Intra-aneurysmal Onyx embolization for distal aneurysms of the cerebellar arteries

Background: Distal cerebellar artery aneurysms are difficult to treat both surgically and endovascularly. The purpose of this study is to assess the efficacy and safety of intra-aneurysmal Onyx embolization of these lesions with parent artery preservation. Methods: Ten consecutive patients harboring 10 distal cerebellar aneurysms were treated with intra-aneurysmal Onyx embolization. Locations of the aneurysms were as follows: superior cerebellar artery in three patients, anterior inferior cerebellar artery in two, and posterior inferior cerebellar artery in five. The technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcome were evaluated. Results: In every case, endovascular treatment was achieved. Immediate angiography demonstrated that all of 10 aneurysms were completely occluded, with parent artery preservation in nine of them. Procedure-related complication occurred in one patient with transient neurological sequelae. None of the treated aneurysms experienced rebleeding or recanalization during the follow-up time (mean, 12.7 months). Conclusion: We found that the intra-aneurysmal Onyx embolization was helpful in the treatment of distal cerebellar aneurysms in which selective occlusion of the aneurysmal sac with coils or open clipping cannot be achieved.