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Mitochondrial fission is a critical cellular event to maintain organelle function. This multistep process is initiated by the enhanced recruitment and oligomerization of dynamin-related protein 1 (Drp1) at the surface of mitochondria. As such, Drp1 is essential for inducing mitochondrial division in mammalian cells, and homologous proteins are found in all eukaryotes. As a member of the dynamin superfamily of proteins (DSPs), controlled Drp1 self-assembly into large helical polymers stimulates its GTPase activity to promote membrane constriction. Still, little is known about the mechanisms that regulate correct spatial and temporal assembly of the fission machinery. Here we present a cryo-EM structure of a full-length Drp1 dimer in an auto-inhibited state. This dimer reveals two key conformational rearrangements that must be unlocked through intramolecular rearrangements to achieve the assembly-competent state observed in previous structures. This structural insight provides understanding into the mechanism for regulated self-assembly of the mitochondrial fission machinery., (© 2024. The Author(s).)

Patient mutations have been identified throughout dynamin-related protein 1 (Drp1), the key protein mediator of mitochondrial fission. These changes generally impact young children and often result in severe neurological defects and, in some instances, death. Until now, the underlying functional defect leading to patient phenotypes has been largely speculative. We therefore analyzed six disease-associated mutations throughout the GTPase and middle domains (MD) of Drp1. The MD plays a role in Drp1 oligomerization, and three mutations in this region were predictably impaired in self-assembly. However, another mutant in this region (F370C) retained oligomerization capability on pre-curved membranes despite being assembly-limited in solution. Instead, this mutation impaired membrane remodeling of liposomes, which highlights the importance of Drp1 in generating local membrane curvature before fission. Two GTPase domain mutations were also observed in different patients. The G32A mutation was impaired in GTP hydrolysis both in solution and in the presence of lipid but remains capable of self-assembly on these lipid templates. The G223V mutation also exhibited decreased GTPase activity and was able to assemble on pre-curved lipid templates; however, this change impaired membrane remodeling of unilamellar liposomes similar to F370C. This demonstrates that the Drp1 GTPase domain also contributes to self-assembly interactions that drive membrane curvature. Overall, the functional defects caused by mutations in Drp1 are highly variable even for mutations that reside within the same functional domain. This study provides a framework for characterizing additional Drp1 mutations to provide a comprehensive understanding of functional sites within this essential protein., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

O-GlcNAcylation is a prevalent form of glycosylation that regulates proteins within the cytosol, nucleus, and mitochondria. The O-GlcNAc modification can affect protein cellular localization, function, and signaling interactions. The specific impact of O-GlcNAcylation on mitochondrial morphology and function has been elusive. In this manuscript, the role of O-GlcNAcylation on mitochondrial fission, oxidative phosphorylation (Oxphos), and the activity of electron transport chain (ETC) complexes were evaluated. In a cellular environment with hyper O-GlcNAcylation due to the deletion of O-GlcNAcase (OGA), mitochondria showed a dramatic reduction in size and a corresponding increase in number and total mitochondrial mass. Because of the increased mitochondrial content, OGA knockout cells exhibited comparable coupled mitochondrial Oxphos and ATP levels when compared to WT cells. However, we observed reduced protein levels for complex I and II when comparing normalized mitochondrial content and reduced linked activity for complexes I and III when examining individual ETC complex activities. In assessing mitochondrial fission, we observed increased amounts of O-GlcNAcylated dynamin-related protein 1 (Drp1) in cells genetically null for OGA and in glioblastoma cells. Individual regions of Drp1 were evaluated for O-GlcNAc modifications, and we found that this post-translational modification (PTM) was not limited to the previously characterized residues in the variable domain (VD). Additional modification sites are predicted in the GTPase domain, which may influence enzyme activity. Collectively, these results highlight the impact of O-GlcNAcylation on mitochondrial dynamics and ETC function and mimic the changes that may occur during glucose toxicity from hyperglycemia., (© 2021. The Author(s).)

Green fluorescent protein (GFP)-tagging is the prevalent strategy to monitor protein dynamics in living cells. However, the consequences of appending the bulky GFP moiety to the protein of interest are rarely investigated. Here, using a powerful combination of quantitative fluorescence spectroscopic and imaging techniques, we have examined the oligomerization dynamics of the GFP-tagged mitochondrial fission GTPase dynamin-related protein 1 (Drp1) both in vitro and in vivo. We find that GFP-tagged Drp1 exhibits impaired oligomerization equilibria in solution that corresponds to a greatly diminished cooperative GTPase activity in comparison to native Drp1. Consequently, GFP-tagged Drp1 constitutes aberrantly stable, GTP-resistant supramolecular assemblies both in vitro and in vivo, neither of which reflects a more dynamic native Drp1 oligomerization state. Indeed, GFP-tagged Drp1 is detected more frequently per unit length over mitochondria in Drp1-null mouse embryonic fibroblasts (MEFs) compared to wild-type (wt) MEFs, indicating that the drastically reduced GTP turnover restricts oligomer disassembly from the mitochondrial surface relative to mixed oligomers comprising native and GFP-tagged Drp1. Yet, GFP-tagged Drp1 retains the capacity to mediate membrane constriction in vitro and mitochondrial division in vivo. These findings suggest that instead of robust assembly-disassembly dynamics, persistent Drp1 higher-order oligomerization over membranes is sufficient for mitochondrial fission.

Purification of dynamin-related proteins is complicated by their oligomeric tendencies. In this chapter, we describe an established purification regime to isolate the mitochondrial fission protein Drp1 using bacterial expression. Key attributes of dynamins include their ability to hydrolyze GTP and self-assemble into larger polymers under specific conditions. Therefore, the GTPase activity of Drp1 should be examined to confirm isolation of functional protein, and we describe a conventional colorimetric assay to assess enzyme activity. To determine the ability of Drp1 to self-assemble, we induce Drp1 polymerization through addition of a non-hydrolyzable GTP analogue. A sedimentation assay provides a quantitative measure of polymerization that complements a qualitative assessment through visualization of Drp1 oligomers using negative-stain electron microscopy (EM). Importantly, we highlight the caveats of affinity tags and the influence that these peptide sequences can have on Drp1 function given their proximity to functional domains.

Introduction: Endoscopy was first employed in the surgical treatment of neurosurgical diseases early in the twentieth century, but did not become an established practice for a long time, mainly because of poor technology and clinical results. After a slow re-appearance in the 1980s, the 1990s saw an explosion of techniques and instrumentation. Continuing technological improvement has led to further expansion of surgical techniques and indications for use of neuroendoscopy., Discussion: The expansion of ventricular endoscopy has led to significant understanding of CSF disorders. Aqueduct stenosis as cause of hydrocephalus and arachnoid cysts are an example of pathologies, the concept and understanding of which now is considerably enhanced, due to the application of neuroendoscopy in their treatment. Management of loculated hydrocephalus has been facilitated considerably with the use of the endoscope. The concepts of aqueductoplasty, septostomy, and foraminoplasty of the foramina of Monro and Magendie emerged, which were previously unknown. Skull base surgery, especially surgery for craniopharyngioma, has seen dramatic improvement in results with the use of the endoscope. Coupling of the endoscope with neuronavigation has expanded technical capabilities even further. Overall, we can do a lot more with the endoscope now in comparison to 30 years ago., Conclusion: We should always remember that the endoscope is only a tool. Its use has indications and limitations related to its design and our ability to extract the maximum, in the context of its shortcomings. Further technological advances will push surgical frontiers even more in years to come., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: Microsurgical resection or ventriculoperitoneal shunt placement was for a long time the only means of treatment for patients with colloid cysts. In the past few years, however, endoscopic procedures have gained increasing significance and have been used more widely. Long-term results are now available for the first time, which enabled us to evaluate this method and assess its future relevance., Methods: Twenty patients with symptomatic colloid cysts of the third ventricle have been treated endoscopically in our department during the past 10 years. Retrospective analysis and follow-up of the patients' clinical and radiological outcomes were performed., Results: In the early postoperative period, 18 patients had excellent outcomes, with clinical signs improving immediately. One patient experienced intraoperative hemorrhage followed by temporary postoperative psychosis and IIIrd cranial nerve palsy. Another patient remained shunt-dependent because of aseptic meningitis after the endoscopic procedure. In the long-term follow-up, one patient had to be reoperated to treat cyst recurrence. The operative time was strongly dependent on the cyst material as well as on the surgeon's experience with endoscopic techniques; it varied between 60 and 300 minutes (mean operative time, 200 min). The average hospitalization time was 9 days. Long-term follow-up ranging from 1 to 10 years showed a clear benefit in each patient. In three individuals with pre- and postoperative short-term memory deficits and in one patient who complained of headaches, symptoms resolved gradually during the first few months after surgery. The patient with intraoperative hemorrhage complained of slight permanent short-time memory deficit. The analysis of postoperative computed tomographic and magnetic resonance imaging scans revealed a remaining cyst wall in the majority of patients and an inconsistent decrease in ventricular size. Postoperative cine magnetic resonance imaging studies showed normalization of cerebrospinal fluid flow in 17 patients., Conclusion: Continued improvement of endoscopic techniques and instruments, together with good long-term results in endoscopically treated patients, have established this method as an alternative to microsurgical techniques and might even set a new standard for treatment.

Intervertebral disc degeneration (IVDD) is a common cause of low back pain. Procyanidin C1 (PCC1) has been demonstrated to exert a protective effect on nucleus pulposus (NP) cells, and therefore, plays a critical role in the prevention and therapy of IVDD. Clarifying the pathophysiological characteristics and molecular mechanisms of IVDD may be helpful in establishing novel preventive and therapeutic strategies. This study aimed to investigate the probable mechanisms underlying the protection against acidic pH stress induced human NP cell injury. In vitro, acidic pH stress induced degeneration, mitochondrial dynamics imbalance, mitophagy, and mitochondria-mediated apoptosis in NP cells, all of which were ameliorated by PCC1. Autophagy inhibition partially eliminated the protective effects of PCC1 on mitochondrial homeostasis in NP cells. Moreover, PCC1 activated the sirtuin 3 (SIRT3)/forkhead box O3 (FOXO3) signaling pathway, a pivotal signaling pathway involved in the regulation of mitochondrial homeostasis in NP cells. In vivo, PCC1 ameliorated IVDD in a rat model and preserved the extracellular matrix of NP cells. Consequently, the protective effects of PCC1 on NP cells may inhibit IVDD progression via regulation of the SIRT3/FOXO3 signaling pathway. Therefore, regulation of the SIRT3/FOXO3 signaling pathway may be a novel preventive and therapeutic strategy for IVDD. [ABSTRACT FROM AUTHOR]

We have developed a method combining microinjection and automated fluorescence microscopy to continuously assess the degradation rate, subcellular localization and intracellular concentration of protein analytes at the single-cell level. Cells are unperturbed and grown in unaltered environmental conditions and show high viability. The injection of analytes at defined ratios and concentrations allows for a clearly defined starting point of degradation, without the entanglement of biosynthesis/uptake, often encountered in existing methods. The possibility to evaluate, add, or remove post-translational modifications prior to injection represents a powerful tool to assess minute protein degradation rate changes with high precision and allowed us to determine the absolute degradation rates caused by N-degron pathway engagement, with a focus on the role of acetylation. The low degradation rate of eGFP was found to be caused by inefficient N-terminal proteasomal unfolding. We moreover quantified the surprisingly strong influences of commonly used peptide tags and detected high variation between fluorescent proteins with regard to both protein degradation and subcellular localization. Furthermore, we have validated the use of chemically coupled dyes as robust reporters for protein degradation, and elucidated the significance of their membrane-permeability, thereby extending the applicability of our method to any protein of interest. [ABSTRACT FROM AUTHOR]

Ganglioneuromas are rare benign tumors that arise from the sympathetic nervous system. The presentation of tumors is variable and associated with adolescent thoracic scoliosis. Herein, we present two case reports and a review of literature. The two cases involved 10 and 13-year-old patients who were asymptomatic for muscle pain or weakness, and ganglioneuromas were incidentally detected through imaging screening. Both patients underwent a two-stage surgery. The first stage involved detachment of the tumor from the spinal cord and simultaneously performing deformity correction surgery from the posterior aspect. The second stage was resection of the ganglioneuroma through the anterior approach without neurological problems. A two-stage surgery was necessary to excise the tumor and correct the deformity, thereby avoiding neurological problems and concurrently establish a pathological diagnosis. Commencing with the posterior approach proved to be safe and was more effective. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to compare the efficacy of ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV) for the treatment of hydrocephalus after thalamic hemorrhage (TH) where external ventricular drainage (EVD) could not be removed after hematoma absorption, and to provide a theoretical basis for the clinical treatment of hydrocephalus after TH. Methods: The clinical data of patients with hydrocephalus after TH whose EVD could not be removed after hematoma absorption were retrospectively analyzed. According to the patients' surgical methods, the patients were divided into the VPS group and ETV group. The operative time, length of hospital stay, complications, and reoperation rates of the two groups were compared. Results: There was no statistically significant difference in intraoperative bleeding, length of hospital stay between the two groups. The EVD tubes were successfully removed in all patients after surgery. There were 4 (9.5%) complications in the ETV group and 3 (6.7%) complications in the VPS group, with no statistically significant difference in postoperative complications between the two groups. During the 1-year follow-up, 7 patients (16.7%) in the ETV group and 3 patients (6.7%) in the VPS group required reoperation. In the subgroup analysis of TH combined with fourth ventricular hemorrhage, 6 patients (14.3%) in the ETV group and 1 patient (2.2%) in the VPS group required reoperation, and the difference between the two groups was statistically significant. Conclusions: ETV had good efficacy in treating hydrocephalus caused by TH and TH that broke into the lateral ventricle and the third ventricle. However, if hydrocephalus was caused by TH with the fourth ventricular hematoma, VPS was a better surgical method because the recurrence rate of hydrocephalus in ETV was higher than that in VPS. Therefore, the choice of surgical method should be based on the patient's clinical features and hematoma location. [ABSTRACT FROM AUTHOR]

Background Transport protein particle (TRAPP) is a multiprotein complex that functions in localising proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in diseases affecting muscle, brain, eye and to some extent liver. We present three patients who are compound heterozygotes for a missense variant and a structural variant in the TRAPPC11 gene. TRAPPC11 structural variants have not yet been described in association with a disease. In order to reveal the estimated genesis of identified structural variants, we performed sequencing of individual breakpoint junctions and analysed the extent of homology and the presence of repetitive elements in and around the breakpoints. Methods Biochemical methods including isoelectric focusing on serum transferrin and apolipoprotein C- III, as well as mitochondrial respiratory chain complex activity measurements, were used. Muscle biopsy samples underwent histochemical analysis. Next- generation sequencing was employed for identifying sequence variants associated with neuromuscular disorders, and Sanger sequencing was used to confirm findings. Results We suppose that non- homologous end joining is a possible mechanism of deletion origin in two patients and non- allelic homologous recombination in one patient. Analyses of mitochondrial function performed in patients' skeletal muscles revealed an imbalance of mitochondrial metabolism, which worsens with age and disease progression. Conclusion Our results contribute to further knowledge in the field of neuromuscular diseases and mutational mechanisms. This knowledge is important for understanding the molecular nature of human diseases and allows us to improve strategies for identifying disease- causing mutations. [ABSTRACT FROM AUTHOR]

The indications for neuroendoscopy are not only constantly increasing, but even the currently accepted indications are constantly being adjusted and tailored. This is also true for one of the most frequently used neuroendoscopic procedures, the endoscopic 3rd ventriculostomy (ETV) for obstructive hydrocephalus. ETV has gained popularity and widespread acceptance during the past few years, but little attention has been paid to the techniques of the procedure. After a short introduction describing the history of ETV, an overview is given of all the different techniques that have been and still are employed to open the floor of the 3rd ventricle. The spectrum of indications for ETV has been widely enlarged over the last years. Initially, the use of this procedure was restricted to patients older than 2 years, to patients with an obvious triventricular hydrocephalus, and to those with a bulging, translucent floor of the 3rd ventricle. Nowadays, indications include all kinds of obstructive hydrocephalus but also communicating forms of hydrocephalus. The results of endoscopic procedures in treating these pathologies are given under special consideration of shunt technologies. In summary, from the review of the publications since the first ETV performed by Mixter in 1923, this technique is the treatment of choice for obstructive hydrocephalus caused by different etiologies and is an alternative to cerebrospinal fluid shunt application.

Objects: The purpose of this study was to describe the indications, surgical techniques and postoperative outcome of neuroendoscopic interventions in a heterogeneous group of intracranial cystic pathologies., Patients and Methods: Between 1992 and 2003, 127 patients with symptomatic intracranial cysts and cystic tumours underwent neuroendoscopic treatment in our department. In 22 patients indication for surgery was colloid cysts, in 9 patients pineal cysts and in 3 patients cavum vergae cysts. Twelve arachnoid cysts, 10 cystic craniopharyngiomas, 2 Rathke's cleft cysts and 69 malignant cystic tumours were operated on. The patients' mean age was 45 years and their clinical presentations varied from typical signs of increased intracranial pressure to focal neurological deficits., Results: One hundred and twenty-seven patients with intracerebral cystic space-occupying lesions were operated on using stereotactic frameless or frame-based endoscopic techniques. There was no operative mortality. The operative morbidity was 3.1% including 1 memory deficit due to fornix injury, 1 hemiparesis due to postoperative haematoma after lesion biopsy, 1 aseptic meningitis and 1 subdural fluid collection., Conclusions: Endoscopic interventions enable neurosurgeons to manage intracranial cystic lesions. Via the same approach, the obstructed CSF pathways may be restored and consequently the increased intracranial pressure diminishes. With the aid of stereotactic guidance or a neuronavigation system, access to the lesion can be gained rapidly and with high accuracy.

Objective: Microsurgical resection or ventriculoperitoneal shunt placement was for a long time the only means of treatment for patients with colloid cysts. In the past few years, however, endoscopic procedures have gained increasing significance and have been used more widely. Long-term results are now available for the first time, which enabled us to evaluate this method and assess its future relevance., Methods: Twenty patients with symptomatic colloid cysts of the third ventricle have been treated endoscopically in our department during the past 10 years. Retrospective analysis and follow-up of the patients' clinical and radiological outcomes were performed., Results: In the early postoperative period, 18 patients had excellent outcomes, with clinical signs improving immediately. One patient experienced intraoperative hemorrhage followed by temporary postoperative psychosis and IIIrd cranial nerve palsy. Another patient remained shunt-dependent because of aseptic meningitis after the endoscopic procedure. In the long-term follow-up, one patient had to be reoperated to treat cyst recurrence. The operative time was strongly dependent on the cyst material as well as on the surgeon's experience with endoscopic techniques; it varied between 60 and 300 minutes (mean operative time, 200 min). The average hospitalization time was 9 days. Long-term follow-up ranging from 1 to 10 years showed a clear benefit in each patient. In three individuals with pre- and postoperative short-term memory deficits and in one patient who complained of headaches, symptoms resolved gradually during the first few months after surgery. The patient with intraoperative hemorrhage complained of slight permanent short-time memory deficit. The analysis of postoperative computed tomographic and magnetic resonance imaging scans revealed a remaining cyst wall in the majority of patients and an inconsistent decrease in ventricular size. Postoperative cine magnetic resonance imaging studies showed normalization of cerebrospinal fluid flow in 17 patients., Conclusion: Continued improvement of endoscopic techniques and instruments, together with good long-term results in endoscopically treated patients, have established this method as an alternative to microsurgical techniques and might even set a new standard for treatment.

Antibodies against two major gangliosides detected in human brain and brain tumors--Glac2 (GD3) and Gtri2 (GD2)--were tested by immunohistochemistry in an unselected sample of intracranial tumors during the years 1986 through 1991. Two groups emerged as evaluable samples, namely gliomas of different grades and meningiomas. In a pilot series, it was shown that these gangliosides could be visualized in frozen sections of cells of gliomas and meningiomas (as well as neurinomas) and in some structures of the normal brain. It was however not possible in frozen sections to further analyze the cellular or subcellular expression pattern of the mentioned components and paraffin sections with conventional processing were only weakly and diffusely stained. A modified protocol therefore was created that replaced alcohol processing by acetone. With this protocol, interpretable results in paraffin sections were obtained. With this method, 133 single intracranial tumors were investigated as to their immunohistologically detectable ganglioside expression. The most consistent result was that the whole cytoplasm of highly fibrillary (gemistocytic) astrocytes in all grades of gliomas was stained by Gtri2 (GD2) and Glac2 (GD3) with high preponderance of Gtri2 (GD2) expression. In all meningiomas, Glac2 (GD3) had a higher expression than Gtri2. No constant pattern in the other entities emerged. By comparison with GFAP expression in gliomas and vimentin in meningiomas, the colocalisation of gangliosides and intermediary filament proteins is supposed.

Background: Glycosphingolipids (GSL) are expressed on the surface of neuroectodermal cells. The correlation of a variety of distinct GSL with different primary brain tumors has been demonstrated. Three distinct GSL-component profiles (GSL-types I, II and III) of human gliomas have been defined by our group. The purpose of this study was to evaluate the correlation of the established GSL-types I-III with survival time and histopathological malignancy grading in 40 human gliomas., Methods: Neutral and acidic GSL-component patterns, histopathological malignancy grade and survival time, and a number of other relevant variables were examined. Kaplan-Meier survival curves were analyzed with the log rank test., Results: GSL-type I was expressed in 18 tumors (17 Glioblastoma multiforme (GBM) and 1 anaplastic astrocytoma (AA)). GSL-type II was expressed in 11 tumors (7 GBM, 3 AA, 1 low grade astrocytoma (LGA)). 10 patients presented with GSL-type III (3 GBM, 4 AA, 3 LGA). Kaplan Meier survival curves of GSL-types I-III differed significantly (p = 0.0231, log-rank-test). However, survival time correlated better to the WHO grades. Within a given malignancy grade, GSL-types gave additional informations about the proliferative properties., Conclusions: This is the first report of a correlation between survival time and human glioma neutral and acidic GSL-components. The results are in agreement with observations of other investigators. The analysis of GSL-type expression might give useful additional information about proliferative properties of human gliomas in a given malignancy grade. In particular, the early prediction of outcomes in anaplastic or low grade gliomas might be possible.

The primary aim of the present study was to compare the immune adjuvanticity of two different groups of glycolipids, i.e., the newly discovered basidiolipids from Basidiomycete mushrooms (Bl-1, Bl-2, Bl-3, and Bl-4), and saponin fractions from Quillaja saponaria. The basidiolipids, though with differential effectiveness of the Bl-components, stimulated the expression of serum immune globulins in mice that recognized co-injected antigens, bovine serum albumin (BSA) or a keyhole-limpet hemocyanin-ganglioside Gfpt1 conjugate (KLH-Gfpt1), respectively. The immune adjuvanticity of the basidiolipids was comparable to that of acidic (QAS2, QAS5, QAS10), and novel neutral (QNS1, QNS2, QNS3) saponin compounds isolated and purified from Quillaja saponaria bark bulk material. Basidiolipids, as well as, the Q. saponin fractions were only marginally antigenic. MPL-A, by contrast, a comparable immune adjuvant, stimulated the expression of specific antibodies that recognized this glycophospholipid. Different from the Q. saponins with restricted toxicity, the basidiolipids displayed no toxic or hemolytic properties.

From the edible mushroom, the basidiomycetes Agaricus bisporus and Agaricus campestris, a novel carbohydrate-homologous series of four glyco-inositol-phospho-sphingolipids, designated basidiolipids, was isolated and the constituents purified. The chemical structures of the basidiolipids were elucidated to be: Manpbeta1-2inositol1-phospho-ceramide, Galpalpha-6[Fucpalpha-2]Galpbeta-6Manpbeta-2i nositol1-phospho-ceramide, Galpalpha-6Galpalpha-6[Fucpalpha-2]Galpbeta- 6Manpbeta-2inositol1-phospho-ceramide and Galpalpha-6Galpalpha-6Galpalpha-6[Fucpalpha-2] Galpbeta-6Manpbeta-2ino sitol1-phospho-ceramide. All four glycolipids contained a ceramide which was composed of phytosphingosine and predominantly alpha-hydroxy-behenic and alpha-hydroxy-lignoceric acid.

Severe spinal spasticity has been shown to be a good indication for continuous intrathecal baclofen infusion (CIBI), but there is only limited experience with this treatment in patients with supraspinal spasticity. Eighteen patients with severe spasticity from traumatic or hypoxic brain injury were treated with CIBI. In all patients spasticity could be reduced significantly. The mean Ashworth score was reduced from 4.5 to 2.33 and the mean Spasm frequency score from 2.16 to 0.94. This reduction of spasticity led to a marked pain reduction. Nursing, perineal care and mobilization became much easier. The complication rate was low. In this series we saw one infection in the pump pocket, one epileptic seizure after a bolus application of baclofen and one spinal catheter displacement. The results are similar to those reported from series of patients with spinal spasticity and correspond to the limited experience we have so far with supraspinal spasticity patients. To prevent limb contractures CIBI should be performed as soon as the patient is in a stable clinical condition after brain injury. Further prospective clinical trials will be necessary to obtain more experience with patients suffering from supraspinal spasticity.

Exposure of glycosphingolipids to air irreversibly destroys the integrity of these lipids within a few hours. It was established that among the natural constituents of air, ozone, at commonly observed daytime levels, is responsible for the observed degradation. As one product of the reaction of glycosphingolipids with air, an aldehydic fragment containing the carbohydrate moiety was identified. This aldehydic fragment was identical to the one obtained by classical glycosphingolipid ozonolysis. Identical with the latter, the air-induced product is further fragmented by mild alkali treatment with concomitant liberation of the free reducing oligosaccharide. As a consequence of the alteration of glycosphingolipids by air, it was shown that the accuracy of methods of analysis of these glycoconjugates that depend on their physico-chemical integrity, e.g., by tlc-immune overlay, is severely influenced by their prior exposure to the atmosphere.

During the 10th meeting of the WSSFN in Maebashi in 1989, we discussed 'endoscopic stereotaxy', and presented our preliminary results. This technique was first designed to optimize stereotactic biopsy, but it proved to be effective for other neurosurgical indications as well, including endoscopic stereotactic evacuation of intraparenchymal and intraventricular space-occupying cysts, endoscopic stereotactic cystoventriculostomy, third ventriculostomy, evacuation of brain abscess and intracerebral hematoma, and retrieval of adherent or free-floating ventricular catheters. Our results with endoscopic stereotaxy in different indications are encouraging, compared to conventional microsurgical techniques and pure stereotactic techniques. From 1989 to 1997 we have performed more than 400 stereotactic endoscopic procedures. The mortality rate is below 1%, the operative morbidity is below 3%.

Background: Chronic subdural hematomas are well delineated collections of fluid (blood) between the dura mater and the arachnoid space. Two types of encapsulated chronic subdural hematoma can be distinguished: the nonseptated and the septated form. The nonseptated form can be treated easily using the burrhole-drainage method, whereas treatment of septated chronic subdural hematoma remains a therapeutical problem. The main problem is the division of the hematoma by neomembranes into compartments, which hinder the efflux of the hematoma fluid through one or two burrholes., Methods: Since 1991 we have operated on 14 patients with septated subdural hematoma using flexible steerable endoscopes through a burrhole approach. The flexible endoscopes are fixed and guided with the help of the Marburg Neuroendoscopy Fixation and Guiding System. For resection of neomembranes small microscissors or microforceps were used. This technique avoids blunt rupture of the membranes which may cause bleeding. A closed drainage system is applied temporarily to guarantee the efflux of the remaining hematoma., Results: From January 1991 to May 1994, 14 patients with the septated variant of chronic subdural hematoma were operated on using the endoscopic technique. After the neuroendoscopic intervention 12 patients had a sufficient or complete hematoma evacuation. One patient had to be operated on a second time, and there was one postoperative subdural infection. Long term follow up of all patients shows no recurrence of the subdural hematoma., Conclusion: Treatment of membraneous septated CSH using an endoscopic operative technique combined with the application of a closed drainage system is a minimally invasive method and a therapeutic alternative to the craniostomy-membranectomy technique.

Since it was considered that an active immunization against ganglioside Gfpt1 (IV2Fuc-, II3NeuAc-Gg4Cer) expressed by human small cell lung cancer cells may be beneficial in the treatment of this neoplasm in humans, an optimal mode of vaccination in model mice was investigated. A novel Gfpt1-muramyldipeptide conjugate (Gfpt1-MDP) was synthesized. Its ganglioside carbohydrate-directed immunogenicity in mice as measured by serum antibody titers was comparable to that of the previously described Gfpt1-keyhole limpet hemocyanin conjugate (Gfpt1-KLH). Similar immunogenicity was displayed by free Gfpt1 in muramyldipeptide-phosphoethanolamine-containing phosphatidyl-choline, -serine (PC,PS) liposomes. Immunization with Gfpt1-vaccines in the presence of monophosphoryllipid A (MPL), in general, raised titers of anti-Gfpt1 antibodies effectively. Immunization with PC, PS-liposomes containing unconjugated Gfpt1 and MPL stimulated the highest titers observed, thereby effectively preventing tumor growth in Balbc nu/nu-mice challenged with human small cell lung cancer cells. However, there was a strong crossreaction of these and most other sera with the structurally related and widely distributed ganglioside Gtet1 (II3NeuAc-Gg4Cer). Only immunization with Gfpt1-KLH conjugate in the presence of MPL stimulated selectively high anti-Gfpt1 antibody titers showing comparably low crossreactivity to ganglioside Gtet1.

Starting in November, 1993, until January, 1994, we performed a survey among 127 Neurosurgical Departments in Austria, Germany, and Switzerland concerning the practice of antiepileptic prophylaxis in head injured patients. Seventy seven percent of the 12-item multiple choice questionnaires were completed and returned. They indicate a variety of attitudes towards prophylaxis for seizures: in 12% of the responding institutions, antiepileptic prophylaxis is given to every brain trauma patient, in 36%, no prophylaxis is carried out. and in 52% some patients receive prophylaxis while others do not. Penetrating injuries, intracranial haemorrhages and electroencephalographic abnormalities were the most frequent reasons why prophylaxis was initiated. Phenytoin is by far the most popular drug, given usually for at least three months, and in most cases monitored by routine serum level observations. Nevertheless, about three out of four neurosurgeons conceded that a general renunciation of antiepileptic prophylaxis after brain trauma might be justified. There is no uniform way in which patients are informed about a possible risk of seizures, as it may be relevant, for instance, in respect of driving abilities.

Stereotactic endoscopic techniques are extremely helpful in diagnosis and therapy of cystic intracerebral space occupying lesions. Acute space occupying lesions can be managed effectively and without major tissue traumatization. Up to now we have operated on more than 70 cystic intracerebral space occupying lesions with a stereotactic endoscopic technique. The main diagnoses were colloid cysts, cystic craniopharyngeoma, arachnoidal and pineal cysts. In must be stressed that in cystic anaplastic astrocytomas and glioblastomas as well as metastases only an acute inner cerebral decompression can be achieved by neuroendoscopic techniques in combination with the application of reservoir systems. In benign parenchymal or intraventricular cysts neuroendoscopic intervention is performed for definitive treatment. The results are overall encouraging. There was no operative mortality and operative morbidity was below 3%. Postoperative follow-up in patients with benign cysts showed no evidence of recurrence.

Interstitial curietherapy with 125-Iodine is an effective therapeutic option in the treatment of low grade gliomas. Four cases with astrocytoma grade II are presented, where tumour growth characteristics have changed to anaplasia during interstitial irradiation after a primary period of tumour regression. Anaplastic transformation could be due to a radiation effect or an insufficient therapeutic influence of interstitial irradiation on natural tumour progression of glioma growth due to genetic events.

The nephropathic effects of Heymann's experimental nephrites involve autoallergic serum antibodies directed against rat kidney membrane constituents. In assessing the action of glycolipids as possible autoallergens in these conditions, it was found that heterologous and autologous Heymann's nephritis sera antibodies recognize that rat kidney sulphatides, II3SO3(-)-Gg3Cer (Stri1), and III3SO3(-)-,II3SO3(-)-Gg3Cer (Stri2). Two antibody populations in Heymann's sera, each reacting with only one of the two sulphatides, could be observed. It was further shown that human factor-H and properdin, pivotal regulators of the alternative pathway of complement activation, both bound to Stri2 in vitro. This binding of factor-H and properdin was differentially affected by affinity-purified anti-Stri2 antibodies of Heymann's nephritis sera. Whereas the interaction between factor-H and Stri2 was inhibited by the antibody, that of properdin was enhanced.

In a search for adjuvants of non-bacterial origin for immunization with ganglioside, we investigated whether chemical coupling to immune stimulatory protein could increase the immunogenicity of sialoglycosphingolipid. A novel method for the linkage of glycosphingolipids, including gangliosides, to protein was established. The procedure includes lysis of the sphingoid double bond by ozone, reduction of the ozonolysis product to the aldehyde, and coupling to amino groups, either directly by reductamination, or by conjugation via a long aliphatic chain dicarboxylic acid linker. Using this method, gangliosides Gfpt1 (IV2-Fuc-, II3NeuAc-Gg4Cer), Glac2 [II3(NeuAc)2-LacCer], and Gtet1 (II3NeuAc-Gg4Cer) were coupled to keyhole limpet hemocyanin (KLH), and the immunogenicity of the conjugates was tested. Immunization of mice with the KLH-ganglioside conjugates led in each case to the formation of IgG- and IgM antibodies that recognized the underivatized gangliosides, respectively. In contrast to this, mixtures of KLH and ganglioside proved ineffective for immunization. KLH-tumor-associated ganglioside conjugates may, therefore, be considered as possible vaccines in immune therapy of cancer.

As far as medical decision making is based on weighing up individual risks and chances of a certain patient receiving a certain treatment, some knowledge is required about signs and symptoms which are associated with a certain outcome: they are called risk factors, or predictive factors. In lumbar intervertebral disc surgery, the most frequent undesired effect of the treatment is unsuccessfulness. Reviewing the literature about risk factors for unsuccessfulness, one recognizes a lot of unconfirmed or even contradictory findings. This inconsistency can possibly be attributed to the common use of a very simplified, unidimensional definition of the target variable "success of treatment". That is why we performed a prospective observational trial on 109 patients in whom the success of lumbar intervertebral disc microsurgery was assessed after half a year using six different target variables. The rate of treatment success varied considerably, from 44% (when "return to previous occupation" served as the target variable) to 91% (with regard to "subjective contentedness"). Further target variables were intensity of sciatica, intensity of low back pain, activities of daily living, and postoperative paresis, giving intermediate success rates. We were able to identify some risk factors (for instance, duration of sick leave and of the recent pain episode, preoperative paresis, intensity of psychosomatic complaints), each of them being relevant to some of the target variables, but none of them associated with all of the target variables. We conclude that the multidimensional rating of treatment successes seems to promote risk research in multidimensional diseases.

A patient with obstructive sleep-apnea-syndrome and congenital temporal and cervical hemangiomas developed severe headache under nasal BiPAP ventilation. Internal hydrocephalus was diagnosed by CCT and MRI and rise of intracranial pressure (ICP) under artificial ventilation was supposed. Polysomnography, ICP-measurement with a ventricular catheter and resistance to outflow-measurement were used to clarify differential diagnosis. During periods of apnea ICP was raised severely with a maximum in REM-sleep. With nasal ventilation no apnea was observed and ICP was normalized. Resistance to outflow was normal. A disturbance of CSF-dynamics or CSF-absorption leading to the patient's headache could be excluded. Duplex-sonography and cerebral angiography did not provide further information. After exclusion of other causes artificial respiration dependent swelling of the subcutaneous temporal and cervical hemangiomas was the most likely cause triggering the headache. A sufficient therapy however was not yet available. Probably the patient suffers from an abortive form of a Sturge-Weber-Krabbe-Dimitri-Syndrome.

Treatment of brain abscess is still a subject of controversy. Craniotomy with primary extirpation and resection of the abscess membrane, burrhole craniotomy with puncture or insertion of a drain, marsupialization, or stereotactic aspiration are different therapeutic approaches. As a consequence of our experiences and results with neuro-endoscopic interventions we have introduced endoscopic stereotactic techniques in brain abscess treatment. Seven patients with brain abscesses were operated on stereotactically using an endoscope. In all cases the abscess contents were aspirated, while the abscess membrane was left in situ. The patients received postoperative antibiotic therapy according to microbial diagnosis. The longest follow-up period was 48 months. Six patients showed a marked improvement of neurological deficit after treatment. One patient died from sepsis caused by a bacterial endocarditis. The results emphasize that endoscopic stereotactic technique as a minimally invasive neurosurgical method can also be used for treatment of brain abscess.

Three types of glycosphingolipid (GSL) component profiles have been established for human intracranial gliomas. GSL-type I shows only Glac- and lacto-series-sialoglycolipids. Type II consist of Glac- and Gtri-gangliosides, whereas only GSL-type III contains sulphatide and, as a major neutral glycolipid, galactocerebroside, besides gangliosides of the Glac-, Gtri-, and Gtet-families. Whole gliomas of malignancy grading I/II, III and IV, display GSL-Types III, II, and I, respectively. Thus, the GSL component distribution of the samples taken after surgery from three individual gliomas and two biopsies correlate closely with the general diagnosis of these tumours. Arthrobacter ureafaciens sialidase was used for the characterization of gangliosides. GSL-type analysis of multiple regional samples, taken from necropsy and biopsy, were determined by microanalysis of microscopic cryostat section, and shown to be in good agreement with their histology. The results validate the relevance of tumour ganglioside analysis for the characterization and diagnosis of gliomas.

Nosocomial infections, which are not uncommon in neurosurgical intensive care medicine, may possibly be favoured by an impairment of immunological competence of the patient. In a prospective observational trial, we investigated several parameters of cellular and humoral immunity in 32 patients before and after resection of an intracranial tumour. We quantified the effects of operative procedure, dexamethasone pretreatment, and tumour type. Dexamethasone alone causes an increase of neutrophilic granulocyte count and monocytes, whereas IgG and eosinophilic granulocytes decrease as well as lymphocytes. CD4+ T lymphocytes (T helper cells) and CD8+ T lymphocytes (T cytotoxic/suppressor cells) were more severely affected than B lymphocytes. Dexamethasone and operation in combination act synergistically on T lymphocytes and IgG, while no synergism is obvious in other clinical test parameters. The skin sensitivity reaction was depressed accordingly. With intracerebral tumours (gliomas WHO grades II to IV), levels of T helper cells and eosinophilic granulocytes were lower, and levels of IgM and neutrophilic granulocytes were higher than with benign extracerebral neoplasms. Postoperative nosocomial infections of the lower respiratory tract occurred almost exclusively in patients subject to severe depression of T helper cells.

Stereotactic neurosurgery was the first "minimal invasive method" in the field of neurosurgery, later followed and partly replaced by endoscopic techniques. One reason for such an approach is sampling of small tissue probes for diagnosis, e.g. in brain tumours not accessible to open surgery. The appropriate method in the hands of the experienced is the "Quetsch" or smear technique. Its reliability is limited by the fact, that the "architectural" or "tissular" components of tumours lack in those purely cytological preparations. Tissue architecture however is crucial for the assessment of different grades in glial tumour progression. The grade of a glial tumour is the most critical information for the patient and the therapist; grading of the supratentorialf gliomas of the adult by means of cellular and tissue pleomorphism therefore forms the basis of Zülchs system of classification and grading of all intracranial tumours by comparison of postoperative survival. The resulting four grade system--slightly modified--is part of the old and new issue of the WHO classification of brain tumours. In order to specify the possibility of correct diagnosis and grading in probes gained by the minimal invasive techniques, we present results of three diagnostic approaches: First: We report results of a study performed during the last twelve years in which a diagnosis of smear preparations had been made on neurosurgical specimens prior to conventional handling. The "blind" cytological diagnosis was then compared with the final diagnosis of the tumour using light and electron microscopy and immunohistochemistry. Second: We report results and estimates of tissue probes gained by the so called sandwich technique in which the removal of material for cytological analysis is done stepwise. By doing so, material representative for different compartments of the neoplasm is obtained. This implies collaboration between neurosurgeon and neuropathologist not only during the time of stereotactic action but also in the planing period; the correct interpretation of the different compartments delivered by imaging methods in this context is essential. Third: We present selected cases of probe sampling under direct visual control by endoscopy. This method is especially useful for tumours bordering the ventricular system. Surface structures and cyst linings can be visualized directly if the endoscopist is familiar with normal and pathological tissue appearance. The specimen for analysis may therefore be taken from the most relevant tumour region and the sandwich technic which means tissue damaging in multiple localisations can be partly or fully avoided.(ABSTRACT TRUNCATED AT 400 WORDS)

In 1989 we introduced "endoscopic stereotaxy" as a new operative procedure into neurosurgery. This technique was first scheduled to optimize stereotactic biopsy. In its further development it proved to be effective for other indications. We choose the term "Minimal Invasive (Endoscopic) Neurosurgery (MIEN)" for these interventions. Minimal invasive endoscopic techniques are applied preferably for diagnostic and therapeutic interventions on preformed or pathological cavities of the central nervous system. The indications are, endoscopic-stereotactic biopsy of space-occupying lesions, ventriculoscopy and endoscopic ventriculostomy in diagnosis and treatment of hydrocephalus, endoscopic evacuation of cystic space occupying lesions, endoscopic evacuation of intracerebral haematoma, endoscopic evacuation of septated chronic subdural haematoma, endoscopic evacuation of subacute or chronic brain abscesses, endocavitary syringostomy. Our results with minimal invasive endoscopic interventions for different indications are encouraging when compared to conventional microsurgical techniques. We have performed more than 300 minimal invasive endoscopic interventions. The mortality rate was below 1%, the operative morbidity was below 2%.

42 cadaver brains in situ were examined endoscopically to work out topographical anatomical landmarks for orientation. The endoscopic route from the chosen precoronal trepanation point to the defined ventricular landmarks has been measured in 22 cases. The identification and measurements of the anatomical landmarks are helpful for safe and atraumatic endoscopical navigation within the ventricular system. Furthermore this article describes and discusses cerebral lesions during ventriculoscopy.

A family with von Hippel-Lindau disease (vHLD) is presented. Three family members suffered from typical cerebellar hemangioblastomas. Another family member presented with a cerebellar neoplasm of different histology. Detailed histological analysis revealed a primitive neuroectodermal tumor (PNET) with neuronal, glial, myoid and ependymal differentiation. This is apparently the first description of the association of vHLD and a cerebellar PNET with multipotent differentiation.

Primary cerebral lymphomas are rare tumors. In the last years the frequency of these space occupying lesions is increasing. Diagnosis by image-generating methods is often difficult. Stereotactic biopsy is a reliable diagnostic tool. Explorative craniotomy with tumor resection should be avoided if possible. An effective multimodal therapeutic regimen is the combination of radiotherapy and chemotherapy. Epidemiologic data, diagnostic methods and therapeutic proceedings are presented and discussed on a series of 7 patients with primary cerebral lymphomas treated in our department.

Two monoclonal antibodies (mabs) were raised against ganglioside GD2 (Gtri2) and tested on human intracranial tumors and normal brain by immunohistochemical methods both in frozen and paraffin embedded sections. In normal brain structures, astrocytes were visualized with both mabs (BW 625 and BW 704) almost exclusively in the subventricular and subpial layer. A minor amount of myelin sheaths in well defined localisation was only recognized in frozen sections. Consequently in astrocytic tumors of different grades of malignancy (WHO I-IV), astrocytes were depicted in their characteristic shape and arrangement around vessels. In addition, staining was observed in meningiomas and schwannomas, but not in pituitary adenomas or metastatic carcinomas. In meningioma und schwannoma the staining was restricted to the cellular periphery and was again present in frozen section material and absent in paraffin embedded tissue. In astrocytes, reactive and neoplastic, obviously fibrous processes and cytoplasm were distinctly stained both in frozen and paraffin embedded sections. It is concluded that some neuroectodermal derived cells as well as myelin of defined localisation express GD2 on the membrane surfaces and in the cytoplasm. The latter may primarily be the case in fibrous astrocytes, which were stained in reactive and pathologic conditions. The reaction can be used as diagnostic tool in astrocytic tumors; its positive therapeutic significance is hampered by the fact that (1) not all cells in heterogeneous tumor populations express the epitope and (2) there are normal structures which do so.

Background: Decompensation of chronic idiopathic hydrocephalus can occur at every age, but seems to be rather frequent in the middle of the second decade. From this observation, the question arises, whether or not in these cases a special manifestation of hydrocephalus occurs and, should the situation arise, whether this finding might influence the discussion about pathogenesis., Methods: We give some casuistic material about six hydrocephalic patients who became symptomatic between their 12th and 16th year of life., Results: All of these patients showed a tri-ventricular appearance of hydrocephalus as well as radiological signs of chronicly elevated intracranial pressure, while clinical signs and symptoms differed considerably. These findings are linked to the discussion of the pathogenesis of so-called aqueductal stenosis., Conclusions: Whenever, after normal development in childhood, symptoms like increasing headache, poor concentration, dizziness or disturbances of gait appear during puberty, X-ray diagnosis of the skull is recommended. If it shows the signs of chronic elevated intracranial pressure, further investigations are necessary.

Human meninges and 29 meningiomas were analyzed as to their glycosphingolipid composition. In the neutral fraction GSL, a mostly even distribution of mono-, di-, tri-and tetrahexoside was demonstrated. In the group of the gangliosides, Glac1 in one broad band in chromatograms occurred in almost all meningiomas; Glac2 was present in 84% of tumours. Members of the Gtn-family were only found in a small minority of tumours while various Gtet-gangliosides were detectable in nearly half of them. No constant pattern or patterns emerged and no correlation to either morphological subtype or malignancy grade could be established. Immunohistochemistry revealed focal presence of Glac2 in a pattern similar to that of vimentin expression. Semiquantitative evaluation showed good correlation between both parameters.

The term "minimally invasive neurosurgery" (MIN) is defined and the present indications for MIN are described. They include endoscopic stereotactic interventions, endoscopic evacuations of chronic subdural haematomas and intracerebral mass-haemorrhages, endoscopic spinal and ventriculoscopic procedures. The advantages compared to conventional diagnostic and therapeutic neurosurgical approaches consist of less operative risk and reduced tissue-traumatization. Endoscopy makes interventions under (real-time) conditions possible. The operative stress for the patient is minimized.

Gangliosides are complex glycolipids found on the outer surface of most cell membranes: they are particularly concentrated in tissues of the nervous system. Gangliosides form part of the immunological identity of mammalian cells and are involved in a variety of cell-surface phenomena such as cell-substrate binding and receptor functions. In tumorous tissue, the ganglioside composition is altered, sometimes in direct proportion to the degree of malignancy. The literature on the glycosphingolipid composition and immunology of intracranial tumors is reviewed. Some gangliosides induce neuritogenesis and exhibit a trophic effect on nerve cells grown in vitro. In vivo, a particular ganglioside, GM1, reduces cerebral edema and accelerates recovery from injury (traumatic and ischemic) to the peripheral and central nervous systems of laboratory animals. Preliminary clinical studies have shown that treatment with gangliosides may have corresponding effects on lesions of the human peripheral nervous system. Gangliosides have not been tested in human subjects with brain injury.

Contradictory results have been reported claiming either none, partial or almost complete correlation between the complexity of GSL compound profiles and the assumed glial tumor differentiation. Therefore an attempt was made to compare GSL patterns with both the general (final) tumor diagnosis and malignancy grade (WHO) as well as the regional evaluation of the histology and the grading in the tumor tissue pieces directly subjected to biochemical analysis. Regional and general (final) diagnosis did not always correspond, especially when more than one tissue sample of a given tumor was analyzed. Four GSL component patterns were identified by TLC: GSL-type I with gangliosides primarily of the simple Glac-family lacking sulfatide and the more complex Gtri- and Gtet-gangliosides, GSL-type II with ganglioside of the Glac- and Gtri-families, also without sulfatide, and GSL-type III, with more complex gangliosides of the Gtri- and Gtet-families in addition to Glac-gangliosides and sulfatide, similar to the normal brain pattern, and the pattern of normal brain. There was only insufficient correlation between these GSL-type patterns and final diagnoses. However, between regional diagnosis of astrocytoma II and GSL-type III on the one hand and glioblastoma multiforme IV and GSL-type I on the other hand, a coincidence of more than 85% was found. In only 50% the intermediate GSL-type II and glioma III were associated. There was no relation between GFAP or vimentin expression and histology or GSL-type both with regard to final and regional diagnoses. Regional astrocytoma architectures exhibiting GSL-type III were mostly fibrillary, whilst glioblastomas with GSL component pattern I had often a giant cell make up.(ABSTRACT TRUNCATED AT 250 WORDS)

The term "midline tumour" is defined partly from the topographic and from the pathogenetic point of view. Problems of modern imagegenerating procedures in establishing the diagnosis of cerebral midline lesions are described. The role of stereotactic diagnostic and therapeutic interventions is emphasized. Stereotactic brain tumour biopsy, installation of shunts and reservoirs under visual control are performed. Interstitial radiotherapy is carried out for low-grade gliomas. As an important innovation, stereotactic procedures are combined with endoscopic techniques. Particular diagnostic and therapeutic difficulties of typical midline tumours such as craniopharyngeoma, germinoma, glioma and primary cerebral lymphoma as a local extension are discussed. A reasonable concept in diagnosis and therapy of cerebral midline lesions is proposed.

In order to analyse the ratio of costs to clinical benefit of the implantation of a neurostimulator (type Medtronic SE-4) we examined a group of 14 patients who required treatment for chronic lumboischialgia after repeated surgery for herniated discs. Over a period of two years we evaluated the pre- and postimplantation costs. The implantation of a DC-Stimulator resulted in a striking decrease in drug requirements, in the total time of clinical treatment, and in the degree of disability. The DCS provides a satisfying method of treatment for chronic lumboischialgia after repeated surgery for herniated discs. Despite relatively high primary costs, treatment with a DCS results in a significant decrease in the accumulated expenses in comparison to other methods of medical treatment in similar cases.