Linear accelerator radiosurgery for brain arteriovenous malformations

Objective: To estimate the results of the arteriovenous malformations treated with linear accelerater-based radiosurgery （Linac RS）. Methods: Fifty-four patients with AVMs were treated between June 1994 and March 2000, there were 36 males and 18 females, mean age 26 yr（11-52 yr）. The diameter of the lesions ranged 1.2-6.0cm（mean 2.9cm）. The AVMs were Grade Ⅰin13 cases, Grade Ⅱin 15 cases, Grade Ⅲ in 21 cases, and Grade Ⅳ in 5 cases, according to the Spetzler-Martin Scale. Twenty-one patients （38.9%） underwent one or more embolization procedures before radiosurgery, 5 patients （9.3%） had undergone incomplete resection of their lesions. Fifty patients were treated with single isocenter and 4 patients with 2 isocenters. The marginal dose ranged from 12 to 23 Gy （mean, 17.9 Gy）. The median follow-up period was 64.8 months（14-82 months）. Results: Presenting symptoms included dizziness and headache were completely relieved after treatment in 34 patients（62.2%）, improved in 5 patients （9.3%）, and unchanged in other cases. Among the 23 patients with seizures, 9 completely relieved after radiosurgery, 10 improved and 4 were unchanged. In this series, the obliteration rate at 2 years after radiosurgery was 81.5%（44/54）. Postradiosurgery hemorrhage occurred in 3 of 54 patients（5.6%） within 1 year. One patient had complete AVMs resection at 9 month after radiosurgery for its rebleeding. Two patients had delayed symptomatic radiation edema.Conclusion: Linac SRS provides a safe and effective management strategy for AVMs, especially in the deep-seated or eloquent areas. It can effectively decrease morbidity, mortality and rebleeding rate, and relieve clinical symptoms.