TREATMENT OF BRAIN ARTERIOVENOUS-MALFORMATIONS BY EMBOLIZATION AND RADIOSURGERY

Embolization was used to reduce the size of brain arteriovenous malfor mations (AVMs) prior to radiosurgical treatment in 125 patients who we re poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at ano ther institution. According to the Spetzler-Martin scale, the AVMs wer e Grade II in 9.6%, Grade In in 31.2%, Grade IV in 30.4%, and Grades V to VI in 28.8% of the cases. Most embolizations were performed using cyanoacrylate delivered by flow-guided microcatheters. Radiosurgery wa s performed using a linear accelerator in 62 patients treated by the a uthors, and 34 patients were treated at other institutions using vario us methods. Embolization produced total occlusion in 11.2% of AVMs and reduced 76% of AVMs enough to allow radiosurgery. Radiosurgery produc ed total occlusion in 65% of the partially embolized AVMs (79% when th e residual nidus was <2 cm in diameter). Embolizations resulted in a m ortality rate of 1.6% and a morbidity rate of 12.8%. No complications were associated with radiosurgery. The hemorrhage rate for partially e mbolized AVMs was 3% per year. No patient with a completely occluded A VM experienced rehemorrhage. Angiographic follow-up review of AVMs emb olized with cyanoacrylate demonstrated a 11.8% revascularization rate, occurring within 1 year. It is concluded that after partial embolizat ion with cyanoacrylate, the risk of hemorrhage from the residual nidus is comparable to the natural history of AVMs and that the residual ni dus can be irradiated with results almost as good as for a native AVM of the same size.