Clinical outcome after repeated radiosurgery for brain arteriovenous malformations

IntroductionWe assessed the clinical and radiological outcome after repeated radiosurgery for brain arteriovenous malformations (bAVMs) after failure of initial radiosurgery.Materials and methodsFifteen patients underwent repeated radiosurgery. The mean bAVM volume at first radiosurgery (S1) was 4.6 ± 4.3 ml and that at second radiosurgery (S2) was 2.1 ± 2.5 ml. The median marginal dose was 18 Gy at S1, and 21 Gy at S2. Modified Rankin Scale (MRS) score was determined in all patients at last follow-up (FU).ResultsComplete obliteration was reached in nine patients (60%). Median time to obliteration was 50 months after S2. An excellent outcome (no new neurologic deficiencies, complete obliteration) was reached in seven patients (47%). Eleven patients (73%) showed a MRS ⩽ 1. Radiation-induced complications occurred in 20%, of which 13% occurred after S2. Radiological complications included cyst formation (n = 1), radiation-related edema (n = 4), and radiation necrosis (n = 1), resulting in an increasing mean MRS of 0.5 at S1, 0.6 at S2, to 0.8 at FU. No (re-)bleedings were encountered during 137-patient years at risk.DiscussionRepeated radiosurgery is a viable option for the treatment of small remnant bAVMs. We report 20% permanent radiation-induced complications. Such complications were mainly seen in relatively large, and therefore difficult to treat, bAVMs.