Factors related to complete occlusion of arteriovenous malformations aftergamma knife radiosurgery

Object. The authors sought to evaluate the effects of gamma knife radiosurg ery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors as sociated with complete occlusion. Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eig ht lesions in 254 patients who were treated with GKS from May 1992 to Decem ber 1999 were analyzed. Several clinical and radiological parameters were e valuated. Conclusions. The total obliteration rate for the cases with an adequate rad iological follow up of more than 2 years was 78.9%. Tn multivariate analysi s, maximum diameter, angiographically delineated shape of the AVM nidus, an d the number of draining veins significantly influenced the result of radio surgery. In addition, margin radiation dose, Spetzler-Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In a ddition to the size, topography, and radiosurgical parameters of AVMs, it w ould seem to be necessary to consider the angioarchitectural and hemodynami c aspects to select proper candidates for radiosurgery.