A retrospective analysis of 139 patients with brain stem cavernous malformations is presented. The material consists of 41 cases from Bern and Phoenix and 98 further well-documented cases from the literature. Sixty-eight patients were male, 70 were female. The average age was 31.8 + 11.8 years. Sixty-two percent of the cavernous malformations were in the pons, 14% were in the mesencephalon, 12% were in the pontomesencephalic and in the pontomedullary junction, and 5% were in the medulla. Eighty-eight percent of the patients showed evidence of recent or previous hemorrhage, 55% had one hemorrhage. 17% had two hemorrhages, and 17% had three or more hemorrhages. Twelve patients died from a hemorrhage, 5 with the first bleeding and 7 with a rebleeding. The minimum bleeding rate was 2.7% per year and the average rebleeding rate 21% per year and per lesion. Most lesions had a diameter between 10 and 30 mm. Increase in size was observed in 12 of the patients; this corresponds to about 21% when only patients with a follow-up of at least one year are considered. In 93 patients the cavernous malformation was removed operatively while in 30 patients the lesion was not removed. In the group with conservative management at the end of the observation period (up to 25 and 32 years), 66.6% had no or only a slight neurological deficit, 6.7% were moderately disabled, 6.7% were completely dependent, and 20% had died. In the group treated surgically 83.9% had no or only a slight neurological deficit, and 15% were moderately disabled. One patient remained severely disabled, no patient died. The limitations of the retrospective nature of this study are stressed.

Identification of the cortical area responsible for motor hand function was similar with functional MR imaging and with direct stimulation at surgery. A space-occupying lesion can change the cortical representation of motor hand function.

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

Of 168 patients operated on consecutively for a supratentorial cavernous malformation, 77 had seizures as the initial symptom. The effectiveness of surgery in controlling seizures and the risk of surgery were evaluated by retrospective review of the patients' charts. The follow-up period was 1 to 9 years (mean 39 months) and the review period totalled 284 lesion-years. Only two patients showed postoperative deterioration in neurological status (morbidity risk: 2.6%), no patient died (mortality: 0%). Sixty-eight (88.3%) patients were seizure-free after operation and five (6.5%) showed a marked reduction in the frequency of their seizures. This corresponds to an overall positive effect of surgery of 94.8% of the patients. There was no substantial evidence that excision of the haemosiderin-stained tissue around the cavernoma along with the lesion itself provided better results than resection of only the cavernoma. Better results with regard to seizure control, however, were associated with shorter duration of symptoms before surgery.

In 30 patients the anatomical configurations of the precentral and central sulcus and gyrus were examined by computed tomography and could be determined with great accuracy. The distances between the coronal suture and the central and precentral fissure, and the angle between the longitudinal fissure and the central fissure were measured. These data are used in the precise localization for a surgical approach to a mass lesion.