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Notes: Summary  Background. The standart surgical treatment of meningiomas is total resection of the tumour. The complete removal of skull base meningiomas can be difficult because of the proximity of cranial nerves. Stereotactic radiosurgery (SRS) is an effective therapy, either for adjuvant treatment in case of subtotal or partial tumour resection, or as solitary treatment in asymptomatic meningiomas.  Method. Between September 1992 and October 1995, SRS using the Leksell Gamma Knife was performed on 46 patients (f:m=35:15), ranging in age from 35 to 81 years, with skull base meningiomas at the Neurosurgical Department of the University of Vienna. According to the indication of gamma knife radiosurgery (GKRS) the patients (n=46) were devided into two subgroups. Group I (combined procedure: subtotal resection followed by GKRS as a planned procedure or because of a recurrent meningioma), group II (GKRS as the primary treatment). Histological examination of tumour tissue was available for 31 patients (67%) after surgery covering 25 benign (81%) and 6 malignant (19%) meningioma subtypes.  Findings. The overall tumour control rate after a mean follow-up period of 48 months (ranging from 36 to 76 months) was 96% (97.5% in benign and 83% in malignant meningiomas). Group I displayed a 96.7% tumour control rate, followed by group II with 93.3% respectively. Neurological follow-up showed an improvement in 33%, stable clinical course in 58% and a persistant deterioration of clinical symtoms in 9%. Remarkable neurological improvement after GKRS was observed in group II (47%), whereas in group I (26%) the amelioration of symptoms was less pronounced.  Interpretation. GKRS in meningiomas is a safe and effective treatment. A good tumour control and low morbidity rate was achieved in both groups (I, II) of our series, either as a primary or adjunctive therapeutic approach. The planned combination of microsurgery and GKRS extends the therapeutic spectrum in the treatment of meningiomas. Reduction of tumour volume, increasing the distance to the optical pathways and the knowledge of the actual growing tendency by histological evaluation of the tumour minimises the risk of morbidity and local regrowth. Small and sharply demarcated tumours are in general ideal candidates for single high dose-GKRS, even after failed surgery and radiation therapy, and in special cases also in larger tumour sizes with an adapted/reduced margine dose.

Notes: Summary  Background. In noncontiguous spinal metastatic disease, anterior or combined anterior-posterior surgery is an effective treatment. The objective of this study is to investigate whether circumferential decompression through a single-stage posterior midline approach with individualized spinal reconstruction can still achieve comparable results for functional improvement and for maintenance of spinal alignment in the absence of the risks associated with the more invasive transcavitary or combined approaches.  Method. Seventeen patients with noncontiguous spinal metastases and plasmocytomas at one or two adjacent levels were included in this series. Circumferential decompression was obtained with anterior reconstruction and posterior fixation in ten patients, and with posterior instrumentation alone in seven patients. Postoperatively the patients were prospectively followed, and their functional status and spinal alignment were periodically evaluated.  Findings. Fourteen patients died from progression of their underlying cancer. Their mean survival time was 8 months (range: 1 to 21 months). Three survivors were evaluated at 10, 4 and 3 months respectively. At one month after surgery, 14 patients (82%) showed neurological improvement. Of 10 preoperative nonambulators, seven regained walking capacity. Five patients who were ambulatory with assistance improved to full functional independence. Local tumour recurrence was recorded in one patient after subtotal vertebrectomy for a plasmocytoma at L5. No other tumour recurrences were noted. In one patient a partial loss of correction occurred at T6 – without functional deterioration, however. Spinal alignment was maintained in all other patients who became or remained ambulatory. No major intra-operative complications or peri-operative deaths occurred. CSF leakage was recorded as the most common complication in four patients.  Interpretation. Circumferential decompression and spinal reconstruction through a single-stage posterior midline approach is feasible and effective. The extent of surgery can be individualized by means of this technique to the patient's specific problem. In patients with limited life expectancy from metastatic neoplastic disease, the results compare favourably with the more invasive anterior or combined antero-posterior procedures.