Rotating Gamma System Radiosurgery for Cerebral Arteriovenous Malformations

Abstract

One hundred and thirty-two patients with cerebral arteriovenous malformations (AVMs) were treated using the Rotating Gamma System, a new radiosurgical system between November 1996 and May 2000. The average size of the AVMs was 23 mm in diameter (range 6 to 69 mm). The mean dose delivered to the AVM margin was 19.2 Gy (range 13 to 25 Gy), and that delivered to the center of the AVMs was 37.6 Gy (range 32.5 to 50 Gy). One hundred and six patients were followed up for an average of 18.4 months (range 5 to 44 months). Five patients (4.7%) experienced rebleeding which took place between 5 and 13 months after treatment, but none of them died from hemorrhage. No bleeding took place after complete angiographic obliteration. Neuroimaging studies showed radiation-induced edema in 19 (22%) of the 87 patients, none of whom had severe permanent neurological deficits. Of the 68 patients followed up for more than one year, 57 underwent angiography at 1 year after treatment. The complete obliteration was demonstrated in 24 patients (42%) at 1 year. Of the 27 patients followed for more than 2 years, 23 patients underwent angiography 2 years after treatment, and complete obliteration was demonstrated in 18 patients (78%). These results are comparable to the results of treatment with other radiosurgical systems.