Giant Fusiform Vertebral Artery Aneurysm Treated With Microsurgical Bypass And Endovascular Coiling After Failed Flow Diversion: A Case Report And Discussion

Background Giant vertebral and vertebrobasilar aneurysms have proven to be extremely challenging vascular entities to treat despite many advances in microsurgical and endovascular techniques. In recent years, there has been more attention paid to combined approaches, including combinations of endovascular and surgical procedures in hopes of decreasing the associated morbidity and mortality of these lesions.Clinical Presentation We present a case of a giant fusiform vertebral artery aneurysm that was initially treated with flow-diverting stents. After the failure of flow diversion to occlude the aneurysm, the lesion was definitively treated with an occipital artery to the posterior inferior cerebellar artery (PICA) bypass and coil embolization of residual aneurysm.Conclusion After bypass and parent vessel deconstruction, angiography confirmed the aneurysm has remained occluded and the PICA patent. This case highlights the use of an extracranial-to-intracranial bypass to salvage a complex residual aneurysm after failed flow diversion.