Gamma knife radiosurgery for arteriovenous malformations: the Furukawa experience.

The Furukawa experience treating 534 patients with cerebral arteriovenous malformations using gamma knife radiosurgery (GKRS) is summarized. By repeating radiosurgery for any residual nidus after the first GKRS, the rates of cumulative complete obliteration 7 years after this initial GKRS, according to four volume categories (< or =1, 4 > or = >1, 10 > or = > 4, > 10cm3), were 92, 89, 68 and 43%, respectively. Bleeding after GKRS was observed in 8.1% of the patients and was more frequently seen in patients with a large nidus and history of bleeding two or more times before GKRS. Cyst formation was recognized in 4.7% of patients, two thirds of which required some form of surgical intervention. Refinement of the total GKRS system contributed to earlier and more effective nidus obliteration.