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Summary Aim: None of the established treatments (surgery, radiotherapy, chemotherapy) for malignant glioma has improved its very poor prognosis. Adjuvant locoregional radioimmunotherapy (RIT) represents a new therapeutic approach. We present our initial experience with this therapeutic tool with respect to adverse effects, biokinetics and clinical follow-up. Methods: Following surgery and radiotherapy, 12 patients with glioma (4, WHO stage III; 8, WHO stage IV) underwent 1-5 RIT-cycles (average dose 1100 MBq 131labelled monoclonal BC-4 antibodies) at six week intervals. Follow-up included serial FDG-PET and MRI investigations. Evaluation of biokinetics included whole body scans, together with analysis of blood, urine and fluid from the tumor cavity. Results: Following RIT, four patients experienced temporary seizures, which, in one case, were associated with temporary aphasia. Eight patients developed HAMA (human anti-mouse antibodies) during follow-up. Mean biologic half-life of the radiopharmaceutical in the resection cavity was 3.9 d (range: 1.0-10.2 d) and remained stable intraindividually during further RIT-cycles. The antibody/radionuclide conjugate remained stable in the tumor cavity for at least 5 d. Median survival presently stands at 18.5 months compared to 9.7 months in a historical patient group (n = 89) undergoing conventional therapeutic strategies. Five patients show no signs of recurrence. In three patients with post-surgical evidence of residual tumor, one patient showed partial remission, one stable disease, and one progressive disease during RIT. Four patients without evidence of residual tumor mass at the beginning of RIT developed recurrence during therapy. Conclusions: Initial experience demonstrates that locoregional RIT is a well tolerated treatment modality that may represent a promising new approach in the management of patients with malignant glioma. Advantages of local application include passage of the blood-brain barrier, high concentration of activity within the resection cavity and low systemic toxicity.

72 patients with isthmic spondylolisthesis have been analyzed prospectively with respect to their clinical presentation, radiological and intraoperative findings, operative techniques and surgical results. Excellent, good and satisfactory results have been obtained in 59 (82%), 10 (14%) and 3 patients (4%), respectively, by use of microsurgical techniques in combination with Louis-plate-fixation in Grade I and double arthrodesis/Cotrel-Dubousset-instrumentation in Grade II spondylolisthesis.

Treatment of patients suffering from severe head injury is so far restricted to general procedures, whereas specific pharmacological agents of neuroprotection including hypothermia have not been found to improve the outcome in clinical trials. Albeit effective, symptomatic measures of the preclinical rescue of patients (i.e. stabilization or reestablishment of the circulatory and respiratory system) or of the early clinical care (e.g. prompt diagnosis and treatment of an intracranial space occupying mass, maintenance of a competent circulatory and respiratory system, and others) by and large constitute the current treatment based on considerable organizational and logistical efforts. These and other components of the head injury treatment are certainly worthwhile of a systematic analysis as to their efficacy or remaining deficiencies, respectively. Deficits could be associated with delays of providing preclinical rescue procedures (e.g. until intubation of the patient or administration of fluid). Delays could also be associated in the hospital with the diagnostic establishment of intracranial lesions requiring prompt neurosurgical intervention. By support of the Federal Ministry of Education and Research and under the auspices of the Forschungsverbund Neurotraumatology, University of Munich, a prospective system analysis was carried out on major aspects of the pre- and early clinical management at a population based level in patients with traumatic brain injury. Documentation of pertinent data was made from August 1998 to July 1999 covering a catchment area of Southern Bavaria (5.6 mio inhabitants). Altogether 528 cases identified to suffer from severe head injury (GCS < or = 8 or deteriorating to that level within 48 hrs) were enrolled following admission to the hospital and establishment of the diagnosis. Further, patients dying on the scene or during transport to the hospital were also documented, particularly as to the frequency of severe head injury as underlying cause of mortality. The analysis included also cases with additional peripheral trauma (polytrauma). The efficacy of the logistics and organization of the management was studied by documentation of prognosis-relevant time intervals, as for example until arrival of the rescue squad at the scene of an accident, until intubation and administration of fluid, or upon hospital admission until establishment of the CT-diagnosis and commencement of surgery or transfer to the intensive care unit, respectively. The severity of cases studied in the present analysis is evident from a mortality of far above 40% of cases admitted to the hospital, which was increased by about 20% when including prehospital mortality. The outcome data notwithstanding, the emerging results demonstrate a high efficacy of the pre- and early clinical management, as indicated by a prompt arrival of the rescue squad at the scene, a competent prehospital and early clinical management and care, indicative of a low rate of avoidable complications. It is tentatively concluded on the basis of these findings that the patient prognosis is increasingly determined by the manifestations of primary brain damage vs. the development of secondary complications.

In October 1997, after a preparatory phase of 8 years, the first patient in Europe was treated by BNCT at the High Flux Reactor (HFR) of the European Commission in Petten, The Netherlands.1 The preparation for the first clinical BNCT trial in Europe included comprehensive scientific experimental and human investigations with the boron compound borocaptate sodium (BSH).2,3 A multitude of open legal and administrative questions had to be overcome. Furthermore a complex structure had to be organized and the procedures had to be defined how to perform a multi-national, multi-institutional study using a nuclear reactor distant from hospital for patient treatment performed by an international team on a multidisciplinary base.4 The international standards of clinical research as well as the accepted rules and definitions of conventional radiotherapy were applied, involving independent experts in order to assure the quality of the study and the quality of the Performance of patient treatment. The goal was to execute the project to a very high Standard as would be expected in the leading radiotherapy depart-ments in Europe.5

Temporary occlusion of cerebral arteries is a common technique to facilitate neurovascular surgery, however, it puts the patient at risk of permanent deficits caused by focal ischemia. Currently, the gold standard of cerebroprotection is barbiturate-induced burst suppression. In addition, the neurosurgical standard drug therapy involves nimodipine, mannitol, and dexamethasone. We have recently demonstrated the superior neuroprotective efficacy of combination therapy with magnesium (calcium- and glutamate-antagonist) + tirilazad (antioxidant) + mild hypothermia (33°C). In the present study we compared this pathophysiologi- cally orientated treatment strategy with the standard regimen. Furthermore, we investigated whether barbiturates provide an additional neuroprotective effect under hypothermic conditions. 142 Sprague-Dawley rats were subjected to 90 min of middle cerebral artery (MCA) occlusion by an intraluminal filament technique, and randomly assigned to the following groups. In part I of the study each drug of the standard regimen was evaluated as monotherapy and in combination. In part II of the study the most effective standard therapy (nimodipine + mannitol + dexamethasone + burst suppression by methohexital) was compared with magnesium + tirilazad + mild hypothermia (33°C). In part III of the study, burst suppression by methohexital and mild hypothermia were evaluated as monotherapy and in combination. Local cortical blood flow was measured by continuous laser Doppler flowmetry. Neurological examinations were performed daily, and infarct size was histologically assessed after 7 days. Part I: Standard drugs alone or in combination moderately limited infarct volume, with mannitol and burst suppression by methohexital being the most effective monotherapies (33% reduction of infarct volume). Most of the animals had residual neurological deficits at the end of the observation period. Part II: Again, combination therapy with standard drugs + burst suppression only moderately limited infarct volume by 36%. In contrast, combination therapy with magnesium + tirilazad + mild hypothermia abolished cortical infarction and reduced total infarct volume by 73% (P

Investigations of the mechanisms of cerebral ischemia have revealed that cell death is mediated, among other things, by a massive release of excitatory amino acids [9], generation of free radicals [50] and, as a final step, calcium influx into cells [49]. This understanding has led to a search for pharmacologic agents that protect the brain against these mechanisms. Although the molecular processes of the postischemic events are still only partially understood, numerous experimental neuroprotective drugs have been developed. Many of them are currently under clinical evaluation for the treatment of ischemic stroke, subarachnoid hemorrhage (SAH), or head injury. Yet, encouraging results from clinical trials are still rare. No trial has shown any single agent to be effective so far [57]. As a multitude of mechanisms is involved in ischemic brain injury, it is conceivable that a single pharmacotherapeutic agent aimed at just one process of ischemic damage is unlikely to be sufficient, and that a combination of treatment procedures would be more promising.

Transcranial Doppler (TCD) can monitor middle cerebral artery (MCA) velocity which can be recorded simultaneously with other physiologic parameters such as end tidal (Et) CO2, arterial blood pressure and intracranial pressure (ICP), in head injured patients. Relative changes in MCA velocity can be used to reflect relative MCA blood flow changes during ICP waves, and also to evaluate cerebral autoregulation, CO2 reactivity and hemodynamic responses to mannitol and barbiturates. The utility and practicality of short intervals of TCD monitoring to evaluate hemodynamic responses, was evaluated in a group of 22 head injured patients (average Glasgow coma score 6). During ICP A waves, MCA velocity always decreased during the peak of the wave, and during ICP B waves, fluctuated synchronously with the ICP. Dynamic cerebral autoregulation, and reactivity to CO2, were reduced within 48 hours of admission. Impaired cerebral autoregulation within 48 hours of admission did not correlate with outcome at 1 month. Mannitol infusion caused an increase in MCA velocity (15.4 +/- 7.9%) which was significantly correlated to the impairment of dynamic autoregulation (r = 0.54, p0.0001). The MCA velocity response to a test dose of barbiturates was significantly correlated to the ICP (r = 0.61, p0.01) response as well as to the CO2 reactivity (r = 0.37, p0.05). Continuous MCA velocity monitoring using TCD may be useful in evaluating a variety of hemodynamic responses in head injury patients and may replace more cumbersome cerebral blood flow techniques which have been used in the past for these purposes.

Successful surgery of the sensori-motor region requires precise pre- and intraoperative localization of the sensori-motor region and pyramidal tract. Important aids are the landmarks of cranio-cerebral topography, coronal suture and bregma and the sulcal anatomy of the sensori-motor region, which can be identified in CT or MR images. Due to considerable displacement and distortion of the anatomical structures, elicited by mass lesions, these aids often fail to render reliable support. In this situation, identification of the motor area can be achieved by electrical stimulation of the precentral gyrus in association with the recording of somatosensory evoked potentials of the pre- and postcentral gyrus. The localisation of the “motor mosaics” in relation to the lesion, enable determination of the direction of displacement of the motor strip and the fan of the pyramidal tract. Based on this information the most appropriate route of access to the lesion is selected, either transcortical or transsulcal. Lesion-specific operative techniques as well as locationspecific approaches are discussed. With consequent application of these principles the risk of a new persistent motor deficit was as low as 4% . Thus, the indication for surgery in this area can now be set with greater confidence and far more generously than in the past.

The exact mechanism responsible for B waves is unclear, however it has been attributed to cerebral blood flow (CBF) fluctuations, thought to be secondary to respiratory variations during abnormal breathing patterns in neurosurgical patients [6]. Transcranial Doppler (TCD) monitoring of blood flow velocity has demonstrated velocity fluctuations at frequencies similar to those of B waves in head injured patients and also in normal subjects [5, 8, 9], Recording of TCD and intracranial pressure (ICP) signals simultaneously has demonstrated synchronous variations in both parameters [5].

Continuous recording of basal cerebral artery velocities using transcranial Doppler may provide a more practical alternative to CBF methods for the assessment of cerebrovascular responses in patients with head injury and other neurological conditions requiring ICP management. A method is described where continuous recordings of blood flow velocity (BFV), arterial blood pressure (ABP), intracranial pressure (ICP), and end tidal CO2 (Et CO2) are obtained by portable equipment which can easily be taken to the ICU. This unit can then be used to test blood flow response to CO2 changes, autoregulation, response to barbiturates and response to mannitol therapy. By obtaining information on the effectiveness of these responses in head injury patients, it may be feasible to use this information to guide therapy.

Until 1988, difficult aneurysms of the proximal internal carotid artery (ICA), particularly those located within the cavernous sinus (CS), were treated in our department by combined occlusion of the internal carotid artery and extra-intracranial bypass surgery. However, due to further improvements of interventional neuroradiological techniques, the management of patients with these lesions has since been changed.

The “conservative” microsurgical lumbar discectomy described by Williams for the treatment of herniated lumbar disc is compared in a retrospective study with the standard microsurgical technique of Caspar and Loew. In order to enable such a retrospective comparison, a special randomization had to be chosen. The data concerning outcome are based on a questionnaire, in which the patient can describe his actual health situation. The result in the group of 56 patients operated on by the Williams technique with a mean follow-up of 27 months is excellent or good in 89% vs. 74% in the standard technique group. Reoperations due to a recurrence were identical in both groups (3.6% and 3.9%).

Currents induced by a rapidly varying magnetic field were applied to the parietooccipital scalps of patients undergoing neurosurgical operations to stimulate simultaneously the ipsilateral facial and trigeminal nerve, as well as other caudal motor cranial nerves. The magnetic stimulation was assumed to generate electrical currents in the cerebrospinal fluid (CSF). The stimulating currents were assumed to pass through the foramina of the respective cranial nerves distal to the CPA, where the nerves are still surrounded by CSF. Thus, the point of excitation for the facial nerve was within the labyrinthine segment of the facial canal; and for the trigeminal nerve was probably within Meckel’s cave.

A European, multicenter, prospective, randomized, double-blind, dose-comparison study on preventive therapy with intravenously administered nimodipine was performed to evaluate the efficacy and tolerability of two different doses: 2 and 3 mg/h. Two hundred four patients fulfilled the criteria for enrollment in the study: surgery within 72 hours after the last subarachnoid hemorrhage, and age between 16 and 72 years. All patients who had Hunt and Hess grades of I to III were operated upon; patients who had poor Hunt and Hess grades (IV-V) were operated on according to the surgeon's choice. This treatment regimen was associated with a low incidence of delayed neurological dysfunction with no significant difference between the two dosage groups: three patients (1.5%) remained severely disabled and two (1%) moderately disabled due to vasospasm with or without additional complications. Among the patients with Hunt and Hess grades of IV or V, the long-term outcome was favorable (good-fair) for 40% and unfavorable for 60%. Among the patients with grades of I to III, the long-term outcome was favorable for 89% and unfavorable for 11%.

Five patients with various types of brain tumours were infused with x-ray contrast material in a schedule designed to maintain a constant plasma concentration of tracer over a period of 3 hours. CT scans from an equatorial section of the tumour were taken at frequent intervals the first hour; then at 2 and 3 hours, and when possible up to 14 hours.

This report introduces the technique of orthodromic neurography for monitoring of facial nerve function during operation in the cerebellopontine angle. By stimulation of the intracisternal segment of the facial nerve, a compound nerve action potential with amplitudes of 15 to 480 μV can be recorded extracranially from the nerve near the stylomastoid foramen after 0.95 to 2.27 ms. Usually there is no need for signal averaging, and the method is independent of the effect of muscle relaxants. With the use of the same electrophysiological equipment as for evoked potential neuromonitoring, immediate and repeated localization of the facial nerve and its discrimination from the trigeminal and the lower cranial nerves during nerve preparation within the tumor capsule is possible.

The intracranial pressure was measured by an intraventricular catheter in 53 patients, in the course of 156 infusions of 40% Sorbitol and 72 infusions of 20% Mannitol. The amounts given and the rate of infusion were varied. The results show that the rate of the infusion is decisive in determining the fall in intracranial pressure, while the duration of the fall is dependent on the amount injected. After Sorbitol the influence on lowering the pressure was more marked and longer lasting than after injections of Mannitol. As a possible treatment for raised intracranial pressure one may conclude that small amounts given over a shorter time (50-80 ml/5 min) produce the most favourable effect.

The development of the intracranial pressure after a subarachnoid haemorrhage was evaluated in 21 patients. A statistically significant relation between the intracranial pressure and the neurological findings was found, whereas vasospasms did not influence the intracranial pressure. In patients in a clinically critical condition, rhythmic pressure waves of a frequency of 1/minute were repeatedly observed.

Es wird ein Fall geschildert, bei welchem durch ein Riesenaneurysma am Abgang der Arteria cerebellaris posterior inferior von der linken A. vertebralis zu einer Kompression der Oblongata mit rasch progredienter Tetraparese gefuhrt hatte. An der analogen Stelle an der rechten Vertebralis wurde ein zweites kleineres Aneurysma gefunden.

In the present study the variation of the localisation and the course of the coronal suture (CS) was examined on the lateral skull X-ray. The study shows a variation of the localisation and course of the CS from the average position within +/−4 mm in 65–77% and extreme differences between minimum and maximum values between 16 and 21 mm. The CS has also a considerable variation in its localisation relative to the precentral gyrus. Additionally the craniocerebral relationships and the localisation of the precentral gyrus and pyramidal tract are altered by the lesion or the space occupying process itself. A more exact localisation of the precentral gyrus, respectively the pyramidal tract can be obtained with CT and intraoperative cortical stimulation of the motor strip2, 4, 5.

In den vorliegenden Untersuchungen sollte die Frage eines sogenannten Filtrationsodems im Rahmen einer cerebralen Vasoparalyse und/oder einer arteriellen Hypertension geklart werden. Bei Gruppen von Hunden wurde in Chloralose-Urethan-Narkose eine cerebrale Vasoparalyse durch Hyperkapnie (PaCO2 um 150 mm Hg) und Hypoxamie (PaO2 40–60 mm Hg), eine arterielle Hypertension sowie eine Kombination von Vasoparalyse und arterieller Hypertension erzeugt. Unter den Bedingungen einer Vasoparalyse und Hypertension kommt es zu einem erheblichen Abfall des cerebrovascularen Widerstandes, wahrend der venose Widerstand geringgradig ansteigt. Die Folge ist eine Zunahme der Hirndurchblutung, eine Zunahme des intrakraniellen Druckes sowie eine Druckzunahme im postcapillaren Bereich (SSWP und CSP). Ein Hirnodem in verschiedenen Hirnarealen konnte bei alleiniger Vasoparalyse bei intakter Blut-Hirn-Schranke nicht nachgewiesen werden, selbst wenn der arterielle Blutdruck mehr als 90 min uber 180 mm Hg lag. Erst wenn neben der Vasoparalyse die arterielle Hypertension langer als 90 min uber 220 mm Hg bestand, konnte eine statistisch signifikante Zunahme des Wassergehaltes in der weisen Substanz gefunden werden. Unabhangig davon fanden sich in der Hirnrinde nach arterieller Hypertension wie auch nach Hypertension und Vasoparalyse punktformige Evans-Blau-Extravasate, welche eine Schadigung der Blut-Hirn-Schranke anzeigen. In diesen blaugefarbten, punktformigen Arealen lag der Wassergehalt deutlich uber der Norm. Aus den Ergebnissen wird geschlossen, das die Vasoparalyse allein nicht in der Lage ist, ein Hirnodem uber den erhohten hydrostatischen Druckgradienten zwischen Intravasalraum und Extracellularraum zu erzeugen. Erst wenn sich zu der Vasoparalyse eine starkere arterielle Hypertension addiert, findet sich in den Arealen der weisen Substanz ein solches Odem. Die akute Hypertension selbst ist aber in der Lage, in der Hirnrinde fokale Storungen der Blut-Hirn-Schranke auszulosen. Das von mehreren Autoren bei den klinischen Zustanden von Vasoparalyse beschriebene „brain swelling“ kann demnach nicht bzw. nicht allein auf Hirnodem zuruckgefuhrt werden, sondern ist meist durch das erhohte Blutvolumen zu erklaren. Die klinischen Konsequenzen dieser Befunde werden diskutiert.

A retrospective analysis of 45 patients with intra- and extracanalicular lumbar disc herniations (ICDH, ECDH), collected over a 3 year period, is presented. When an intra- or extracanalicular DH was suspected, 1.5 mm axial cuts were made with a GE9800 from the cranial pedicle through the intervertebral canal to the pedicle of the lower vertebral body. Constructions were then made in coronal and paraxial planes to identify the pathology and its relation to the nerve root. 47% of all ICDH and ECDH were found at the level L4/5, 24% each at the levels L3/4 and L5/S1 respectively and 4% at the level L2/3. In 78% of our patients, the disc fragment was extruded and found well above the level of the disc space, in 22% at the level of the disc space. The coronal reformated views were in general better for demonstrating the course of the compressed nerve root at the levels L2/3-L4/5, while at L5/S1 the paraxial reformated view may yield better images. The distance from the midline of the spinal canal to the medial and lateral edge of the ECDH averages 16.4 +/- 3.4 and 33.3 +/- 3.6 mm and in some cases the lateral edge was found 39-44 mm from the midline. Pitfalls in the diagnosis of ECDH may be caused by scar tissue, sometimes by an upwardly displaced nerve root or ganglion and, very rarely, by a neurinoma. Pitfalls in therapy, i.g. false negative intraspinal exploration in cases of intra- or extracanalicular disc herniations or exploration of the wrong intervertebral canal, may result due to insufficient neuroradiological analysis or from insufficient consideration of the anatomical situation by the neurosurgeon.

We report on 3 patients with meningoradiculoneuritis (MRN) due to Lyme-borreliosis (LB), which presented clinically as vertebral disc herniation. In 2 cases the underlying infection was discovered only after unsuccessful neurosurgical treatment. In the differential diagnosis between MRN and disc herniation the following criteria are suggestive of MRN and should raise suspicion of a non-discogenic aetiology: History of tick bite or erythema chronicum migrans, fever or general malaise, mono- or oligoradiculopathy with absent or insignificant lumbar pain and complaints of a burning character of the radiating pain. In suspicious cases we recommend blood investigations including antibody determination against borrelia burgdorferi and CSF investigations including cell count and cytology, protein and glucose determination, nephelometry and isoelectric focusing to exclude MRN and other conditions that may mimic disc herniation.

A prospective open multicenter study on the preventive effect of nimodipine on symptomatic vascular spasm was performed in 120 (consecutive) patients with aneurysmal subarachnoid haemorrhage (SAH). All patients underwent early surgery (i.e. within 72 hours post SAH) and were in neurological grades I–III in Hunt and Hess. Grade IV and V as well as patients with significant intracerebral haematoma are not included. On preoperative CT, SAH was mild in 28 cases, moderate in 56 and severe in 36 cases. 25 patients (21%) were in grade I, 63 patients (53%) in grade II and 32 patients (26%) in grade III. The ruptured aneurysm was located on the anterior cerebral artery complex in 57 patients, on the internal carotid artery complex in 35, on the middle cerebral artery in 24 patients and on the basilar artery in 4 patients. After occlusion of the ruptured aneurysm, the lipophilic calcium channel blocker nimodipine was administered in the following manner: Nimodipine was well tolerated and neither significant hypotension nor any other adverse reaction attributable to the drug was observed. Ischaemic cerebral dysfunction of delayed onset with permanent neurological deficit occurred in 2 patients (2%). Another 8 patients showed transient ischaemic symptoms. At 6 months follow-up, 93 % of the patients were classified as having made a full recovery, 16% as being minimally disabled, 5% as being moderately disabled and 3% as being severely disabled. Three patients had died. The present study supports the concept that preventive nimodipine treatment may reduce delayed ischaemic deficit in early aneurysm surgery.

The strength of aneurysm walls obtained intraoperatively or at autopsy immediately after death was evaluated by measurements of the force response to one-directional stretch and compared to the walls of intracranial arteries. The maximum stress that aneurysm tissue could tolerate was found slightly lower than in arteries, which is most probably due to the amount of immature forms of collagen. The stress resistance of aneurysms and arterial tissue decayed over a period of several hours. The relaxation curve could be approximated by the sum of 2 exponential terms. The half decay times of these terms were found identical in aneurysms and arteries, they appear to be collagen characteristics. The strength measured in vitro was compared to the stress in vivo, which was calculated on the basis of blood pressure and aneurysm radius. The stress tolerated by aneurysm walls over a period of 24 hours was found to be in the range of the stress that is imposed in vivo by the mean blood pressure. Arteries resisted stresses corresponding to pressures 10 to 20 times higher than physiological values. The thickness of the aneurysm walls correlated with the aneurysm radius in a linear fashion. It is suggested that aneurysm growth can be understood as passive yield to blood pressure, and reactive healing and thickening of the wall with increasing aneurysm diameter.

As a basis for the CT diagnosis of lateral disc herniations, the normal anatomy of the nerve roots from L4 to S1 within the lateral recess, is described and compared with the myelographic and CT findings. In myelograms, the roots can be demonstrated from where they leave the dural sac, for about the height of one vertebral body as far as the spinal ganglion in the upper part of the intervertebral foramen, where the subarachnoid space terminates. By non-enhanced CT, the roots can be distinguished from the surrounding fat only in the widening lower part of the lateral recess. The ganglion and the spinal nerve can be shown in the intervertebral foramen and further distally where they can no longer be seen on the myelogram,. Thus, of both these complementary techniques, CT s more suitable for the diagnosis of lateral disc herniations.

Nach ihrer Lokalisation lassen sich die lateralen Bandscheibenvorfalle in drei Typen einteilen. Beim Typ I besteht ein Vorfall im Recessus lateralis, der im Myelogramm von lateral her den Duralsack komprimiert mit einem Abbruch der zum nachstunteren Zwischenwirbelloch ziehenden Nervenwurzel. Der Prolaps des Typs II liegt am Eingang zum Foramen intervertebrale und stellt sich myelographisch durch einen Abbruch der dort befindlichen Nervenwurzel dar. Beim Typ III komprimiert der extrem laterale Prolaps das Spinalganglion im Foramen intervertebrale und bewirkt keine oder allenfalls minimale Veranderungen im Myelogramm. Alle drei Typen, besonders auch der myelographisch nicht nachweisbare Vorfall im Foramen intervertebrale, konnen im Leer-CT direkt dargestellt werden. Die sich aus der Lokalisation ergebenden gunstigsten operativen Zugangswege werden beschrieben. Lateral disc herniations can be classified into three types according to their location. Type I is a prolapse within the lateral recess. In myelograms, it compresses the lateral part of the dural sac and the adjacent nerve root which is running to the intervertebral foramen below. Type II is situated at the entrance of the intervertebral foramen and compresses the adjacent nerve root only. The extreme lateral prolapse of type III compresses the ganglion within the intervertebral foramen, but offen does not produce myelographic findings. All three types, especially the extreme lateral prolapse without myelographic changes, can also be demonstrated directly by the non-enhanced CT examination. The best operative approach, which depends on the location of each prolapse, is described.

The flow velocities in glass and silastic aneurysm models located at bifurcations were quantitatively determined using the non-invasive laser-Doppler method. The geometrical relation between aneurysm and parent vessels was found to be the primary factor governing the intra-aneurysmal flow pattern. Flow was stagnant in straight terminal models, with the aneurysm forming an extension of the afferent vessel, as long as the outflow through the branches of the bifurcation was balanced. Average flow velocities in the fundus were small but turbulent flow fluctuations of high amplitudes were observed. Asymmetric outflow through the branches of the bifurcation induced a rotatory intra-aneurysmal circulation from the dominant to the subordinate branch. The circulation in angled terminal aneurysms with the aneurysmal axis at a 45 degree angle to the plane of the bifurcation was a vortex, which was a natural consequence of the excentric inflow from the afferent vessel. Maximum flow velocities measured in the centre plane of the angled terminal aneurysms were in the range of 50 to 80% of the axial velocity in the afferent vessel. The elasticity of the models did not affect the global turnover rates but it damped the intra-aneurysmal pulse wave. On the basis of the measured velocity gradients near the walls maximum shear stresses on the wall of human terminal aneurysms were estimated to be in the order of 50 dynes/cm2 (5 Pascal), a value that is similar to the maximum wall shear stresses estimated for lateral aneurysms.

Computerized tomography (CT) was used to study the pathways of oedema spreading in man. Based on the assumption that local changes in CT numbers in oedematous white matter closely correspond to changes in tissue water content, CT numbers of consecutive tissue blocks of 3.0–3.6 mm were examined in the main directions of oedema spreading: a) towards the deep white matter, b) towards the cortex and c) towards the ventricle. Tumours with oedema grade II and III showed a reduction of CT number of 10 + 1.8. The corresponding increase in water content of about 10–12% seems to be an upper limit of fluid accumulation in the white matter. From this oedema centre, water content very slowly and gradually decreased along the oedema projection into the deep white matter. In contrast, if oedema reached the cortex of adjacent gyri, the decline in water content was very sharp. A similar observation was made in the external capsule where oedema sharply declined at the border to the adjacent grey matter, putamen and claustrum. Oedema projection towards the ventricle showed a nearly uniform magnitude from the centre to the ventricular lining, suggesting a certain resistance by a limited capacity of transependymal drainage of oedema fluid. It is assumed that the spatial distribution and extension of oedema around a brain tumour is determined by a system of differential resistance to fluid movement in the following order: grey matter — ventricular lining — white matter.

Thirty-five patients with meningiomas were compared with 37 patients with astrocytomas with respect to the postoperative course of their ICP and elastance. In the case of the meningioma patients, the ICP increased on average over a longer period and achieved higher values than in the astrocytoma patients. In the first group, the elastance attained values that were three times as high as in the second group. There was no fixed relationship between pressure and elastance in the two groups of patients.

The results of a double-blind-study on the effects of placebo, a low dose and a high dose of dexamethasone on severe closed head injury are presented. 95 patients were selected and carefully analyzed according to mortality, neurological course and symptoms, midbrain lesions and final outcome. The results demonstrate that dexamethasone, particularly given in high doses, reduces mortality and improves the neurological course. The steroid treatment seems to improve chances as well as quality of survival. Apart from the dose, timing of administration is of great importance.

485 patients with a lumbar disc herniation were operated upon microsurgically. The results, the rate of complications and true recurrent herniations will be presented. The results of the microsurgical technique are compared to the results of the conventional technique. The final outcome after the microsurgical operation was excellent in 39%, good in 34% and satisfactory in 19%, 9% of the patients had a poor final outcome. The results obtained with microsurgery are attained with the standard techniques only by few groups, probably highly experienced surgeons. Following microsurgery a uniformly high percentage (88-98%) of results are reported as being satisfactory, whereas the analogous figures range between 40 and 98% following the standard technique.

A diagnostic protocol for patients with suspected instability and irritative state of a "lumbar motion segment" following lumbar disc surgery is presented and the results of internal fixation are analyzed. In this group of patients the clinical picture and physical signs may be quite distinct and suggestive of instability and irritation of a "lumbar motion segment", however, in isolation, they do not allow to decide upon surgery. Radiological studies favour a decision for surgery only in cases with an obvious instability of a "motion segment". Anaesthethizing the articular nerves permits localization of the irritable segment and non-surgical therapeutic decisions (thermocoagulation) can only be taken in cases of an isolated facet-syndrome when instability has been ruled out. The trial plaster jacket holds the most important position with respect to the indication for internal fixation as demonstrated by the conformity of the results of the plaster jacket and the results of surgery. After internal stabilization excellent, good, satisfactory and moderate results were obtained in 20, 3, 1 and 1 patients, respectively.

Previous studies showed that resolution of brain oedema may occur by clearance into the CSF. The present study was performed to measure quantitatively the amount of oedema clearance in cold-induced oedema in cats. In order to determine the minute amounts of oedema fluid entering the CSF the oedema fluid was labelled with a high concentration of an extracellular marker (S35-sodium-thiosulphate). Ventriculo-cisternal perfusion was used to collect the marker in the cisternal outflow. By using the assumption that oedema fluid has the same marker concentration as the plasma, the distribution profile of extracellular space as well as the clearance rate of oedema into CSF could be computed. Oedema and thiosulphate space were most pronounced in the white matter underlying the cortical cold injury. The values then declined progressively with the distance from the lesion towards the ventricle. Oedema fluid clearance into the ventricular CSF at 24 hours following the cold injury amounted to 0.8-1.2 microliter/min or 1.15 ml/day. These data support the assumption that this may be one of the main mechanisms of the resolution of vasogenic brain oedema.