Combined staged therapy of complex arteriovenous malformations: initial experience.

Definitive treatment of complex supratentorial arteriovenous malformations (AVMs) has been classically assigned to ruptured or progressively symptomatic cases. The aim of this study is to report our initial experience in the treatment of complex AVMs by means of staged embolization with Onyx followed by microsurgery. Thirteen consecutive patients with supratentorial Spetzler-Martin grades III, IV and V AVMs were treated between January 2009 and June 2010. Mean age at the beginning of the therapy was 34. All patients were symptomatic. Mean AVM size was 48 mm, and mean volume prior to embolization was 47 ml. Mean number of endovascular procedures was 3, and mean volumetric obliteration prior to surgery was 79.2%. Mean time between two embolizations was 24 days. One patient showed a non-disabling complication after endovascular procedures. Mean time between the last embolization and surgery was 42 days. Two patients showed disabling complications after surgery, and one patient showed a non-disabling complication. Follow-up angiography showed the complete removal of permeable AVM in all patients. According to the modified Rankin Scale, all patients were non-dependent concerning daily life activity at 6-month follow-up. One-year follow-up angiography has been performed in 11 patients so far showing an absence of permeable AVM in spite of the remainder intravascular Onyx. Staged preoperative embolization with Onyx followed by microsurgery has made possible 100% cure of complex AVMs with 0% mortality, 15.4% disabling complications and 15.4% non-disabling complications. Complete Onyx resection is not essential to achieve the cure of the patient.