Stereotactic radiosurgery of cerebral arteriovenous malformations: long-term follow-up in 164 patients of a single institution

This retrospective study aimed to investigate long-term outcome in patients with arteriovenous malformations (AVM) treated with stereotactic radiosurgery (SRS). Between 1998 and 2008, 164 patients with AVM received SRS. Median age was 36 years (range 7–69 years). Before SRS, 39 % of the patients experienced haemorrhage and 27 % suffered from epileptic seizures, whereas 43 % received previously embolization, 7.9 % neurosurgery and 1.8 % proton radiotherapy. Primary SRS was applied in 51.2 % of the patients. Median single dose was 19 Gy (80 % isodose; range 18–20 Gy) and median target volume was 4 cc (range 0.1–24.4). Median follow-up was 93 months (range 12–140). Complete obliteration (CO) was observed in 100 (61 %) patients at a median time of 29 months (range 6.1–88.5). The 3 and 5-year CO rates were 61 and 88 %, respectively. In multivariate analysis, radiation dose ≥19 Gy (p = 0.044) and target volume <4 cc (p = 0.015) were associated with significantly higher rates of CO. Intracranial haemorrhage was seen in nine patients (5.5 %) after SRS, whereas three patients (1.8 %) died as a consequence of bleeding. The annual bleeding risk was 1.3 % after 1 year and 1.3 % after 2 years, respectively. In multivariate analysis, only target volume >4 cm³ (p = 0.031) and Spetzler–Martin grade III–V (p = 0.046) retained significance for increased risk of intracranial bleeding. After SRS an improvement in epileptic episodes, headaches and motor-sensory deficits was found in 8.5, 14 and 15 % of patients, respectively. Our long-term follow-up data show that SRS is an effective treatment option in AVM with low toxicity and bleeding risk, depending on AVM size and Spetzler–Martin grade. An improvement of neurologic symptoms is achievable.