Blind-Alley Formation and Occipital Artery-Posterior Inferior Cerebellar Artery Bypass for the Treatment of Unclippable Vertebral Artery Aneurysms with Posterior Inferior Cerebellar Artery Involvement

Abstract

Unclippable vertebral artery aneurysms (UVAs) are difficult to treat with direct clipping, especially in cases involving the origin of the posterior inferior cerebellar artery (PICA). Bypass with trapping is the common procedure used for these conditions. The authors used the blind-alley formation technique, which is a simpler method than trapping and can avoid some complications. To report 7 cases of UVA with PICA involvement treated with blind-alley formation and occipital artery (OA)-PICA bypass as well as their surgical outcomes and complications and to describe the operative techniques. Seven patients with UVA and PICA involvement underwent OA-PICA bypass and blind-alley formation (occlusions of the PICA origin and vertebral artery proximal to the aneurysm). Vertebral artery dissecting aneurysms and fusiform atherosclerotic vertebral artery aneurysms were detected in 6 patients and 1 patient, respectively. All patients presented with subarachnoid hemorrhage, and 71.4% of them were classified into the poor-grade group. Good bypass patency and complete aneurysm obliteration were achieved in all cases. Six aneurysms (85.7%) were completely obliterated according to computed tomography angiography performed immediately postoperatively. Another aneurysm was 50% and 100% thrombosed immediately and at 7 days after the operation, respectively. Surgical complications were found in 1 patient (14.3%) who had postoperative diparesis with dysphagia. Three patients (42.9%) achieved a Glasgow Outcome Score of 4 or 5 one month after the operation. Blind-alley formation and OA-PICA bypass are simple, safe, and effective for the treatment of patients with UVA with PICA involvement.