Abstract 156: Embolization Followed by Radiosurgery for the Treatment of Brain Arteriovenous Malformations (AVMs)

Purpose: Multimodality therapy of brain AVMs with embolization followed by radiosurgery is controversial. We present the largest case series to date of AVM patients treated with embolization and radiosurgery. Methods: Retrospective review of our institutional AVM database identified 92 patients treated from 1995-2009 with embolization followed by radiosurgery. Patients treated with surgery or radiosurgery prior to embolization were excluded. Pre- and post-embolization AVM volumes were calculated using angiography. The modified Pollock-Flickinger (PF) score was also calculated pre and post-embolization. PF scores from pre-embolization volumes were used to report obliteration rates. Post-radiosurgical obliteration was assessed using angiography or MRI. Results: Mean AVM volume went from 19.95 ml (IQR, 10.3 - 32.75) to 10.17 (3.15 - 20.65) following embolization (p<0.001) and mean PF scores decreased from 2.78 (1.77-3.94) to 1.83 (1.07 - 2.79), p<0.001. 2/92 (2.2 %) had new fixed deficits following embolization, however no patient had new disabling deficits (mRS>2). 61/92 (66%) have had ≥3 year follow-up and 35/61 (57%) had excellent outcomes (complete obliteration without neurologic decline). Excellent outcome was seen in 88% of patients with modified PF score <1, 67% of patients with score 1-1.5, 44% patients with score 1.5-2, and 48% of patients with score >2. In addition 16 patients had complete obliteration with further treatment (total 51/61 patients- 84%). Two patients died in the follow-up period due to AVM bleed. Conclusion: These data suggest that embolization of brain AVMs can safely and effectively reduce the treatment volume prior to radiosurgery. Combined therapy with embolization and radiosurgery does not adversely affect rates of excellent outcome.