Intracranial arteriovenous malformations treated with linear accelerator–based conformal radiosurgery: clinical outcome and prediction of obliteration

BackgroundLittle is written about the clinical outcome and predictor factors of obliteration and treatment success in patients with intracranial AVMs treated with LINAC-based conformal radiosurgery in Mexican institutions.MethodsWe analyzed 40 patients with intracranial AVMs with a mean follow-up of 29 (range, 23-34) months. Seven AVMs (17.5%) had a volume <1 cm3; 10 (25%), 1 to 4 cm3; 13 (32.5%), 4.1 to 10 cm3; and 10 (25%), >10 cm3. The mean prescription dose was 15.4 Gy. Twenty-six patients (68%) presented hemorrhage before treatment; 4 (10%), chronic headache; 14 (35%), seizures; and 3(8%), neurologic deficit.ResultsSeven patients (17.5%) underwent objective clinical improvement. Thirty patients (75%) remained without clinical changes. Three patients (7.5%) developed edema and 1 (2.5%) had a rebleeding after treatment. Twenty-five patients (63%) presented complete obliteration of the AVM. A successful treatment (obliteration without a new deficit) was obtained in 23 (58%) of the cases. The percentage of obliteration was in <1 cm3 (86%), 1 to 4 cm3 (80%), 4.1 to 10 cm3 (54%), and >10 cm3 (40%), without a significant difference between groups (P = .1). Patients with RBAS of ≤1.9 had an obliteration of 79% and, those with >1.9, 48%; the successful treatment in the former resulted in 79% and, in the latter, 38% (P = .08 and P = .02, respectively).ConclusionsThe clinical outcome was similar to other series. The RBAS seems to be a good predictor of obliteration and successful treatment in patients with AVMs treated with LINAC-based conformal radiosurgery.