Information is provided from the basic and clinical sciences on the mechanisms damaging the brain from trauma or ischemia. New aspects involve the endoplasmic reticulum, mitochondrial failure, pathobiology of axonal injury, molecular signals activating glial elements, or the emerging therapeutical role of neurotrophins. Experimental issues involve a better analysis of the ischemic penumbra, the salvagable tissue. Therapeutic contributions reach from the environmental influence to gene expression, including neuroprotection, such as hibernation - mother nature's experiment - or hypothermia which is reported to induce cell swelling. Treatment issues deal also with thrombolysis and combination therapies, or with the clearance of adverse blood components - LDL/fibrinogen - by a novel procedure using heparin. Other highlights are discussing the specificities of pediatric vs. adult brain trauma, or the evolving role of the Apolipoprotein-E e4 gene in severe head injury. An update is also provided on an online assessment of the patient management during the pre- and early hospital phase in Southern Bavaria. The empirical observation of neuroworsening is analyzed in further details, whether this is a specificity autonomously driving the posttraumatic course. Finally, the unsolved question why drug trials in severe head injury have failed so far in view of the promising evidence from the laboratory is subjected to an expert analysis.

Advances in epilepsy in recent decades have allowed for improved algorithms for diagnosis and a common understanding of terminology with the development of the International Classifications of Seizures and the Epilepsies. Nevertheless, no common system exists for the estimation of epilepsy severity or its impact on quality of life. Therefore, epileptologists lack the ability to make quantitative assessments of individual patients for comparison of care or for meta-analyses in clinical trials. This book on the Quantitative Assessment of Epilepsy Care approaches this omission by addressing the potential application of clinimetrics within the framework of epilepsy treatment. Clinimetrics is a fast growing discipline concerned with the quantification of clinical symptoms with respect to decision making relating to diagnosis, treatment, and prognosis. These methods allow for the development and validation of clinical scoring systems. For example, the Glasgow Coma Scale is widely used. As a chronic disorder, epilepsy would benefit from clinimetric methodology to create uniformity and to allow for comparisons among evaluations. In addition, epileptologists have not yet developed assessments of health related quality of life to define the overall condition of the chronic epilepsy patient and various therapeutic endpoints. While clini metric tools are essential for research, they will also be useful in clinical practice for the care of individual patients by documenting status and changes over time. This treatise will provide critical analyses of whether existing rating scales and techniques are valid to use, and which types of scales and techniques require further development.

2 3 4 5 6 7 8 9 1011 1 2 3 4111 This book provides coverage of a broad range of topics in the ?eld of neurosurgery, 5 for residents and registrars in training and for recent graduates of training programs. 6 As neurosurgical training incorporates expertise from centers worldwide, there is a 7 need to have input from specialists in neurosurgery from various countries. This text 8 is a compilation by expert authors in the USA and the UK to provide information on 9 the basic knowledge and clinical management required for optimal care of neuro- 2011 surgical patients. 1 The text is an up-to-date synopsis of the ?eld of neurosurgery from American and 2 British perspectives, which covers the most common clinical conditions encountered 3 by neurosurgeons. The chapters are organized under broad topics, including inves- 4 tigative studies, perioperative care, the role of newer techniques and the management 5 of tumors, vascular and traumatic lesions. Additional topics are then covered, includ- 6 ing pediatrics, spine and peripheral nerve lesions, as well as functional neurosurgery 7 and infections. We anticipate that trainees will ?nd this information useful for certi?- 8 cation examinations and recent graduates of neurosurgical training programs can 9 utilize this text as an update of the most important neurosurgical topics.

Recent radiologic procedures in bone and joints, some of which eliminate the need for surgery are exposed, including: trephine biopsies of the thoracic and lumbar spine, sacro-iliac joints, peripheral bones synovial membrane and soft tissues, using either fluoroscopic echographic or CT guidance - chemonucleolysis - vascular embolization of skeletal tumors and management of vertebral hemangiomas - selective steroid injection in a broad spectrum of diseases including vertebral facet syndrom, cervicobrachial nerve root pain, rotator cuff calcium deposits, bone cysts. This unique volume supplies the reader with complete information regarding the performance of all these techniques.

Recent breakthroughs in understanding the effectiveness of brain hypothermia treatment have been brought about by rapid progress in experimental gene studies along with new findings in the areas of brain-injury mechanisms, brain thermo-pooling, hemoglobin dysfunction, insulin-resistant hyperglycemia, radical damage involving states of consciousness, management of lipid-dominant metabolism in the intensive care unit (ICU), and management of immune crises under conditions of hypothermia. This book explains the mechanism of brain hypothermia and presents advanced techniques for ICU management of brain hypothermia for critically brain-injured patients. Especially useful for bedside care in the ICU are the easy-reference care-management "cards" in the appendix of the book. Brain Hypothermia Treatment provides a valuable resource and practical guide for professionals in the fields of neurosurgery and emergency and critical care medicine.

The death 'Of a child, 'One wh'Ose vulnerability and unfilled promise c'Omp'Ounds the tragedy 'Of any death, t'Ouches us deeply. When that death 'Occurs due t'O the generally unexpected and sudden loss 'Of brain functi'On, it is particularly P'Oignant. And yet, when death c'Omes, it sh'Ould be diag- nosed expediti'Ously. The professi'Onal resP'Onsibilities 'Of the physician require that he b'Oth rec- 'Ognize brain death and inf'Orm the family 'Of its occurrence. In additi'On, since recent advances in transplantati'On provide the P'Ossibility 'Of using the 'Organs 'Of a brain-dead child t'O save the lives 'Of 'Other children, the c'Oncepts 'Of beneficence an~ charity further c'Ompel physicians t'O facilitate such transplantati'Ons by inf'Orming the family about this P'Ossibility. Criteria 'Of brain death have been refined 'Over about 30 years since the term coma depasse (bey'Ond c'Oma) was coined by M'Ollaret and G'Oulon in 1957 (Kaufman and Lynn, 1986). The last maj'Or criteria ev'Olved 'On a nati'Onal level were th'Ose 'Of the President's C'Ommissi'On in 1981. H'Owever, studies t'O date have c'Oncentrated 'On adults, and relatively little work has been rep'Orted ab'Out devel'Oping brain death criteria f'Or the y'Oung. Indeed, the advis'Ors t'O the President's Com- missi'On suggested that there are significant-although n'Ot well defined~ifferences in the ability of the brains 'Of th'Ose under five years 'Of age t'O rec'Over from clinical states that W'Ould be accepted as indicative 'Of c'Omplete and irreversible l'OSS of brain functi'On in adults.

Since the introduction of electrosurgery the techniques of surgery on the nervous system have passed through further improvements (bipolar coagulation, microscope), even if the procedure was not substantially modified. Today, laser represents a new "discipline," as it offers a new way of performing all basic maneuvers (dissection, demolition, hemostasis, vessel sutures). Furthermore, laser offers the possibility of a special maneuver, namely reduction of the volume of a tumoral mass through vaporization. Its application is not restricted to traditional neurosurgery but extends also to stereotactic and vascular neurosurgery. Laser surgery has also influenced the anesthesiologic techniques. At the same time new instrumentation has been introduced: CUSA ultrasonic aspiration, echotomography, and Doppler flowmeter. I have had the chance to utilize these new technologies all at a time and have come to the conclusion that we are facing the dawn of a new methodology which has already shown its validity and lack of inconveniences, and whose object is to increase the precision of neurological surgery. The technological development is still going on, and some improvements are to be foreseen. Laser scalpel is splitting the initial laser surgery into NO TOUCH and TOUCH surgery with laser. As new instrumentarium will be developed, a variable and tunable beam will become available. For example, in a few years Free Electron Laser will further add to the progress in this field."

The small neck of the aneurysm afforded an easy surgical attack. An ordinary flat silver clip was placed over the sac and tightly compressed obliterated it completely. The clip was flush with the wall of the carotid artery. The sac, lateral to the silver clip, was then picked up with the forceps and thrombosed by the electocautery. Walter Dandy reporting his successful operation of a posterior communicating aneurysm on March 23, 1937. Walter Dandy's patient left the hospital in good health 2 weeks later, and from his report one may gain the impression that the operation was an easy task. Despite continuous developments during the following decades, it was not until the introduction of the operating microscope and microsurgical techniques that surgical treatment was generally accepted. During the microsurgical era surgical results have continued to improve due to diagnostical, neuroanaesthesi ological, and microsurgical refinements, and improved neurointensive care. Endovascular obliteration has become an important treatment alternative but this has not been included in this particular volume. The purpose of the present supplement of the ACTA NEUROCHIRURGICA is to review some of the elements in the neurosurgical management of patients with aneurysmal subarachnoid haemorrhage that are important for a successful outcome. Professor Helge Nornes has been a major force in the development of new techniques and research strategies in this area for a number of years and has recently retired from the National Hospital in Oslo."

Various textbooks on stereotactic neurosurgery have been published during the last few years (Riechert 1980, Schaltenbrand and Walker 1982, Spiegel 1982), all of them dealing with functional stereo tactics as the major subject in the field. Diagnostic and therapeutic stereotactic interventions are only briefly described, whereas localization techniques are not yet mentioned. Since 1980, however, an increasing number of reports has been published on CT guided and computer monitored stereotactic performances which enable the surgeon to combine diagnostic and therapeutic efforts in one session. With recent progress in scanning techniques, including high resolution CT, NMR, and PET imaging of the brain, it has become possible to study and localize any brain area of interest. With the concomitant advances in computer technology, 3-dimensional reconstruction of deep seated lesions in stereotactic space is possible and the way is open for combined surgery with stereotactic precision and computer guided open resection. This type of open surgery in stereotactic space is already being developed in some centers with the aid of microsurgical, fiberoptic, and laser beam instrumentation. With these advances stereotactic techniques will rapidly become in tegrated into clinical neurosurgery. Stereotactics has become a metho dology which enables the surgeon to attack deep seated and subcortical small tumors. Neurosurgeons may abandon therapeutic nihilism, still frequently seen in glioma treatment, in the near future when stereotactic resection will be feasible and remaining tumor cells may be killed by adjuvant treatment modalities still in development."

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."

The presence of sophisticated auditory processing in mammals has permitted perhaps the most significant evolutionary development in humans: that of language. An understanding of the neural basis of hearing is thus a starting point for elucidating the mechanisms that are essential to human communication. The cochlear nucleus is the first region of the brain to receive input from the inner ear and is therefore the earliest stage in the central nervous system at which auditory signals are processed for distribution to higher centers. Clarifying its role in the central auditory pathway is crucial to our knowledge of how the brain deals with complex stimuli such as speech, and is also essential for understanding the central effects of peripheral sensorineural hearing loss caused by, for example, aging, ototoxic drugs, and noise. Ambitious new developments to assist people with total sensorineural deafness, including both cochlear and cochleus nuclear implants, require a detailed knowledge of the neural signals received by the brainstem and how these are processed. Recently, many new data have been obtained on the structure and function of the cochlear nucleus utilizing combinations of anatomical, physiological, pharmacological and molecular biological procedures. Approaches such as intracellular dye-filling of physiologically identified neurons, localization of classical neurotransmitters, peptides, receptors and special proteins, or gene expression have opened the door to novel morphofunctional correlations.

INHALT: The Concept of the BBB: an Historical Perspective Anatomy of the BBB Pathophysiology of BBB * Brain oedema Breakdown of the BBB BBB Dysfunction after SAH * Clinical Monitoring Neuroradiological Evaluations of BBB Dysfunction after SAH * Computerised Tomography and Magnetic Resonance * SPECT and PET Experimental Data * Literature Review of BBB Dysfunction after Experimental SAH * Qualitative Assessments * Quantitative Assessments * Time Course of BBB Dysfunction after SAH * Additional Pathophysiological Changes after SAH - Cerebral Vasospasm - CSF Eicosanoids - Cerebral Metabolism - Behavioural and Neurological Deficits - Intracranial Pressure - Blood Pressure, Blood Gases, Plasma pH, Plasma Glucose, Body Temperature Strategies for Pharmacological Interventions * Hydroxyl Radical Scavenger AVS * Glutamate Antagonist Felbamate * Calpain Inhibitor II Challenges and Future Directions * Advances in Cerebrovascular Pathophysiology Elucidation * Gene Therapy

Memory is essential for the retention of learning. In the presence of memory deficits, new learning is impaired and performance of previously learned habits deteriorates. What is the nature of memory? Where does it reside in the brain? What biological events are associated with the formation and retrieval of memory? These questions are explored in the first chapter of this volume. The answers are not final, but we have learned a great deal about memory processes during the past few decades. Memory is influenced by most of the pathological processes that influ ence the brain such as infection, trauma, cerebrovascular disorders, and met abolic and degenerative diseases. The nature and course of memory impairment are unique for each of the disorders and are fairly distinguishable. More than fifty conditions are known to cause dementia, which now affects several million Americans. In Alzheimer's disease, memory disorder predominates for two to three years before other intellectual functions are affected. Many neurological diseases, such as Huntington's disease, Friedreich's ataxia, and multiple sclerosis, are associated with progressive memory deficits. Forgetting is a problem that becomes progressively worse with age. Most individuals in their forties begin to experience some difficulty in quick recall of past events. By age sixty definite changes are evident in the process of registration, storage, and recall of memory. At this age the material that is to be remembered is processed more slowly, stored less firmly, and poorly recalled."

At the present time several techniques are available for studying quantitatively global and regional blood flow and metabolism of the human brain. How ever, many scientists working in the clinical and research field who would like to use these tools for their investigations may be less familiar with the indi cations and limitations of the individual methods. The rapid development of both modern imaging techniques and new tracers may have led to some con fusion in answering the question as to which method is appropriate to solve the diagnostic problem of an individuum with brain disease. Scepticism and ignorance as to the methods to be used as tools in differential diagnosis of brain disorders may have prevented their widespread introduction into clinical practice. Thus, the significance of circulatory and metabolic parameters involved in the majority of diseases of the central nervous system may have been overlooked. The contributions compiled in this book describe in detail the individual techniques, outline their indications and limitations and deal in particular with newer methods such as the atraumatic 133Xe technique, stable xenon tomogra phy, three-dimensional techniques such as 133Xe single photon emission tomog raphy and N-isopropyl-P23-iodoamphetamine. Positron emission tomography studies provide information on function and metabolism, particularly that of oxygen and glucose, in regional brain areas of interest. Nuclear magnetic reso nance may be a promising method for studying metabolic parameters; however, accurate circulation measurements can not be performed at present."

Malignant glioma is generally considered one of the most therapeutically difficult cerebral tumors. This book deals with many aspects of gliomas, including factors related to incidence and epidemiology, and surveys the history of glioma therapies. Experimental studies carried out by the Sendai Group of Neurosurgeons are reported, together with the results of many clinical studies of RAFP therapy. This particular theorapy involves the administration of radiation treatment and three chemical compounds: ACNU, Futraful and PSK. A recent technique for evaluating the effectiveness of therapy based on MRI diagnostic methods is introduced. This book thus offers valuable information and guidelines for future developments in treatment.

Professor Fox has undertaken the monumental In his Preface, Dr. Fox has quoted Cannon task of compiling the available data on intracra- and Rosenblueth in questioning where to stop nial arterial aneurysms. The magnitude and ex- the record. One can only document progress tent of the undertaking attest to the tremen- to date-and certainly the advances in this field are noteworthy-and then make some cau- dous amount of information which has accumulated in the past few decades and to tious predictions for the future. They have cor- the accelerated pace at which the field has ex- rectly made note that the overall morbidity and mortality of these aneurysm patients re- panded, particularly since the end of World War II. mains unacceptably high, largely as a result of Our heritage can be traced to many sources, the secondary complications of the subarach- among whom should be mentioned such nota- noid hemorrhage itself. More attention should as Willis, Quincke, Blackall, Moniz, Dott, be directed in the future to the recognition of bles Dandy, Hounsfield, and others. The modern era those patients with unruptured aneurysms and those with minimal bleeds. Hopefully infor- includes a number of investigators and clini- cians, some of whom have contributed to this mation will be forthcoming as to which indi- magnificent tome. The bibliography of over viduals are at risk because of some unusual con- 4000 references represents the increasing in- genital, metabolic, or acquired defect.

Progress in traumatology of the vertebral spine has been restrained for a long time by two hindering factors. The first obstacle is presented by the differences in approach and a conflict of competences. The neurosurgeons, considering only the spinal chord, have confined themselves to indications for laminectomy, an insufficient and usually ineffective intervention. The orthopedic surgeons, on the other hand, obsessed by the fear of medullary lesions, have long hesitated to apply the fundamental rules for the treatment of fractures, namely precise reduction followed by strict immobilization, thus depriving themselves of the efficacy of radiculomedul lar decompression and of the protection this procedure affords to these structures when they are themselves involved in the trauma. Taking these facts into account, together with the rather poor results of laminectomy, the specialists have wisely and successfully recommended that one should abstain from treating the initial lesion, but rather attenuate the damage by appropiate nursing care and adequate reeducation. The second hindering factor was the insufficient knowledge of the extreme complexity of the anatomic lesions. This explains the orthopedists' relative caution; one only treats well what one knows well. More precise analysis of the lesions, not only of the bones but also of the joints, i. e., the osteofibrous involvement, is mainly based on strict radiologic semiology, which is rendered difficult because these structures are simultaneously affected. We are greatly indebted to Dr. DOSCH, radiologist at our Center, for having untertaken this difficult task, using all available conventional radiologic techniques."

The second common meeting of the European Section and the Cervical Spine Research Society took place in Marseille (France) from June 12 to 15, 1988 and was organized by Rene Louis. More than 130 specialists from every part of Europe, from America and Asia participated, representing, among others, the fields of Orthopedics, Neurosurgery, Traumatology, Neurology, Anatomy, Rheumatology and Radiology. This meeting again was convincing proof of the growing interest which exists in Europe in research into injuries and diseases of the cervical spine. The main topics of this meeting were the subluxation of the lower cervical spine (chapter 1) and the infectious diseases of the cervical spine (chapter 2). Chapters 3 and 4 of this volume deal with degenerative lesions and the upper cervical spine. In chapter 5 experimental reports are presented, so that a good synopsis is provided of our present state of knowledge of diseases of the cervical spine. The European Section of the Cervical Spine Research Society was founded by Mario Boni in 1984, who unfortunately died in 1986 and was proclaimed Honory President of the European Section. There is a European meeting every summer and one every three years with our colleagues from the United States of America, Canada and Japan organized in Europe. The first combined meeting was organized by Pierre Kehr in Strasbourg (France) in 1985 and the presented papers were published in Cervical Spine I (Springer, Wien-New York, 1987).

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").

Alzheimer's disease is one the foremost health problems facing every society fortunate enough to attain a level of medical care that ensures an average lifespan of over 70 years of age. The cause of the disease remains unknown, and no single therapeutic approach has yet been found highly efficacious. Indeed, as the complexity of its effects on brain neuronal systems becomes elucidated, the concept emerges that Alzheimer's disease may be an umbrella term for multiple Alzheimer's-type syndromes that can be differentiated based on etiology (hereditary versus sporadic), neurochemical deficits, and extent of pathology. Whether one or more disease processes is involved, it seems increasingly unlikely that any single drug will provide efficacious relief across the broad spectrum of symptoms reflected in large subject populations. Rational therapeutic approaches may yield long term amelioration of many symptoms in selected groups of patients; and individual symptoms may be ameliorated in larger populations. Multiple approaches may be combined to optimize therapeutic effects. For example, a variety of approaches remain focused on restoration of cholinergic neurodegeneration and enhancing cholinergic neurotransmission, whereas other approaches attempt to retard the of the brain that occurs during Alzheimer's disease. Chapters cover continuous degeneration topics from growth factor secretion of proteases, which could modify amyloid processing, to neuronal gene delivery using viral vectors. The breadth and thoroughness of the chapters truly embrace a broad spectrurn of models, pathological mechanisms and therapeutic approaches.

During the past ten years, technology has been progressing at a rapid pace in the field of medical science, and there have been great improvements in the basic understanding, diagnosis, and treatment of hydrocephalus. The present volume contains the proceedings of the International Symposium on "Hydrocephalus" that was held in Kobe, Japan, from November 12-14, 1990. The purpose of the symposium was to highlight the recent advances in this field and to provide a unique opportunity for exchange of basic and clinical knowledge among experts in this field. During the symposium, 84 papers were presented by 240 contributors from 14 countries. This volume is a compre hensive description of the current knowledge in this area, and it may help to define what is known and to find new strategies to understand the patho genesis, pathophysiology, diagnosis, and treatment of the hydrocephalic process. The editors take great pleasure in expressing their thanks to the contributors for their participation and cooperation, and to Springer Verlag for personal and technical assistance in publishing the proceedings. We sincerely hope that this volume will contribute to improving the treat ment for hydrocephalus. August 1991 The Editors V Contents Preface.......................................................... V List of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . XV . . . . . . . . . . . . . Special Exhibition 1 Hydrocephalus: Historical Review H. Sato and S. Matsumoto. . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . ."

In 1992 the Editors published the first volume of Minimally Invasive Neurosurgery (MIN I) which described the current state of the art in this rapidly developing field of neurosurgery and reported first clinical experiences with these new technologies. The subject of MIN II is limited to endoscopic anatomy, technical devices and surgical management of disorders suitable for endoscopic procedures. The indications and approaches in different diseases are still highly preliminary and longterm results are not yet available. The clinical value and the benefit to the patients treated with these new techniques must still be proven against the well established standards of microsurgery. This volume presents a critical update of neuroendoscopy.

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.

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."