Despite recent technological innovations in neuroradiology, the ultimate diagnosis of brain tumors is still based on the histopathological findings from specimens taken during surgery. The material in this atlas represents approximately 700 brain tumor specimens collected mainly in the authors' own clinics. In most cases, complementary light-and-electron-microscopic images of the same case are presented. This volume is a clear and comprehensive guide to the pathology of tumors arising from the central nervous system and should prove useful to pathology residents, neurologists, neurosurgeons, neuroradiologists, and senior medical students.

Up until two decades ago, clinical interest in the etiopathogenetic interpretation of lumbo-radicular syndromes was prevalently concentrated on the pathology of the inter vertebral disc. This vision gradually changed and grew as a result of the affirmation of the concept of pathological narrowing of the osteoligamentous vertebral canal as a cause of compression of the lumbar nervous structures. Finally, in the last ten years, lumbar stenosis has become more and more a subject of current interest not only as a result of problems related to nosography, diagnosis, and therapy, but also as a result of the increasing frequency with which vertebral canal or nerve root canal stenosis syndromes are recognized and treated. At the same time there was a tendency to include in stenotic pathology other pathological conditions responsible for lumbo-radicular syndromes. This led to dilation of the concept of stenosis, which perhaps no longer responded to reality, and which was not useful from a practical point of view. The need to define stenotic pathology and to correctly locate it within the vast field of lumbar pathology inspired the writing of this volume. This monograph gathers many diagnostic and therapeutic concepts matured at our In stitution over the years. Some of these concepts have already been defined in scientific meet ings or in publications."

Spontaneous intracerebral haemorrhages are the most dangerous complication of cerebral vascular disease. Because of their frequency and the fact that they lead to serious injuries, prolonged disabilities and, often, death, they have acquired an enormous significance, both medically and socially. Their precise diagnosis, location, wide extent and accomp ying manifestations were for a very long time uncertain and, in small and deeply situated haematomas, these factors were impossible to determine. Diagnosis was confirmed by the clinical picture, by angiography and sometimes by ventriculography and included, in the main, both lobar and more extensive haematomas. The results of operative treatment following the first attempt of H. Cushing in 1903 were poor and remained unsatisfactory in spite of the endeavours of numerous authors (Guillaume et al. 1956; Lazorthes 1956; McKissock et al. 1959; Luessenhop 1967 and many others). Especially for the most frequent and typically hypertensive haematomas in the region of the internal, capsule, the opinion was often expressed that operative treatment was useless.

Statistically speaking, head and neck cancer per se (excluding melano ma and basal cell carcinoma) does not outwardly seem to pose a serious threat - 27,500/870,000 total cancer cases estimated for 1984 (or 3.2% of all cancers) and 9,350/450,000 total cancer deaths in 1984 (or 2.1 %) for the United States. Yet in clinical practice, by the time that diagnosis is made, more than 60% of oral cancers have already spread to the nearby lymph node system. And while the overall five-year survival rate for localized oral cancer is 67%, this rate decreases drastically to only 25% when the original cancer has metastasized. Scientific textbooks all too often are merely a compilation of dis crete parts, rather than a correlated, integrated whole. Dr. Hamner and his colleagues have achieved such an integrated, succinct version in The Management of Head and Neck Cancer. The outstanding group of contributors bring to the book a wealth of accumulated knowledge and expertise in their various cancer spe cialty disciplines. They are associated with some of the most distin guished cancer centers in the United States.

As an addition to the European postgraduate training system for young neurosurgeons we began to publish in 1974 this series of Advances and Technical Standards in Neurosurgery which was later sponsored by the European Association of Neurosurgical Societies. This series was fust discussed in 1972 at a combined meeting of the Italian and German Neurosurgical Societies in Taormina, the founding fathers of the series being Jean Brihaye, Bernard Pertuiset, Fritz Loew and Hugo KrayenbUhl. Thus were established the principles of European co operation which have been born from the European spirit, flourished in the European Association, and have throughout been associated with this series. The fact that the English language is well on the way to becoming the international medium at European scientific conferences is a great asset in terms of mutual understanding. Therefore we have decided to publish all contributions in English, regardless of the native language of the authors. All contributions are submitted to the entire editorial board before publi cation of any volume. Our series is not intended to compete with the publications of original scientific papers in other neurosurgical journals. Our intention is, rather, to present fields of neurosurgery and related areas in which important recent advances have been made. The contributions are written by specialists in the given fields and constitute the fust part of each volume."

In the last decade there has been a growing interest in the study of the interactions between the heart and the brain, especially in the field of cerebral ischemia. The interactions between cardiovascular and cerebrovascular diseases are of relevance not only for research investigation, but also for clinical implications in the daily clinical practice. i.e. A wealth of information has been gathered particularly on three topics, cardiovascular consequences of cerebral injuries, cardioembolic stroke, and association of carotid and coronary artery disease. The available information, however, is still sparse and fragmentary mainly because of the lack of commun ication between neurologists and cardiologists. With the aim of improving communication between several disciplines and technologies, we started to organize since 1987 in Bologna, Italy, an international Symposium on heart brain interactions to be held every 3 years. Our intention was to gather prominent clinicians and researchers from outstanding cardiologic and neuro logic institutions actively involved in the study of heart-brain interactions. The ambitious goal has been to fit different pieces of information like in a puzzle. This book originates from the contributions presented at the 2nd Sympo sium which was held in Bologna on November 30-December 1, 1990. The book is subdivided into three sections: I cardiovascular consequences of cerebral damage, II cardiogenic cerebral ischemia, III cerebrovascular and coronary artery disease."

A different kind of book! The clivus of skull base is an area difficult to reach in neurosurgery, otorhinolaryngolo- gy, maxillo-facial surgery, plastic surgery, reconstructive surgery, and orthopedic surgery. It is for this reason that the various specialities gave found different approaches for different operations.

The introduction of the operating microscope as a surgical tool revolutionized the treatment of peripheral nerve lesions. A new era thus began in the early 1960s, which led to a substantial improvement in the management of nerve lesions. The results of nerve grafting techniques have demonstrated that, independent of the length of the defect, lesions can be successfully bridged. The free tissue transplants with microvascular anastomosis have also opened new, rewarding possibilities for peripheral nerve reconstruction procedures, facilitating the achievement not only of satisfactory anatomical but also of satisfactory fUhctional results. In order to evaluate the state of the art and reflect retrospectively on 25 years of microneurosurgical treatment of peripheral nerves, numerous outstanding scientists and clinicosurgical physicians were invited to Hanover in order to exchange their viewpoints and experiences. An active und fruitful discussion resulted which dealt with the many aspects of anatomy, pathology, clinical and neuro physiology, diagnosis, and with the surgery and physiotherapy which constitute modern-day peripheral nerve lesion treatment. The excit ing ongoing experimental and clinical activities have led us to support the wish and idea to publish the scientific exchange which took place during the Hanover symposium. I truly believe that the articles presented in this book cover so many interesting subjects concerned with peripheral nerve lesions that the book will serve the interested and dedicated physician involved with such cases as a reference work for the basics and also provide him with the therapeutic guidelines to assist him in his daily work."

Percutaneous lumbar discectomy is a new surgical method for treating lumbar disc diseases. The goal of the procedure is decompression of the spinal nerve root by percutaneous removal of the nucleus pulposus under local anesthesia. Probably 20 % of all patients requiring lumbar disc surgery can be successfully treated by this method. During the past two years, percutaneous discectomy has spread rapidly, and it is now performed in most clinical departments engaged in spinal surgery. The first International Symposium on Percutaneous Lumbar Discectomy, held in Berlin in August 1988, covered all current procedures known as "percutaneous discectomy" and the entire range of percutaneous techniques, both clinical and experimental. Its publication is important because of the recency of this new surgical procedure, the outstanding experience of the speakers - including the Japanese, American, and European "pioneers" of the technique - and last but not least the gaps in the knowledge of physicians concerning this topic. This procedure opens up new perspectives in the surgical treatment of degenerative diseases of the lumbar spine.

Selected papers from the prestigious Stonwin Medical Conference, which each summer invites a small group of neurosurgical investigation. This volume presents recent advances in research and practice of surgery of the severed spinal cord. Future volumes will treat similarly focused, cutting-edge topics. In terms of editorial strategy, this series will afford Springer entree to a select groups of neurosurgeons.

The question facing anyone contemplating a book on low back pain is: Why write another book? It is certainly true that there are many books on this topic addressing a wide variety of audiences. Some books are all inclusive and scholarly in nature, others are personal descriptions of diagnostic and treat ment philosophies. This book is a combination of these two extremes. It represents our views on the low back problem, supported by scientific data. Most aspects on back pain presented in this book can be found in other texts. The organization of the material is unique, however. Our approach is to start by listening to and looking at the patient. It becomes apparent, then, that patients can be classified into one of the syn dromes described in chapters 4 through 13. We believe that this syndrome classification, which is quite simple to make clinically, will allow you to diagnose and treat your patients more effectively. To set the stage for the syndrome chapters the first three chapters of the book are generic to the remaining chapters. They reviewe the epidemiology, pathology, biomechan ics, etiologic theory, diagnostic methods, and treatment modalities applicable to the low back syndromes. They should be read before the syndrome chap ters. At the end of the book you will find four chapters that are specific to disease entities."

1 2 3 O. D. Wiestler , U. Schlege1 , andJ. Schramm lInstitut flir Neuropathologie, Universitatskliniken Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany 2Neurologische Universitatsklinik, Sigmund-Freud-Str. 25, 53127 Bonn, Germany 3Neurochirurgische Universitatsklinik, Sigmund-Freud-Str. 25,53127 Bonn, Germany In contrast to various other neoplastic disorders, there has still been no dramatic progress in the treatment of gliomas. Modem microsurgical and imaging techniques have made more tumors surgically accessible and have allowed a more extensive surgical resection. However, these new developments have not improved the clinical outcome. Recently, molecular biological studies on genes and genetic loci affected in tumors of the nervous system have yielded significant new insights into pathoge- netic machanisms. Many neuro-oncologists are therefore looking forward to transla- ting molecular genetic findings into novel diagnostic and therapeutic strategies for the management of these devastating neoplasms. We have produced this volume with the intention of highlighting major developments in both molecular and clinical neuro-oncology and of stimulating the communication and cooperation between these two fields. Two major families of growth-controlling genes have emerged from the past decade of intense research on the molecular genetics of tumors: oncogenes and tumor suppressor genes. Oncogenes are characterized by their potential to stimulate the growth of susceptible cells whereas tumor suppressor genes share a growth-inhibi- ting property. A stringently controlled interplay between these two regulatory me- chanisms is required to maintain a stable composition of tissues.

Sensorimotor systems are not rigidly wired predetermined networks but rather highly plastic structures that learn and modify their entire performance in response to changes in external or internal conditions. Lesions or distortions of the system's input, which initially cause a functional disorganization, induce an active reorganization which often leads to a recovery of function. Examples of lesion-induced neural plasticity have been known for some hundred years; however, an awareness of their value as research tools is relatively new. This current interest is a consequence of rapid ly changing ideas concerning the nature of CNS organization. Out of these, concepts are emerging which describe neural nets as modifiable, highly dynamic, self-organizing structures. This trend is clearly reflected in this volume, which contains the proceedings of a symposium held in Bremen in July 1980 as a satellite meeting of the XXVIIIth International Congress of Physiological Sciences. The first part of this conference was devoted to some gen eral aspects of plasticity, discussing the current theories of functional recovery as well as morphological, neurochemical, physiological, molecular, and ontogenetic aspects. The second part dealt with lesion induced plasticity in specific sensorimotor systems of the spinal cord, brain stem, and cerebral cortex."

The pioneering work by Pierre Janny and Nils Lundberg added a new tool to the investigative armamentarium of the neurosurgeon: continuous monitor ing of intracranial pressure (ICP). A small group of basic and clinical sci entists recognized the importance of this method and in 1972 an International Symposium was organized by Mario Brock in Hannover, Germany. The workers "of the first hour" had high expectations and thought that the problem of intracranial hypertension could finally be dealt with. The Symposium con tinued to grow during subsequent meetings in Lund (1974), Groningen (1976) and Williamsburg (1979). However, the advent of the modern imaging tech niques of CT and MRI have dramatically changed the scene in clinical neurology and neurosurgery. These new methods as well as other monitoring techniques have put ICP in its proper place as just one of the many aspects, albeit an important one, in the management of patients with intracranial space-occupying lesions. The symposia in Tokyo (1982), Glasgow (1985) and Ann Arbor (1988) confirmed the steady interest in ICP recording, both as a research tool and as a clinical method. and yielded many new developments in the field of ICP. This book comprises the proceedings of the Eighth International Symposium on Intracranial Pressure that was held in Rotterdam, The Netherlands, from June 16th to 20th, 1991."

The brain stem and cerebellum are structures that have fascinated and puzzled physicians, anatomists, and physio- logists for centuries. Relatively small in volume compared to the much larger and more majestic human cerebrum, and hidden away in relative obscurity in the back of the head under the protection of the bony posterior fossa and the firm dural envelope, the tentorium cerebelli, these critical neural structures defied precise study during life until very recently. Recent advances in brain and vascular imaging and improved understanding of brain-stem reflex and tract functions and their measurement by electrophysiological techniques have presented an opportunity for clinicians and researchers to better study, during life, patients with stroke and other conditions that involve the brain stem and cere- bellum. A congress was held at the Neurology Clinic of the University in Mainz, April 4-5, 1992, during which clinicians and researchers reported and discussed modern topical diagnosis of diseases of the brain stem and cere- bellum. This volume represents the edited proceedings of that congress. Early information about brain stem anatomy and func- tions came from anatomical studies by Ludwig Turk, Paul Flechsig, Rudolph von K6lliker, Karl Burdach, Vladimir Bekterew, and Benedikt Stilling, among others, all working in Germany during the middle years of the nineteenth century. Johann Reil, a German anatomist, in the begin- ning of the nineteenth century had described the structure and some functions of the cerebellum which he called the little brain ("Kleinhirn").

"Child development" has always been a traditional component of well child care and a particular area of interest for pediatricians, child neu rologists, and psychologists. However, it was not until the early 1960s that children with developmental disabilities (i. e. , chronic handicapping disorders) became a major focus of public and professional attention. During this period, children with "special needs" were dramatically catapulted into the limelight and "exceptional" became the buzzword of the day. Public and professional awareness of these issues reached new peaks and recognition of the potential psychosocial impairments of chil dren with developmental disabilities created national anxiety. A variety of factors contributed to an unprecedented societal advocacy for chil dren with developmental problems: (1) a national concern generated by President Kennedy'S particular interest in mental retardation; (2) in creased activity and visibility of parent advocacy/lobbying groups (e. g. , the Association for Children with Learning Disabilities); (3) the enact ment of federal legislation designed to protect the rights of the handi capped (e. g. , PL94-142); and (4) the popularization of developmental behavioral disabilities by the various communications media. Cumulatively these events precipitated a redefinition of the real mean ing of "comprehensive health care for children," resulting in an empha sis on the child's neurodevelopmental, educational, psychological, and social needs. For the pediatrician, a myriad of new management respon sibilities were mandated, in addition to the traditional health care con cerns.

It is amazing to discover how little importance has been attached to narrow lumbar canal syndromes up to now. Though H. VERBIEST gave a very accurate description in 1949, the neurologist's and neurosurgeon's preoccupations were mainly focused on discal pathology, disregarding the problem of an exclusively bony origin in canalar stenosis. A. WACKENHEIM and E. BABIN have the merit of becoming aware of the impor tance and originality of this problem; they organized in the beautiful surround ings of the Bischenberg near Strasbourg, a postgraduate course, in which the most eminent European specialists in this field participated. I am very honored to have been asked to write the introduction to this mono graphy, which contains all the studies reported and commented on during this meeting. Before considering the problem from the various radiologic points of view, it is in my opinion indispensable to define the term "stenosis." We could not do so more accurately than by assuming the definition proposed by A. WACKENHEIM and E. BABIN and unanimously confirmed by all those who attented the session."

There is no question that the topic of this meeting in Seeheim, Germany, on intracranial and intralabyrinthine fluids is pertinent. This was the first international meeting at which these two closely-related topics were addressed together. Combining the clinical and research aspects of fluid and pressure regulation in the intracranial and the intralabyrint hine compartments as well as discussions on the clinical implications of abnormal fluid pressure was an excellent idea. The presentations and discussions of both the clinicians and basic scientists who participated proved that the concept of having such a combined focused gathering was both original and relevant. The two topics of the meeting in Seeheim have much in common. Maintaining both the intracranial pressure (lCP) and the intralabyrinthine pressure within normal limits is important for the normal functions of both the central nervous system and the ear. The intracranial space and the intralabyrinthine space are closed compartments that communicate with each other in an intricate manner. Deviations from normal intracranial pressure result in specific symptoms and signs. Medical problems related to elevated intracranial pressure vary from subtle to severe. Accumulated knowledge indicates that there are adverse effects from even relatively small elevations in ICP. Elevations in ICP may cause injuries to the brain and the ear. Abnormal pressure in the ear may cause abnormal function and injury. Maintaining the intracranial pressure within normal limits depends on a normally functioning pressure regulation."

Lumbar spine or back pain is one of the most important problems in orthopedics and neurosurgery today. Two key ways of treating this malady, lumbar fusion and stabilization, are critically discussed in the forty-three papers in this volume. They represent the best of the contributions to the 5th ICLFS, carefully selected and edited to give a good overview of recent knowledge and the state of the art.

The development of magnetic resonance imaging (MRI) will deep ly change the relationship between neuroanatomy and the neuro logical sciences, particularly neuroradiology. Presentation of nor mal or abnormal brain structures is sometimes more precise in MRI sections than in brain or spinal-cord sections under macro scopic examination. It is our conviction that a better exchange be tween neuroanatomy and neuroradiology will improve knowledge of the brain. This international meeting held in Marseille, 26-27 September 1986 (under the Presidency of G. Lazorthes and G. Di Chiro in collaboration with M. Habib, secretary of redaction for the Congress and its publication) would like to contribute to this field. Marseilles, January 1988 A. Gouaze G. Salamon Table of Contents Introduction G. Lazorthes 1 External References of the Bicommissural Plane U. Bergva71, C. Rumeau, Y. Van Bunnen, J. M. Corbaz, and M. Morel. . . . . . . . . . . . . . . . . . . . . . . 2 Identification of Cortical Sulci and Gyri Using Magnetic Resonance Imaging: a Preliminary Study C. Rumeau, A. Gouaze, G. Salamon, J. LafJont, F. Gelbert, H. Einseidel, M. Jiddane, P. Farnarier, M. Habib, and S. Perot . 11 The Hippocampal Formation and Related Structures of the Limbic Lobe: Anatomic - Magnetic Resonance Correlation T. P. Naidich, D. L. Daniels, V. M. Haughton, A. Williams, P. Pech, K. Pojunas, and E. Palacios. . . . . . . . . . . . . 32 Brain Stem and Cerebellum: Normal and Pathological Anatomy C. M. Strother and C. Raybaud . . . . . . . . . . . . . . . . . 65 Magnetic Resonance Imaging of the Eyes and the Optic Pathways J. C. Tamraz, M. T. Iba Zizen, and E. A. Cabanis . . . . . . ."

Although in the last few years more experience in the field of epilepsy surgery with amygdalo-hippocampectomies was gained in several hos- pitals, a detailed microanatomical and microsurgical description meet- ing the requirements of the modern neurosurgeon has not been achieved so far. Recently the allocortex - the so-called "limbic system" - has doubtlessly received more attention, as can be gathered from the recently published monography by Duvernoy, which however only considers anatomical points of view. Lately not only epilepsies but also tumorsurgical operations on the border between temporal lobe and basal ganglia can be - thanks to modern MR-examinations - carried out more exactly. Here the tumor-conditioned deformations of the temporo-medial area and its connections with the adjacent basal gang- lia as well as their blood supply are of great importance. Using conven- tional techniques the postoperative morbidity was especially high until recently. The author has at the suggestion of his teacher G. M. Ya argil approached the problem first of all morphologically by developing his own techniques of brain dissection. After some developmental and topographic-anatomical descriptions he has described the vessel-supply by using injection-preparations. Particular aspects of A. chorioidea ant. with her lateral, medial and Tractus opticus penetrating perforat- ing arteries to the basal ganglia and Capsula into have never been described in such a convincing manner before. It is of great importance in the operative removal of the amygdalo- hippocampal area to realize that it is not sufficient to preserve the A.

This volume contains selected contributions from the XIth Meeting of the European Society for Stereotactic and Functional Neurosurgery held in September 1994 in Antalyaffurkey. Most of the papers deal with the many therapeutic and technical advancements made in this field of neurosurgery. The emergence of new stereotactic methodologies such as frameless stereotaxy and other forms of neuronavigation have become an indispensable tool for all types of neurosurgical operations. An increasing number of young neurosurgeons takes an interest in the neurosurgical approaches to the treatment of movement disorders, chronic pain and epilepsy. This is a clear sign ofthe growing awareness of the long neglected fact that these neurosurgical treatments can be offered to large patient populations. Neurotransplantation as a novel treatment of Parkinson's disease has paved the way for the application of this technology for other indications. The pioneering work performed by the late Edward Hitchcock is reviewed here. There is a renewed interest in pallidotomy for dealing with certain forms of Parkinson's disease and certain aspects of this operation are discussed in another paper. Progress in the neurosurgical treatment of pain is dealt with by contributions on refined techniques of percutaneous cordotomy, DREZ operations and critical evaluations of spinal cord stimulation. A novel approach is a report on the experiences of treating cancer pain by intraspinal implantation of chromaffin cells. Several contributions cover the important issues of novel techniques for the study of neural dysfunction, peroperative monitoring with PET, microrecording, magneto-encephalography and other techniques.

These collected papers represent only a small part of the large amount of new work in the field of stereotaxy. The number of contributions to the Birmingham meeting was such that only selected papers, chosen as representative of advances in the field, could be printed. These papers present the most up to date accounts of major advances in stereotactic imaging and the renewed interest in the stereotactic treatment of movement disorders. Contents Section I. Stereotactic Imaging, Tumours and Haematomas Lipinski, H. G., Struppler, A., Birk, P.: Transformation Modes in Computerized Human Thalamic Brain Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 3 . . . Giunta, F., Marini, G., Bertossi, M.: Stereotactic Computer Graphic System with Brain Maps. . ., 7 Giorgi, c., Cerchiari, U., Broggi, G., Contardi, N., Birk, P., Struppler, A: An Intraoperative Interactive Method to Monitor Stereotactic Functional Procedures . . . . . . . . . . . . . ., . . . 10 Giorgi, c., Cerchiari, u., Broggi, G., Passerini, A.: 3-D Reconstruction of Cerebral Angiography in Stereotactic Neurosurgery . . . . . . . . . . . . . . . . . . . . . . .. . . . 13 . . Vandermeulen, D., Suetens, P., Gybels, J., Oosteriinck, A: Angiographic Localizer Ring for the BRW Stereotactic System . . . . . . . . . . . . . . . . . . . . . . . . . ., . . 15 . . . Uematsu, S., Rosenbaum, A. E., Erozan, Y. S., Gupta, P. K., Moses, H., Nauta, H. J., Rigsby, W. H., Wang, A, Weiderman, L., Kumar, A J.: Intraoperative CT Monitoring During Stereotactic Brain Surgery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 18 . . .

Das vorliegende Buch enth{lt die Beitr{ge eines internatio- nalen Symposiumszum Thema "Stimulierte Hirndurchblutung." Vorgestellt werden zun{chst neue Erkenntnisse zur Regulation der Hinrdurchblutung. Im 2. Abschnitt kommen verschiedene Methoden zur Messung der Hirndurchblutung zur Sprache, die sowohl unter experimentellen als auch unter klinischen Be- dingungengetestet wurden. Es folgt ein Abschnitt, der ver- schiedene M-glichkeiten zur Stimulation der Hirndurchblutung aufzeigt. Im letzten Abschnitt wird aufdie Bedeutung der stimulierten Hirndurchblutungsmessung zur Bestimmung der ce- rebrovascul{ren Reservekapazit{ten hingewiesen. Dieser Para- meter hat nach den vorliegenden Untersuchungen klinisch- praktische Bedeutung, beispielsweise f}r die Indikations- stellung bei cerebrovascul{ren Eingriffen zur Isch{mie-Pro- phylaxe.

The region of the skull base was long considered a surgical barrier because of its complex anatomy. With few exceptions, the region immediately beyond the dura or bony skull base constituted a "no man's land" for the surgeon working from the other direction. A major reason for this was the high morbidity associated with operative procedures in that area using traditional dissection techniques. This situation changed with the advent of the operating microscope. Used initially by ear, nose and throat specialists for resective and reconstructive surgery of the petrous bone and parana sal sinuses, the operating microscope was later introduced in other areas, and neurosurgeons began using it in the mid-1960s. With technical equality thus established, the groundwork was laid for taking a new, systematic, and interdisciplinary approach to surgical problems of the skull base. Intensive and systematic cooperation between ear, nose and throat surgeons and neurologic surgeons had its origins in the departments of the University of Mainz bindly supported by our chairmen Prof. Dr. Dr. hc Kurt Schiirmann (Department of Neurosurgery) and Prof. Dr. W. Kley (Depart ment of Ear, Nose and Throat Diseases, Head and Neck Surgery). The experience gained from this cooperation was taught in workshops held in Hannover from 1979 to 1986, acquiring a broader interdisciplinary base through the participation of specialists from the fields of anatomy, patholo gy, neuroradiology, ophthalmology, and maxillofacial surgery.