Search

Zusammenfassung: 1928 beschrieb Hugo Friedrich Kufs erstmalig eine Familie mit zerebralen, retinalen und kutanen Kavernomen. Mittlerweile wurden über 300 weitere Familien beschrieben. Ebenfalls wurden drei Genloci 7q21-q22 (mit dem Gen CCM1), 7p15-p13 (Gen CCM2) und 3q25.2-q27 (Gen CCM3) beschrieben, in denen Mutationen zu Kavernomen führen. Das Genprodukt von CCM1 ist das Protein Krit1 (Krev Interaction Trapped 1), das über verschiedene Mechanismen mit der Angiogenese interagiert. Das neu entdeckte CCM2-Gen enkodiert ein Protein, das möglicherweise eine dem Krit1 ähnliche Funktion in der Regulation der Angiogenese hat. Das CCM3-Gen wurde noch nicht beschrieben. In dieser Arbeit werden sowohl die klinischen und genetischen Befunde bei 15 deutschen Familien beschrieben

Familiare und multiple Kavernome beruhen haufig auf autosomal-dominant vererbten Mutationen, die sich mit einer Penetranz von etwa 60% klinisch manifestieren. Wir berichten uber einen 2-jahrigen Patienten mit angeborener vaskularer Hautmalformation des Oberschenkels. Bei der zerebralen Bildgebung wurde ein eingeblutetes Kavernom diagnostiziert und anschliesend mikrochirurgisch reseziert. Die Familienanamnese war positiv, und beim Indexpatienten wurde eine neue CCM1-Mutation (c.1780_1783delinsTACCTGTTACCAAA) gefunden, sodass eine prasymptomatische genetische Diagnostik im Rahmen einer genetischen Beratung in dieser Familie moglich ist.

Background: Gliomas are the most common primary tumours of the central nervous system and exhibit rapid growth that is associated with neovascularisation. Adrenomedullin is an important tumour survival factor in human carcinogenesis. It has growth promoting effects on gliomas, and blockade of its actions has been experimentally shown to reduce the growth of glioma tissues and cell lines. There is some evidence that the calcitonin receptor-like receptor (CRLR) mediates the tumorigenic actions of adrenomedullin. Aim: To determine whether CRLR is expressed in human gliomas and the probable cellular targets of adrenomedullin. Methods: Biopsies from 95 human gliomas of varying grade were processed for immunohistochemical analysis using a previously developed and characterised antibody to CRLR. Results: All tumour specimens were positive for CRLR. As previously found in normal peripheral tissues, CRLR immunostaining was particularly intense in the endothelial cells. This was evident in all the various vascular conformations that were observed, and which are typical of gliomas. In addition, clear immunostaining of tumour cells with astrocyte morphology was observed. These were preferentially localised around vessels. Conclusions: This study has shown for the first time that the CRLR protein is present in human glioma tissue. The expression of the receptor in endothelial cells and in astrocytic tumour cells is consistent with the evidence that its endogenous ligand, adrenomedullin, may influence glioma growth by means of both direct mitogenic and indirect angiogenic effects. CRLR may be a valuable target for effective therapeutic intervention in these malignant tumours.

OBJECTIVE To investigate if the intracisternal distribution of subarachnoid hemorrhage (SAH) following aneurysm rupture allows the correct prediction of the symptomatic aneurysm site. [nl] METHODS Ninety-nine consecutive patients with acute SAH and angiographically proven aneurysm were included into the study. The parent vessel of the diagnosed aneurysms were the anterior communicating artery (ACoA) in 38 patients, the middle cerebral artery (MCA) in 26 patients, the internal carotid artery (ICA) in 25 patients, the pericallosal artery (A2) in 5 patients, the basilar artery (BA) in 4 patients and the vertebral artery (VA) in 1 patient. In 21 patients, an additional asymptomatic aneurysm was diagnosed. The initial computerized tomography (CT) scans of the 99 patients were given to 2 experienced vascular neurosurgeons, who were blinded for the angiography findings. The 2 investigators had to predict the site of the ruptured aneurysm. [nl] RESULTS Investigator 1 correctly predicted the aneurysm site in 56 (57 %), investigator 2 in 59 of the 99 patients (60 %). Investigator 1 correctly identified 81 % of the MCA aneurysms, and investigator 2 74 % of the ACoA aneurysms. However, in only 46 of the 99 patients (47 %), the aneurysm site was correctly predicted by both investigators together. [nl] CONCLUSION The results indicate, that the distribution of the subarachnoid blood as shown on the first CT scan after aneurysm rupture barely allows to predict the symptomatic aneurysm site. Thus, neurosurgical decision making (identification of the ruptured aneurysm in patients with multiple aneurysms; surgical exploration in patients with non-perimesencephal SAH, but negative angiography) should not rely on the first CT scan after SAH.

A unilateral laminotomy for bilateral access to the lumbar spinal canal was investigated in human cadaver spine specimens to test its practicability in the treatment of spinal stenosis. Micro-surgical decompression was performed by partial resection of the ipsilateral facet, the medial portion of the laminar arch, the contralateral facet and by complete removal of the ligamentum flavum. Anatomical, radiological and morphometrical studies on 4 adult cadaver spine specimens have proved the feasibility of this unilateral approach. Complete bilateral flavectomy and partial bilateral facetectomy were the essential surgical steps for an adequate operative decompression.

Collins' law, known as period of risk for recurrence (PRR), has been discussed as a reliable scheme for the prediction of recurrence or cure of embryonal tumours including medulloblastomas. The PRR is defined as the age at diagnosis plus 9 months of gestation. According to Collins' law, a patient who has no clinical evidence of recurrence within this time period is considered cured. We have applied this system to 66 patients (age range from 0 to 47 years) who underwent surgery for medulloblastoma at a single center between 1975 and 1990. Three patients in whom a recurrence could not be verified died within 6 months. Eight patients (12.1%, age range from 1 to 14 years) survived the PRR without relapse and are free of risk for recurrence according to Collins' law. Of the remaining 55 patients, 35 showed a relapse within the PRR with a mean latency of 18 months (0-78); Twenty patients are alive with no recurrence as yet, but are still within the PRR Three patients had non-recurrent benign brain tumours not connected to the initial tumours with a mean latency of 10 (8-14) years after medulloblastoma surgery. Thus, all our patients fulfilled the criteria for Collins' law. In conclusion, a patient's risk for medulloblastoma recurrence is significantly higher before than after the completion of the PRR. Therefore, the PRR is a helpful prognostic parameter that provides additional information about the risk of medulloblastoma recurrence. A medulloblastoma cure cannot be presumed with certainty by Collins' law because relapses after the PRR have been reported in other studies (1.4% of the cases). Intracranial lesions detected after a long follow-up might be radiotherapeutically induced second tumours.

The authors report about a 3-years experience with helical CT and 3-D surface reconstruction applied in neurosurgical patients. All examinations were performed in addition to preexisting diagnostic CT, MRI, or angiography. The aim of this study was to assess the clinical value of this method with regard to planning of the surgical approach to anterior, middle, and posterior skull base and spinal lesions. 75 examinations of 55 patients were analysed and ranked as follows: A = examination with significant additional information for neurosurgical planning of skull base or spinal procedures or for postoperative evaluation of the neurosurgical approach, B = examination with some useful information for the neurosurgical planning or postoperative control, however, without significant advantage as compared to established diagnostic methods, C = examination without significant additional information. Classification was performed independently by two experienced surgeons. Examinations of anterior, middle, and posterior skull base lesions including cerebral aneurysms were in the majority rated as helpful and significantly informative, (A = 21, B = 24, C = 9, n = 54). Three-dimensional imaging of the spine was of clinical value only in specific cases (A = 6, B = 6, C = 9, n = 21). The authors conclude that three-dimensional imaging is a valuable diagnostic tool for pre- and postoperative imaging of tumorous and vascular lesions adjacent to the skull base, allowing for optimal surgical approaches with minimal invasiveness.

Six patients with a dural arteriovenous fistula (DAVF) of the floor of the anterior cranial fossa underwent microsurgical treatment. Two of them were operated using a conventional frontobasal approach, and four using an interhemispheric approach. The interhemispheric approach offers the advantages of sparing the frontal sinus, minimizing frontal lobe retraction, and providing a visual angle perpendicular to the floor of the anterior fossa and an excellent view of the fistula located on the cribriform plate at the level of the foramen caecum. Using the interhemispheric route, the malformation was occluded in all the cases by dividing the vascular connection between the dura of the cribriform plate and the intradural draining vein. There were no complications related to the surgical procedure. This route avoids some disadvantages of the more frequently reported frontobasal approach. It is therefore a recommendable alternative for the management of frontal DAVFs.

Although primary treatment of medulloblastoma is now successful in a high percentage of patients, its secondary manifestations still bear a poor prognosis. Thorough studies of secondary manifestations are therefore pivotal to plan therapeutic approaches for the long-term management of medulloblastoma. Here we describe the incidence of secondary tumour manifestations in 66 patients of a single centre who underwent surgery for medulloblastoma between 1975 and 1990. No patient was excluded due to a poor postoperative course. Thirty-five patients showed evidence of secondary tumour growth. Of these, 17 suffered from local recurrence, and 27 developed metastastatic disease. The median latencies for secondary manifestations were 25 months for local recurrence (n = 17), 11 months for spinal metastases (n = 10), 15 months for supratentorial metastases (n = 8), 8 months for subleptomeningeal dissemination (n = 6), and 23 months for systemic metastases (n = 8). Two patients developed primary metastatic spread to the posterior fossa. Of 8 patients with supratentorial metastases, 6 developed fronto-basal lesions. In our patients, 89% of secondary lesions occurred within less than 3 years after primary diagnosis. 85% of patients with extra-axial tumour spread had been treated with a permanent shunt. Radical tumour resection and radiotherapy with 30 Gy to the neuraxis and 20 Gy boost to the posterior fossa was an important prognostic factor in this series. Patients with additional chemotherapy did not benefit significantly from this treatment. We conclude that optimal management of the primary lesions should aim at (i) total resection, (ii) avoid permanent shunting, and (iii) completion of the radiotherapy with inclusion of the medial frontobasal cisterns in the radiotherapeutic regimen. Our analysis suggests that adequate postoperative screening programmes should consist of 3-monthly scans of the neuraxis in the first three postoperative years and 6-monthly scans thereafter.

Although recently survival of some medulloblastoma patients increased remarkably, it remains a serious diagnosis in others. In order to predict the postoperative prognosis in patients treated for medulloblastoma, a new staging, scoring and grading system was developed. Sixty-six patients operated on microsurgically between 1975 and 1990 at a single neurosurgical center were fully followed-up. No patient was excluded due to a poor postoperative course. Completion of commonly used radiotherapy protocols was attempted in all patients. Survival of patients was evaluated by the Kaplan-Meier method. The following 5 parameters were selected to define subgroups: patients' age, tumour location and histology, degree of resection and presence or absence of metastases. Patients older than 10 years had a better prognosis than individuals aged 10 or less (p < 0.01), patients with lateral tumours had a better prognosis than patients with midline tumours with brain stem infiltration (p < 0.05), patients with complete tumour resection had a more favourable prognosis than individuals with subtotal (p < 0.01) or partial resection (p < 0.001), patients without metastases at the time of diagnosis had a better prognosis than individuals without such evidence (p < 0.001), patients with the desmoplastic tumour variant had a better prognosis than patients with classical tumour histology (p < 0.01). According to the prognosis of a distinct subgroup, scoring points were distributed which correlated with the degree of inter-subgroup significances. The sum of a single patient's scoring points was called the total score. Based on this score, three groups of prognosis were distinguished.(ABSTRACT TRUNCATED AT 250 WORDS)

We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important.

According to their strategic location, intraaxial lesions of the foramen magnum may cause severe symptoms. The primary goal of surgery is to decompress the lower brain stem and upper cervical cord without additionally impairing the neurological function, or, as in vascular lesions, to eliminate the risk of recurrent bleeding. Secondary goals of surgery are to preserve the atlanto-occipital stability, to minimize traumatization of various muscles in the craniovertebral region, to preserve the sigmoid sinus and jugular bulb and to avoid air embolism or excessive venous bleeding during surgery. The most common intraaxial lesions encountered at the level of the foramen magnum are cavernous malformations, gliomas, ependymomas, and hemangioblastomas. They are located either in the medulla oblongata (up to the pontomedullary junction) or within the cervical cord at the level of C1. These lesions may be located either totally intraaxially, with or without contact to the surface of the brain stem or spinal cord, or, in other instances, they may be partially exophytic (1). Moreover, from the surgical point of view, particularly in terms of accessibility, lesions located in the dorsal and lateral region of the brain stem and spinal cord significantly differ from those located anteriorly or anterolaterally. Hemangioblastomas may sometimes involve the proximal intradural vertebral artery and its branches.

Twelve patients with severe intraventricular haemorrhage (IVH) underwent intraventricular thrombolysis with recombinant tissue plasminogen activator (rtPA). External ventricular drainage was performed in all patients within 24 hours of haemorrhage. Fibrinolytic therapy was started within 24 hours from the onset of symptoms in ten cases, and in two further cases after 48 hours and 5 days, respectively. Two to 5 mg of rtPA were injected via the ventricular catheter into one or both lateral ventricles. The injection was repeated at intervals ranging from 6 to 24 hours until CT scans demonstrated a substantial reduction of intraventricular blood. The total rtPA doses per patient ranged from 3 to 31 mg. CT scans showed a marked reduction of intraventricular blood and normalization of ventricular size within 24 to 48 hours from the beginning of the fibrinolytic therapy. Rapid reduction of elevated intracranial pressure by continuous diversion of cerebrospinal fluid could be achieved in all patients, because the ventricular catheters never became obstructed by clotted blood during the fibrinolytic therapy. During the period of treatment, the level of consciousness, as classified according to the Glasgow Coma Scale, improved from a mean value of 7 to 12. One fatal case of meningitis most probably due to the ventriculostomy was the only complication related to the treatment. This method of treatment might improve the prognosis in patients in whom a large intraventricular haematoma volume, ventricular dilatation, and impaired cerebrospinal fluid circulation are major determinants for the outcome.

We review here 10 cases of cerebellar infarction and associated occlusive hydrocephalus. Surgical therapy consisted of placement of a permanent shunt in 4, and a temporary external ventricular drainage in 6 individuals. This treatment regimen was effective in 9 cases and remained without adequate response in only 1 patient with multiple supra- and infratentorial infarctions. These results and similar reports from the literature suggest that treatment of the hydrocephalus alone might be sufficient in most cases and should therefore constitute the primary treatment of choice in patients presenting with cerebellar infarction and obstruction of cerebrospinal fluid (CSF) pathways.

Over a 15-year period, 15 patients with craniospinal malformations were operated on using the transoral route. Ten patients had basilar impression and five had atlantoaxial dislocation; nine patients had associated lesions. Patients treated with reposition and dorsal fusion recovered well without ventral decompression. We found that transoral odontoidectomy is suitable as a primary decompressing measure only in ventral compression or nondislocated atlantoaxial conditions.

The authors review 26 patients with deep-seated cavernous angiomas which were removed by microsurgery. Ten of the angiomas were located in the insula and basal ganglia, 2 in the thalamus, 5 in the midbrain, 8 in the pons, and 1 in the brachium pontis. The patients were among 73 consecutive cases operated on between August 1983 and December 1989 for symptomatic cavernous angiomas in various locations. In 11 cases total excision of the cavernoma was achieved without producing additional neurological deficits. Postoperative neurological recovery was delayed in 7 patients. In the remaining 8, the complicated postoperative course was caused by bleeding from residual parts of the malformation or damage to long-tract pathways in two cases, respectively, vascular injury during dissection in three cases, and paradoxical air embolism in one case. In order to achieve a satisfactory surgical result, it is stressed that particular attention has to be paid to the operative approach, to careful dissection and complete removal of the malformation, to perforating arteries, and to anomalous venous drainage.

According to recent clinical data, motor cortex stimulation (MCS) is an alternative treatment for central pain syndromes. We present our minimal invasive technique of image guidance for the placement of motor cortex stimulating electrode and assess the clinical usefulness of both neuronavigation and vacuum headrest. Neuronavigation was used for identification of precentral gyrus and accurate planning of the single burr-hole. The exact location was reconfirmed by intraoperative phase reversal of somatosensory evoked potential (SSEP) and clinical response after electrical stimulation test. Implementation of navigation technique facilitated localization of the precentral gyrus with a high degree of accuracy. Determination of stimulating electrode placement was possible in every case. Postoperative clinical and neuroradiological evaluations were performed in each patient. All patients experienced postoperative relief from pain. Our preliminary series may confirm image guidance as a useful tool for surgery of MCS. Additionally, minimal and safe exposure can be performed using a single burr-hole and vacuum head rest.

Posttraumatic tremor is often one of the causes of disability in head injury patients. Usually, pharmacotherapy for this type of tremor is not effective. Since early 1970s, surgical ablation of the ventral thalamus has been used to treat various types of tremor. Nowadays, deep brain stimulation (DBS) confirms its efficacy in alleviating different forms of tremor, including posttraumatic tremor. Such therapy has been reported achieving around 80% success rate in the treatment of posttraumatic tremor. These successful results suggest that the application of DBS therapy can be considered as one of the alternative treatments for minimizing the tremor occurring from different pathologies.

In 1928, Hugo Friedrich Kufs reported on a family with cerebral, retinal, and cutaneous cavernous malformations. Since then, more than 300 families with inherited cavernous malformations have been reported. Genetic studies showed three loci, on chromosomes 7q21-q22 (with the gene CCM1), 7p15-p13 (CCM2), and 3q25.2-q27 (CCM3). The gene product of CCM1 is Krit 1 (Krev interaction trapped 1), a protein interacting with angiogenesis by various mechanisms. Recently, CCM2 has also been identified; its product is a protein which might have a function similar to that of Krit 1. However, the CCM3 gene has still not been found. In this study, we present clinical and genetic findings on 15 German families.

The present study aims to provide preliminary results of the thermal effects on rat brain tissue after argon plasma coagulation (APC). It also presents and discusses the clinical experiences in the treatment of brain tumor using APC.A controlled study of APC in the rat brain was conducted. Twelve rats were randomly divided into 2 experimental groups. In the first group (n = 6), histopathological evaluation was performed 2 days following the coagulation. In the second group (n = 6), the evaluation was performed 12 days post operation. In a prospective study of APC-treated tumor tissue in 3 patients, the depth of plasma penetration and histological alteration were evaluated.In the animal experiment, extent of tissue defect became significantly smaller after 12 days (p = 0.010). The maximum depth of tissue alteration after APC application was limited to 2.15 mm (range: 1.5-2.15 mm) at day 2. The histological alteration of tissue after the thermal injury can be divided into 3 zones. In addition, the depth of tissue alteration in the APC-treated human brain tumor was measured in vertical and horizontal planes under light microscope. Similar to the animal experiment result, penetration of the plasma energy in human brain tumors was limited to a maximum of 2.13 mm (range: 1.6-2.13 mm).The limited depth of energy penetration may confirm APC as a safe and beneficial tool for coagulation of human brain tissue. However, further clinical studies are required to evaluate the suitability and indications of this method in brain tumor treatment.

To investigate if the intracisternal distribution of subarachnoid hemorrhage (SAH) following aneurysm rupture allows the correct prediction of the symptomatic aneurysm site. [nl]Ninety-nine consecutive patients with acute SAH and angiographically proven aneurysm were included into the study. The parent vessel of the diagnosed aneurysms were the anterior communicating artery (ACoA) in 38 patients, the middle cerebral artery (MCA) in 26 patients, the internal carotid artery (ICA) in 25 patients, the pericallosal artery (A2) in 5 patients, the basilar artery (BA) in 4 patients and the vertebral artery (VA) in 1 patient. In 21 patients, an additional asymptomatic aneurysm was diagnosed. The initial computerized tomography (CT) scans of the 99 patients were given to 2 experienced vascular neurosurgeons, who were blinded for the angiography findings. The 2 investigators had to predict the site of the ruptured aneurysm. [nl]Investigator 1 correctly predicted the aneurysm site in 56 (57 %), investigator 2 in 59 of the 99 patients (60 %). Investigator 1 correctly identified 81 % of the MCA aneurysms, and investigator 2 74 % of the ACoA aneurysms. However, in only 46 of the 99 patients (47 %), the aneurysm site was correctly predicted by both investigators together. [nl]The results indicate, that the distribution of the subarachnoid blood as shown on the first CT scan after aneurysm rupture barely allows to predict the symptomatic aneurysm site. Thus, neurosurgical decision making (identification of the ruptured aneurysm in patients with multiple aneurysms; surgical exploration in patients with non-perimesencephal SAH, but negative angiography) should not rely on the first CT scan after SAH.

Optimal management of patients with unruptured intracranial aneurysms (UIAs) remains controversial. Recent studies have found conflicting data regarding the natural history and the treatment outcome of UIAs. Based on the recommendations published by the American Heart Association, the Section of Vascular Neurosurgery of the German Society of Neurosurgery has formed a task force to summarize the available data and to develop a practical framework for the management of UIAs. For UIAs, only evidence from nonrandomized historical cohort comparisons and case series without control subjects are available, supporting only grade C recommendations (options), but no standards (grade A) and no guidelines (grade B). The present recommendations have been developed as a neurosurgical, neuroradiological and neurological consensus. They are based on the existing data of both treatment risks and the risks of the natural history of UIAs.

The objective of this study was to determine the feasibility, toxicity, and potential therapeutic benefits of an adjuvant active immunotherapy using a tumour specific ganglioside (GD2) conjugate for the adjuvant treatment of recurrent or progressive gliomas. Seven patients with proven GD2 expression in surgical specimens underwent a vaccination course with GD2-KLH/MPL-A conjugate. The follow-up was performed according to WHO guidelines regarding common toxicity criteria. Antibody titres against the ganglioside and the adjuvants were analysed. All patients developed a local type 4 reaction. Anti-GD2-antibody titres could not be detected, despite high titres against the immunoadjuvants. No tumour regression was observed. The disease remained stable for a median of 21.5 weeks (6-34 weeks). The median survival time after the first immunization was 47 weeks. The medial total survival time was 76 weeks. Adverse effects have not been observed. Active GD2-KLH/MPL-A immunization was technically feasible, but did not elicit anti-GD2 antibody generation.

The goal of this study was to evaluate factors for the prognosis of patients with metastatic spinal tumors. 139 patients with vertebral metastases were studied. The modified Tokuhashi Score (a preoperative score composed of six parameters) and single factors were analysed with statistical methods. The modified Tokuhashi Score showed a significant correlation (p = 0,0019) with survival time of patients. Additionally, only the Karnofsky Index as single parameter showed statistically significant correlation(p = 0.0016). Regarding the logistic regression, primary tumor, age, sex and Karnofsky Index were identified as prognostic factors for survival time. This trial could demonstrate that the Tokuhashi Score is a successful predicting tool for the assessment of prognosis of patients with vertebral metastases.

Complex pain syndromes due to spasticity and central deafferentation often fail to respond to medical therapy and create challenging problems in the pain management. So far, only spasticity associated musculosceletal pain has been reported to respond to intrathecal baclofen application [1, 2].We report the treatment of severe neuropathic pain in a patient with ED and the combined intrathecal application of baclofen and morphine in 5 patients with severe spasticity related pain.Continuous intrathecal baclofen infusion resulted in a pain free period of 20 months in the patient with ED. Patients with spasticity treated with intrathecal application of baclofen and morphine were pain free for a mean period of 2 years.Intrathecal baclofen and morphine application proved to be effective in spasticity related and central deafferentation pain and should therefore be considered in the management of these patients.

In many cases, the treatment of neuropathic pain by intrathecal opioids fails to meet expectations. In a trial involving 10 patients, the intrathecal administration of clonidine combined with opioids in the treatment of chronic pain was introduced in our department for the first time. Eight patients with neuropathic pain syndromes were subjected to a continuous intrathecal clonidine application in addition to intrathecal morphine. At an average dose of 44 µg clonidine/day, a 70–100% reduction in pain was achieved. Residual non-neuropathic pain in 4 of 8 patients was successfully treated with clonidine and low doses of opioids. On the basis of the results achieved so far, we recommend that clonidine should be routinely tested for intrathecal drug administration, especially in patients with a prominent neuropathic pain component.

We report on the dislocation of the tip of a lumbo-peritoneal shunting catheter into the cerebral parenchyma 10 months after insertion. The progressive migration towards the deep structures of the brain, once the catheter had left the peritoneal cavity, might have been caused by CSF-flow. Such hypothesis is supported by modern MRI technology visualizing CSF-flow in a spino-cerebral direction.

BACKGROUND Craniotomy with a mechanical twist drill is a standard, minimally invasive procedure in neurosurgery, widely used for the drainage of chronic subdural hematomas and the placement of ventricular drains. Nevertheless, the use of a standard twist drill trephine bears the risk of causing cerebral lesions. METHOD A commercially available mechanical twist drill system has been modified by a special self-controlling drill and a pre-adjustable distance holder that limits intracerebral penetration. After initial cadaver testing, the modified trephine has been used for 65 trephinations in patients (37 chronic subdural hematomas, 21 external ventricular drains, 6 frontal hygromas, 1 tumor cyst). RESULTS There were no complications related to the modified trephine; cerebral lesions caused by drilling too deeply or by uncontrolled penetration were safely prevented. In our series no procedure related infections occurred, and the drilling time was reduced significantly. CONCLUSION The described modified mechanical twist drill enables fast, easy, and safe craniotomy without jeopardizing the advantages of a mechanical twist drill. Therefore, it can be recommended particularly for difficult emergency conditions.

Monitoring of partial pressure of brain tissue oxygenation P(ti)O2, brain tissue ph (brph), partial pressure of brain tissue CO2 [P(ti)CO2] and intracranial pressure (ICP) by invasive methods, calculation of cerebral perfusion pressure (CPP), and hemodynamic monitoring of middle arterial blood pressure (MABP) are the main strategies in multimodal neuromonitoring. Using this multimodal approach the therapy of raised intracranial pressure with diffuse brain edema has undergone fundamental changes during recent years [2, 3, 7, 9, 19, 24, 25, 40, 42].

Collins' law, known as period of risk for recurrence (PRR), has been discussed as a reliable scheme for the prediction of recurrence or cure of embryonal tumours including medulloblastomas. The PRR is defined as the age at diagnosis plus 9 months of gestation. According to Collins' law, a patient who has no clinical evidence of recurrence within this time period is considered cured. We have applied this system to 66 patients (age range from 0 to 47 years) who underwent surgery for medulloblastoma at a single center between 1975 and 1990. Three patients in whom a recurrence could not be verified died within 6 months. Eight patients (12.1%, age range from 1 to 14 years) survived the PRR without relapse and are free of risk for recurrence according to Collins' law. Of the remaining 55 patients, 35 showed a relapse within the PRR with a mean latency of 18 months (0-78); Twenty patients are alive with no recurrence as yet, but are still within the PRR Three patients had non-recurrent benign brain tumours not connected to the initial tumours with a mean latency of 10 (8-14) years after medulloblastoma surgery. Thus, all our patients fulfilled the criteria for Collins' law. In conclusion, a patient's risk for medulloblastoma recurrence is significantly higher before than after the completion of the PRR. Therefore, the PRR is a helpful prognostic parameter that provides additional information about the risk of medulloblastoma recurrence. A medulloblastoma cure cannot be presumed with certainty by Collins' law because relapses after the PRR have been reported in other studies (1.4% of the cases). Intracranial lesions detected after a long follow-up might be radiotherapeutically induced second tumours.

The transcallosal route has been propagated as a safe approach to midline tumors. The present study was performed in order to elucidate the neurobehavioral late sequelae in patients after transcallosal microsurgery on near-midline tumors.The present study was performed retrospectively with a delay between surgery and follow-up examination ranging from 2 to 36 months (mean 10.2 months).The study was performed in the Department of Neurosurgery, University Hospital of the University of Technology (RWTH) Aachen, Germany.A consecutive series of 18 patients treated for an intracranial lesion by transcallosal surgery was included into the study. The patients had to be not younger than 16 and not older than 67 years. The age mean was 38.9 years (range 16 to 65 years).The surgical approach was performed along the falx cerebi under microneurosurgical conditions with direct use of the microscope after opening the dura.Beyond neurological examinations, the patients were submitted to an extensive neuropsychological testing battery. Furthermore, quality of life was examined by means of a questionnaire.Surgery was performed without persistent new neurological deficits. Cognitive deficits were found in short- and long-term memory, motor fine-coordination, reaction time, divided attention and fronto-cortical capacity. The quality of life was particularly impaired in the area of cognitive capacity in daily life. These findings could be related to the duration of preoperative symptoms and to the tumor location.The deficits found cannot be explained by surgical damage to the corpus callosum itself. Rather, they seem to correspond to an extra-callosal pathology. Further studies with a prospective evaluation of larger patient samples are called for in the future.

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%.

The surgical aim in the treatment of symptomatic lumbar spinal stenosis is the relief of the patient's complaints by an adequate neural decompression. Unilateral laminotomy and bilateral spinal canal decompression represents such a safe, effective and minimally invasive surgical method. This technique has been successfully used in the operative treatment of 29 patients with symptomatic mono- or multisegmental lumbar stenosis. There was no surgically induced neurological deterioration. In one patient, an inadvertent dural tear occurred, and due to unchanged symptoms another patient with a multisegmental stenosis had to be re-operated on at an additional level. Postoperatively, 25 of the 27 patients with neurogenic claudication (93%) demonstrated a marked improvement of the walking distance. The follow-up of 25 patients (mean follow-up time was 18 months) demonstrated an excellent result without pain in 7 patients (28%); a good outcome with mild residual pain, but a normal working capacity in 15 patients (60%); and a fair outcome with unchanged postoperative low-back pain but markedly improved working capacity and walking distance in 3 patients (12%). Postoperative morphometric evaluation as well as the clinical improvement of the patient's symptoms clearly demonstrated that bilateral ligamentectomy and recess decompression were adequately and successfully achieved via unilateral approach.

Hemangioblastomas of the spinal cord and the brainstem make up 4% of all spinal tumors and are less common than cerebellar hemangioblastomas. CT and MRI are essential for preoperative diagnosis. Nevertheless, cerebral and spinal angiography are also mandatory, since they allow a detailed study of the vascular situation, which is decisive for exact planning of a surgical strategy. The purpose of this study was to evaluate the diagnostic and therapeutic factors which influence surgical morbidity and postoperative outcome. Twelve patients harbouring spinal(8 cases) or medullary (4 cases) hemangioblastomas, all symptomatic with sensorimotor deficits corresponding to the level of the lesion were evaluated. All patients were treated in our department between December 1989 and September 1994. Complete resection of the lesion was achieved in each case. Postoperatively, none of the patients showed deterioration. Nine patients had immediate postoperative improvement of neurological signs and symptoms; in three patients the initial neurological deficits remained unchanged during the in-patient period. Late postoperative outcome demonstrated a clear improvement; in only one patient was there no change of the clinical signs, while in the other 11 patients a significant improvement of pre-existing neurological deficits was experienced. We conclude that microsurgical resection of spinal and medullary hemangioblastomas with low morbidity is feasible.

The glucose metabolism of 62 meningiomas was measured by fluorine -18-2-fluorodeoxyglucose (FDG) PET and correlated with proliferation rate (Ki-67 index) and tumor cellularity. The mean metabolic rate (MRG1u) for meningiomas was 0.26 ± 0.13 mikromol/g/min (range 0.08–0.62 mikromol/g/min).

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the micro-anatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the microanatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

The choice of the surgical approach and operative technique for the management of cerebrospinal fluid (CSF) fistulas of the anterior cranial fossa are still a controversially discussed topic. Although "extracranial" approaches through the paranasal sinuses are becoming increasingly more popular among otolaryngologists and maxillo-facial surgeons, most neurosurgeons traditionally prefer the "intracranial" repair of CSF fistulas by a craniotomy. We present an approach through the frontal sinus for the repair of dural defects behind the posterior wall of the frontal sinus and at the floor of the anterior cranial fossa. The operative procedure comprises the following main steps: 1) exposure of the anterior wall of the frontal sinus by a bicoronal incision; 2) excision of the anterior wall without frontal burr holes; 3) bilateral removal of the posterior wall of the frontal sinus; 4) extradural inspection of the dura behind the frontal sinus and above the cribriform plate, ethmoidal roof, and orbital roof bilaterally; 5) closure of dural tears by direct suture and a periosteal graft; 6) reinsertion of the anterior wall of the frontal sinus and fixation with titanium micro plates. Twenty-five patients operated upon using this technique are described. The aetiology of the frontobasal lesion was traumatic in 23, and an ethmoid carcinoma in two. In all patients, the dural fistulas were successfully repaired during the initial procedure. One patient died from sudden circulatory arrest after an uneventful postoperative course of nine days. Otherwise, there were no postoperative complications. This technique affords atraumatic extradural inspection and repair of dural fistulas bilaterally behind the frontal sinus, and above the cribriform plate and the ethmoidal and orbital roofs with none or minimal brain retraction. It therefore allows early repair of CSF fistulas also in patients with severe brain injury. Although we consider the extradural closure of fistulas the method of choice, this approach also allows for a combined extradural-intradural procedure, thus enabling the surgeon to treat associated intradural pathologies, such as traumatic lesions or tumours of the frontal cranial base.