Geometry of Saccular Cerebral Aneurysms Not Associated with a Branch Vessel

Saccular aneurysms occurring at nonbranching sites are uncommon. Their geometry is particularly favorable for flow directed stents and is most amenable to aneurysms located on large-diameter conducting vessels such as the internal carotid, vertebral, and vertebrobasilar vessels. Smaller parent arteries harboring this type of aneurysm will require new technology to maintain patency of these more distal vessels. If endovascular techniques cannot achieve aneurysm sac obliteration, then open craniotomy and aneurysm clipping will provide a satisfactory alternative.