Jacques Magnan MD
Professor Emeritus University Aix-Marseille (F)Head of ORL & Head and Neck Surgery Hopital Nord, Marseilles (1989-2011)Past President–EAONO Past President–Politzer Society, President–MSOA Chairman 2nd EAORL-HNS, Nice 2013 Causse/Champeau Clinics,
Beziers, France
Bhavin Parikh MS (ENT) Fellowship in Otology
Bharti ENT Care Center Vadodara,
Gujarat, India
Hidemi Miyazaki MD (ORL)
Department of Otorhinolaryngology Jikei University School of Medicine Tokyo Kyosai Hospital
Tokyo, Japan
Foreword Prof. Georges Albert Bremond
Headquarters
Jaypee Brothers Medical Publishers (P) Ltd
4838/24, Ansari Road, Daryaganj
New Delhi 110 002, India
Phone: +91-11-43574357
Fax: +91-11-43574314
Email: jaypee@jaypeebrothers.com
Overseas Offices
J.P. Medical Ltd
83, Victoria Street, London
SW1H 0HW (UK)
Phone: +44-2031708910
Fax: +02-03-0086180
Email: info@jpmedpub.com
Jaypee-Highlights medical publishers Inc.
City of Knowledge, Bld. 237, Clayton
Panama City, Panama
Phone: +507-301-0496
Fax: +507-301-0499
Email: cservice@jphmedical.com
Jaypee Medical Inc.
The Bourse
111 South Independence Mall East
Suite 835, Philadelphia, PA 19106, USA
Phone: + 267-519-9789
Email: joe.rusko@jaypeebrothers.com
Jaypee Brothers
Medical Publishers (P) Ltd
17/1-B Babar Road, Block-B
Shaymali, Mohammadpur
Dhaka-1207, Bangladesh
Mobile: +08801912003485
Email: jaypeedhaka@gmail.com
Jaypee Brothers
Medical Publishers (P) Ltd
Shorakhute, Kathmandu
Nepal
Phone: +00977-9841528578
Email: jaypee.nepal@gmail.com
Website: www.jaypeebrothers.com
Website: www.jaypeedigital.com
© 2013, Jaypee Brothers Medical Publishers
All rights reserved. No part of this book may be reproduced in any form or by any means without the prior permission of the publisher.
Inquiries for bulk sales may be solicited at: jaypee@jaypeebrothers.com
This book has been published in good faith that the contents provided by the authors contained herein are original, and is intended for educational purposes only. While every effort is made to ensure accuracy of information, the publisher and the authors specifically disclaim any damage, liability, or loss incurred, directly or indirectly, from the use or application of any of the contents of this work. If not specifically stated, all figures and tables are courtesy of the authors. Where appropriate, the readers should consult with a specialist or contact the manufacturer of the drug or device.
Functional Surgery of Cerebellopontine Angle by Minimally Invasive Retrosigmoid Approach
First Edition: 2013
9789350905258
Printed at:
5Dedicated to
Our late ENT colleagues: Jean-Pierre Pradoura and Richard De Gasquet.
The nurses and personnel of ORL operation theater at Hopital Nord, Marseilles for their selfless support in all our endeavors.
6Foreword
De longue date les complications de l'otite chronique nous avait fait franchir la dure-mère, mais cela était la main forcée car à cette époque, nous sommes dans les années 60-70, la dure-mère était considérée comme une frontière que seuls les neurochirurgiens savaient et pouvaient franchir.
En fait, c'est par la pathologie du nerf facial avec ses paralysies que le froid n'expliquait pas plus que la décompression ne les guérissait, puis surtout par les vertiges invalidants qui bénéficiaient de la neurotomie vestibulaire, qu'il nous est apparu qu'en prenant les précautions nécessaires il n'y avait pour l'otologiste aucun interdit à franchir la dure-mère. Déçu par la voie sus-pétreuse, je pris alors la décision avec mon élève Jacques Magnan d'explorer la face postérieure du rocher. Or pour cela il fallait pénétrer dans l'espace ponto-cérébelleux baigné de LCR, encombré de tout un complexe de nerfs et de vaisseaux d'une extrême importance. Nous avons franchi la dure-mère retro-sigmoïde et ce fut une véritable révélation.
Par la suite des avancées techniques ont facilité nos actions aussi bien diagnostiques comme le scanner ou l'IRM qu'opératoire avec l'endoscopie et le monitoring. Maintenant, à l'heure actuelle, je mesure les progrès accomplis, l'angle ponto-cérébelleux n'est plus « le coin sombre » de notre spécialité tel que je l'avais appris et même enseigné.
Prof. Georges Albert Bremond
7Foreword
(As translated from original Foreword in French)
In the past, complications of chronic otitis made us go beyond the dura mater. We were forced to do so, because in the 1960s–1970s, the dura mater was otherwise considered an implacable border that only neurosurgeons knew how to and were allowed to cross. Later in facial nerve pathology with accompanying paralysis of idiopathic cause and where mastoid segment decompression did not heal, and then in patients with incapacitating vertigo that required vestibular neurotomy made us realize that if we took the necessary precautions there was no reason why an otologist could not go beyond the dura mater. Disappointed by the middle fossa approach, I decided with my pupil Jacques Magnan to explore the posterior side of the petrous bone in early 1970s. To do this we had to penetrate into the cerebellopontine space immerged in cerebrospinal fluid, filled by complex nerves and blood vessels of the utmost importance. We crossed the retrosigmoid dura mater and what a revelation it was.
Subsequently technical progress has facilitated our work, be it for diagnosis with the CT scan and MRI, or for surgery, with endoscopy and monitoring. Today, I take full measure of the progress and accomplishments made. The cerebello-pontine angle is no longer “the dark corner” of our specialty as I had once learned and even taught.
9Preface
As an ENT resident, I had the privilege to witness the first retrosigmoid approach performed by Professor Michel Garcin in 1970 at Hopital Nord in Marseilles, France. It was Professor Georges Bremond through his stature and charisma that espoused and developed it. I can thus say that I began my career with the retrosigmoid approach and that I am terminating it by writing this book. The retrosigmoid approach is undoubtedly the most simple and direct access to the cerebellopontine angle. Curiously, this approach is also the least well known amongst otologists.
The purpose of this book is to discover, popularize and practice the retrosigmoid approach as it was originally conceived “by otologists for otologists”, but of course it can be used by all surgical specialties involved with pathologies of the cerebellopontine angle. To understand why this approach has become indispensable for us, i.e. the otologists, we have to go back in time. During the 1970s, the operating microscope was widely used in all ENT centers, while its utility was just appearing in neurosurgery. The original concept of the “a minima” (French word for minimally invasive) retrosigmoid approach was to adapt the techniques of microsurgery of ear to surgery of the acousticofacial nerve bundle. Another purpose of developing the retrosigmoid approach was to reduce morbidity so as to distinguish it from the legendary seriousness of the suboccipital approach.
Though the retrosigmoid approach by its topography and its objective was the daughter of the suboccipital approach, it is contrary to it in many aspects. The patient's position, the type of operating microscope, the instruments, the size of the craniotomy and its guiding landmarks, the absence of mechanical retraction, the postoperative consequences and no age limit. To try to do a minimally invasive retrosigmoid approach with neurosurgical “armamentarium” is quite difficult. Obviously the intrusion of ENT specialists in this deep and delicate space, the surgical elite's reserve, was subject to criticism not only by neurosurgeons but also by ENT specialists themselves. Thus to criticize the “exiguous nature” of the retrosigmoid approach, and to differentiate it from the large opening of the classical suboccipital approach, it was given the nickname of “keyhole” approach. Though originally used as pejorative, the term Keyhole approach has gradually become an incredible promotion underlining the minimally invasive character of the surgery. In fact nowadays the distinction between retrosigmoid approach and suboccipital approach tends to merge into the common denomination of posterior retrosigmoid approach, confirming the value of this approach even if it is practiced in different ways.
The retrosigmoid approach benefitted from the formidable challenge initiated by William House and perfected by Ugo Fisch. We were all beginners, residents and heads of department alike. But we were lucky; we could go to the morgue and practice anatomical dissections to master the translabyrinthine approach, the middle fossa approach, the retrolabyrinthine approach progressively. The initial operations for cerebellopontine angle pathologies were long and laborious resulting in a narrow and deep operating field in which it was difficult to identify the elements of the acoustico-facial nerve bundle, even with the help and collaboration of a neurosurgeon. The only practical access as practiced on cadavers that seemed simple and with least danger for the cochlea and facial nerve was the retrosigmoid approach.
My revered teachers—Professors Bremond and Garcin, inaugurated the retrosigmoid approach on elderly and fragile patients suffering from trigeminal nerve neuralgia referred by neurosurgeons to otologists for treatment using less invasive approaches. After partial retrogasserian rhizotomy, indications for the retrosigmoid approach were extended to vestibular neurotomy, and then to small acoustic neuroma in the ‘otological stage’ (when the patients do not have any neurological complaints). We had to wait until the 1990s when intraoperative endoscopic procedure was added to our armamentarium to be convinced of the reality of neurovascular conflicts as the main cause of trigeminal neuralgia and hemifacial spasm. Thus, the minimally invasive retrosigmoid approach became the endoscope-assisted retrosigmoid approach.
During these 40 years, technical progress has been considerable and has been taken into consideration by all specialties involved in this surgery, above all anesthesiology. Deep anesthesia and assisted ventilation make the cerebellum retract spontaneously and eliminate the need for peroperative lumbar puncture or Mannitol hypertonic solutions. This spontaneous retraction of the cerebellum is an essential step of this cerebellopontine angle surgery to have access to and open the posterior fossa cistern. It is difficult to believe in the spontaneous retraction of the cerebellum during surgery 10particularly when looking at a preoperative MRI showing the cerebellum in contact with the petrous bone or when the cerebellum obstructs the access to the cerebellopontine angle during anatomical dissection.
The retrosigmoid approach has been more than just a technical adventure, it had been a fantastic human journey with its moments of nobleness and baseness. We will only remember the former when adversity has been changed into opportunity. During these years, I had been graceful to develop:
- Enduring friendship with Professor Carlo Zini's team in Parma and his brilliant student turned master Professor Mario Sanna and his “Gruppo Otologico”.
- The European Academy of Otology and NeuroOtology (EAONO) with the support of 90 European experts and the authority of Professors Mirko Tos and Ugo Fisch.
- Broadcasting of teaching by video-conferencing with the help of the Live International Otolaryngology Network (LION) and the Tempus TransmedEast project.
The originality of the retrosigmoid approach attracted many visitors to my department at the Hopital Nord in Marseilles. Drs Bhavin Parikh and Hidemi Miyazaki made themselves particularly available and were very eager to see this book appear. They followed me to the Causse-Champeaux Clinics in Beziers when I retired from the Hopital Nord. Dr Bhavin has been the driving force in editing this work. Over and above his epistolary talent, he was responsible for collecting the data and the clinical cases included. Dr Hidemi has brought the most recent developments of the retrosigmoid approach with intraoperative monitoring of cranial nerves, especially cochlear nerve. Thank you so much to both of you and my best wishes for a brilliant career.
Finally, I would like to thank more than 2000 patients who were operated using this surgical procedure for their trust and their gratitude.
Jacques Magnan
11Preface
Newer horizons have opened due to conjunction of the use of endoscope and microscope in the surgery of cerebellopontine angle (CPA) in the last two decades. Endoscope provides brilliant illumination and excellent preview of anatomy of CPA unforeseen before its advent. Endoscope-assisted retrosigmoid approach gives an opportunity to perform surgery for functional disorders (non life-threatening benign conditions that cause significant worsening of quality of life) of CPA in minimally-invasive manner with small external incision, accurate precision and significantly reduced morbidity and is increasingly practiced even in elderly population.
My maiden voyage in the field of lateral skull base surgery initiated when I first met Professor Jacques Magnan at a live surgery workshop in New Delhi in the December of 2008. He was operating a case of hemifacial spasm using endoscope-assisted retrosigmoid approach. This approach allowed clear and concise view of anatomy of the contents of cerebellopontine angle and was performed from a completely different perspective. With the intent of getting opportunity to work with Professor Magnan to enhance my knowledge and skills regarding skull base surgeries, I contacted him and after 8 months I was pleased to receive an invitation to work in his department of ENT at Hopital Nord, Marseilles, France. During my visit to Marseilles at his department and later at Beziers, I experienced his generosity as a host, his kind-heartedness and charisma as a leader. He will always inspire me with his didactic character and adorable surgical skills.
Professor Magnan sensed the necessity to convey this core knowledge of endoscope-assisted retrosigmoid approach to future generation of neuro-otologists and neurosurgeons. Professor Magnan being a pioneer in this novel approach and with such tremendous experience would be the ultimate source for imparting this invaluable information, that too in a “how I do it” format and in a “step-by-step” manner. The completion of this work was made possible because of my close academic association with Professor Magnan. I am indebted to him for being a wonderful teacher and mentor, and for generously sharing his profound knowledge and wisdom with me. His presence was a constant source of inspiration, and his untiring interest, healthy criticism and invaluable guidance provided the impetus to shape this work to the desired level of accuracy and completeness. My colleague and friend Hidemi, has been pioneer in developing and implementing a newer design of electrodes useful in continuous cochlear and facial nerve monitoring that I am sure is going to significantly alter the rate of functional preservation of hearing and facial nerve function in various functional surgeries of CPA by retrosigmoid approach. His collaboration in preparing this book on functional surgery of CPA was irreplaceable and I would like to express my sincere appreciation to him for sharing and imparting us with detailed knowledge on the same.
I would like to thank my wife and father for enduring long periods of my absence at home and for their love and support. Lastly, blessings of the Almighty and my late mother's influence has been a source of continuous inspiration and has been the driving force in all my efforts.
13Preface
It was in the autumn of 2004 that I first had the opportunity to knock the door of Professor Jacques Magnan's department. I was astonished to see the world of Jacques where cerebellopontine angle (CPA) surgeries by retrosigmoid approach (RSA) were performed almost daily and for a moment I felt like I had come to a wrong department. But repeatedly devoting my mind in drawing the sketches of the surgical field, I became fascinated with the elegant surgical field and the talented operating hands. The five months of my stay just flew passed. Following this stay till the end of 2005, I was fortunate to have introductory lessons on various other otologic approaches to skull base under the masters of skull base surgery worldwide. In the same period, I happened to meet a skull base surgeon named Dr Hirofumi Nakatomi. A year and a half after I returned to Japan, we met again by chance, and from spring 2007 we jointly embarked on the development of continuous electrophysiological monitoring system which measures the dorsal cochlear nucleus action potential (DNAP). The person who appreciated our concept the most and gave us the chance to demonstrate our system was Jacques. In February 2008, through the case which became clear during the operation to be facial schwannoma, we were able to show not only the continuous electrophysiological monitoring by DNAP but also the effectiveness of continuous electrophysiological monitoring on facial nerve we were developing at the same time. On this technique, I presented the results in the Politzer Society Meeting in autumn of 2009 and at that time Jacques commented “When I heard about the technique from him, to be honest, I did not believe it. But, when I saw their technique with my eyes in Tokyo and had it performed in Marseilles, I was convinced that it was real. His words were real.”
I rejoined Jacques's surgical team from spring 2012. Coauthoring this book with Bhavin and writing the preface are all things unimaginable for me nine years ago. In return for the kindness Jacques gave me up to now, I have written in this book the concept of continuous electrophysiological monitoring centered on the experience I had so far.
I would like to devote this book to all otologists and otoneurosurgeons who handle operations in this field. Combining the allies of continuous electrophysiological monitoring, a new cochlear nerve mapping technique together with minimally invasive retrosigmoid approach systematized by Professor Magnan, I wish that the quality of life can be significantly improved for all our patients undergoing surgical procedures for the cerebellopontine angle pathologies by preserving the neural function and conducting the targeted surgery in minimally invasive way. I wish that more and more surgeons conduct function-preservation cerebellopontine angle surgery confidently resulting in excellence and wish this book to provide the basis for achieving this goal.
Lastly, I would like to thank my family who supported me in all my endeavors, especially adjusting to the difficulties arising due to my dual duties in Europe and Japan.
15Acknowledgments
With the collaboration of:
Francois Caces (Beziers/Villefranche-Rouergue, France), Andre Chays (Marseilles/Reims, France), Arnaud Deveze (Marseilles, France), John Economides (Athens, Greece), Amr Hegab (Cairo, Egypt), Renaud Meller (Marseilles, France), Hirofumi Nakatomi (Tokyo, Japan), Agadurappa Mahadevaiah (Bengaluru, India), Honnurappa Vijayendra (Bengaluru, India) and Gruppo Otologico (Piacenza/Rome, Italy).
With the contributions by:
Miguel Aristegui, Gregorio Babighian, Jean-Pierre Bebear, Gerard Bonnaud, Per Cayer-Thomassen, Carlos Cenjor, Cor Cremers, Christian Dubreuil, Emilio Garcia-Ibanez, Thomas Lenarz, Masahiro Miura, Shreeram Murthy, Masaaki Nakajima, Kazimierz Niemczyk, Gerard O'Donoghue, Erwin Offeciers, Munehito Okada, Nuri Ozgirgin, Ranjan Aiyer, Archana Desai, KK Ramalingam, Philippe Romanet, Hitoshi Sano, Witold Szyfter, Jens Thomsen, Mirko Tos, Patrice Tran Ba Huy, Alain Uziel, Francois Vaneecloo and Hans Peter Zenner.
For their work:
Alfredo Vega Alarcon, Nacim Ait Mesbah, Hacene Ait Mimoune, Fayed Ashraf, Yakoot Ashraf, Sinnathuray Ar, Andrea Bacciu, Omar Bacha, Fathi Baki, Marco Barbieri, Jean-Francois Belus, Makhlouf Benzamit, Lukadz Borucki, Brahim Boutassetta, Laurent Broder, Michel Bruzzo, Mercedes Alvarez Buylla, Valeriu Buza, Francesco Canani, Rameh Charbel, Marina Cihanek, Olivier Coulet, Claire Lise Curto, Pavel Dimov, Jacob Economides, Christine Fatou-Balansard, Cristina Ferrario, Hani El Garem, Bhat Gautham, Davide Giordano, Melvin Guardado, Nicolas Guevara, Hella Hajri, Dirk Kunst, Benoit Lafont, Daniel Latil d'Alberta, Bob Lerut, Ali Mardassi, Mounir Marrakchi, Stavros Mavroidakos, Cyrille Menelli, Jean-Rene Millet, Badr El Din Mostafa, Mohamed Moussa, Sofiane Ouhah, Nazim Rous, Elaini Sherif, Laurent Tardivet, Franco Trabalzini and Pradeep Vundavalli.
For their support:
Denise Alpe, Roger Authie, Michel Autric, Jean Luc Breitenstein, Gerard Barki, Michel Lucciano, Jean Christophe Girardot, Frederic Giraud, Michel Salvati, Andreas Tedde, Christian Vuolo and Michel Lacour.
For their teaching: