Gamma Knife radiosurgery: indications, techniques, and results in 200 patients treated at the Midwest Gamma Knife Center.

During radiosurgery, a single high dose of ionizing radiation is delivered with exquisite precision to a radiographically defined intracranial target. More than 60,000 patients have been treated worldwide since the first Gamma Knife was installed in Stockholm in 1968. Indications include arteriovenous malformation, cerebral metastasis, acoustic neuroma, meningioma, malignant glioma, and trigeminal neuralgia. Two hundred patients have been treated at the Midwest Gamma Knife Center in the first 21 months of operation beginning in September 1994.

Long-term results of microlumbar discectomy.

A long-term prospective study was carried out of 100 consecutive patients undergoing microlumbar discectomy (MLD) and fulfilling stringent selection criteria. A 95% long-term follow-up result was obtained at a mean duration of 8.6 years. At the 7-11-year assessment, 88% of patients had an excellent result, 5% a good result and 7% had either a poor result or new symptoms. Ten patients (10.5%) underwent repeat MLD during the course of the study; nine of the ten reoperations were performed at the same level as the original surgery. The percentage with an excellent result remained relatively constant (88-89%) throughout the study. No reliable predictors of long-term outcome were identified. The results suggest that microlumbar discectomy compares favourably with other surgical techniques with regard to long-term outcome.