Progress in neurological surgery
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The purpose of this study was to analyze tumor control and possible complications of gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas using low marginal doses and conformal multiple shots to fit irregular tumor shapes. The authors evaluated 152 patients with more than 5 years of follow-up. Marginal doses were 9-15 Gy (median 12 Gy), with corresponding treatment volumes ranging from 0.1 to 18.7 cm3 (median 2.0 cm3). ⋯ Hydrocephalus was recognized in 5.3% of all patients, and tended to occur in cases with larger tumors (p = 0.0024). GKRS provides a safe and effective therapy for small to medium-sized tumors. However, indications for larger tumors must be carefully considered, as they are more difficult to control and liable to produce ataxia due to transient expansion.
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Gamma knife (GK) thalamotomy for functional disorders, primarily Parkinson disease and central pain, are described herein. The goal was to extend our present indications for selective thalamotomy. Our target for tremor surgery is about 45% of the thalamic length. ⋯ In most of our cases, the protocol was 130 Gy, delivered in one shot with a 4-mm collimator. The time courses of thalamic lesion changes and clinical improvement after irradiation were assessed. Thus, despite thalamic reaction changes being variable, we achieved a clinical success rate of approximately 80% with negligible complications.