No special field of surgery dealing with the cranial nerves exists today. This is not surprising in view of the characteristics of this group of morphologically and topo graphically heterogenous nerves. Morphologically we must differentiate between central nerves (I, II and VIII) and the so-called peripheral nerves (nn. III to VII and IX to XII), in which post-lesion rgeneration is quite different. Anatomo-topographi cally we must consider an intracranial and an extracranial part of each cranial nerve. For practical reasons at operation, further subdivisions of the intracranial course of cranial nerves are to be distinguished in the anterior, middle and posterior cranial fossae as well as within the petrous bone. This underscores the extensive tasks awaiting surgeons operating in the ventral part of the brain and facial skull as well as in the more dorsal part of the skull and neck. This very wide field cannot be covered by a single surgical discipline alone. In our opinion, considerable progress has been made in surgery of the cranial nerves only in recent years. This may be explained by the increased mastery of microsurgical techniques by all surgeons in terested in the surgery of the base of the skull as well as with the initiation of more interdisciplinary consultation and jointly performed operations. Possibilities of fu ture development can be discerned in the text. The base of the skull separating the extra-and intracranial part of cranial nerves should not be a barrier but a connect ing link."

The sellar region and paranasal sinuses constitute the anatomical sections of the skull base in which pathological entities warrant interdisciplinary management. Processes originating in the paranasal sinuses can reach and involve the skull base in and around the sella, sometimes not respecting the natural dural boundary. On the other hand, lesions involving the sellar block, such as pituitary adenomas and meningiomas, can also extend downwards into the paranasal sinuses. The orbit and cavernous sinus may be subject to involvement and infiltration by both paranasal and sellar pathology. The advancement and new achievements of modern diagnostic procedures, such as high-resolution CT, three-dimensional reconstruc tion, MRI, and MRI angiography, as well as the detailed selective angiographic protocols and endovascular techniques, have increased the possibilities for surgical management of this type of pathology with extra- and intracranial involvement. Long-standing and intense inter disciplinary work has led to sophisticated operative approaches which for benign tumors allow total excision with preservation of structures and function, and for some malignant lesions permit an en bloc resec tion via a combined intracranial-extracranial approach. This volume reflects the work and scientific exchange which took place during the IV International Congress of the Skull Base Study Group, held in Hanover. Leading authorities in the basic sciences including anatomy joined with diagnosticians, clinicians, and surgeons from different fields to evaluate the state of the art of this topic in skull base surgery."

It is, of course, a real challenge to summon together an International Sym- posium in and around the Brain Stem and Third Ventricle. Up to this mo- ment the various experiences and papers on this subject were distributed throughout the world literature, making it very difficult for someone in- terested in the matter to have access to the actual state of knowledge. Therefore I believe such a meeting was long overdue and is a considerable attempt to open closed doors for present and future ambitious neurosurgi- cal activities. After succeeding in previous symposiums of similar interest in Hanno- ver, it was obvious that Prof. Madjid Samii and his coworkers took the in- itiative of organizing such a meeting, bringing together - in the pure sense of the word - Neurosurgeons with Anatomists, Neurologists, Neuro- physiologists, Neuroradiologists, ENT-, Maxillofacial-, Stereotactic-, and Radiosurgeons as well as other colleagues. One contribution after the other followed, from the basic sciences up to the operative management con- sidering very new and actual concepts. Through the application of new microsurgical techniques and the incorporation of new understanding for the many problems afflicting the midline of the eNS, and based on a growing closer cooperation between the various disciplines, a wide field has opened up which concerns us all.

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."

As a result of its structure, the skull base forms a borderline between different medi cal and surgical specialties. Nevertheless, the pathology of the skull may involve crossing these boundaries. Consequently, treatment may require a multidisciplinary approach with close cooperation between different specialists, each with his specific knowledge and capabilities. A good example is the cooperation needed in the treat ment of skull base trauma. The Skull Base Study Group was founded some years ago in view of this situa tion. Its purpose is to organize international conferences on topics related to skull base pathology. The first was held in June 1982 and focused on the area of trauma tology. The present volume contains articles written by the highly qualified con tributors to the June 1982 conference, dealing with the anatomical, biomechan ical, and neuroradiological aspects of skull base fractures and their consequences in neurologic and vascular dysfunction and deficits. Many authors from Europe and abroad have contributed to the high standard of this book. I would like to congratulate the Editors on the publication of this volume. It contains many important and interesting aspects of particular value to all medical and surgical specialists working in or on one of either sides of the skull base."

Die Pinealisregion umfaBt den dorsalen Abschnitt des 3. Ventrikels und des Zwischenhirns, den dorsalen Anteil des Mittelhirns und die Vierhii- gelzisterne mit den benachbarten Liquorriiumen. In der Diagnostik und in der chirurgischen Therapie raumfordernder Prozesse dieser Region ist in den letzten zwanzig Jahren mit der Erweiterung mikroanatomischer Kenntnisse, der Entwicklung moderner neuroradiologischer Verfahren und der Einfiihrung des Operationsmikroskops ein beachtlicher Fort- schritt erzielt worden. Dennoch sind noch viele Probleme ungelost, vor allem weil Tumoren der Pinealisregion selten vorkommen und weil die Funktion der Pinealis nicht vollig gekliirt ist - zwar weiB man, daB die Pinealis eine endokrine Driise ist, die Melatonin produziert, doch ist die Wirkung des Melatonin beim Menschen unbekannt. Bei einem Tumor der Pinealisregion beeinfluBt die Artdiagnose ent- scheidend die Wahl und die Reihenfolge der therapeutischen MaJ3nah- men. Deshalb sind nach der genauen Feststellung seiner Lokalisation und Ausdehnung durch Angiographie, Computertomographie und Kernspintomographie die liquorzytologische Untersuchung und die Serum-und Liquoranalyse indiziert. Dennoch bleibt die Frage nach dem biologischen Verhalten des Tumors oft unbeantwortet. In einem solchen Fall kann diese Frage durch die stereotaktische Biopsie gekliirt werden. Das vorliegende Buch liefert einen wertvollen Beitrag zur Kenntnis der raumfordernden Prozesse der Pinealisregion, da sowohl aufpatholo- gische und klinische als auch auf diagnostische und therapeutische Aspekte eingegangen wird. 1m Abschnitt iiber die Pathologie wird die Nomenklatur und die Tumorklassifikation erliiutert, die Biologie der verschiedenen Tumoren der Pinealisregion ausfiihrlich beschrieben und auch aufhistochemische Befunde Bezug genommen.