C93 Mind the hole: dual web deployment in a basilar ‘donut’ aneurysm

<h3>Introduction</h3> Complex and giant basilar apex aneurysms, particularly those with atypical morphology, remain a significant challenge in endovascular therapy. Intrasaccular flow disruptors such as the WEB device offer promising results, but their efficacy may be limited in cases with dissecting features or dynamic morphological evolution. We present a case illustrating the need for a flexible, multimodal approach to achieve complete aneurysm occlusion. <h3>Case Description</h3> A giant basilar tip aneurysm with a donut-like configuration—featuring a central lumen and two lateral lobes—was initially treated by deploying two WEB devices into each aneurysmal compartment. Shortly after treatment, follow-up imaging revealed complete transformation of the aneurysm morphology, likely due to a dissecting component, resulting in a single large cavity. A second endovascular procedure was performed, during which the aneurysm was densely coiled and a flow-directing stent was implanted to reinforce aneurysm exclusion and redirect blood flow. Final basilar angiography confirmed complete occlusion with preserved flow in all parent vessels. However, angiography from the right internal carotid artery revealed residual filling at the aneurysm neck via a large posterior communicating artery (PCoA). A third-stage treatment with a low-profile flow diverter from PCoA to PCA is planned. <h3>Conclusions</h3> This case underscores that no single technique is universally sufficient for complex aneurysms. Achieving complete and durable occlusion often requires combining multiple endovascular strategies. Tailored, staged approaches guided by aneurysm evolution and collateral flow anatomy are essential for treatment success in such challenging cases. <h3>Conflict of Interest</h3> No