A new embolic material for brain arteriovenous malformations (AVMs)—Onyx liquid embolic system—has become available in Japan. We report our initial experience with surgical resection of AVMs after Onyx embolization and the pathological findings of the resected specimens.
AVMs of three patients were embolized with Onyx followed by surgical resection. A high rate of Onyx penetration into the nidus was obtained when the plug of Onyx was formed around the tip of the microcatheter navigated as closely to the nidus as possible. Otherwise, Onyx injection resulted in partial occlusion of the nidus or proximal occlusion of the feeders. Total resection of the nidus was safely achieved in every case. The plane of dissection between the brain and the embolized nidus that demonstrated a firm consistency was easily identified. Uncontrollable bleeding from the perinidal capillary network was rarely encountered. Pathological examination did not show angionecrosis in the walls of the embolized vessels. Infiltration of macrophages was observed in the embolized vessels in the specimens resected more than five days after embolization.
Onyx embolization followed by surgical resection is a safe and effective treatment for AVMs.