Management Strategy for Ruptured Posterior Inferior Cerebellar Artery (Pica)-Involved Vertebral Artery Dissecting Aneurysms During the Acute Stage and Vascular Territory of the PICA

Urgent treatment of ruptured vertebral artery dissecting aneurysm (VADA) is imperative because of the high incidence of rebleeding and high mortality of recurrent bleeding. Especially, ruptured posterior inferior cerebellar artery (PICA)-involved VADA requires both prevention of rebleeding and revascularization of the PICA. Since 2001, we have treated 8 patients with ruptured PICA-involved type VADA during the acute stage, within 3 days after the hemorrhage. The treatment strategy included endovascular proximal occlusion followed by occipital artery-PICA bypass and PICA origin clipping (3 cases), proximal occlusion followed by internal trapping of the aneurysm after successful balloon test occlusion (1 case), only proximal occlusion (1 case), coil embolization of the aneurysmal dilatation followed by OA-PICA bypass and PICA origin clipping (1 case), internal trapping of the aneurysm (1 case), OA-PICA bypass, proximal clipping and proximal clipping (1 case). Aneurysmal shape change after acute treatment was observed in 5 cases. In 1 case to which the aneurysm decreased in size, PICA supplied only vermis branches. In 2 cases in which the size of the aneurysm did not change, PICA supplied vermis, tonsilar and hemispheric branches in 2. In 2 cases in which the size of the aneurysm increased, PICA supplied vermis, tonsilar and hemispheric branches in 1 and PICA supplied vermis, tonsilar, hemispheric and meningeal branches in 1. Because the possibility is high that the aneurysm will remain cases in which PICA supplied vermis, tonsilar and hemispheric branches, it is necessary to plan additional treatment with PICA revascularization.