Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations: Past, Present and Future

Stereotactic Radiosurgery (SRS) is a minimally invasive and effective therapeutic modality for appropriately selected patients harboring intracranial arteriovenous malformations (AVMs). For patients with Spetzler-Martin grade I or II AVMs, microsurgery often offers safe and effective treatment [1,2]. However, treatment of Grade IV or V AVMs remains challenging and involves significant risks with lower success rates regardless of treatment modality [3,4]. In a recent retrospective review of 110 patients with high-grade AVMs treated with SRS, we found low obliteration rates of 10% and 23% at 3 and 5 years, respectively [3]. In the same study, symptomatic radiation-induced changes (RIC) were observed in 12% of patients, with permanent post-SRS clinical deterioration occurring in 10% of patients. For patients with large (>10 cm3) AVMs unsuitable for surgery a volumestaged SRS approach has endorsed by certain groups. Kano et al. reported cumulative obliteration rates of 28% and 35% at 5 and 10 years, respectively, for these patients following two-stage SRS [4]. No mortality was observed in the study, but 13% of patients suffered from symptomatic adverse radiation effects. Although SRS may be used to treat large AVMs with moderate efficacy, the optimal management strategy, including the risks versus benefits of surveillance compared to multimodality therapy, for these lesions is still unclear.