Superior Cerebellar Artery Aneurysms, the "Sui Generis" in Posterior Circulation: The Role of Microsurgery in the Endovascular Era

Background: Endovascular treatment in the present form has almost taken over the management of posterior circulation aneurysms. However, superior cerebellar artery (SCA) aneurysms are among the few that are said to be surgeon friendly with comparable outcome with microsurgery. This study includes a comparative analysis of the SCA aneurysms treated with microsurgery and endovascular techniques at our institute along with a pooled analysis of available literature on overall outcomes in these 2 forms of treatment.

Methods: This retrospective study included our patients with SCA aneurysms from 2000 to 2015. Clinical outcomes were assessed by the Glasgow Outcome Scale (GOS) at discharge and modified Rankin Scale (mRS) at follow-up. A literature review was performed for clinical series on SCA aneurysms from 1991 to 2015 describing more than 10 patients for pooled analysis.

Results: Among the 20 patients (microsurgery, 12; endovascular, 8), 66% from microsurgery and 75% from the endovascular arm had good outcomes (GOS score >3 and mRS score <3) (P = 0.54). Microsurgery had an 88.8% complete occlusion rate compared with 75% in endovascular treatment (P = 0.45). Pooled analysis of 12 studies showed that endovascular coiling is significantly associated with good clinical outcome (88.1% vs. 76.9%; P = 0.003). Microsurgery provides better radiologic outcome in terms of complete occlusion rate (90.1% vs. 67.4%; P = 0.0001) and lower recurrence rate (0% vs. 11.8%; P = 0.005).

Conclusions: Individual series on SCA aneurysms have not proved any outcome benefit of either treatment modality over the other. However, pooled analysis suggests that microsurgery provides complete and sustainable aneurysm occlusion, although with an inferior clinical outcome.