Critical appraisal of endovascular treatment of brain arteriovenous malformation using Onyx in a series of 92 consecutive patients

Background: The introduction of Onyx has led us to adopt a new treatment approach for brain arteriovenous malformation (AVM), using endovascular embolization with Onyx as the first line treatment with a curative intent. The aim of the present report is to evaluate our results using this strategy, with special emphasis on angiographic characteristics affecting treatment risks and success rates. Methods: From October 2006 to December 2009, 92 consecutive patients harboring brain AVM were treated with Onyx during 177 procedures. Results: Endovascular treatments were completed in 68 out of 92 patients. Median number of procedures was two. Complete obliteration using embolization exclusively was achieved in 25 patients, resulting in a 37 % cure rate in patients who concluded treatments (25/68), and 27 % in the cohort. In Spetzler-Martin grades 1 & 2 AVMs, complete obliteration was achieved in 48 % of the cases. Complete obliteration rates were significantly higher in lesions with superficial big feeding arteries. There were 15 bleeding complications during 177 embolization sessions (8.4 % per procedure); seven cases resolved in less than 3 months. Permanent disability rate was 6.5 %; mortality rate was 2.2 %. Bleeding was related to the use of the microcatheter/guidewire in six cases and to the use of the embolization material in nine, the amount of Onyx injected was significantly higher in those nine cases. Conclusions: Embolization of brain AVM using Onyx and detachable tip microcatheters results in a relatively high rate of complete obliteration. Angioarchitecture of the lesion can predict treatment success. Higher amounts of Onyx injected per session increase the bleeding risk.