Onyx embolization prior to stereotactic radiosurgery for brain arteriovenous malformations: a single-center treatment algorithm.

BACKGROUND: Embolization before stereotactic radiosurgery (SRS) for brain arteriovenous malformations (BAVMs) is controversial.

OBJECTIVE: To compare clinical and radiographic outcomes in patients undergoing pre-SRS embolization with ethylene copolymer (Onyx) with outcomes in patients undergoing SRS alone.

METHODS: Seventy consecutive patients with BAVMs who underwent SRS were retrospectively reviewed. Univariate and multivariate analyses were performed to assess the factors associated with radiographic obliteration and complication.

RESULTS: Forty-one (59%) patients presented without BAVM rupture and 29 (41%) patients presented with rupture. Pre-SRS embolization was used in 20 patients (28.6%; 7 unruptured and 13 ruptured). Twenty-five of 70 (36%) patients sustained a complication from treatment, including 6 (9%) patients with a post-SRS latency period hemorrhage. Ten (14%) patients had persistent neurological deficits after treatment. Functional outcome (as modified Rankin Scale), complication rate, and radiographic obliteration at last follow-up were not significantly different between embolized and non-embolized groups in both unruptured and ruptured BAVMs. For unruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 23% and 73% for non-embolized patients and 20% and 60% for embolized patients, respectively. For ruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 45% and 72% for non-embolized patients and 53% and 82% for embolized patients, respectively.

CONCLUSION: Pre-SRS embolization with Onyx was not associated with worse clinical or radiographic outcomes than SRS treatment without embolization. Pre-SRS embolization has a low complication rate and can safely be used to target high-risk BAVM features in carefully selected patients destined for SRS.