

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Table 40.4  Potential complications of thoracic outlet decompression Intraoperative hemorrhage Pneumothorax or air-leak Postoperative bleeding, localized hematoma, or hemothorax Wound infection (cellultitis or abcess) Pleural effusion (serosanguinous) Persistent lymph leak, chylothorax Brachial plexus nerve dysfunction (temporary or sustained) Phrenic nerve dysfunction (temporary or sustained) Long thoracic nerve dysfunction (temporary or sustained) Deep vein thrombosis, pulmonary embolism Subclavian or axillary artery thrombosis Adverse drug reactions, interactions, and medication side-effects Persistent pain, numbness, and/or paresthesias Diminished upper extremity range of motion, “frozen” shoulder Complex regional pain syndrome (CRPS) Persistent or recurrent neurogenic thoracic outlet syndrome

accomplishing them with acceptably low complication rates requires a considerable amount of training and experience. The overall results of operations for neurogenic TOS have also been remarkably consistent in large clinical series, whether the primary operation is conducted by transaxillary first rib resection or supraclavicular decompression, with excellent/good outcomes in 80–90% of patients. In a collection of studies published from 1973 to 2001 encompassing 1222 operations, the results for supraclavicular decompression were good in 59–91% (mean 77%), fair in 5–33% (mean 15%), and poor in 3–18% (mean 8%) [3]. Hempel and colleagues reported a particularly large series of 770 supraclavicular operations in 637 patients, describing excellent or good results in 86% of cases [35]. Sanders has presented one of the most comprehensive analyses of surgical results for neurogenic TOS, in which the life-table method was used to compare outcomes for different operative procedures [28, 34, 36, 59]. In comparing patients that underwent transaxillary first rib resection (n  =  112), supraclavicular scalenectomy alone (n  =  286), or supraclavicular scalenectomy with first rib resection (n  =  249), he

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found no difference in the initial success rate between these three procedures (91%, 93% and 93%, respectively). The percentage of patients with successful outcomes declined over time with all three procedures, with the long-term success of supraclavicular scalenectomy and first rib resection appearing somewhat better at 10–15  years (71%) than the results for either scalenectomy alone (66%) or transaxillary first rib resection (64%), but there were no statistically significant differences between these operations [59]. Sheth and colleagues conducted a randomized study comparing follow-up results in patients that had undergone transaxillary first rib resection versus supraclavicular brachial plexus “neuroplasy” (without scalenectomy or first rib resection) [60]. The results indicated that patients in both groups had a substantial improvement in symptoms but that the reduction in pain, numbness and tingling symptoms was greater after transaxillary first rib resection. This led the authors to conclude that outcomes are improved when first rib resection is included in the operative approach to neurogenic TOS, countering several previous reports [61–63]. However, it is noted that the supraclavicular approach used in this comparison was not equivalent to that used in current practice, as it did not include elements considered to be important (complete scalenectomy and first rib resection), so it remains difficult to draw firm conclusions from this study. Altobelli et  al. subsequently presented an interesting and relevant report, in which patients with neurogenic TOS first underwent primary transaxillary first rib resection, followed by planned supraclavicular decompression for any persistent or recurrent symptoms [64]. Of 254 operations, the primary success rate of transaxillary first rib resection was only 46% during follow-up, with 80  second-stage supraclavicular operations performed. This study also showed that recurrent neurogenic TOS tended to occur within 12–18  months after operation, indicating that long-term follow-up and pre-defined measures of outcome are needed to accurately assess results. More recently, Hosseinian and colleagues conducted a retrospective review of complications

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and outcomes for 32 transaxillary and 63 supraclavicular operations performed for neurogenic TOS, with follow-up to 24 months after surgery [55]. Although there was no difference between groups in the prevalence of various operative or postoperative complications, after 6 months follow-­up the incidence of persistent pain, symptoms, and the need for reoperation was significantly greater after transaxillary first rib resection (8%) than after supraclavicular decompression (0%).

40.6 Conclusions The debate over which operative approach for neurogenic TOS is “best” will likely continue for some time to come, in the absence of any strong prospective, randomized, clinical trial evidence supporting one approach over the other(s). Indeed, there would appear to be little enthusiasm for undertaking complicated clinical trials to address this question, as it is evident that in the hands of expert surgeons performing the operation that they prefer, the clinical results are excellent, with 85–95% of patients having a substantial improvement in symptoms, and nearly equivalent results with either transaxillary first rib resection or supraclavicular decompression. Early recovery from operation, complication rates, and the trajectory of rehabilitation also appear to be no different between these operations. The rate of unsatisfactory outcomes after surgery for neurogenic TOS is approximately 5–10% regardless of operative approach, and is likely due to poorly defined factors that are unrelated to the specific operation performed. With further investigation, one area that may distinguish results between transaxillary first rib resection and supraclavicular decompression is in the rate and extent of recurrent neurogenic TOS during long-term follow-­up, but to date there are few studies in which the actual recurrence rates are well-defined or characterized. In addition to the other advantages of supraclavicular decompression outlined above, we predict that careful analysis of recurrence rates will ultimately favor the supraclavicular approach.

40  Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic…

In the end, the single most important determinant of successful outcomes for the surgical treatment of neurogenic TOS remains that operations be performed by a surgeon with expertise and experience in a high-volume clinical setting. The specific approach used should be that with which the TOS surgeon is most comfortable and familiar. Like other areas of surgery, there appears to be an important volume-outcome relationship in the management of neurogenic TOS, with operative volume likely serving as a surrogate for many other related factors (e.g. certainty of clinical diagnosis, efficacy of associated physical therapy, selection criteria for treatment, consistency of postoperative care) and this likely overrides other factors that might influence surgical results and patient satisfaction, including the specific operative approach selected. Acknowledgements  This work was supported in part by the Thoracic Outlet Syndrome Research and Education Fund of the Foundation for Barnes Jewish Hospital, BJC Healthcare, St. Louis, Missouri. The authors are indebted to our clinical office staff, operating room personnel, inpatient care teams, and collaborating pain management and physical therapy experts for helping to care for our patients with neurogenic TOS.

References 1. Illig KA. Neurogenic thoracic outlet syndrome: bringing order to chaos. J Vasc Surg. 2018;68:939–40. 2. Illig KA, Donahue D, Duncan A, Freischlag J, Gelabert H, Johansen K, et  al. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. J Vasc Surg. 2016;64:e23–35. 3. Thompson RW.  Thoracic outlet syndrome: neurogenic. In: Sidaway AN, Perler BA, editors. Rutherford’s vascular surgery. 9th ed. Philadelphia, PA: Elsevier; 2018. p. 1619–38. 4. Povlsen B, Hansson T, Povlsen SD.  Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2014;11:CD007218. 5. Balderman J, Abuirqeba AA, Eichaker L, Pate C, Earley JA, Bottros MM, et al. Physical therapy management, surgical treatment, and patient-reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2019;70:832–41. 6. Roos DB.  Transaxillary approach for first rib resection to relieve thoracic outlet syndrome. Ann Surg. 1966;163:354–8.

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7. Roos DB. Congenital anomalies associated with thoracic outlet syndrome. Am J Surg. 1976;132:771–8. 8. Dale A.  Thoracic outlet compression syndrome: critique in 1982. Arch Surg. 1982;117:1437–145. 9. Horowitz SH. Brachial plexus injuries with causalgia resulting from transaxillary rib resection. Arch Surg. 1985;120:1189–91. 10. Cherington M, Happer I, Machanic B, Parry L. Surgery for thoracic outlet syndrome may be hazardous to your health. Muscle Nerve. 1986;9:632–4. 11. Wilbourne AJ.  Thoracic outlet syndrome surgery causing severe brachial plexopathy. Muscle Nerve. 1988;11:66–74. 12. Melliere D, Becquemin JP, Etienne G, Le Cheviller B.  Severe injuries resulting from operations for thoracic outlet syndrome: can they be avoided? J Cardiovasc Surg. 1991;32:599–603. 13. Urschel HC Jr. The transaxillary approach for treatment of thoracic outlet syndromes. Semin Thorac Cardiovasc Surg. 1996;8:214–20. 14. Urschel HC Jr, Razzuk MA. Neurovascular compression in the thoracic outlet: changing management over 50 years. Ann Surg. 1998;228:609–17. 15. Urschel HC, Kourlis H.  Thoracic outlet syndrome: a 50-year experience at Baylor University medical Center. Proc Bayl Univ Med Cent. 2007;20:125–35. 16. Machleder HI, Moll F, Verity MA. The anterior scalene muscle in thoracic outlet compression syndrome: histochemical and morphometric studies. Arch Surg. 1986;121:1141–4. 17. Makhoul RG, Machleder HI. Developmental anomalies at the thoracic outlet: an analysis of 200 consecutive cases. J Vasc Surg. 1992;16:534–42. 18. Kashyap VS, Ahn SS, Machleder HI. Thoracic outlet neurovascular compression: approaches to anatomic decompression and their limitations. Semin Vasc Surg. 1998;11:116–22. 19. Chang DC, Rotellini-Coltvet LA, Mukherjee D, De Leon R, Freischlag JA. Surgical intervention for thoracic outlet syndrome improves patient’s quality of life. J Vasc Surg. 2009;49:630–5. 20. Rochlin DH, Gilson MM, Likes KC, Graf E, Ford N, Christo PJ, et  al. Quality-of-life scores in neurogenic thoracic outlet syndrome patients undergoing first rib resection and scalenectomy. J Vasc Surg. 2013;57:436–43. 21. Likes KC, Orlando MS, Salditch Q, Mirza S, Cohen A, Reifsnyder T, et al. Lessons learned in the surgical treatment of neurogenic thoracic outlet syndrome over 10 years. Vasc Endovasc Surg. 2015;49:8–11. 22. Orlando MS, Likes KC, Mirza S, Cao Y, Cohen A, Lum YW, et al. A decade of excellent outcomes after surgical intervention in 538 patients with thoracic outlet syndrome. J Am Coll Surg. 2015;220:934–9. 23. Gelabert HA, Rigberg DA, O’Connell JB, Jabori S, Jimenez JC, Farley S.  Transaxillary decompression of thoracic outlet syndrome patients presenting with cervical ribs. J Vasc Surg. 2018;68:1143–9. 24. Soukiasian HJ, Shouhed D, Serna-Gallgos D, McKenna R III, Bairamian VJ, McKenna RJ Jr. A

384 video-assisted thoracoscopic approach to transaxillary first rib resection. Innovations. 2015;10:21–6. 25. George RS, Milton R, Chaudhuri N, Kefaloyannis E, Papagiannopoulos K.  Totally endoscopic (VATS) first rib resection for thoracic outlet syndrome. Ann Thorac Surg. 2017;103:241–5. 26. Nuutinen H, Riekkinen T, Aittola V, Makinen K, Karkkainen JM.  Thoracoscopic versus transaxillary approach to first rib resection in thoracic outlet syndrome. Ann Thorac Surg. 2018;105:937–42. 27. Burt BM. Thoracic outlet syndrome for thoracic surgeons. J Thorac Cardiovasc Surg. 2018;156:1318–23. 28. Sanders RJ, Monsour JW, Gerber FG, Adams WR, Thompson N.  Scalenectomy versus first rib resection for treatment of the thoracic outlet syndrome. Surgery. 1979;85:109–21. 29. Qvarfordt PG, Ehrenfeld WK, Stoney RJ.  Supraclavicular radical scalenectomy and transaxillary first rib resection for the thoracic outlet syndrome: a combined approach. Am J Surg. 1984;148:111–6. 30. Sanders RJ, Raymer S. The supraclavicular approach to scalenectomy and first rib resection: description of technique. J Vasc Surg. 1985;2:751–6. 31. Reilly LM, Stoney RJ.  Supraclavicular approach for thoracic outlet decompression. J Vasc Surg. 1988;8:329–34. 32. Cina C, Whiteacre L, Edwards R, Maggisano R. Treatment of thoracic outlet syndrome with combined scalenectomy and transaxillary first rib resection. Cardiovasc Surg. 1994;2:514–8. 33. Atasoy E.  Combined surgical treatment of thoracic outlet syndrome: transaxillary first rib resection and transcervical scalenectomy. Handchir Mikrochir Plast Chir. 2006;38:20–8. 34. Sanders RJ.  Thoracic outlet syndrome: a com mon sequelae of neck injuries. Philadelphia: J.  B. Lippincott Company; 1991. 35. Hempel GK, Shutze WP, Anderson JF, Bukhari HI. 770 consecutive supraclavicular first rib resections for thoracic outlet syndrome. Ann Vasc Surg. 1996;10:456–63. 36. Sanders RJ.  Results of the surgical treatment for thoracic outlet syndrome. Semin Thorac Cardiovasc Surg. 1996;8:221–8. 37. Thompson RW, Petrinec D, Toursarkissian B. Surgical treatment of thoracic outlet compression syndromes. II.  Supraclavicular exploration and vascular reconstruction. Ann Vasc Surg. 1997;11:442–51. 38. Duwayri YM, Thompson RW.  Supraclavicular approach for surgical treatment of thoracic outlet syndrome. In: Chaikof EL, Cambria RP, editors. Atlas of vascular surgery and endovascular therapy. Philadelphia: Elsevier Saunders; 2014. p. 172–92. 39. Thompson RW, Vemuri C.  Neurogenic thoracic outlet syndrome exposure and decompression: supraclavicular. In: Mulholland MW, Hawn MT, Hughes SJ, Albo D, Sabel MS, Dalman RL, editors. Operative techniques in surgery. Philadelphia: Wolters Kluwer Health; 2015. p. 1848–61.

F. J. Caputo and R. W. Thompson 40. Sanders RJ, Hammond SL, Rao NM.  Observations on the use of seprafilm on the brachial plexus in 249 operations for neurogenic thoracic outlet syndrome. Hand. 2007;2:179–83. 41. Sanders RJ, Annest SJ. Amnion membrane improves results in treating neurogenic thoracic outlet syndrome. J Vasc Surg Cases Innov Tech. 2018;4:163–5. 42. Ohman JW, Abuirqeba AA, Jayarajan SN, Balderman J, Thompson RW.  Influence of body weight on surgical treatment for neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2018;49:80–90. 43. Sanders RJ, Rao NM. The forgotten pectoralis minor syndrome: 100 operations for pectoralis minor syndrome alone or accompanied by neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2010;24:701–8. 44. Sanders RJ. Recurrent neurogenic thoracic outlet syndrome stressing the importance of pectoralis minor syndrome. Vasc Endovasc Surg. 2011;45:33–8. 45. Caputo FJ, Wittenberg AM, Vemuri C, Driskill MR, Earley JA, Rastogi R, et  al. Supraclavicular decompression for neurogenic thoracic outlet syndrome in adolescent and adult populations. J Vasc Surg. 2013;57:149–57. 46. Vemuri C, Wittenberg AM, Caputo FJ, Earley JA, Driskill MR, Rastogi R, et  al. Early effectiveness of isolated pectoralis minor tenotomy in selected patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2013;57:1345–52. 47. Vemuri C, McLaughlin LN, Abuirqeba AA, Thompson RW.  Clinical presentation and management of arterial thoracic outlet syndrome. J Vasc Surg. 2017;65:1429–39. 48. Vemuri C, Salehi P, Benarroch-Gampel J, McLaughlin LN, Thompson RW.  Diagnosis and treatment of effort-induced thrombosis of the axillary subclavian vein due to venous thoracic outlet syndrome. J Vasc Surg Venous Lymphat Disord. 2016;4:485–500. 49. Cheng SWK, Stoney RJ. Supraclavicular reoperation for neurogenic thoracic outlet syndrome. J Vasc Surg. 1994;19:565–72. 50. Ambrad-Chalela E, Thomas GI, Johansen KH. Recurrent neurogenic thoracic outlet syndrome. Am J Surg. 2004;187:505–10. 51. Greenberg JI, Alix K, Nehler MR, Johnston RJ, Brantigan CO. Computed tomography-guided reoperation for neurogenic thoracic outlet syndrome. J Vasc Surg. 2015;61:469–74. 52. Gelabert HA, Jabori S, Barleben A, Kiang S, O’Connell J, Jimenez JC, et  al. Regrown first rib in patients with recurrent thoracic outlet syndrome. Ann Vasc Surg. 2014;28:933–8. 53. Likes K, Dapash T, Rochlin DH, Freischlag JA.  Remaining or residual first ribs are the cause of recurrent thoracic outlet syndrome. Ann Vasc Surg. 2014;28:939–45. 54. Chang DC, Lidor AO, Matsen SL, Freischlag JA. Reported in-hospital complications following rib resections for neurogenic thoracic outlet syndrome. Ann Vasc Surg. 2007;21:564–70.

40  Point/Counterpoint: Supraclavicular Decompression Is the Best Approach for Neurogenic Thoracic… 55. Hosseinian MA, Loron AG, Soleimanifard Y.  Evaluation of complications after surgical treatment of thoracic outlet syndrome. Korean J Thorac Cardiovasc Surg. 2017;50:36–40. 56. Peek J, Vos CG, Unlu C, van de Pavoordt HDWM, van den Akker PJ, de Vries JPM.  Outcome of surgical treatment for thoracic outlet syndrome: systematic review and meta-analysis. Ann Vasc Surg. 2017;40:303–26. 57. Rinehardt EK, Scarborough JE, Bennett KM. Current practice of thoracic outlet decompression surgery in the United States. J Vasc Surg. 2017;66:858–65. 58. Nejim B, Alshaikh HN, Arhuidese I, Obeid T, Lum YW, Canner J, et al. Perioperative outcomes of thoracic outlet syndrome surgical repair in a nationally validated database. Angiology. 2017;68:502–7. 59. Sanders RJ, Pearce WH.  The treatment of thoracic outlet syndrome: a comparison of different operations. J Vasc Surg. 1989;10:626–34.

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60. Sheth RN, Campbell JN.  Surgical treatment of thoracic outlet syndrome: a randomized trial comparing two operations. J Neurosurg Spine. 2005;3:355–63. 61. Dellon AL.  The results of supraclavicular brachial plexus neurolysis (without first rib resection) in management of post-traumatic “thoracic outlet syndrome”. J Reconstr Microsurg. 1993;9:11–7. 62. Cheng SW, Reilly LM, Nelken NA, Ellis WV, Stoney RJ.  Neurogenic thoracic outlet decompression: rationale for sparing the first rib. Cardiovasc Surg. 1995;3:617–23. 63. Fantini GA. Reserving supraclavicular first rib resection for vascular complications of thoracic outlet syndrome. Am J Surg. 1996;172:200–4. 64. Altobelli GG, Kudo T, Haas BT, Chandra FA, Moy JL, Ahn SS.  Thoracic outlet syndrome: pattern of clinical success after operative decompression. J Vasc Surg. 2005;42:122–8.

Does the First Rib Always Need to Be Removed?

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Richard J. Sanders and Stephen J. Annest

Abstract

The importance of first rib excision in the treatment of NTOS has been debated. It has been shown that in most patients pathology (fibrosis) exists in the scalene muscles, implying that rib entrapment may not be the underlying issue. Several reports have shown that longterm improvement rates are similar following scalenectomy alone versus first rib resection. Rib resection adds complexity to the operation and can result in injury to adjacent structures. Yet, many surgeons always remove the first rib. We propose that rib removal should be selective rather than routine, and suggest that a possible way of selecting patients needing first rib resection is to assess the proximity of the lower trunk of the brachial plexus to the first rib. We also propose that patients who are most likely to benefit from rib resection are those with a fairly straight, vertical first rib seen on preoperative chest x-ray.

R. J. Sanders (*) Emeritus Clinical Professor of Surgery, University of Colorado Medical School, Aurora, CO, USA e-mail: [email protected]

Critical Take-Home Messages 1. Results of both scalenectomy alone and transaxillary first rib resection are about the same. 2. Shape of first rib on chest x-ray can tell whether or not first rib removal is needed. 3. On x-ray, a straight, vertical first rib should be removed. 4. Pathology is in the scalene muscles (fibrosis) not the first rib.

41.1 Introduction The anatomic position of the first rib, deep to the clavicle, makes surgical removal by any route difficult. Whether through the axilla or via a supraclavicular, infraclavicular, or posterior approach, exposure is difficult and can be hazardous. The reason many surgeons always remove the first rib is that while supraclavicular total scalenectomy alone helps the majority of patients [1], many failures continue to occur. Because both patients and surgeons wish to avoid two operations for the same condition, one operation that can achieve both scalenectomy and first rib resection is appealing.

S. J. Annest Department of Vascular Surgery, St. Joseph’s Hospital, Vascular Institute of the Rockies, Denver, CO, USA © Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_41

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41.2 T  he Pathology Is in the Scalene Muscles It has been well documented that the pathology in most patients with neurogenic thoracic outlet syndrome (NTOS) lies mainly in the scalene muscles (primarily anterior but also middle). Supporting this point of view are the following observations. First, histologic examination of the scalene muscles shows a threefold increase in the amount of scar tissue in NTOS patients [2] (also see Chapter 6, Pathology, and Pathophysiology of NTOS). In addition, scalene muscles in these patients show an increase in slow twitch muscle fibers (Type 1) and decrease, atrophy, and anisocytosis of fast twitch fibers (Type 2) [2, 3] (Fig. 7.7a, b). Critically important is the observation that scalene muscle blocks with lidocaine, theoretically relaxing the anterior scalene muscle, often relieves symptoms within 120 seconds [4, 5]. Finally, and most importantly, several reports note that scalenectomy without first rib resection have achieved as good a success rate as scalenectomy with first rib resection [6, 7]. Although first rib resection is still a common operation for relief of symptoms of NTOS, we suggest that it is successful not because the first rib has been removed but rather because in performing rib resection the scalene muscles must be released. However, removing the first rib also takes away the floor of the scalene triangle relieving any pressure against the lower trunk of the brachial plexus. In fact, this relationship was tested a few years ago. By observing the proximity of the lower trunk to the first rib this protocol was followed: If the nerve was in contact with the rib, or was within 1–2 mm of the rib, the rib was removed; otherwise the rib was not removed. In following this protocol we found that only about 30% of patients required first rib resection while 70% could require scalenectomy alone. The overall success rate in both groups was equivalent [8, 9]. In a retrospective review of chest x-rays in patients who did or did not have their first ribs excised, patients in whom the rib was excised had a vertical, straight first rib on chest x-ray (Fig.  41.1a) while most patients who retained their first rib had a wide curve in their first ribs.

a

b Fig. 41.1 (a) Almost vertical first rib which rests against the lower trunk of the brachial plexus and is excised. (b) Curved first rib which usually lies free of the lower trunk and is not removed. Reprinted with permission from Sanders RJ. Thoracic outlet syndrome: General considerations. In Cronenwett JL, Johnston KW. Eds. Rutherford’s Vascular Surgery, seventh Edition. Philadelphia, Saunders 2010 p.1867

(Fig. 41.1b) The chest x-ray can be a valuable tool to predict who will benefit from first rib excision, but difficult choices present in patients whose x-rays show just a little curve. Because this is subjective, and not totally accurate, the final decision of who needs their first rib excised, must still be made on observations in the operating room. (Unpublished observations by author RJS).

41.3 Advantage of Sparing the First Rib Complications are more frequent with rib resection compared to scalenectomy without rib resection. In an analysis of complications in 740 primary TOS operations (301 scalenectomies alone and 439 rib resections, both transaxillary and supraclavicular), the incidence of permanent plexus injuries, long thoracic nerve

41  Does the First Rib Always Need to Be Removed?

injuries, and major hemorrhage, each occurred in 0.3–2% of patients after rib resection versus 0–0.4% for those undergoing scalenectomy alone [10]. Furthermore, recovery time was shorter and morbidity less when the first rib was spared. Currently, there has not been enough published data to confirm these observations. To date, no single approach to thoracic outlet decompression has been proven to be better than any other. Perhaps the explanation for this is that each of the approaches fails for the same reason—postoperative scarring. In the past, to protect the nerves of the plexus from scar tissue, we and others have used several different materials (Seprafilm [11], hyaluronic acid [12], Surgiwrap, steroids, and Gortex), [Seprafilm by Gemnzyme, Caimbridge, Ma, Surgiwrap by Mast Biosurgery, San Diego, Ca, Gortex by W.  L. Gore & Associates, Newark, De] but none have produced an obvious reduction in recurrence. We are currently exploring the benefits of another material, Amnion Membrane (AlloWrap DS, AlloSource, Centennial, Co) as a barrier against scar tissue formation. We have used this in 110 patients operated upon over the past 3 years with encouraging results [13], although obviously because of the low incidence of recurrence in general, a larger number and longer follow up will be needed before this can conclusively be shown to be of benefit.

41.4 Conclusion Essentially all would agree that decompression of the neurogenic thoracic outlet requires at least anterior and middle scalenectomy. We believe that for many patients, probably the majority, this may be enough. First rib resection may be needed in some patients, but we feel these are in the minority. If this algorithm is accepted, selecting which patients will benefit from rib resection is the dilemma surgeons face. A possible way of selecting patients needing first rib resection is by observing close proximity of the lower trunk of

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the brachial plexus to the first rib. We believe that these patients will often have a fairly straight, vertical first rib rather than one with a large curve visible on preoperative chest X-ray. At this time, more data are needed to confirm these suggestions, but our results using this protocol have been excellent.

References 1. Qvarfordt PG, Ehrenfeld WK, Stoney RJ.  Supraclavicular radical scalenectomy and transaxillary first rib resection for the thoracic outlet syndrome. A combined approach. Am J Surg. 1984;148:111–6. 2. Sanders RJ, Jackson CGR, Banchero N, Pearce WH. Scalene muscle abnormalities in traumatic thoracic outlet syndrome. Am J Surg. 1990;159:231–6. 3. Machleder HI, Moll F, Verity A. The anterior scalene muscle in thoracic outlet compression syndrome: histochemical and morphometric studies. Arch Surg. 1986;121:1141–4. 4. Jordan SE, Machleder HI. Diagnosis of thoracic outlet syndrome using electrophysiologically guided anterior scalene blocks. AnnVasc Surg. 1998;12:260–4. 5. Sanders RJ, Haug CE.  Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia: Lipppincott; 1991. p. 91–3. 6. Sanders RJ, Pearce WH.  The treatment of thoracic outlet syndrome: a comparison of different operations. J Vasc Surg. 1989;10:626–34. 7. Cheng SWK, Reilly LM, Nelken NA, Ellis WV, Stoney RJ.  Neurogenic thoracic outlet decompression: rationale for sparing the first rib. Cardiovasc Surg. 1995;3:617–23. 8. Thomas GI. Diagnosis and treatment of thoracic outlet syndrome. Perspect Vasc Surg. 1995;8:1–28. 9. Martin GT. First rib resection for the thoracic outlet syndrome. Br J Neurosurg. 1993;7:35–8. 10. Sanders RJ, Haug CE.  Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia: Lipppincott; 1991. p. p162. 11. Sanders RJ, Hammond SL, Rao NM.  Observations on the use of Seprafilm on the brachial plexus in 249 operations for neurogenic thoracic outlet syndrome. Hand. 2007;2:179–83. 12. Ikeda K, Yamauchi D, Osamura N, Hagiwara N, Tomita K. Hyaluronic acid prevents peripheral nerve adhesion. Br J Plast Surg. 2003;56:342–7. 13. Sanders RJ, Annest SJ.  Amnion membrane improves results in treating neurogenic thoracic outlet syndrome. J Vasc Surg Cases Innov Tech. 2018;4:163–5.

Controversies in NTOS: What Is the Evidence Supporting Brachial Plexus Neurolysis and Wrapping

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Chetan Dargan and Karl A. Illig

Abstract

The motor and sensory deficits of NTOS may be due in part to neurologically active, fibrotic tissue surrounding the brachial plexus. The pathophysiologic mechanism behind the formation of this tissue begins with an inciting traumatic event or repetitive mechanical tension leading to an inflammatory environment promoting Schwann cell activation and neural ingrowth. Surgical treatment of NTOS should target this fibrotic tissue and includes brachial plexus neurolysis as well as human amnion membrane wrapping. To date, no significant randomized controlled trials or large retrospective studies have been performed to assess their efficacy in the NTOS population. However, treatment of athletes with NTOS, recurrent NTOS patients, and those with traumatic brachial plexus injuries has included brachial plexus neurolysis and shows promising results. Wrapping with human amnion membrane has been proven to decrease the formation of scar

C. Dargan Division of Vascular Surgery, University of South Florida, Tampa, FL, USA e-mail: [email protected] K. A. Illig (*) Dialysis Access Institute, The Regional Medical Center, Orangeburg, SC, USA e-mail: [email protected]

tissue in animal models. Small series involving neurolysis and wrapping of peripheral nerves in entrapment syndromes have also shown positive results. Human amnion wrapping is currently being employed in the treatment of at least 100 NTOS patients, and 1 year results have revealed a significant decrease in rates of recurrence. Critical Take-Home Points 1. The scar tissue surrounding the brachial plexus in NTOS patients is neurologically active and secretes numerous pro-­ inflammatory substances, leading to the neuropathic symptoms in NTOS 2. The formation of this scar tissue begins with an inciting traumatic event or repetitive mechanical tension, leading to Schwann cell activation and neural ingrowth. 3. Retrospective studies involving athletes with NTOS, recurrent NTOS patients, traumatic brachial plexus injuries, and peripheral nerve entrapment syndromes support the use of neurolysis. 4. Many studies involving animal models have proven human amnion membrane wrapping to decrease the formation of scar tissue surrounding peripheral nerves. 5. Current use of human amnion membrane wrapping in NTOS patients have shown great, preliminary results in decreasing the rates of recurrence.

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_42

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to the level of the posterior first rib with the goal of complete mobilization of the brachial plexus Neurogenic Thoracic Outlet Syndrome (NTOS) and decompression of the nerve roots. Caution is partially attributed to dense fibrous tissue must be taken to not disrupt the perineurium, in adherent to the brachial plexus and cervical nerve which case a herniation of nerve tissue will be roots. The formation of this tissue generally seen. Upon completion of the procedure, the brabegins with either direct trauma (e.g. seatbelt, chial plexus may be wrapped with various mateflexion-extension, or acute stretch trauma during rials to diminish the risk of reformation of scar motor vehicle accidents) or constant mechanical tissue around the nerve roots and the recurrence tension (e.g. repetitive work or sports injury) of of TOS. the brachial plexus and its rami [1, 2]. These To date, no randomized control trials or large events produce an inflammatory environment retrospective studies have been performed comleading to Schwann cell activation and neural paring surgical treatment for NTOS with and ingrowth, resulting in the investing fibrosis seen without brachial plexus neurolysis. However, surrounding the brachial plexus and adjacent there is a multitude of evidence in various popustructures in NTOS patients [3–5]. lations in which surgical management of NTOS Examination of this fibrous tissue removed included neurolysis that supports the use of this through neurolysis during thoracic outlet decom- technique. pression has confirmed it to be neurologically Traditionally, surgical management of NTOS active, secreting a number of pro-inflammatory has demanded the resection of the first rib. substances involved in pain, hyperesthesia, and However, this practice has started to be quesautonomic dysfunction. Additionally, the extra- tioned, indicating the importance of the other cellular matrix in this tissue holds significant aspects of thoracic outlet decompression. For numbers of inflammatory cells, including macro- example, a recent retrospective study involving phages, mast cells, and fibroblasts [6]. The pres- 448 patients who underwent rib-sparing surgical ence of “innervated fibrosis” has been implicated treatment for NTOS, including scalenectomy, in numerous other neuropathically active condi- brachial plexus neurolysis, and pectoralis minor tions, including endometriosis and a variety of release, was performed by Johansen from the migraines [7, 8]. Therefore, it has been easy to Swedish Medical Center in Seattle, Washington. attribute this same mechanism to help explain the 99.6% of this cohort experienced significant symptoms experienced by patients with NTOS improvement in their symptoms, defined as a [9, 10]. greater than 50% reduction in QuickDaSH scores This pathophysiologic model provides a justi- at the 6 month post-operative time interval comfication for the relief of symptoms through pared to pre-operative scores [11]. aggressive neurolysis as well as protection Athletes, especially those involved in overagainst recurrent symptoms by prevention of hand throwing motions, are particularly prone to recurrent scar formation with wrapping. NTOS and treatment has historically involved neurolysis with concomitant FRR with or without scalenectomy. In one small retrospective 42.2 Neuroloysis study, 18 athletes diagnosed with NTOS underwent first rib resection (FRR) and brachial plexus Neurolysis may be performed through the supra-­ neurolysis. Of these patients, 83% were able to clavicular, trans-axillary, and posterior return to full competitive levels in their respective approaches. All five nerve roots are identified, sports. Additionally, in the 70% of patients from and if significant scar tissue is noted to be sur- whom pre- and post-operative QuickDaSH scores rounding them, neurolysis is undertaken. Using were obtained, a significant reduction from 43.4 microspring or tenotomy scissors, the fibrosed pre-operatively to 11.7 6 months post-operatively tissue is carefully removed from each nerve root was seen [12].

42  Controversies in NTOS: What Is the Evidence Supporting Brachial Plexus Neurolysis and Wrapping

In a larger retrospective study, 232 competitive athletes with NTOS underwent supraclavicular FRR, complete or partial scalenectomy, and brachial plexus neurolysis. Of the 30% of patients who responded to a follow-up survey (on average, 3.9 years post-operatively), 96% of patients were taking less pain medication, 82% were relieved of their symptoms, and 70% were able to return to their respective sport at the same or higher level [13]. Neurolysis is also an important component of the surgical treatment of recurrent TOS, as this syndrome is caused by significant scar tissue formation involving the brachial plexus. Wagstaff et al. of University of California Davis reported 16 recurrent NTOS cases, 10 of which were due to dense scar tissue formation and the vast majority of the remaining cases due to recurrent injury [14]. Urschel et  al. first reported a series of 30 recurrent TOS patients, all of which were noted to have significant scarring around the brachial plexus and 24 of which had a posterior first rib remnant. These patients underwent neurolysis of the brachial plexus and complete resection of the first rib if indicated. Nerve conduction velocities and symptomology were significantly improved across the entire cohort. Only three patients had inadequate results with mild pain and paresthesias of the affected limb [15]. In another retrospective study of 20 patients with recurrent TOS performed by Greenberg et  al., 80% underwent trans-axillary FRR with concomitant neurolysis due to bone persistence or regrowth, scar tissue, or intact scalene muscle(s) seen on pre-operative CT scans. 80% of the entire cohort experienced improvement in their symptoms at a mean follow up of 43.3  months, with 45% experiencing significant improvement or resolution of their symptoms [16]. A smaller retrospective study by Gelabert et al. was conducted involving eight patients with recurrent TOS due to regrown first ribs. Ten decompressive surgeries were performed in this cohort, all of which included trans-axillary resection of the regrown first rib as well as brachial plexus neurolysis. At least partial resolution of symptoms were seen in the entire cohort, and four of these patients had complete resolution [17].

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Interestingly, isolated neurolysis for NTOS may also offer promising results. Lafosse et  al. recently published a prospective case series supporting the use of an all arthroscopic technique for brachial plexus neurolysis and pectoralis minor release in NTOS patients. In the 21 patients included in the study, the average decrease in DASH scores by 6 months post-operatively was 36. No patient underwent FRR or scalenectomy. Of note, one patient showed worsening symptomology and two patients failed to improve post-­ operatively [18]. Finally, given the traumatic etiology in abundant NTOS cases, it is important to study the value of neurolysis in traumatic brachial plexus injury. A retrospective study of 33 patients with infraclavicular brachial plexus injury due to traumatic shoulder dislocation revealed great results after surgical treatment in 85% of cases. The majority of cases (29 of 33) were able to be treated with external neurolysis alone. The mean time to surgery after trauma was 9 months, allowing for significant scar tissue formation after the injury [19]. A larger retrospective study from China involving 510 patients operated on for traumatic brachial plexus injuries also revealed promising results. Of these patients, 73 were able to be treated with neurolysis alone and also participated in the greater than 3  years of follow up. 79.5% of these patients showed significant motor function recovery post-operatively, defined as a grade three or higher on the Louisiana State University Medical Center grading scale. Of course, these results must be analyzed with caution, given that this select cohort of patients experienced less traumatic injuries than the rest of the cohort who required more extensive repairs [20]. Neurolysis appears to be an integral portion of the repair in various pathologies resulting in significant inflammation and scarring around the brachial plexus, including neurogenic TOS. The symptomatology of NTOS is complex, requiring different aspects of repair during surgical treatment. Further studies will need to be performed to establish the contribution of neurolysis in comparison to other components of thoracic decompression in NTOS. The elimination of scar tissue

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around the brachial plexus results in both improved sensory and motor function of the affected nerves. Therefore, the prevention of such scar formation after brachial plexus release should be considered just as paramount.

42.3 Wrapping The major etiology behind recurrent NTOS is the formation of dense scar tissue around the brachial plexus. Given the high rate of failure of surgical treatment for NTOS ranging from 25–30%, various materials have been developed to prevent the reformation of scar tissue after thoracic outlet decompression [14, 21]. Most of these, including Seprafilm, Surgiwrap, and Goretex, have not been successful at reducing the rate of recurrence of TOS [22]. However, recent literature has supported the use of human Amnion Membrane (HAM) as the material of choice for brachial plexus wrapping. HAM exhibits both antifibrotic and anti-inflammatory properties by mitigating the ability of fibroblasts to adhere to the amniotic epithelial cells, reduction in TGF-β signaling, and inhibition of numerous pro-inflammatory cytokines, making it an ideal candidate in the use of brachial plexus wrapping [23, 24]. While no randomized control trials or retrospective studies have been performed in NTOS patients, HAM has proven its ability to reduce adhesive and scar tissue formation in other populations. Numerous studies in animal models have shown HAM wrapping to reduce the formation of scar tissue and adhesions in both the central and peripheral nervous system. HAM was shown to decrease the amount of epidural adhesions and scar tissue formation compared to negative control groups in both rat and canine models treated with laminectomy [25, 26]. In another study, the ulnar nerves in rabbit models were exposed, repaired, and half were wrapped with HAM. Upon re-exploration, the wrapped nerves showed significantly less perineural adhesions and fibrosis when compared to the control group [27]. Similarly, HAM significantly reduced the formation of adhesion and scar tissue in the sciatic nerves of adult rats after epineurectomy [28].

Research involving human models have also shown promising results. Gaspar et  al. recently published a retrospective case series of eight patients with recurrent cubital tunnel syndrome treated with recurrently neurolysis and HAM wrapping. All patients experienced significant improvements in both pain and motor function at a mean follow up period of 30 months [29]. In a smaller case series, three patients with secondary Wartenberg syndrome were treated with neurolysis and HAM wrapping of the radial nerve. All patients again noted significant improvement in both pain and function [30]. Finally, a single case report of an NTOS patient recently showed great results. A 34 year old female was initially treated with trans-­axillary FRR, pectoralis minor release, scalenectomy, and neurolysis. The brachial plexus was subsequently wrapped with HAM (AlloWrap DS®). She required re-operation for recurrent NTOS at 1  year post-operatively. During re-exploration, the portion of the brachial plexus that had been wrapped was found to be free of scar tissue and adhesions. However, the proximal portion of the brachial plexus that had not been wrapped was encased by scar tissue to which her symptoms were attributed [31]. Brachial plexus wrapping with HAM has been used in at least 97 NTOS operations in the past four years. One year results available in 40 of these patients have shown a recurrence rate of 5%, a dramatic decrease from the previously reported recurrence rate. Given that the vast majority of recurrences occur within 18 months from the original operation, these results continue to show HAM as a promising adjunct to surgical NTOS treatment. Indeed, literature regarding the use of brachial plexus wrapping with HAM is still lacking, and further studies are needed to validate its use in the NTOS population [14, 31].

References 1. Breig A.  Adverse mechanical tension in the central nervous system. Stockholm: Almqvist & Wiksell International; 1978.

42  Controversies in NTOS: What Is the Evidence Supporting Brachial Plexus Neurolysis and Wrapping 2. Sanders RJ, Haug CE.  Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia: J.B. Lippincott Company; 1991. 3. Gupta R, Steward O.  Chronic nerve compression induces concurrent apoptosis and proliferation of Schwann cells. J Comp Neurol. 2003;461(2):174–86. 4. Neuwelt EA, Bauer B, Cahlke C, Fricker G, Iadecola C, Janigro D, et al. Engaging neuroscience to advance translational research in brain barrier biology. Nat Rev Neurosci. 2011;12:169–82. 5. Watkins LR, Maier SF.  Beyond neurons: evidence that immune and glial cells contribute to pathological pain states. Physiol Rev. 2002;82(4):981–1011. 6. Ellis W, Cheng S. Intraoperative thermographic monitoring during neurogenic thoracic outlet decompressive surgery. Vasc Endovasc Surg. 2003;37(4):253–7. 7. Anaf V, Simon P, Nakadi IE, Fayt I, Simonart T, Buxant F, et  al. Hyperalgesia, nerve infiltration and nerve growth factor expression in deep adenomyotic nodules, peritoneal and ovarian endometriosis. Hum Reprod. 2002;17(7):1895–900. 8. Geppetti P, Capone JG, Trevisani M, Nicoletti P, Zagli G, Tola MR. CGRP and migraine: neurogenic inflammation revisited. J Headache Pain. 2005;6(2):61–70. 9. Bridges D, Thompson S, Rice A. Mechanisms of neuropathic pain. Br J Anaesth. 2001;87(1):12–26. 10. Zimmermann M.  Pathobiology of neuropathic pain. Eur J Pharmacol. 2001;429(1–3):23–37. 11. Johansen K. Five hundred rib-sparing scalenectomies for the treatment of neurogenic thoracic outlet syndrome. J Vasc Surg. 2019;70(3):e83. 12. Chandra V, Little C, Lee JT.  Thoracic outlet syndrome in high-performance athletes. J Vasc Surg. 2014;60(4):1012–8. 13. Shutze W, Richardson B, Shutze R, Tran K, Dao A, Ogola GO, et  al. Midterm and long-term follow-up in competitive athletes undergoing thoracic outlet decompression for neurogenic thoracic outlet syndrome. J Vasc Surg. 2017;66(6):1798–805. 14. Wagstaff KA, Davis R, Humphries MD, Freischlag JA.  PC122 causes and treatment of recurrent symptoms after first rib resection for thoracic outlet syndrome. J Vasc Surg. 2017;65(6):172S–3S. 15. Urschel HC, Razzuk MA, Albers JE, Wood RE, Paulson DL. Reoperation for recurrent thoracic outlet syndrome. Ann Thorac Surg. 1976;21(1):19–25. 16. Greenberg JI, Alix K, Nehler MR, Johnston RJ, Brantigan CO. Computed tomography-guided reoperation for neurogenic thoracic outlet syndrome. J Vasc Surg. 2015;61(2):469–74. 17. Gelabert HA, Jabori S, Barleben A, Kiang S, O’Connell J, Jiminez JC, et  al. Regrown first rib in patients with recurrent thoracic outlet syndrome. Ann Vasc Surg. 2014;28(4):933–8. 18. Lafosse T, Hanneur ML, Lafosse L.  All-endoscopic brachial plexus complete neurolysis for idiopathic

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neurogenic thoracic outlet syndrome: a prospective case series. Arthroscopy. 2017;33(8):1449–57. 19. Gutkowska O, Martynkiewicz J, Mizia S, Bak M, Gosk J.  Results of operative treatment of brachial plexus injury resulting from shoulder dislocation: a study with a long-term follow-up. World Neurosurg. 2017;105:623–31. 20. Li G-Y, Xue M-Q, Wang J-W, Zeng X-Y, Qin J, Sha K.  Traumatic brachial plexus injury: a study of 510 surgical cases from multicenter services in Guangxi. China Acta Neurochir. 2019;161(5):899–906. 21. Sanders RJ, Pearce WH.  The treatment of thoracic outlet syndrome: a comparison of different operations. J Vasc Surg. 1989;10(6):626–34. 22. Sanders RJ, Hammond SL, Rao NM. Observations on the use of Seprafilm® on the brachial plexus in 249 operations for neurogenic thoracic outlet syndrome. Hand. 2007;2(4):179–83. 23. Lemke A, Ferguson J, Gross K, Penzenstadler C, Bradl M, Mayer RL, et al. Transplantation of human amnion prevents recurring adhesions and ameliorates fibrosis in a rat model of sciatic nerve scarring. Acta Biomater. 2018;66:335–49. 24. Marchesini A, Raimondo S, Zingaretti N, Riccio V, Battiston B, Provinciali M, et al. The amnion muscle combined graft (AMCG) conduits in nerves repair: an anatomical and experimental study on a rat model. J Mater Sci Mater Med. 2018;29(8):120. 25. Choi HJ, Kim KB, Kwon Y-M.  Effect of amniotic membrane to reduce postlaminectomy epidural adhesion on a rat model. Journal of Korean Neurosurgical Society. 2011;49(6):323–8. 26. Tao H, Fan H.  Implantation of amniotic membrane to reduce postlaminectomy epidural adhesions. Eur Spine J. 2009;18(8):1202–12. 27. Kim S, Sohn S, Lee K, Lee M, Roh M, Kim C. Use of human amniotic membrane wrap in reducing perineural adhesions in a rabbit model of ulnar nerve neurorrhaphy. J Hand Surg Eur Vol. 2009;35(3):214–9. 28. Ozgenel GY, Filiz G. Combined application of human amniotic membrane wrapping and hyaluronic acid injection in epineurectomized rat sciatic nerve. J Reconstr Microsurg. 2004;20(2):153–7. 29. Gaspar MP, Abdelfattah HM, Welch IW, Vosbikian MM, Kane PM, Rekant MS. Recurrent cubital tunnel syndrome treated with revision neurolysis and amniotic membrane nerve wrapping. J Shoulder Elb Surg. 2016;25(12):2057–65. 30. Gaspar MP, Kane PM, Vosbikian MM, Ketonis C, Rekant MS.  Neurolysis with amniotic membrane nerve wrapping for treatment of secondary Wartenberg syndrome: a preliminary report. J Hand Surg Asian-Pac Vol. 2017;22(2):222–8. 31. Sanders RJ, Annest SJ. Amnion membrane improves results in treating neurogenic thoracic outlet syndrome. J Vasc Surg-Cases Innov Tech. 2018;4(2):163–5.

Part V Neurogenic TOS: Outcomes and Future Directions

Neurogenic TOS: Early Postoperative Care

43

Karen M. Henderson, Farzana Najrabi, Marilynn N. Robinson, Katherine Kolster, and Robert W. Thompson

Abstract

Postoperative care after surgery for neurogenic TOS is an important consideration in optimizing patient outcomes. This begins with setting appropriate expectations prior to surgery and extends from the immediate postoperative period through outpatient office follow-up. Concerns during the immediate postoperative inpatient hospitalization revolve around attention to the volume and character of drain output, various pharmacological approaches to pain management, dietary recommendations, monitoring for and treatment of common and unusual complications, and early implementation of physical therapy. Development and use of a consistent protocol for early postoperative care is of great benefit to the surgeon and clinical team responsible for patients with neurogenic TOS.

Critical Take-Home Points 1. A consistent postoperative protocol for care after thoracic outlet decompression is valuable in optimizing outcomes for patients K. M. Henderson · F. Najrabi · M. N. Robinson K. Kolster · R. W. Thompson (*) Center for Thoracic Outlet Syndrome, Section of Vascular Surgery, Department of Surgery, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, MO, USA e-mail: [email protected]

undergoing surgical treatment for neurogenic TOS. 2. Effective postoperative care includes attention to the volume and character of drain output, various pharmacological approaches to pain management, monitoring for and treatment of common and unusual complications, and implementation of physical therapy. 3. Setting appropriate expectations and early office follow-up helps facilitate the transition from hospital care to recovery and rehabilitation following surgery for neurogenic TOS.

43.1 Introduction Consistent postoperative protocols for care after thoracic outlet decompression are important in optimizing outcomes for patients undergoing surgical treatment for neurogenic TOS, following models for integrated multidisciplinary care pathways in other areas of surgery [1]. Such pathways, often referred to as “enhanced recovery after surgery” (ERAS) approaches, have become popular strategies to promote patient and family-­ centered care, improved outcomes, decreased complication rates, reduced hospital stays, and greater levels of patient and provider satisfaction [2, 3]. In this chapter we outline our approach to the initial management of patients that have had surgical treatment for neurogenic TOS using the supraclavicular approach (scalenectomy, brachial

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400 Table 43.1  Postoperative care pathway for neurogenic TOS. Schematic diagram outlining the intended pathway for patients following surgical treatment for neurogenic TOS Postoperative care pathway: Neurogenic TOS Postop day Diet Activity Medications Day of NPO As –PCA surgery tolerated –Senecot-S 1 tab BID –Scopolamine patch 1.5 mg Q 72 H –Zofran PRN –Methocarbamol 500 mg PO Q8H –Ibuprofen 600 mg PO Q6H –Miralax 17 g daily PRN POD Clear Begin PT/ –Add PRN short acting pain #1 liquids OT D/C medications (if not Foley already present) Continue –Discontinue PCA POD Low fat therapy #2 diet (20 g fat) place dietician order POD Continue Continue –Remove On-Q pain #3 diet therapy ball by 0200 Neurogenic TOS Postoperative Medication Changes at Hospital Discharge: –MS Contin or Oxycontin Q12H as needed for moderate to severe pain, dispense 10 tablets (may eliminate if not needed, provider discretion), – Percocet 5/325 Q4-6H as needed for mild to moderate pain, dispense #40, –Methocarbamol 500 mg TID, 30-day supply (#90), –Ibuprofen 600  mg QID, 30-day supply (#120)

plexus neurolysis and first rib resection). Special considerations for patients that have had surgical treatment for venous or arterial TOS are discussed in other sections of this textbook. To assist hospital providers, a schematic outline of the integrated postoperative care pathway for ­neurogenic TOS is posted in the work area of the postoperative surgical unit (Table 43.1).

43.2 Surgical Floor Monitoring. The patient is admitted from the recovery room to a dedicated vascular surgery floor after surgery, using “observation” status for the first 48  h and then transitioning to standard

a

b

Fig. 43.1  Postoperative chest radiographs after surgery for neurogenic TOS.  Typical chest radiographs obtained after supraclavicular decompression for neurogenic TOS. (a) Postoperative day 2, right-sided operation. (b) Postoperative day 2, left-sided operation, with elevation of the ipsilateral hemi-diaphragm suggestive of phrenic nerve dysfunction

“floor” status thereafter. A daily upright portable chest x-ray is ordered for the first 3 days after surgery (Fig. 43.1). The closed-suction drain placed at the time of surgery, which typically extends into the upper pleural space, is maintained on attachment to a suction bulb, but water-seal suction is not needed in the absence of an air-leak. Small pleural effusions or elevation of the ipsilateral diaphragm are not unexpected early after surgery, and are simply managed expectantly. In some cases, the finding of a large pleura effusion may prompt positioning the patient supine or periodically in the Trendelenburg position, to facilitate evacuation of sero-sanguinous fluid through the closed-suction drain placed in the

43  Neurogenic TOS: Early Postoperative Care

posterior upper pleural space. Rarely, a persistent large pleural effusion or hemothorax may require management by pleurocentesis or by reoperation through the supraclavicular incision. It is common for patients to describe numbness and tingling in the affected arm or hand early after surgery for neurogenic TOS, and some patients will experience neck tightness, arm weakness or pain-limited difficulty in using the upper extremity. These symptoms are managed expectantly and do not warrant further consultation or other evaluations during the hospital stay. Blood counts and electrolyte levels are monitored daily for the first 3 days after surgery. Pain management and other medications. Postoperative pain management is facilitated by continuous perineural infusion of local anesthetic, with 0.5% bupivacaine, through two small perfusion catheters placed near the brachial plexus at the time of surgery and connected to a “pain ball” osmotic pump system. These catheters are maintained until the morning of postoperative day 3 and then removed. Intravenous patient-controlled analgesia (PCA) with opioid medications is also used from the immediate postoperative period until postoperative day 2, after which the patient receives oral opioid pain medications as needed. The patient may also use ice and/or heat over the neck and shoulder, but not directly over the incisional wound, as needed for comfort. A non-steroidal anti-inflammatory agent, usually ibuprofen, is started on postoperative day 2 and continued on a regular schedule. One or more muscle relaxants are also started on postoperative day 2 and continued during the course of the hospital stay and after discharge. At the time of surgery patients are given a ­scopolamine patch (placed behind the ear, opposite the side of surgery) to help minimize postanesthesia nausea and vomiting, which is replaced 3 days later if needed. Concomitant use of other medications to combat nausea and/or constipation is also advised due to the frequent side effects of opioid pain medications. A description of analgesics and other medications commonly used after surgery for neurogenic TOS is provided in Table 43.2. Diet. Oral intake is withheld on the day of surgery, with intravenous fluids continued and the

401 Table 43.2  Medications commonly used after surgery for neurogenic TOS Pain medications  Morphine (intravenous), hydromorphone (intravenous)  Oxycodone (oral), hydrocodone (oral), tramadol (oral) Anti-inflammatory agents  Ibuprofen (oral), celecoxib (oral)  Baclofen (oral) Muscle relaxants  Diezepam (intravenous or oral), alprazolam (oral)  Methocarbamol (oral), cyclobenzaprine (oral), carisoprodol (oral) Neuropathic medications  Gabapentin (oral), pregabalin (oral)

patient transitioned to a clear liquid diet on postoperative day 1. On postoperative day 2 the patient is advanced to a low fat (20  g per day) diet, while the character and volume of drain output is monitored. If a lymph leak is suspected, the diet is returned to clear liquids and treatment with octreotide is started until drain output is less than 100  mL per day. If a high-volume lymph leak persists for more than 5  days, intervention is planned by either lymphatic embolization or reoperation, as discussed in other chapters of this textbook. In the absence of a suspected lymph leak, the low-fat diet started on postoperative day 2 is maintained for 4 weeks after surgery before resuming a non-restricted regular diet. Prior to hospital discharge the patient is seen by an inpatient dietician to reinforce the need for a low-fat diet and to clarify food choices. Activity and physical therapy. The urinary catheter placed at the time of surgery is maintained the first night, and then removed on the morning of postoperative day 1. The patient is permitted activity is as tolerated, including ­walking in the hallway. No sling is used on the arm and activity with the affected upper extremity is permitted as tolerated, with caution to avoid overhead positioning or lifting, carrying, pushing or pulling any weight above 5 pounds. On postoperative day 1 the patient begins gentle physical therapy exercises for stretching and range of motion along with mild activity. Activity is steadily increased on postoperative days 2 and 3. The patient will continue the indi-

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vidualized exercises provided by the inpatient physical therapist after hospital discharge for the first 3–4  weeks after surgery, which are focused on neck and shoulder stretches, breathing exercises, and passive shoulder abduction. The patient is also instructed in use of an incentive spirometer to promote deep diaphragmatic breathing, which is continued after hospital discharge. During the hospital stay the patient may have sponge baths with assistance from a nurse or family member, with showers permitted after postoperative day 3 with the area of the wound and drain site covered with a secure waterresistant dressing. Anti-embolism protection. Lower extremity sequential compression devices (SCD) are applied throughout the hospital stay, being removed only when the patient is being bathed or when walking. Prophylactic subcutaneous heparin is also administered daily, beginning on postoperative day 1 and continued until discharge.

43.3 Hospital Discharge The average postoperative hospital stay after supraclavicular decompression for neurogenic TOS is 3–5 days [4, 5]. Prior to surgery, patients are advised to plan on staying in a location relatively close to the hospital, usually at a local hotel, for several days after discharge. The patient is instructed to call the operating surgeon or clinical office staff with any concerns following hospital discharge. Pain. The patient will be given a prescription for pain medication at discharge, which usually consists of a strong opioid (e.g., oxycodone) to be taken on a regular schedule as needed. It is expected that the strong opioid will be tapered and replaced by a moderate opioid (e.g., hydrocodone) within 2–3  weeks after surgery, and tapered further to a weak opioid (e.g., tramadol) by the end of the first 4–6  weeks with no opioids prescribed after 6 weeks. For patients with substantial pain that persists for more than 6–12  weeks after sur-

K. M. Henderson et al.

gery, the patient is referred to the Pain Management team for further evaluation and treatment. This protocol is described in a written “pain contract” generated by the surgeon’s office and signed by each patient prior to operation (Fig. 43.2). Activity. The patient is instructed to continue walking for cardiovascular and pulmonary exercise, up to 1 h each day. The patient will continue the physical therapy exercises provided in the hospital, 2–3 times daily, until the 4-week follow-­up visit. Patients are advised to limit any overhead or repetitive use of the affected arm, and to avoid any repetitive strain activity with no lifting, carrying, pulling or pushing any weight greater than 5  pounds. These restrictions are maintained for a minimum of 4–6  weeks after surgery, and often for a longer period depending on individual progress. Drain management. The closed-suction drain placed during surgery is left in place up to 72 h after hospital discharge, with drain output collected and recorded every 8 h. Unless drain output is considered excessive (e.g., greater than 200  mL per day), the drain is removed in the outpatient office 2–3  days after discharge. An upright chest x-ray is obtained immediately after drain removal and if considered satisfactory, the patient is permitted to leave the local area for home the following day (including airline travel). The dressing over the drain site is removed 48 h after drain removal and the adhesive strips on the incision site are removed approximately 1  week later, when the incision site can be left open to air. Patients are permitted to use local wound ointments, such as siliconbased adhesive gels marketed for scar reduction, after the first 3–4 weeks. Physical therapy. The patient will continue gentle physical exercises 2–3 times a day after hospital discharge, but no therapist visits are needed during the first 3–4  weeks. Patients are instructed to cease stretching exercises if there is any undue increase in pain, and to follow the restrictions described at the time of discharge. Daily walking and regular use of the incentive spirometer is reinforced.

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Washington University Center for Thoracic Outlet Syndrome at Barnes-Jewish Hospital Opioid/Pain Management Agreement for Patients Undergoing Surgery for TOS The purpose of this agreement is to inform you of the narcotic (opioid) prescribing policy of the Center for Thoracic Outlet Syndrome as well as to prevent any misunderstandings regarding the medications you will be taking for pain management. This agreement is to help you and your provider comply with the law regarding controlled pharmaceuticals. Please initial each individual item below and sign at the bottom of the form, to indicate your understanding and consent. I understand that I will be prescribed narcotic pain medications (opioids) following my surgical procedure for Thoracic Outlet Syndrome (TOS). I also understand that it is the policy of the Center for Thoracic Outlet Syndrome to prescribe opioids for no longer than 12 weeks following surgery. During the course of my recovery, the clinical staff of the TOS Center will assist me in a step-down process off the opioids over the course of the 12 weeks following surgery. If it appears that I will not be able to discontinue opioid medications by the end of 12 weeks or if it appears that I am in need of additional support in pain management, I understand that I will be referred to a Pain Management specialist provider or to my Primary Care Physician. I understand that there is a risk of psychological and/or physical dependence and addiction associated with chronic use of controlled substances. I understand that this agreement is essential to the trust and confidence necessary in a provider/patient relationship and that my provider undertakes to treat me based on this agreement. I understand that if I break this agreement, my provider will stop prescribing these pain control medications. In this case, my provider will taper off the medications over a period of several days, as necessary, to avoid withdrawal symptoms. Also, a drug-dependence treatment program may be recommended. I will communicate fully with my provider about the character and intensity of my pain, the effect of the pain on my daily life, and how well the medication is helping to relieve the pain. I understand that chronic use of opioid pain medications can exacerbate and increase pain symptoms in some individuals. I will not use any illegal controlled substances nor will I misuse or self-prescribe/medicate wrth legal controlled substances. Use of alcohol will be limited to times when I am not driving or operating machinery. I will not share my medication with anyone. I will not attempt to obtain any controlled medications, including opioid pain medications, controlled stimulants, or anti-anxiety medications, from any other providers. I will safeguard my pain medications from loss, theft, or unintentional use by others. I understand that lost or stolen medications will not be replaced. I agree that refills of my prescriptions for pain medications will be made only at the time of an office visit or during regular office hours. No refills will be available during evenings or on weekends. I authorize the provider and my pharmacy to cooperate fully with any city, state or Federal law enforcement agency in the investigation of any possible misuse, sale, or other diversion of my pain medication. I authorize my provider to provide a copy of this agreement to my pharmacy, primary care provider and local emergency departments. I agree to waive any applicable privilege or right of privacy or confidentiality with respect to these authorizations. I understand that my provider will be verifying that I am receiving controlled substances from only one prescriber and only one pharmacy by checking the Prescription Monitoring Program web-site periodically throughout my treatment period. I agree that I will use my medication at a rate no greater than the prescribed rate and that useof my medication at a greater rate will result in my being without medication for a period of time. All of my questions and concerns regarding treatment have been adequately answered. A copy of this agreement has been offered to me. Patient Signature

Patient Name (printed):

Date:

Provider Signature:

Provider Name (printed):

Date:

Witness Signature:

Witness Name (printed):

Date:

Fig. 43.2 Opioid/pain management agreement for patients undergoing surgery for TOS. Example of an opioid/pain management agreement that each patient under-

going surgical treatment for neurogenic TOS is asked to review and sign prior to scheduling

43.4 Office Follow-Up

of symptoms and physical examination, the surgical team outlines medications to be continued or changed. In addition to pain medications, it is typical for patients to continue one or more muscle relaxants for at least 4–6 weeks after surgery. The physical therapist will outline an indi-

Each patient is seen for a follow-up outpatient office visit with the surgeon 4  weeks after surgery, with a same-day appointment to be seen by a TOS-specialist physical therapist. After review

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vidualized program for continuing physical therapy. Similar to the approach taken with initial physical therapy management of neurogenic TOS, for patients living at a distance from our medical center the physical therapy program can be implemented by a physical therapist close to the patient, provided there is appropriate supervision and oversight provided by the TOSspecialist physical therapist. Activity levels and restrictions are reassessed at the same office visit. Patients can usually be permitted to drive an automobile, with the exception of long distances, by 2–3 weeks. High school and college students are typically able to resume attending classes 3–4  weeks after surgery. It is expected that the average patient will be able to return to an office-­ type work environment 4–6  weeks after surgery, with more vigorous use of the upper extremity requiring at least 2–3  months. Overhead throwing athletes are permitted light tossing at 6  weeks with a gradual increase in activity thereafter, based on a progressive throwing schedule provided at the 4-week office visit. Each patient is subsequently seen for planned follow-up office visits at 12  weeks and then every 3 months thereafter for the first 1–2 years after surgery. Despite the generalizations outlined here, it is important to note that there remain substantial individual variations in the pace of recovery from surgery and the trajectory of rehabilitation is often difficult to predict for individual patients.

43.5 Conclusion Postoperative care after thoracic outlet decompression surgery for neurogenic TOS is an important consideration toward optimizing patient

outcomes. This begins with setting appropriate expectations prior to surgery and includes attention in the immediate postoperative hospitalization to the volume and character of drain output, various pharmacological approaches to pain management, monitoring for and treatment of common and unusual complications, and early implementation of physical therapy. Development and use of a consistent protocol for early postoperative care is of great benefit to the surgeon and clinical team responsible for patients with neurogenic TOS.

References 1. Baker SG, Sachs R, Louden C, Linnard D, Abu-Own A, Buckland J, Murphy S.  Integrated care pathways for vascular surgery. Eur J Vasc Endovasc Surg. 1999;18:207–15. 2. Ljungqvist O, Scott M, Fearon KC. Enhanced recovery after surgery: a review. JAMA Surg. 2017;152:292–8. 3. Wick EC, Galante DJ, Hobson DB, Benson AR, Lee KH, Berenholtz SM, Efron JE, Provonost PJ, Wu CL. Organizational culture changes result in improvement in patient-centered outcomes: implementation of an integrated recovery pathway for surgical patients. J Am Coll Surg. 2015;221:669–77. 4. Caputo FJ, Wittenberg AM, Vemuri C, Driskill MR, Earley JA, Rastogi R, Emery VB, Thompson RW.  Supraclavicular decompression for neurogenic thoracic outlet syndrome in adolescent and adult populations. J Vasc Surg. 2013;57:149–57. 5. Balderman J, Abuirqeba AA, Eichaker L, Pate C, Earley JA, Bottros MM, Jayarajan SN, Thompson RW.  Physical therapy management, surgical treatment, and patient-reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2019;70:832–41.

Perioperative Pain Management for Thoracic Outlet Syndrome Surgery

44

Chelsea Thomas and Kara Segna

Abstract

Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage (Williams and Craig, Pain, 157(11):2420–2423, 2016). Pain control for patients with Thoracic Outlet Syndrome (TOS) can be quite challenging, as there are often various pain profiles and presentations of pathology. In this chapter, we will describe best practices for safe and effective pain control during the perioperative course, broken down into preoperative, intraoperative, and postoperative sections. We will also discuss different medications that may be used together in a multimodal approach to managing pain.

Three to Five Critical Take-Home Points 1. First rib resection is unusually painful for most patients 2. The best approach to pain management is multimodal, utilizing small doses of different pain medications that work together.

C. Thomas · K. Segna (*) Johns Hopkins Hospital, Baltimore, MD, USA e-mail: [email protected]

3. Pain management should begin in the preoperative time period prior to the start of surgery. 4. In addition to pain medications, nerve blocks can have a significant role in pain management.

44.1 General Concepts In the initial assessment of a patient presenting with neurogenic thoracic outlet syndrome (NTOS) who experiences pain, it is important to delineate specific characteristics specific to their condition. Information such as onset, duration, timing, and aggravating or alleviating factors are important. Does the pain occur at rest? Is it primarily neuropathic in nature, or are there other factors at play? Due to the wide age range of patients who present with TOS (from teenagers to adults in their 50s or 60s), the pain profiles and experience with analgesic medications will differ greatly among individual patients. Some will present with little to no pain, while others may have excruciating pain that affects their activities of daily living, performance at work, or their ability to engage in extracurricular activities. Multimodal analgesia is the utilization of two or more analgesic medications that have different mechanisms of action and work at different sites along the physiologic pain pathway [1]. This allows for effective pain control as the various

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analgesics often have a synergistic effect and provide a broader scale of coverage for a given pain profile. Multimodal analgesia combines non-­ opioid medications, opioids, and local anesthetics to achieve superior pain control. By incorporating a broader range of medications, the patient is relying less on one type of drug (i.e. opioids) and may therefore minimize or avoid some of the potential adverse side effects of that medication class [1]. Please see (Table 44.1) for additional information medications used in a multimodal approach to pain management. Multimodal analgesia has also become a cornerstone within Enhanced Recovery After Surgery (ERAS) protocols, which are specific patient care pathways designed to speed recovery and shorten hospital length of stay [2].

44.1.1 Non-opioid Adjuvant Medications Gabapentin and Pregabalin are the two most commonly utilized anticonvulsant medications that work well for neuropathic pain. They have gained favor over antidepressants due to their lower side effect profile and are more easily titratable. Through blockade of voltage-gated calcium channels, transmission of nociceptive stimuli is attenuated as it is transmitted from the peripheral to the central nervous system. Care should be taken to adjust the dosing for patients with chronic renal insufficiency as well as in elderly patients, who may be more susceptible to drowsiness as a side effect. Acetaminophen is arguably the most ubiquitous medication available for mild to moderate pain, as it can be easily purchased over the counter. It is a centrally acting COX inhibitor that gives it its analgesic as well as an antipyretic effect. Acetaminophen is often prepared in combination with other drugs, such as opioids, cold or flu, and allergy medications. Patients should be counseled to count all sources of Acetaminophen toward their daily maximum, which is 4000 mg per day for the adult patient with no contraindications. Patients who are not taking Acetaminophen for pain control already may start administration 1 day prior to surgery and should continue postop-

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eratively as they wean off opioid prescription pain medication. Acetaminophen can be administered intravenously in the operating room if not taken orally preoperatively [3]. Nonsteroidal anti-inflammatory drugs (NSAIDS) are peripherally acting COX inhibitors that decrease prostaglandin production and therefore decreases pain and inflammation. While they are most commonly purchased over-the-­counter (i.e. Ibuprofen), certain selective COX inhibitors require prescription (i.e. Meloxicam, Celecoxib). Studies show that NSAIDs and Acetaminophen can be given safely together and may improve pain relief without an increased dose of either medication. Care should be taken not to exceed the daily maximum of 3000  mg per day for the adult patient. With the regular use of NSAIDs, there is a risk of renal function impairment and/or peptic ulcer proliferation in patients who are susceptible to these adverse events [4]. Much like acetaminophen, NSAIDS should be continued postoperatively as the patient weans off prescription pain medications. Ketorolac is an intravenous NSAID that may be administered in the operating room during surgery. There should always be a discussion between the anesthesiology and surgery teams prior to administering ketorolac due to the potential concern for increased bleeding risk or delayed wound healing, both of which are unlikely with a single dose [3]. Lidocaine patches: Lidocaine is a local anesthetic that can cause numbness to the skin when administered topically. It takes effect directly at the application site to provide local analgesia via nonspecific sodium channel blockade of small afferent nerve fibers. Lidocaine patches come in standard concentrations of 5% and are placed directly over the area where pain is the greatest. They are relatively safe and can be applied directly to intact skin without concern for significant systemic absorption or toxicity [4]. However, this is not the best pain management approach alone and should be used in conjunction with other methods. Lidocaine products come in a variety of formulations including creams, gels, and patches. Muscle relaxants: Oral medications such as cyclobenzaprine or tizanidine can sometimes help with pain by alleviating muscle spasms.

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Table 44.1  Multimodal medications for perioperative pain control: overview Drug by class Name Anticonvuslants Gabapentin

Pregabalin Anxiolytics

Lorazepam

Alprazolam

Diazepam

Muscle relaxants

Cyclobenzaprine

Tizanidine

Non-opioid analgesics

Opioids

Acetaminophen

Nonsteroidal anti-­ inflammatory drugs (NSAIDS) Morphine, Oxycodone, Hydromorphone, Hydrocodone Tramadol

Sedative/ hypnotics

Ketamine

Dexmedetomidine

Topical agents

5% Lidocaine patches

Pharmacology Voltage-gated calcium channel blockade

Initial dosing regimen Adverse effects 100 mg TID or Dizziness, somnolence, 100–300 mg QHS edema, cognitive changes Voltage-gated calcium 75 mg BID Dizziness, somnolence, channel blockade headache Enhanced GABA 0.5–1 mg TID prn Sedation, dizziness, receptor function memory impairment, disorientation Enhanced GABA 0.25–0.5 mg TID prn Sedation, dizziness, receptor function memory impairment, disorientation Enhanced GABA 2.5–5 mg TID prn Sedation, dizziness, receptor function memory impairment, disorientation 5–10 mg TID prn Dizziness, drowsiness, Increased blurred vision, dry norepinephrine release mouth in locus coeruleus Alpha-2 adrenergic 2 mg TID prn Dizziness, drowsiness, receptor agonist hypotension, bradycardia asthenia, xerostomia Centrally acting COX 1000 mg TID or QID Nausea, vomiting, inhibitor stomach pain, constipation rash, itching Peripherally acting 800 mg TID or Stomach pain, COX inhibitor 600 mg QID heartburn, headache, dizziness tinnitus, rash Nausea, vomiting, Mu, kappa, and delta Varied dosing q4 receptor agonist hours prn, maximum constipation, pruritus drowsiness, respiratory 90 mg morphine depression equivalents per day 25–50 mg q4 hours or Nausea, vomiting, Mu receptor agonist q6 hours prn constipation, pruritus serotonin and drowsiness, respiratory norepinephrine uptake depression inhibitor Dizziness, slurred NMDA receptor 0.5–1 mg/kg bolus antagonist with induction of GA, speech, hallucinations, nystagmus, cognitive 0.1–0.2 mg/kg impairment infusion Transient hypertension, Alpha-2 adrenergic 0.5–1 mg/kg bolus receptor agonist with induction of GA, hypotension, 0.2–1 mg/kg infusion bradycardia Sodium channel 1–3 patches q24 hours Skin reactions, systemic blockade (12 h on/12 h off) toxicity

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These medications have various centrally-acting mechanisms that attenuate the central nervous system and lead to muscle relaxation with decreased spasticity. They can be used in addition to a multimodal management strategy if the pain is not controlled with NSAIDS, acetaminophen, and lidocaine patches. Muscle relaxants do not have the side effect profile of respiratory depression as seen with opioids but can have mild addictive and sedating properties. If ordered, these medications are typically administered on an as-needed basis, meaning the patient requests a dose instead of being automatically given a dose on a set schedule [5]. Anxiolytics are typically derived from the benzodiazepine medication class, including lorazepam and alprazolam. Through enhanced effects of the GABA neurotransmitter to reduce neuron excitability, these medications have anxiolytic and sedative properties. Some patients take medications for anxiety at baseline which should be continued throughout the perioperative period. Diazepam is an example of a benzodiazepine that has the dual effect of being an effective anxiolytic drug while also providing muscle relaxant properties. Midazolam is a common short-acting benzodiazepine that is administered intravenously to patients in the preoperative area. Much like muscle relaxants, anti-anxiety medications should be offered on an as-needed basis. There is a risk of tolerance and dependence with long term use, with the potential for withdrawal if not weaned appropriately [6]. Ketamine is an intravenous sedative/hypnotic medication that works primarily by noncompetitive antagonism of the N-methyl D-aspartic acid (NMDA) receptor. It has also been found to interact with several other sites, including monoamine, cholinergic, adrenergic, and opioid receptors. Ketamine has dose-dependent anesthetic actions and can produce a profound dissociative state at higher doses. At lower doses, such as an intraoperative infusion, ketamine provides significant analgesia, potentiates other pain medications, and reduces the overall anesthetic requirement. This medication has been utilized in several treatment settings, including chronic pain

syndromes, treatment for drug abuse, and depression. The more common side effects of ketamine include sympathetic stimulation and psychotomimetic effects (often tempered by co-­administration of a benzodiazepine) [4]. If initiated, this medication is given in the operating room by a member of the anesthesiology team. In rare cases, a ketamine infusion may be continued after surgery but must be managed by a physician with specialty expertise or training. Dexmedetomidine is an intravenous anesthetic that is a centrally acting alpha-2 adrenergic receptor agonist. It provides sedation, analgesia, and decreased anxiety in a dose-dependent manner. It also has the effect of potentiating other analgesic/anesthetic medications and carries sympatholytic properties [4]. Similar to ketamine, this medication is typically only given in the operating room as a background infusion and may further allow the anesthesiology team to reduce the amount of opioid medications throughout the case.

44.1.2 Opioids Opioids interact with mu, kappa, and delta receptors in the central nervous system to create an inhibitory effect and reduce neuronal excitability. Common opioid pills include morphine or its synthetic derivatives such as oxycodone, hydrocodone, hydromorphone, and tramadol. Often times these medications are prescribed as a combination drug with acetaminophen (i.e. Percocet) [7]. These drugs are considered controlled substances and have a high risk for addiction and dependence. As such, they should only be prescribed on an as-needed basis and taken when all other available non-opioid medications have failed. While it is common for increased patient satisfaction with the initiation of opioid medication, there is also a likelihood to develop tolerance and physical dependence if taken frequently or for a prolonged period of time. Opioids have many side effects including sedation, drowsiness, somnolence, nausea, vomiting, itching, or constipation. An overdose is quite dangerous because

44  Perioperative Pain Management for Thoracic Outlet Syndrome Surgery

these medications may cause shallow or slowed breathing, and in some unfortunate circumstances this can lead to death. This is especially a risk when mixed with other central nervous system depressants such as alcohol, benzodiazepines, or muscle relaxants. The patient cannot drive while taking opioids and should take necessary precautions before returning to work [7]. While the goal is always to utilize opioids sparingly, they should not be neglected or avoided entirely. Opioids are necessary in the event that a patient does not receive a preoperative nerve block and are often minimized in the presence of a preexisting nerve block. Shorter acting, rapid onset opioids such as fentanyl work well in the perioperative setting as they are easy to titrate. Longer acting opioid medications, such as hydromorphone or morphine may also be used in the perioperative setting if there is concern for significant postoperative discomfort. This includes patients with chronic pain, home opioid use, or those who did not receive a preoperative nerve block [8]. Administration will require appropriate clinical judgement from both physicians and nursing staff. Many patients who present for surgical intervention of TOS have experienced some degree of chronic pain, which may develop if there is a delay in diagnosis [9]. In the event that a patient is taking opioids prior to surgery, they usually present with a higher tolerance to pain medication and will likely need higher doses of analgesics. In patients with a history of chronic pain and a high opioid tolerance, methadone may be utilized. It is an opioid with a prolonged duration of action and is usually given as a single 5–10 mg intravenous bolus intraoperatively [10]. Patient-controlled analgesia (PCA): This is a computerized pump that gives patients better control of their pain medication administration via a demand dose at the push of a button. The PCA regulates a reservoir of opioid medication (usually fentanyl, hydromorphone, or morphine), which is connected to the patient’s intravenous line. It is programmed to administer a predetermined dose of medication with a mandatory waiting period (lockout interval) between each dose.

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The PCA keeps a record of the frequency of use and total amount of medication administered over time. This information is useful to tabulate opioid requirements and allow for a conversion calculation to oral medication prior to discharge [11].

44.1.3 Nerve Block Procedures Nerve blocks entail the targeted injection of a local anesthetic, with the goal to anesthetize the nerves that relay pain sensation from a specific area of the body. These procedures are often performed by a team of anesthesiologists who specialize in nerve block procedures. Paravertebral (PVB) blockade has emerged as the goal standard for TOS corrective procedures. The PVB space is found bilaterally along the length of the vertebral column and is bordered by the superior costotransverse ligament laterally, parietal pleura anteriorly, and posterior vertebrae medially [12]. Though several structures are commonly found running within this space, the target for anesthetic blockade are the spinal nerves as they exit the intervertebral foramen. Adequate analgesia for a first rib resection requires injection of local anesthetic within the thoracic levels 1–3 paravertebral space. PVB blocks allow for a higher concentration and volume of local anesthetic to be given compared to an epidural procedure. They also provide unilateral analgesic coverage which minimizes hemodynamic shifts [13]. PVB blocks can be performed via landmark technique or with ultrasound guidance. The block can be performed as a single injection lasting 12–18 h or can be extended longer through placement of a continuous infusion catheter. Medications such as bupivacaine or ropivacaine are commonly used. Lidocaine should be avoided due to its limited duration of action [14]. According to the American Society of Regional Anesthesia (ASRA) guidelines, PVB blockade should follow the same anticoagulation rules set in place for neuraxial blockade procedures [15] (Figs. 44.1 and 44.2). A superficial cervical plexus block provides analgesia to the ipsilateral anterolateral neck and

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a

b

Fig. 44.1 (a) Transverse approach to the paravertebral space with ultrasound probe oriented in the transverse plane, lateral to the second thoracic level (T2) spinous process. (b) Corresponding ultrasound image. A: Erector

a

spinae muscle; B: Paravertebral space (target for injection of local anesthetic); C: Lung parenchyma; D: Transverse process

b

Fig. 44.2 (a) Sagittal approach to the paravertebral space with the ultrasound probe oriented in the sagittal plane, lateral to the T2 spinous process. (b) Corresponding ultra-

sound image. A: Erector spinae muscle; B: Paravertebral space (target for injection of local anesthetic); C: Transverse process; D: Lung parenchyma

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a

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b

Fig. 44.3 (a) The superficial cervical plexus block can be performed with the patient supine and the head of bed elevated or with the patient sitting, using a transverse approach. (b) Corresponding ultrasound image. A:

Sternocleidomastoid muscle; B: Internal jugular vein; C: Internal carotid artery; D: Fascial plane holding the superficial cervical plexus; E: cervical level 5 vertebral body F: Anterior scalene muscle

clavicle, and it is effective for scalenectomy or supraclavicular approach to the first rib. It involves the injection of local anesthetic just deep to the sternocleidomastoid muscle and targets the sensory branches of the cervical levels 2–4 nerve roots [16]. Much like PVB blocks, the superficial cervical plexus block can be performed via landmark technique or with ultrasound guidance. Either ropivacaine or bupivacaine can be used. A single injection can provide analgesia for up to 12–24 h (Fig. 44.3).

weeks afterward. Some patients undergoing this surgery are pain free at baseline, but others may be in excruciating pain which requires narcotics and physical therapy. It is critical that physicians have a good assessment of baseline narcotic dependence. While it is best for patients to wean off or use minimal narcotics in the days to week(s) leading up to surgery, this is not always possible. Understanding baseline narcotic use allows hospital providers to make sure any home drug dosages are not only continued but accompanied with a step-up in dosage as appropriate for each patient. Any increase in home regimen is temporary and utilized only in the immediate postoperative period on a case by case basis. Multimodal therapy, starting in the preoperative period, is especially important for patients who have baseline chronic pain. Utilization of a multimodal pain approach can help provides a smoother transition to weaning off narcotics postoperatively [1].

44.2 Preoperative Strategies Planning a preoperative pain management strategy is important to both physical and mental recovery. Strategies will not only help establish expectations but will also assist with personal pain management immediately after surgery and

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44.3 Intraoperative Strategies Patients will undergo general anesthesia during surgery for TOS, which is typically achieved via endotracheal intubation. Given the nature of the procedure with close proximity to vital structures (lung parenchyma, blood vessels, etc.) and the desire for paralysis to optimize surgical conditions, it is important for the patient to be fully anesthetized with a secured airway. While patients will have no memory of the operation while under general anesthesia, it is vital to maintain adequate analgesia throughout the procedure. Doing so will help curtail the physiological inflammatory response to surgical stimuli, allow the patient a smoother transition into their postoperative course, and decrease the length of stay in the recovery unit [17]. Common analgesic modalities used inside the operating suite include a combination of opioid and non-opioid intravenous medications. If a nerve block has not been done preoperatively, it can be done in the operating room prior to the initiation of general anesthesia. If the patient is not a candidate for a nerve block then the surgeon can inject a small to moderate amount of local anesthetic around the incision or drain sites to help with pain control after surgery. The surgical team may also do an intercostal block under direct visualization ­ (targeting the nerves parallel to the ribs), which may help with deeper surgical pain [18]. It is

prudent for the surgeon and anesthesiologist to communicate and work together, in order to avoid administering a volume of local anesthetic that would approach the patient’s toxic dose.

44.4 Postoperative Strategies The transition from intraoperative to postoperative pain control is critical for a speedy recovery and timely discharge home. Prior to surgery, realistic expectations should be set with every patient in regards to postoperative pain control and the amount of pain they will experience. Every patient should be mentally and emotionally prepared to experience some level of discomfort, which is often highly variable and difficult to anticipate. The goal is not to have a completely pain-free postoperative course. Instead, the focus should be placed on having adequate pain control, where the patient is able to tolerate a diet, ambulate, sleep, toilet, interact with friends and family, and complete basic activities of daily living [2]. Often times, some amount of trial and error is necessary to find the balance between adequate pain control while maintaining an ­adequate recovery pace and avoiding the potentially negative side effects of pain medications. There are several commonly used visual analogue and numeric pain rating scales to aid in postoperative pain assessment and treatment (see Fig. 44.4) [19]. Typically, patients

Fig. 44.4  Example pain scale for patient assessment

0 No Pain

5 Moderate

10 Most Severe

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Fig. 44.5  Example pain steps for analgesic medication escalation

Severe Pain

Mild Pain Pain score:

Moderate Pain

1-3

4-6

7-10

Non-opioid adjuncts every 6-8 hours

Low dose opioids every 4-6 hours as needed

Higher dose opioids every 3-4 hours as needed

are able to maintain a reasonable level of function with a pain score of 4 or 5 out of 10, which is a commonly targeted pain score immediately after surgery. A good pain management plan postoperatively should be approached similarly to that of the preoperative plan: from a multimodal perspective. If the patient received an adequate nerve block then pain scores typically are lower than those who did not receive one. However, based on the local anesthetic used the block variably wears off within 12–18  h [14]. Once this has occurred, the patient will have a noticeable step up in pain on their subjective pain scale. Therefore, a good multimodal approach might include scheduled acetaminophen, NSAIDS, gabapentin and lidocaine patches with titratable doses of opioids and muscle relaxants given as needed [2]. Clear communication and a set schedule are very important for patient satisfaction and to prevent missed doses of pain medication. Providers can also consult the World Health Organization (WHO) ladder (see Fig.  44.5) for safe ways to escalate pain management [20].

Opioids are important when controlling pain but can be dangerous if not well managed. Some providers utilize a PCA pump initially, which allows the patient to safely administer themselves small aliquots of intravenous opioids over a preset time interval. The PCA should be discontinued as soon as possible (normally the morning after surgery), with the intravenous medication converted to oral dosing (minus 20%) for continued use when discharged home. It is prudent to remember that chronic pain patients who are on opioids prior to surgery must be restarted on their home regimen immediately after surgery. Further escalation of opioid medications should be anticipated in the immediate postoperative period, given their likely increased tolerance for these medications. Patients should continue a multimodal pain management schedule for 5–7  days postoperatively. Pain from the procedure may peak at 2–3 days after surgery and then start to decline. After approximately 5  days the goal is to be weaned off opioids completely or back to the patient’s baseline pain regimen.

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44.5 Conclusion In conclusion, pain management is an important factor when considering surgical correction of Thoracic Outlet Syndrome. Minimizing narcotics should be a goal that all providers strive for. The Centers for Disease Control and Prevention (CDC) has published guidelines warning of the dangers of opioid overdose and addiction. Multimodal pain therapy effectively covers multiple types of pain receptors, and success has been especially had when this approach is used in conjunction with regional nerve blocks. Establishing appropriate analgesic expectations prior to surgery is a key component to patient satisfaction and recovery [21].

References 1. Buvanendran A, Kroin JS.  Multimodal analgesia for controlling acute postoperative pain. Curr Opin Anesthesio. 2009;22(5):588–93. 2. Lassen K, Soop M, Nygren J, Cox PB, Hendry PO, Spies C, von Meyenfeldt MF, Fearon KC, Revhaug A, Norderval S, Ljungqvist O. Consensus review of optimal perioperative care in colorectal surgery: enhanced recovery after surgery (ERAS) group recommendations. Arch Surg. 2009;144(10):961–9. 3. Jahr JS, Lee VK.  Intravenous acetaminophen. Anesthesiol Clin. 2010;28(4):619–45. 4. White PF. The changing role of non-opioid analgesic techniques in the management of postoperative pain. Anesth Analg. 2005;101(5S):S5–22. 5. Borenstein DG, Korn S. Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials. Clin Ther. 2003;25(4):1056–73. 6. Olkkola KT, Ahonen J. Midazolam and other benzodiazepines. In: Modern anesthetics. Berlin; Heidelberg: Springer; 2008. p. 335–60. 7. Fields H. State-dependent opioid control of pain. Nat Rev Neurosci. 2004;5(7):565. 8. Gordon DB, de Leon-Casasola OA, Wu CL, Sluka KA, Brennan TJ, Chou R. Research gaps in practice guidelines for acute postoperative pain management

C. Thomas and K. Segna in adults: findings from a review of the evidence for an American Pain Society clinical practice guideline. J Pain. 2016;17(2):158–66. 9. Huang JH, Zager EL.  Thoracic outlet syndrome. Neurosurgery. 2004;55(4):897–903. 10. Gottschalk A, Durieux ME, Nemergut EC. Intraoperative methadone improves postoperative pain control in patients undergoing complex spine surgery. Anesth Analg. 2011;112(1):218–23. 11. Grass JA. Patient-controlled analgesia. Anesth Analg. 2005;101(5S):S44–61. 12. Karmakar MK.  Thoracic paravertebral block. In: Atlas of ultrasound-guided regional anesthesia. Philadelphia: Elsevier; 2019. p. 286–315. 13. Conacher ID, Kokri M.  Postoperative para vertebral blocks for thoracic surgery: a radiological appraisal. Br J Anaesth. 1987;59(2):155–61. 14. Kotze A, Scally A, Howell S. Efficacy and safety of different techniques of paravertebral block for analgesia after thoracotomy: a systematic review and metaregression. Br J Anaesth. 2009;103(5):626–36. 15. Horlocker TT, Wedel DJ, Benzon H, Brown DL, Enneking KF, Heit JA, Mulroy MF, Rosenquist RW, Rowlingson J, Tryba M, Yuan CS. Regional anesthesia in the anticoagulated patient: defining the risks (the second ASRA consensus conference on neuraxial anesthesia and anticoagulation). Reg Anesth Pain Med. 2003;28(3):172–97. 16. Pandit JJ, Dutta D, Morris JF. Spread of injectate with superficial cervical plexus block in humans: an anatomical study. Br J Anaesth. 2003;91(5):733–5. 17. Kelly DJ, Ahmad M, Brull SJ. Preemptive analgesia I: physiological pathways and pharmacological modalities. Can J Anaesth. 2001;48(10):1000–10. 18. De Cosmo G, Aceto P, Gualtieri E, Congedo E. Analgesia in thoracic surgery. Minerva Anestesiol. 2008;75(6):393–400. 19. Bieri D, Reeve RA, Champion GD, Addicoat L, Ziegler JB. The faces pain scale for the self-assessment of the severity of pain experienced by children: development, initial validation, and preliminary investigation for ratio scale properties. Pain. 1990;41(2):139–50. 20. Vargas-Schaffer G. Is the WHO analgesic ladder still valid?: twenty-four years of experience. Can Fam Physician. 2010;56(6):514–7. 21. Gan TJ, Habib AS, Miller TE, White W, Apfelbaum JL. Incidence, patient satisfaction, and perceptions of post-surgical pain: results from a US national survey. Curr Med Res Opin. 2014;30(1):149–60.

Rehabilitation After First Rib Resection

45

Jeanne A. Earley and Cassandra Pate

Abstract

Rehabilitation of patients diagnosed with neurogenic thoracic outlet syndrome receiving first rib resection surgery involves several tiers of treatment. All the upper quarter tissues are considered for treatment including cervical tissues, glenohumeral and scapulothoracic muscles and joints, and neural tissues. The treatments include therapeutic exercise for range of motion and strength, postural alignment, movement patterns and accessory motions of the upper quarter joints, and neural mobility. The progression of activity is guided by the degree of symptom reproduction and is variable for each patient. The patient’s recovery is also enhanced by education of nociception and nociplastic changes that occur with surgery. Parameters of activity engagement after surgery are important for a return to selfcare, housework, A special thank you to the following who helped with the illustrations for this chapter: Lindsay Eichaker, PT, DPT, COMT, CCI, Carter Pate, student at SIUE,  and Russell Smith, MOT, OTR/L. J. A. Earley (*) Washington University School of Medicine, St. Louis, MO, USA C. Pate Anderson Wellness Center, Anderson Hospital, Maryville, IL, USA

work tasks, and recreation. The individualized treatment and gradual progression of each post-operative patient follows guidelines for successful outcomes.

Critical Take-Home Messages 1. Successful recovery after first rib resection is most effective with rehabilitation using gradual progressions from post-operative day one for gentle range of motion, progressing in intensity to the patient’s tolerance to activities. 2. During the rehabilitation process, therapy involves all tissues involved in the diagnosis and all movements in the neck, shoulder, arm and hand. 3. Since neurogenic thoracic outlet syndrome is often painful prior to their first appointment at the surgeon’s clinic, it is beneficial to educate the patient on the lengthy recovery process and neurophysiology of pain. 4. Patients with cervical, upper extremity and thoracic symptoms needing surgery are often limited in their selfcare, household, childcare, recreational and work activities. Rehabilitation from surgery includes recommendations for individual functional activities early in the rehabilitation process.

© Springer Nature Switzerland AG 2021 K. A. Illig et al. (eds.), Thoracic Outlet Syndrome, https://doi.org/10.1007/978-3-030-55073-8_45

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45.1 Introduction Our physical therapy team for treatment of thoracic outlet syndrome (TOS) treats many of the patients that have had the first rib resection (FRR) surgery. Treatment from the time of surgery to approximately 24  weeks are described in this chapter. We have learned a lot during the years working with this patient population. One of the lessons is that no one patient copes with the symptoms and limitations of TOS in the same way or benefits from the same program progressions. We are constantly adjusting our treatments as we encounter individual responses to the diagnosis, surgery and post-operative recovery. David Butler writes about this variability in pain: “Pain is a complex unique experience to each individual: there is no pain exactly alike.” [1]. For this reason, we have titled the document that we send with the patient to their therapist a “guideline” to treatment, not a “protocol”. The challenge in achieving the best outcomes after first rib resection (FRR) surgery and rehabilitation is related to factors prior to the first pre-­ operative visit. The variability of each patient’s signs, symptoms and chronicity guides the rehabilitation progress. From these experiences, patients often demonstrate peripheral or central hypersensitivity, in addition to the thoracic and upper extremity symptoms. Another aspect of recovery from surgery is the contribution of the multiple nerves that may be inflamed and hypersensitive with TOS including cervical nerves as they exit the spine through the thoracic outlet to the upper extremity (UE). With these pre-morbid complexities and involvement of multiple joints and soft tissues, all contributing factors must be considered for successful rehabilitation. The therapy program described may be provided by either a physical or an occupational therapist depending on the practice setting in the patient’s clinic. Goals for rehabilitation following FRR are: 1. Healing and optimal repair of the tissues involved in the surgical procedure 2. Symptom management 3. Restoration of functional range of motion (ROM)

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4. Restoration of functional strength 5. Return to their prior level of activities including exercise, work, housework, child care, and recreational or gym activities. With the goal of optimal healing, the cervical and thoracic spines, the glenohumeral and scapulothoracic joints are addressed. They should be assessed for range of motion (ROM), strength, and adequate recruitment of each joint’s intrinsic and extrinsic muscles, focusing on the patterns of movement during functional activities. Good outcomes in rehabilitation are dependent on the basic principles of movement and postural alignment of the cervical spine, scapula-­ thoracic, and glenohumeral joints, and muscles of the thorax. Discussions about movement patterns and postural corrections are not the central purpose of this chapter; however, thorough descriptions of strategies to lessen symptoms in the upper quarter via alignment and movement patterns are found in two textbooks (both by Sahrmann and her associates): Movement System Impairment Syndromes of the extremities, cervical and thoracic spines [2] and Diagnosis and Treatment of Movement Impairment Syndromes [3]. The exercises used for our rehabilitation program after FRR are described in these texts.

45.2 Timetable for Rehabilitation Although guidelines vary, in a broad sense rehabilitation may be divided into three phases: 1. Immediately postoperative to 4–6 weeks, with the goals being surgical recovery and ROM, 2. 1–3  months, with the goals being intensive, “formal” rehabilitation, and 3. Long-term rehabilitation with the goals being returning to functional activities.

45.2.1 Immediate Postoperative Rehabilitation After surgery, therapy begins during the inpatient stay. Patients are given a home program of exer-

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b

Fig. 45.1  Cervical AROM into right (a) and left (b) rotation exercise

cises and patient education. The goals are: (1) to allow initial healing of surgical tissues, (2) avoid stiffness and excessive edema, (3) begin the process of improved alignment, posture, and movement patterns and (4) assure that the patient maintains a level of conditioning necessary for healing. The inpatient therapist provides the patient with exercises to address the surgical tissues. These initial exercises allow the patient to move through ROM without increased or intense pain. Parameters of exercise performance are adjusted by the reports of pain. Repetitions may be as few as five for two to three times per day. The patient’s understanding of the parameters is important to avoid further irritation of the healing surgical tissues. 1. Cervical active range of motion (AROM) into right and left rotation (Fig. 45.1a, b) and  cervical right and left lateral flexion (Fig. 45.2) are two of the instructed exercises. These exercises are performed in supine or sitting with arms propped on pillows to avoid the pull of the scapular muscles that attach onto the cervical and thoracic  spinal segments. Initially cervical rotation movements are performed by the intrinsic muscles provid-

ing precise movement around the rotational axis [2]. Left and right lateral flexion occurs in the frontal plane [4]. 2. Gentle chin tucks or head nods are recommended for alignment of the head over the cervical spine. 3. Shoulder flexion is performed in supine or hook-lying and is initiated as an active assisted range of motion (AAROM) exercise with the non-surgical hand performing the flexion motion. Initially the elbow may be flexed to shorten the lever arm. 4. Supine or hook-lying AROM in shoulder medial and lateral rotation (MR/LR) exercise is performed with the elbow propped on a pillow or towel roll for neutral alignment of the glenohumeral joint. Initially the arm is positioned in approximately 10° of abduction close to the patient’s side. 5. The instructions for sitting posture include arms supported on the armrests or pillows, gentle chin tuck or nod, chest raise, feet flat on the floor and gentle abdominal tightening (Fig. 45.3). During rest, the vertebral borders of the scapulae are parallel to the thoracic spine approximately 3  inches from the midline of spine with the scapulae, flat on the tho-

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Fig. 45.4  Supine sleeping posture after surgery supports the upper quarter in neutral gleno-humeral alignment. Cervical roll for neck support is optional. Corrected sleeping postures are recommended for all phases of treatment

Fig. 45.2  Cervical right and left lateral flexion exercise

Fig. 45.3  Sitting posture with arm support, chin tucked and raised chest is helpful to align joints in the upper quarter

rax at levels of the second through seventh thoracic [2]. Cues of “chin tuck” and “chest raise” for gentle corrections help with alignment of the head, cervical spine and ­

scapulae. Recommendations for frequent corrections throughout the day may be coupled with a habitual activity such as looking at their phone or passing a directional sign when riding or driving. 6. During supine sleeping the operative arm is propped on a pillow for appropriate glenohumeral alignment and upper extremity support (Fig.  45.4). During side-lying sleeping the surgical arm should be resting on pillows (Fig. 45.5a, b) Patients should avoid sleeping prone or on the surgery side during this stage of rehabilitation. 7. Pain management techniques: Moderation of activities are recommended for the initial post-operative tissue healing. Ice or heat can be used for symptom management avoiding insensate areas. 8. Walking or conditioning programs and parameters for motion are important throughout the rehabilitation from surgery. Schmidt has described increased central and peripheral circulating brain-derived neurotrophic factor (BDNF) with treadmill walking in rats [5]. BDNF, a polypeptide, protects neurons from death and degeneration, and the authors hypothesized “that exercise could be a simple and cost-effective means of enhancing DNA damage repair rates.” [5]. Increased BDNF is also noted after aerobic activity of humans. Hiejnen and colleagues report that post-­ operative exercise walking can assist with protein enhancement, mood, depression and cortisol production [6].

45  Rehabilitation After First Rib Resection

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pocket or waist band, or holding the surgical arm with the other arm or across the chest.

45.2.2 Months 1 to 3 Rehabilitation Most TOS surgeons recommend a period ranging between 3 and 6  weeks for progression from AAROM and AROM-directed rehabilitation (as described above) before progressing to a strengthening program. Our TOS team recommends waiting a full 6 weeks. Even though patients are instructed in early exercises while still in the hospital, the opportunity for education is important b at the 6-week visit. The patient is usually less painful and ready to process and return to more normal activities. As with any surgery, there are variations in the patient’s presentation which may include age, presence of generalized pain and previous levels of endurance and tolerance for daily activities. At this therapy visit, subjective assessment includes compliance with exercise and conditionFigs. 45.5 (a) Side lying sleeping with thorax and neck ing activities, sleep quality and positions, sitting supported by pillows. Cervical roll supporting the neck is postures, breathing comfort, and current sympoptional. (b) Side lying sleeping with pillow support of toms. Objective assessment includes cervical operative arm AROM, shoulder AROM or AAROM, scapular mobility with upper extremity elevation, breathing pattern, sleep and sitting positions, and grip and shoulder strength. Objective outcome meaWalking is the conditioning exercise of choice sures (Cervical Brachial Symptom Questionnaire for post-operative NTOS patients due to easy (CBSQ) [8] and Quick DASH [9] are completed. access at all venues: the hospital corridor, at The patient is referred for therapy on a one to two home, at a gym or when away from home. The times per week basis with recommendations for “exercise is medicine” (EIM) initiative recom- progression of the TOS program. mends the goal for walking exercise at 150 min The exercises initiated at hospital are reviewed per week [7]. Initial parameters for exercise for precise performance, movement patterns, walking will vary depending on the patient’s pre-­ postural alignment and parameters of frequency, surgical level of fitness. Initially daily walking number of repetitions and intensity. Cervical for 5–10 min for two to six times per day may be AROM into right and left rotation and lateral the appropriate dosage, with instructions to flexion may be progressed by increasing the increase duration, frequency and intensity gradu- range of movement. Progressions for shoulder ally. One caveat in patients following FRR sur- flexion include increasing the excursion of shoulgery is that the operative UE should not be swung der flexion, increased elbow extension with or hanging in a dependent position, as momen- movement, or standing AAROM against gravity. tum of the swing and weight of the UE may cause Attention to the scapular movements of upward stress on the healing tissues. Suggestions to rotation and elevation are important throughout address this include placement of the hand in a the rehabilitation process. Normal coupled move-

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a

b

Figs. 45.6 (a) Shoulder flexion or scaption exercise with hands resting on the wall for de-weighting the upper extremity or scaption  helps to promote upward rotation

and elevation of the scapulae. (b) Upper extremity elevation with hands on wall: this photo shows limited scapular upward rotation and elevation

ments of the glenohumeral and scapular joints are: scapular upward rotation to 60°; then approximately one-to-one elevation of scapula and humerus [4]. Supine or hook-lying AROM in medial and lateral rotation (MR/LR) shoulder range of motion progressions may include increasing the shoulder abduction to 90°, and increased ROM into medial and lateral rotation. With supine MR and LR, the upper arm should  be supported with a towel roll or pillow to assure a neutral position at the glenohumeral joint. Any anterior glide of the humerus while performing MR should be corrected. Additional exercises for strengthening may be added at this 6-week intervention. Progression of shoulder elevation includes side lying shoulder flexion with surgical side resting on pillows,

standing facing wall scaption (scapular plane shoulder elevation) or shoulder flexion monitoring scapular upward rotation and elevation (Fig. 45.6a, b). Specific strengthening exercises of the middle and lower trapezii may be introduced at this phase of rehabilitation. A good progression for strengthening these muscles begins with prone elbow lifting with elbows in 90° of flexion (Fig. 45.7a, b) progressing to arm lifting (Fig. 45.7b), then lifting fully extended arms (Fig. 45.7c) and middle trapezii strengthening (Fig. 45.8). Scapular stabilizing exercises are discussed by Moezy: “This study demonstrating the positive effect of strengthening the scapular muscles had a positive effect on increasing shoulder ROM decreasing forward head and shoulder postures and pectoralis minor

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a

b Fig. 45.8  Strengthening of middle trapezii muscles using towel rolls for blocking anterior translation of humeri

c

Fig. 45.7 (a) Starting alignment for recruitment of lower trapezii muscles using pillow for trunk and towel roll for forehead and towel rolls under the humeri. (b) prone elbow lift. Over recruitment of the upper trapezii should be corrected. (c) Progression to arm lifting with fully extended arms  Middle trapezius strengthening exercise may be added

flexibility.” [10]. Peripheral strengthening of hand, forearm and elbow muscles are appropriate at this time. Other recommended activities may include quadruped positioning for stretching of the scapular muscles (latissimus dorsi, rhomboids, and teres major muscles). This can be performed when the patient is able to tolerate weight bearing with the surgical arm. With the head in a “chin tucked” or neutral position, the posterior cervical

Fig. 45.9  Starting position for quadruped rocking back. The hands should be directly under the shoulders in this exercise

muscles can be stretched in the rocking back from the quadruped start position (Figs. 45.9 and 45.10). Using the quadruped position is also effective for strengthening of the scapular stabilizer muscles (Fig. 45.11). Using the quadruped positioning the therapist can observe the movements of the scapulae. Often the scapula appears guarded or stiff and the patient benefits from treatments of gentle scapular mobilizations to promote mobility for UR and elevation during shoulder elevation. The conditioning program should be reviewed and patient educated for increasing duration and intensity, and increasing to a normal arm swing. Other options

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Fig. 45.10  Progression of quadruped rocking back for stretching posterior scapular muscles. With neutral head and cervical alignment the posterior cervical muscles can be gently stretched

Fig. 45.11  Quadruped positioning for strengthening the muscles of scapular stabilization. The operative side is strengthened with lifting operative side and stabilized during non-operative arm lift

for the conditioning program include treadmill walking or jogging, elliptical and UE ergometers, and aquatic programs. If the patient is chest breathing which is addressed with patient education and exercises for diaphragmatic breathing. Another topic that should be addressed at this session is the quality of sleep. Rehabilitation from any trauma or surgery is enhanced by restorative sleep during the deepest stage of sleep when the growth hormone stimulates tissue healing and circulation. Siengsukon states, “Sleep is critical for immune function, tissue healing, pain modulation, cardiovascular health, cognitive function and learning and memory.” [11]. Sleep hygiene is described in a paper published by UC Berkeley entitled, The ABCs of Sleep 2019 [12].

J. A. Earley and C. Pate

Depending on the pre-operative work/home/ childcare activities, the 6-week visit is an appropriate opportunity to discuss the expectations for returning to work and housework activities. It is also important to understand the patient’s need and motivation for return to these activities. Depending on the lifting cautions ordered by the surgeon; lifting, reaching and carrying activities are included in their home program. Returning to sports, gym and exercise programs are individual to each patient, and are customized by their previous levels of activity. A discussion of ergonomics for work and home activities is provided in chapter 19 of this text.

45.2.3 Long-Term Maintenance Ongoing therapy will involve further strengthening of the shoulder and scapular muscles, and instruction as to work, household, and recreational tasks. Progressive exercises for this stage may include resistance exercises with exercise bands, hand weights, proprioceptive neuromuscular facilitation (PNF) techniques and UE ergometer training. Each patient will have a progression individualized by their symptom reproduction and strength of the upper quarter muscles. Also included may be manual treatments, neural glides, and mobilization of scapulae. Neural glides of the median, ulnar, radial nerves may be beneficial when the upper extremity nerves are irritated. Coppieters [13] describes the benefits of sliding the nerves at two joints when he states, “In a sliding technique at least 2 joints are moved simultaneously in such a manner that the movement in one joint counter-balances the increased in nerve strain caused by another movement.”

45.3 Special Considerations Occasionally the long thoracic nerve is irritated and the therapist observes winging of the scapula on the side of the surgery. Rehabilitation of normal scapular dynamics is essential for upper extremity function. Strategies for rehabilitation of scapular winging may include shortening of the lever arm during shoulder flexion exercises

45  Rehabilitation After First Rib Resection

by resting the forearm on the wall, resting the UE on pillows during side-lying exercises, or ­limiting the ROM of shoulder flexion to the range in which the winging doesn’t occur. Winging of the scapula resolves over time if the nerve is irritated. In addition, the phrenic nerve can be affected during surgery. If shortness of breath is noticed with exercises, at any stage of rehabilitation, therapists assess the movements included in diaphragm breathing. Education and exercises for diaphragm breathing are taught. Gradual progression of patients may be critical in returning them successfully to their normal functional activities. Variability of presentation is common in patients after FRR surgery and individual progression is beneficial. Emphasis on the quality of movement rather than number of repetitions is important to avoid faulty movements which may have contributed to the neural impingement prior to being diagnosed with thoracic outlet syndrome. The patients who report to the surgeon’s clinic for FRR surgery have often experienced widespread pain and other symptoms for an extended period of time expecting surgery to resolve their pain complaints. Neurophysiology of pain education should be added to the program at all stages of rehabilitation. In 1979 International Association for the Study of Pain provided the following definition: “.an unpleasant sensory, emotional, and cognitive experience associated with actual or potential tissue damage or described in terms of such damage.” [14]. In 2016, the IASP added the terminology “nociplastic” to address persistent pain: “Pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain” [15]. Psychotherapeutic interventions [16, 17], cognitive behavioral therapy (CBT), and graded motor imagery [18], provide patients with a complete rehabilitation from surgery. There are excellent descriptions of neurophysiological nature of pain and programs available for therapists while treating their patients [1, 19, 20]. Educating the patient prior to surgery about the expectations for duration, intensity, and rea-

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sons for surgical pain helps with post-operative pain. Adriaan Louw, studied the effects of pain education prior to low back surgery and concluded: “… despite ongoing pain and disability, the pain neuroscience education (PNE) patients spent 45% less on health care in the year following surgery compared to the non-PNE group” [21]. He provides a mantra for the patients experiencing pain: “KNOW PAIN; KNOW GAIN.” [22].

45.4 Physical Therapy Results from FRR Surgery For approximately 2 years the physical therapists at The Rehabilitation Institute of St. Louis have been tracking outcomes for performance improvement of post-operative thoracic outlet syndrome patients. The patients were treated one to two times per week. Treatments for the post-­ operative clients included a variety of activities; and included manual therapy, postural retraining, exercises to improve shoulder and cervical joint range, shoulder and scapular muscle strengthening exercises and patient education for fine motor, work, home activities and endurance training. Areas of comparison include outcome measurement scores on the Quick Dash and cervical-­ brachial symptom questionnaire (CBSQ); shoulder and cervical ROM; shoulder, scapular and grip strengths. Measurements were collected at the first post-operative visit and at the 6–8-­ week follow-up visits. The outcomes of TOS patients collected show the following results: CBSQ: 48% of the clients demonstrate improved scores of 10% or greater, Quick Dash: 59% improved by 10%. Assessment of cervical range change of 5° in at least two motions was met by 74% of the clients. Shoulder ROM improved by 10° in two of the motions on the involved side, demonstrating a 91% achievement rate. Scapular and shoulder strength improved by ½ muscle grade achieved by 83% for scapular stability strength and 86% for shoulder. With the positive results on the data that has been collected with the 29 patients, there is a need for continued results on the treatments

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p­ rovided following the surgery and the effectiveness of therapy for this patient population.

45.5 Conclusion Rehabilitation after first rib resection is challenging and requires the medical personnel to work as a team to address the complexities of TOS and FRR surgery. The treatments mentioned in this chapter are shared with our readers with the intention that these treatments may be considered as guidelines. The other intention for sharing our clinic’s program is that others will participate in the conversation to add to the guidelines for treatment following FRR surgery. We anticipate conversations to further develop beneficial and efficacious treatments for the patients suffering from thoracic outlet syndrome.

References 1. Butler DS.  The sensitive nervous system. Adelaide: NOI Group Publications; 2000. 2. Sahrmann SA and Associates. Movement system impairment syndromes of the extremities, cervical and thoracic spines. St. Louis: Elsevier/Mosby; 2011. 3. Sahrmann SA. Diagnosis and treatment of movement impairment syndromes. St. Louis: Mosby; 2002. 4. Kendall FP, McCreary EK. Muscles; testing and function. 3rd ed. Baltimore: Williams & Wilkins; 1983. 5. Schmidt RH, et al. Exercise as gene therapy: BDNF and DNA damage repair. Asia Pac J Ophthalmol (Phila). 2016;5:309–11. 6. Heijnen S, et  al. Neuromodulation of aerobic exercise  – a review. Front Psychol. 2016;6(mini review):1–6.

J. A. Earley and C. Pate 7. Sallis R.  Exercise is medicine: a call to action for physicians to assess and prescribe exercise. Phys Sportsmed. 2014;43:22–6. 8. Rochlin DH, et  al. Quality-of-life scores in neurogenic thoracic outlet syndrome patients undergoing first rib resection and scalenectomy. J Vasc Surg. 2013 Feb;57(2):436–43. 9. Moradi A, et al. Update of the quick DASH questionnaire to account for modern technology. Hand (NY). 2016 Dec;11(4):403–9. 10. Azar M, et  al. The effects of scapular stabilization-­ based exercise therapy on pain, posture, flexibility and shoulder mobility in patients with shoulder impingement syndrome: a controlled randomized clinical trial. Med J Islam Repub Iran. 2014;28:1–15. 11. Siengsukon CF, et  al. Sleep health promotion: practical information for physical therapists. Phys Ther. 2017;97:826–36. 12. Swartzberg JE, Cooke J.  The ABCs of sleep. Berkeley: University of California. School of Public health; 2019. 13. Coppieters MW, et  al. Excursion of the sciatic nerve during nerve mobilization exercises. JOSPT. 2015;45:731–7. 14. IASP Subcommittee on Taxonomy. The need of a taxonomy. Pain. 1979;6:249–52. 15. IASP. Taxonomy. Pain. 2016;157(11):2420–242. 16. Lu S. Easing pain. APA. 2015;46:1–5. 17. Linton SJ, et al. Understanding the etiology of chronic pain from a psychological perspective. Phys Ther. 2018;98:315–24. 18. Moseley GL, et  al. The GMI handbook. Adelaide: NOI Group Publications; 2012. 19. George SA.  Pain management: road map to revolution. Phys Ther. 2017;97:217–26. 20. Stralke SW.  Hand therapy treatment. Han Clin. 2016;32:63–9. 21. Louw A, et  al. Use of an abbreviated neuroscience education approach in the treatment of chronic low back pain: a case report. Physiother Theory Pract. 2011;28:50–62. 22. Louw A, et al. Know pain, know gain?: a perspective on pain neuroscience education in physical therapy. JOSPT. 2016;46:131–4.

Outcomes After Treatment of NTOS

46

Rebecca Sorber and Ying Wei Lum

Abstract

The role of surgical therapy for neurogenic thoracic outlet syndrome (NTOS) is not always straightforward, but for most who treat this disease, such intervention remains a mainstay of therapy. Assessing outcomes of treatment for NTOS, especially compared to the vascular forms of the syndrome, has been difficult due to a lack of reliable objective criteria to both diagnose the syndrome and to track outcomes. Methods utilized include subjective reporting, visual analogue scales, patient satisfaction scores, and functional or quality of life questionnaires, none of which have reached acceptance as a gold standard for following the outcomes of NTOS patients. Likewise, to select the NTOS patients most likely to benefit from surgical decompression, a number of factors can be considered, including presenting and confounding symptoms, patient demographics, duration of symptoms and response to anterior scalene muscle blockade. Overall, most series have demonstrated that with assiduous patient selection, surgical decompression

R. Sorber · Y. W. Lum (*) Department of Vascular Surgery and Endovascular Therapy, The Johns Hopkins Hospital, Baltimore, MD, USA e-mail: [email protected]; [email protected]

for NTOS is effective, with one meta-analysis demonstrating that >70% of patients have a meaningful improvement in symptoms along with a low risk of complications. With these data in mind, for properly selected NTOS patients surgical decompression remains a safe and effective therapeutic option.

Critical Take-Home Points 1. Surgical intervention for NTOS is a safe and effective method of treating NTOS, particularly for those patients who have failed physical therapy and show a good response to scalene muscle blockade. 2. Outcomes for medical and surgical treatment of NTOS are challenging to assess and incorporate both quality of life and functional outcomes as endpoints. 3. The expected rate of success for surgical decompression of NTOS is >70%. Currently no particular surgical technique has demonstrated superiority in improving outcomes.

46.1 Introduction Surgical intervention remains the mainstay of therapy for the treatment of neurogenic thoracic outlet syndrome (NTOS). Several different tech-

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niques (transaxillary, supraclavicular, transthoracic, posterior or subclavicular) are used for surgical decompression [1], with no obvious difference in success rates between the various surgical approaches. Evaluation of results and long-term outcomes following surgical treatment has been difficult because there are no reliable, standardized or objective criteria to establish a diagnosis of NTOS and there is great variability in follow-up time and criteria for outcome. Furthermore, other pathologic conditions such as herniated cervical disk, rotator cuff injuries, peripheral nerve entrapment, chronic pain syndromes (such as chronic regional pain syndromes and fibromyalgia), as well as psychological conditions may mimic NTOS and affect long-term results. It is this difficulty in diagnostic ­variability that compromises patient selection and measurement of outcomes that accounts for the wide range of results achieved in the literature.

46.2 Assessment of Outcomes While widely variable in the literature, early postoperative success for surgical treatment of NTOS has been reported to occur in as many as 90% of cases [2]. Unlike venous or arterial TOS, there is no objective test that has been firmly established to measure differences in baseline and post-therapeutic intervention levels. Various more subjective methods including subjective reporting, [1, 3] functional questionnaires [4–6], quality of life questionnaires [7, 8], visual analogue scales and satisfaction scores [9, 10] have all been used to try to determine whether treatment has benefitted the patient. These scales integrate various subjective measurements of pain relief, ability to return to usual work or pain medication usage, and freedom from re-intervention to determine outcome. Regardless of the method in assessing outcome, early success rates have remained similar in various studies using multiple different outcome measurements.

R. Sorber and Y. W. Lum

46.3 Predictors of Surgical Outcomes One of the most well-established factors predicting outcome in patients with NTOS is the cause of the problem. Several investigators have documented that injury due to trauma or repetitive stress injuries in the work place are predictors of a worse outcome [3, 11–14]. It has been postulated that secondary gain factors such as economic compensation and litigation issues are the confounding factors that lead to this. Conversely, non-laborious positions are associated with better outcomes than laborious occupations [15, 16]. A longer duration of symptoms prior to surgical intervention has been associated with poorer outcome [3, 14, 17]. For example, Cheng found poorer surgical outcomes in patients whose symptom duration was greater than 24  months prior to treatment [17]. Some have postulated the possibility of repetitive stimulation of central pain pathways that result in autonomous pain generators over time, in a fashion similar to the situation in patients with chronic regional pain syndrome [4, 18]; this concept correlates well with the notion that vague symptomatology also has a negative effect on surgical outcomes [5, 6]. The exact duration of symptoms prior to surgical intervention that is likely to adversely affect outcome remains to be determined and is likely highly “fuzzy.” A duration of symptom cutoff as long as 24 months was previously described [3, 17], but others have noticed delays as short as 6 months correlate with worsened outcomes [1]. One group has gone as far as excluding patients with symptoms greater than 12  months, which interestingly resulted in more durable long-term outcomes [4]. Intuitively, a longer duration of symptoms could also translate into a higher number of prior interventions, which in turn has also been identified as a factor correlating with a lower rate of surgical success [3]. There is evidence that the results of preoperative anterior scalene muscle blockade correlate with surgical outcome [4, 19–21]. The accuracy

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of these procedures to selectively inject the anterior scalene muscle can be further increased with the adjunctive use of electromyography [19], ultrasonography [22], and/or computerized tomography [23]. Demographic factors such as age have been less well studied [14]. One group found a higher rate of continued disability following surgery for NTOS in patients that were older at age of injury. Similarly, unpublished data at our institution derived from 159 first rib resection and anterior scalenectomy procedures show that surgery was more likely to relieve symptoms (at 12 months) in patients younger than 40 (90% vs. 77.8%, p