Search

Background: Gamma Knife radiosurgery (GKRS) is a well-established treatment for residual or growing pituitary adenomas (PAs) post-partial resection. However, some PAs grow even after initial GKRS, for which the efficacy of repeat GKRS is unclear. The primary objective of this study was to determine long-term progression-free survival (PFS) following repeated GKRS in patients with PA. The secondary objective was to determine predictors of tumor progression in these patients., Methods: Single-center, population-based consecutive cohort study of patients with recurrent PAs treated with repeated GKRS due to tumor progression between 1999 and 2022 at the Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden. PFS and predictors of tumor growth were assessed., Results: 23 patients were included, with a median follow-up time of 6.3 years. The 5-year PFS rate was 57%, and the median duration from repeat GKRS to tumor progression was 2.6 years. Tumor growth after repeat GKRS occurred exclusively within the first three years post-treatment. Older age at the time of repeat GKRS was a significant predictor of continued tumor growth (OR 1.09, p = 0.036)., Conclusion: Repeat GKRS is a feasible treatment alternative for PAs that exhibit growth following initial GKRS., Competing Interests: Declarations. Ethical approval: This article does not contain any studies with human participants or animals performed by any of the authors. Informed consent was not collected as this study contains no identifying details. Conflict of interest: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Pituitary adenomas (PAs) often require adjuvant Gamma Knife radiosurgery (GKRS) due to partial resection or postoperative recurrence. The purpose of this study was to evaluate the long-term efficacy of GKRS for such cases., Methods: Population-based, observational cohort study of patients who underwent GKRS for postoperative residual or recurrent PAs between 1999 and 2020. We assessed long-term progression-free survival (PFS), identified predictors of tumor growth, and documented adverse radiation events (AREs)., Results: 147 patients were included, with a median follow-up time of 8.1 years. Following GKRS, the 5-year and 10-year PFS was 86% and 68%, respectively, with a median PFS of 18.7 years. Somatotrophic adenomas showed a significantly lower risk of tumor progression in the regression analysis (OR 0.11, p = 0.003). Hypopituitarism was the most common ARE, affecting 32% of patients., Conclusion: GKRS is an effective treatment option for recurrent or residual PAs, offering substantial long-term control. However, the risk for AREs, particularly hypopituitarism, is not negligeable., Competing Interests: Declarations. Ethical approval: This article does not contain any studies with human participants or animals performed by any of the authors. Informed consent:  Informed consent was not collected as this study contains no identifying details. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

In May 1968, Lars Leksell and Erik-Olof Backlund achieved a pioneering breakthrough by performing the first Gamma Knife radiosurgery (GKRS) on a craniopharyngioma (CP). Today, more than 50 years later, this patient remains under continuous monitoring, providing the longest documented follow-up of a GKRS-treated CP. This case report provides a complete record of the patient's preoperative presentation, surgical assessment, GKRS, and an extensive long-term follow-up with multiple interventions. The investigation involved analysis of archived and digitalized patient records and radiological images. The patient was a 21-year-old female who presented with amenorrhea and low levels of gonadotropins. Pneumoencephalography showed a calcified 2 × 2.5 cm mass located in the suprasellar region, indicative of a CP. Subsequent stereotactic puncture confirmed a predominantly solid nature of the CP. Given the size and composition of the tumor, the surgical team opted for GKRS. Dose planning was performed manually, with coordinates determined using Leksell's stereotactic frame. The tumor was targeted with a total dose of 50 Gy using 179 beams of 60 Co. Over the subsequent 55 years, the patient underwent radiological and clinical follow-ups. Throughout this period, 4 cystic tumor recurrences occurred and were managed by stereotactic puncture and Yttrium-90 instillation radiotherapy. The solid component remained stable without repeated GKRS. The patient suffered lateral quadrant anopsia and endocrinological deficits, necessitating pharmaceutical intervention. Despite these challenges, the patient is still living an active life at age 76 years. This case stands as historic evidence of long-term safety and efficacy of GKRS for CPs., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

In December of 2016, a Consensus Conference on unruptured AVM treatment, involving 24 members of the three European societies dealing with the treatment of cerebral AVMs (EANS, ESMINT, and EGKS) was held in Milan, Italy. The panel made the following statements and general recommendations: (1) Brain arteriovenous malformation (AVM) is a complex disease associated with potentially severe natural history; (2) The results of a randomized trial (ARUBA) cannot be applied equally for all unruptured brain arteriovenous malformation (uBAVM) and for all treatment modalities; (3) Considering the multiple treatment modalities available, patients with uBAVMs should be evaluated by an interdisciplinary neurovascular team consisting of neurosurgeons, neurointerventionalists, radiosurgeons, and neurologists experienced in the diagnosis and treatment of brain AVM; (4) Balancing the risk of hemorrhage and the associated restrictions of everyday activities related to untreated unruptured AVMs against the risk of treatment, there are sufficient indications to treat unruptured AVMs grade 1 and 2 (Spetzler-Martin); (5) There may be indications for treating patients with higher grades, based on a case-to-case consensus decision of the experienced team; (6) If treatment is indicated, the primary strategy should be defined by the multidisciplinary team prior to the beginning of the treatment and should aim at complete eradication of the uBAVM; (7) After having considered the pros and cons of a randomized trial vs. a registry, the panel proposed a prospective European Multidisciplinary Registry.

Object: This report has been prepared to ensure more uniform reporting of Gamma Knife radiosurgery treatment parameters by identifying areas of controversy, confusion, or imprecision in terminology and recommending standards., Methods: Several working group discussions supplemented by clarification via email allowed the elaboration of a series of provisional recommendations. These were also discussed in open session at the 16th International Leksell Gamma Knife Society Meeting in Sydney, Australia, in March 2012 and approved subject to certain revisions and the performance of an Internet vote for approval from the whole Society. This ballot was undertaken in September 2012., Results: The recommendations in relation to volumes are that Gross Target Volume (GTV) should replace Target Volume (TV); Prescription Isodose Volume (PIV) should generally be used; the term Treated Target Volume (TTV) should replace TVPIV, GTV in PIV, and so forth; and the Volume of Accepted Tolerance Dose (VATD) should be used in place of irradiated volume. For dose prescription and measurement, the prescription dose should be supplemented by the Absorbed Dose, or DV% (for example, D95%), the maximum and minimum dose should be related to a specific tissue volume (for example, D2% or preferably D1 mm3), and the median dose (D50%) should be recorded routinely. The Integral Dose becomes the Total Absorbed Energy (TAE). In the assessment of planning quality, the use of the Target Coverage Ratio (TTV/ GTV), Paddick Conformity Index (PCI = TTV2/[GTV · PIV]), New Conformity Index (NCI = [GTV · PIV]/TTV2), Selectivity Index (TTV/PIV), Homogeneity Index (HI = [D2% –D98%]/D50%), and Gradient Index (GI = PIV0.5/PIV) are reemphasized. In relation to the dose to Organs at Risk (OARs), the emphasis is on dose volume recording of the VATD or the dose/volume limit (for example, V10) in most cases, with the additional use of a Maximum Dose to a small volume (such as 1 mm3) and/or a Point Dose and Mean Point Dose in certain circumstances, particularly when referring to serial organs. The recommendations were accepted by the International Leksell Gamma Knife Society by a vote of 92% to 8%., Conclusions: An agreed-upon and uniform terminology and subsequent standardization of certain methods and procedures will advance the clinical science of stereotactic radiosurgery.

Objective: The current study retrospectively assessed delayed gamma knife radiosurgery (GKRS) in the management of high-grade glioma recurrences., Methods: A total of 55 consecutive patients with high-grade glioma comprising 68 World Health Organization (WHO) III and WHO IV were treated with GKRS for local recurrences between 2001 and 2007. All patients had undergone microsurgery and radiochemotherapy, considered as standard therapy for high-grade glioma. Complete follow-up was available in all patients; median follow-up was 17.2 months (2.5-114.2 months). Median tumor volume was 5.2 mL, prescription dose was 20 Gy (14-22 Gy), and median max dose was 45 Gy (30-77.3 Gy)., Results: The patients with WHO III tumors showed a median survival of 49.6 months with and a 2-year survival of 90%. After GKRS of the recurrences, these patients showed a median survival of 24.2 months and a 2-year survival of 50%. The patients with WHO IV tumors had a median survival of 24.5 months with a 2-year survival of 51.4%. After the recurrence was treated with GKRS, the median survival was 11.3 months and a 2-year survival: 22.9% for the WHO IV patients., Conclusion: The current study shows a survival benefit for high-grade glioma recurrences when GKRS was administered after standard therapy. This is a relevant improvement compared with earlier studies that had had not been able to provide a beneficial effect timing radiosurgery in close vicinity to EBRT., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Chemotherapy has made substantial progress in the therapy of systemic cancer, but the pharmacological efficacy is insufficient in the treatment of brain metastases. Fractionated whole brain radiotherapy (WBRT) has been a standard treatment of brain metastases, but provides limited local tumor control and often unsatisfactory clinical results. Stereotactic radiosurgery using Gamma Knife, Linac or Cyberknife has overcome several of these limitations, which has influenced recent treatment recommendations. This present review summarizes the current literature of single session radiosurgery concerning survival and quality of life, specific responses, tumor volumes and numbers, about potential treatment combinations and radioresistant metastases. Gamma Knife and Linac based radiosurgery provide consistent results with a reproducible local tumor control in both single and multiple brain metastases. Ideally minimum doses of ≥18Gy are applied. Reported local control rates were 90-94% for breast cancer metastases and 81-98% for brain metastases of lung cancer. Local tumor control rates after radiosurgery of otherwise radioresistant brain metastases were 73-90% for melanoma and 83-96% for renal cell cancer. Currently, there is a tendency to treat a larger number of brain metastases in a single radiosurgical session, since numerous studies document high local tumor control after radiosurgical treatment of >3 brain metastases. New remote brain metastases are reported in 33-42% after WBRT and in 39-52% after radiosurgery, but while WBRT is generally applied only once, radiosurgery can be used repeatedly for remote recurrences or new metastases after WBRT. Larger metastases (>8-10cc) should be removed surgically, but for smaller metastases Gamma Knife radiosurgery appears to be equally effective as surgical tumor resection (level I evidence). Radiosurgery avoids the impairments in cognition and quality of life that can be a consequence of WBRT (level I evidence). High local efficacy, preservation of cerebral functions, short hospitalization and the option to continue a systemic chemotherapy are factors in favor of a minimally invasive approach with stereotactic radiosurgery., (Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Radiosurgery is the main alternative to microsurgical resection for benign meningiomas., Objective: To assess the long-term efficacy and safety of radiosurgery for meningiomas with respect to tumor growth and prevention of associated neurological deterioration. Medium- to long-term outcomes have been widely reported, but no large multicenter series with long-term follow-up have been published., Methods: From 15 participating centers, we performed a retrospective observational analysis of 4565 consecutive patients harboring 5300 benign meningiomas. All were treated with Gamma Knife radiosurgery at least 5 years before assessment for this study. Clinical and imaging data were retrieved from each center and uniformly entered into a database by 1 author (A.S.)., Results: Median tumor volume was 4.8 cm³, and median dose to tumor margin was 14 Gy. All tumors with imaging follow-up < 24 months were excluded. Detailed results from 3768 meningiomas (71%) were analyzed. Median imaging follow-up was 63 months. The volume of treated tumors decreased in 2187 lesions (58%), remained unchanged in 1300 lesions (34.5%), and increased in 281 lesions (7.5%), giving a control rate of 92.5%. Only 84 (2.2%) enlarging tumors required further treatment. Five- and 10-year progression-free survival rates were 95.2% and 88.6%, respectively. Tumor control was higher for imaging defined tumors vs grade I meningiomas (P < .001), for female vs male patients (P < .001), for sporadic vs multiple meningiomas (P < .001), and for skull base vs convexity tumors (P < .001). Permanent morbidity rate was 6.6% at the last follow-up., Conclusion: Radiosurgery is a safe and effective method for treating benign meningiomas even in the medium to long term.

A dose gradient index (GI) is proposed that can be used to compare treatment plans of equal conformity. The steep dose gradient outside the radiosurgical target is one of the factors that makes radiosurgery possible. It therefore makes sense to measure this variable and to use it to compare rival plans, explore optimal prescription isodoses, or compare treatment modalities. The GI is defined as the ratio of the volume of half the prescription isodose to the volume of the prescription isodose. For a plan normalized to the 50% isodose line, it is the ratio of the 25% isodose volume to that of the 50% isodose volume. The GI will differentiate between plans of similar conformity, but with different dose gradients, for example, where isocenters have been inappropriately centered on the edge of the target volume. In a retrospective series of 50 dose plans for the treatment of vestibular schwannoma, the optimal prescription isodose was assessed. A mean value of 40% (median 38%, range 30-61%) was calculated, not 50% as might be anticipated. The GI can show which of these prescription isodoses will give the steepest dose falloff outside the target. When planning a multiisocenter treatment, there may be a temptation to place some isocenters on the edge of the target. This has the apparent advantage of producing a plan of good conformity and a predictable prescription isodose; however, it risks creating a plan that has a low dose gradient outside the target. The quality of this dose gradient is quantified by the GI.

Radiosurgery is considered one of the most revolutionary recent developments in the therapy of certain intracranial tumors. It is generally accepted that radiosurgery with the Gamma Knife or stereotactic Linac is the least invasive effective treatment for cerebral metastases. The Gamma Knife provides so far the highest possible and practically applicable precision of radiation. Radiosurgery of brain metastases with a size of less than 12 cm3 results in excellent local tumor control rates and very low associated morbidity. The Gamma Knife has been shown to be highly effective also against multiple metastases and is likewise effective even for tumors that are relatively resistant to traditional external beam radiation therapy. Radiosurgery replaces open tumor operation in some indications. As an additive therapy it allows the conventional surgeon to operate less radically resulting in a lower complication rate. The goal is short hospitalization time and increased quality of life.

Object: The purpose of this study was to assess the long-term treatment efficacy and morbidity of patients who undergo gamma knife radiosurgery (GKS) for craniopharyngioma., Methods: Twenty-one consecutive Swedish patients were evaluated retrospectively: 11 children (< or = 15 years) and 10 adults. The time from diagnosis to the most recent follow-up imaging study was 6.3 to 34.3 years (mean 18.2 years, median 16.8 years). Tumor volumes and morbidity from GKS or other treatments were assessed at the time of the most recent imaging study or at the time of a subsequent new treatment. The observation period ranged from 0.5 to 29 years (mean 7.5 years, median 3.5 years). The prescription dose ranged from less than 3 Gy to 25 Gy. The mean tumor volume was 7.8 cm3 (range 0.4-33 cm3). There were 22 tumors in 21 patients treated with GKS. Five of these tumors were reduced in size, three were unchanged, and 14 increased. Tumor progression correlated with a low dose to the tumor margin. Eleven (85%) of 13 tumors that received a dose of less than 6 Gy to the margin increased in size, whereas only three (33%) of nine tumors that received 6 Gy increased. This difference was statistically significant (p = 0.01). In five of six patients tumors that became smaller after GKS there were no recurrences within a mean follow-up period of 12 years. Nine (82%) of 11 tumors in children ultimately increased after GKS, compared with five (50%) of 10 in adults. In eight patients there was a deterioration of visual function. In all except one this could be related to a volume increase but radiation-induced damage could not be excluded as a factor in any of them. Four patients developed pituitary deficiencies., Conclusions: Gamma knife radiosurgery is effective in controlling growth of craniopharyngiomas with a minimum dose of 6 Gy. The findings also suggest that other stereotactic techniques, such as cyst aspiration and intracystic treatment, are only of value in reducing tumor volume in preparation for safe GKS.

Background: In symptomatic infants with chronic subdural fluid collections a variety of treatment strategies, such as observation, repeated subdural tapping, external or internal subdural drainage, and craniotomy have been advocated. Until now, the ideal management for this etiologically heterogenous group of children seems controversial., Methods: The authors present their treatment with subdural-peritoneal and subdural-atrial shunts and the follow-up in 8 infants (mean age, 7 months) with bifrontal subdural hygromas and hematomas caused by different etiologic conditions., Results: Initially, all children were symptomatic, and repeated subdural taps showed no clinical and neuroradiologic benefit. Shunting resulted in disappearance of all clinical signs in all infants, with complete removal of the chronic subdural fluid collections in 6 cases and remarkable improvement in 2 cases. In all infants the shunt system was removed after disappearance of signs and decrease of fluid collections. As the only complication the shunt system had to be removed in 1 case on the fourth postoperative day because of infection without any further disadvantages. In none of the cases was a recurrence of the fluid collections seen during the follow-up., Conclusion: These results suggest that in infants with symptomatic chronic subdural fluid collections who fail to respond to repeated tapping, the early placement of an unilateral subdural-peritoneal shunt with a low pressure valve represents a safe, benign, and effective treatment option.

Objective: To investigate whether angiograms obtained 2 years after radiosurgery, proving total arteriovenous malformation (AVM) occlusion, represent the final state of treated AVMs and adjacent normal vessels., Methods: Angiograms were obtained for 48 patients 5 to 24 years after gamma knife radiosurgery and 4 to 17 years after the AVMs had been proven to be totally occluded after the treatment; changes in normal vessels and signs of recanalization were recorded. Ten of the patients developed clinical symptoms attributable to the AVMs or the treatment after having been declared cured, whereas the other patients did not exhibit symptoms., Results: There was evidence of AVM nidi at the sites of previously occluded AVMs for two patients and of nidi adjacent to those sites for another two patients. Three of the four recurrent AVMs were associated with hemorrhaging. All patients who experienced hemorrhaging from previously occluded AVMs were < or = 14 years of age at the time of gamma knife radiosurgery. There were signs of segmental narrowing in normal vessels that had been irradiated with high doses (nine patients) or a low dose (one patient). The segmental narrowing decreased with time for four of these patients, was unchanged for four, and increased for two. These vascular changes did not produce clinical symptoms in any of the patients., Conclusion: There is a small possibility that AVMs may reappear after having been totally occluded after radiosurgery, especially in pediatric patients. Segmental narrowing in normal arteries after radiosurgery is a benign condition that rarely progresses and does not produce clinical symptoms.

Objective: To our knowledge, this is the first long-term follow-up study of high-dose single-session irradiation to the human brain and provides new data concerning late tissue reactions after irradiation to small target volumes. The long-term lesional brain changes in 14 patients subjected to bilateral gamma knife capsulotomy for otherwise intractable anxiety disorders were retrospectively analyzed by magnetic resonance imaging., Methods: The prototype gamma unit was used for the radiosurgical procedure, and the collimators provided rectangular cross-sectional fields with an anteroposterior diameter of 3 mm and a transverse diameter of 5 or 11 mm. Maximum target doses were 120 to 180 Gy. Magnetic resonance imaging was performed 15 to 18 years (mean, 17 yr) after treatment, and dose-volume histograms were calculated for the dose distributions., Results: One patient had been irradiated twice on one side. In all but one of the remaining 27 targets, lesions with a volume of less than 100 mm3 were revealed by magnetic resonance imaging. The volumes of the lesions were confined within the volume corresponding to a minimum dose of approximately 110 Gy, with one exception. In one of three targets receiving a maximum dose of 120 Gy, no lesion was detected. There were no late radiation effects such as cyst formations, telangiectasias, hemorrhagic infarctions, or neoplasms., Conclusion: This investigation indicates that a minimum dose of 110 Gy, with the currently used 4-mm collimator, to the edge of the target volume is required to create a lesion. The results prove that gamma knife surgery can be used in functional neurosurgery for producing small permanent lesions in the normal human brain.

Considerable but uncontrolled evidence suggests that stereotactic capsulotomy by means of thermolesions may provide symptomatic relief for patients with otherwise therapy refractory "malignant" obsessive compulsive disorder (OCD). Unlike in other functional stereotactic interventions, target localization for capsulotomy is based upon anatomical definition only. Few systematic attempts have been made to correlate the site and size of the capsular lesions with postoperative clinical outcome. Between 1976 and 1989 bilateral thermo-capsulotomy (TC) was performed in 22 OCD patients. In 19 patients complete quantitative pre- and postoperative psychiatric rating of OCD symptoms and long-term postoperative MRI studies were available. Cohorts of patients fulfilling criteria for good or poor outcome were contrasted, cases with intermediate treatment effect being excluded. Median postoperative MRI follow-up was 8.4 years (2.4-20.3 y). 9/19 patients fulfilled criteria for good postoperative outcome. In these patients all lesion sites overlapped covering a small area within the right anterior limb of the internal capsule. Lesions within the group of patients with poor outcome (n = 5) were located elsewhere, mostly further anterior in the internal capsule. Differences of lesion overlap between the two outcome groups were significant for the right side (Fisher's Exact Test: p < 0.005). Common topographic features of lesion sites within the right internal capsule were identified in OCD patients responding favourably to capsulotomy.

The current study analyses the long-term clinical course of 12 patients with pineal germinomas. The histological diagnosis was established by stereotactic biopsy in all cases. In 11 of the 12 cases the diagnosis was correct. There was no operative mortality or morbidity. All patients were treated by external radiotherapy. The median follow-up period for the surviving patients is 5.9 years (range 4.5-8.8 years). After radiotherapy, CT and MRI follow-up examinations showed complete tumor remissions with no local tumor recurrences in all cases. Two patients died of other, unrelated, illnesses 1.4 and 5.8 years after diagnosis of the pineal germinoma. Since long-term survival and morbidity do not document any superiority of operative resection of germinomas, the minimally invasive approach with stereotactic biopsy and radiotherapy is strongly advocated. There is no longer any justification for irradiating pineal tumors to check the diagnosis now that stereotactic biopsy is available.

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 (MRGlu) for meningiomas was 0.26 +/- 0.13 mikromol/g/min (range 0.08-0.62 mikromol/g/min). The relative tumor FDG-uptake (Q-MRGlu) (tumor/contralateral cortex) of all meningiomas was calculated with 0.73 +/- 0.37 (0.24-1.79). Differences of Q-MRGlu were significant between the groups with high vs. low cellularity (p < 0.01), increased vs. normal proliferation rate (p < 0.025) and low (WHO grade I) vs. higher (WHO grades II, III) graded tumors. In recurrent meningiomas (14 tumors) the glucose metabolism was not increased. The data show that 18 FDG-PET is suitable to serve as non-invasive predictor of tumor growth characteristics in meningiomas.

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake of 25 human meningiomas was preoperatively evaluated in vivo by positron-emission tomography (PET). After surgery, meningioma biopsies were analyzed cytogenetically. Five meningiomas showed partial monosomy for chromosome 1p additional to other typical chromosome aberrations. This aberrant karyotype was correlated with increased FDG uptake. Three of five meningiomas with monosomy 1p were classified as grade II according to WHO, while only one of 20 tumors without monosomy 1p was classified as grade II. Thus, monosomy 1p and elevated FDG uptake in PET are to be regarded as cytogenetic and metabolic parameters for the aggressiveness of meningiomas.

The global improvement of all parkinsonian symptoms after stereotactic pallidotomy has been demonstrated by Leksell. Recently, Laitinen, re-evaluating this target in the neurosurgical treatment of Parkinson's disease, confirmed the real value of this approach, and emphasized the necessity of locating the lesion in the ventroposterolateral part of the pallidum internum. Because we know that high-frequency stimulation of the ventrolateral part of the thalamus has the same clinical effect on tremor as high-frequency coagulation, this technique has now been applied bilaterally in one session in three patients who have severe Parkinson's disease, with akinesia and levodopa-induced dyskinesias in the foreground. The very satisfactory clinical results, up to 12 months in the first case, confirm the observation of Laitinen, but with the difference that the approach discussed here is both nondestructive and reversible, and unwanted side effects are avoided.

62 intracranial meningiomas in 60 patients were studied with 18FDG-PET prior to neurosurgery in order to evaluate the relationship between 18FDG uptake and biological aggressiveness of the tumors. Histopathological grading, cellular density, Ki-67 proliferation index and evidence of chromosomal aberrations were used to assess tumor aggressiveness. Significantly elevated 18FDG uptake was found in grade 2- and 3- compared to grade 1-meningiomas, in tumors of high cellularity compared with those of low cellularity, and in meningiomas with an elevated Ki-67 proliferation index (above 2%). The two meningiomas with the most pronounced chromosomal aberrations revealed the highest 18FDG uptake of all cytogenetically studied meningiomas. We conclude that 18FDG-PET is useful for estimating the biological aggressiveness of intracranial meningiomas.

Since 1982, we have been able to control involuntary movements associated with deaf-ferentation by means of chronic electrical stimulation of the thalamic sensory nucleus through implanted programmable neuropacemakers. Since 1987, we have been using the same system with electrodes chronically implanted in the VL for treating selected cases of tremor due to Parkinson's disease, multiple sclerosis and in cases of essential tremor. In our series of 60 patients, suppression of tremor was achieved in almost all cases; however, due to dysarthria in 30% of the cases (cases after previous thalamotomy in the other side or with bilateral stimulation), the amplitude of stimulation was corrected and thus some tremor was still observed. The rigidity of parkinsonism was in all cases improved. One case of hemiballism was perfectly controlled with the same technique. Finally, 3 cases of Parkinson's disease with severe hypokinesia, speech and gait disturbances, and on-off phenomenon have been globally improved by a bilateral chronic stimulation of the pallidum.

This report describes a patient who developed bilateral chronic subdural haematomas after a stab injury to the thoracic meninges causing prolonged cerebrospinal fluid leakage into the epidural space. Diagnostic findings and therapeutic management are presented and possible pathogenic mechanisms are discussed. This case suggests that patients who have symptoms or signs of increased intracranial pressure after a penetrating spinal injury should be studied for subdural haematoma.

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.

A simple system for cerebral angiography under stereotactic conditions using standard components is described. X-ray tubes and power generator belong to the usual equipment of the stereotactic operating room. A film changer and an injection pump were integrated into the stereotactic arrangement. Angiographic documents with reduced X-ray magnification were obtained. For topographical orientation 5 films per seriogram were sufficient. The system also allows stereoscopic viewing by performing an additional oblique sequence after the head ring is rotated exactly 6 degrees. The combination of the necessary diagnostic procedures, as CT scan, angiography, ventriculography, serial biopsy within a single three coordinate reference system offers considerable advantages for brain tumour patients.

In previous studies we demonstrated that administration of buthionine sulfoximine (BSO) to athymic BALB/c mice bearing intracranial human glioma xenografts resulted in highly selective depletion of glutathione in neoplastic tissue with minimal effects on contralateral normal brain tissue. In the present study we treated athymic BALB/c mice bearing intracranial human glioma (D-54 MG) or medulloblastoma (TE-671) xenografts with melphalan alone or BSO followed by melphalan. Administration of BSO depleted intracellular glutathione to 7.5% of the control level. BSO plus melphalan resulted in a significant increase in median survival over that produced by melphalan alone: 45.3% versus 26.4% in TE-671 and 69% versus 27.6% in D-54 MG. These studies justify further efforts to modulate chemotherapeutic and radiotherapeutic interventions of primary malignant brain tumors by depletion of glutathione.

It is always difficult to interpret abnormalities in pupillary reflexes when a patient who has suffered injuries to the upper part of the face is unconscious. Nevertheless, thorough examination of pupillary reflexes can provide vital information about possible damage to the central nervous system. Decisions about treatment of and prognosis for patients with multiple injuries can be made more accurately when the status of the nerves supplying the eye are taken into account. Anatomical and physiological relationships of pupillary reflexes and oculomotor reactions in a patient with multiple injuries are discussed.