Unusual collateral channel of ruptured vertebral artery fusiform aneurysm involving the posterior inferior cerebellar artery: a case report

Abstract

Approximately 10% of vertebral artery (VA) aneurysms are fusiform and originate from the posterior inferior cerebellar artery (PICA) [1,2]. The ideal treatment for fusiform aneurysms is completely isolating them from the circulation while preserving flow to parent vessel branches. Fusiform aneurysms are treated surgically (proximal clip ligation, trapping, and microvascular bypass) or endovascularly (coil embolization, stenting, stent-assisted coiling, and flow diversion) [3–7]. The patient in this study was diagnosed with subarachnoid hemorrhage due to a ruptured right VA fusiform aneurysm originating from the PICA. Digital subtraction angiography (DSA) was performed after confirming subarachnoid hemorrhage using brain computed tomography (CT). We confirmed a preexisting collateral channel between the PICA and posterior meningeal artery A 60-year-old female patient presented to the emergency department with comatose mentation. Brain computed tomography angiography revealed subarachnoid hemorrhage due to a ruptured right vertebral artery (VA) fusiform aneurysm originating from the posterior inferior cerebellar artery (PICA). Subsequent digital subtraction angiography confirmed that the PICA was supplied by collateral circulation via the ipsilateral posterior meningeal artery. Coil embolization of the ruptured VA fusiform aneurysm was performed. Generally, the PICA is involved in dissecting VA aneurysms, and a therapeutic strategy without reconstructive therapy could pose a significant risk of morbidity. However, this case, we could perform parent artery occlusion without bypass surgery or stenting because of the unusual collateral channel.