Comprehensive Hybrid Treatment of Complex Fusiform Aneurysms Using Endovascular Therapy and Distal Bypass

Introduction: Fusiform aneurysms represent circumferential dilations of an intracranial artery without a typical neck, which usually require more advanced techniques. A comprehensive approach incorporating novel endovascular devices and fourth-generation bypass may provide avenue with less injury and improved efficacy. This study aimed to summarize the paradigm of hybrid bypass followed by endovascular management for complex fusiform aneurysms and to propose an algorithm for designing a comprehensive approach.

Methods: Patients with fusiform aneurysm who underwent bypass followed by endovascular occlusion of parent artery or flow diversion were identified from a prospectively maintained database of intracranial aneurysms. The treatment method and outcomes were analyzed to propose an algorithm for designing a comprehensive approach.

Results: Between 2016 and 2023, 7 patients were treated for fusiform aneurysms: four (57.1%) A2 anterior cerebral artery, one (14.3%) BA tip, one (14.3%) V4 vertebral artery (VA) and one (14.3%) basilar artery (BA)-VA. Endovascular occlusion of parent artery was performed in 5 (71.4%) patients, including four A2 and one VA. Flow diverters were deployed in 2 aneurysms (28.6%), one in VA and the other in BA-P1. All the seven bypasses were performed distal to aneurysms, with anastomosis patency of 100%. To occlude parent arteries, four (57.1%) bypasses were performed on parent arteries distal to aneurysms and one (14.3%) bypass for major branches. Two bypasses were performed on distal end of major branches to diminish branch vessels interfering flow diversion. In situ intracranial-to-intracranial (IC-IC) side-to-side bypasses were performed in 5 (71.4%) patients: four with A3-A3 bypass and one with p3-p3 posterior inferior cerebellar artery (PICA)-PICA bypass. Extracranial-to-intracranial (EC-IC) bypasses were performed in 2 (28.6%) patients: one with high flow and the other with low flow.

Conclusion : Bypass reconstruction at distal segments of parent artery or major branch can be achieved with less technical challenges, which thereby prepared conditions for endovascular trapping or flow diversion of fusiform aneurysms, with less invasiveness but improved safety and efficacy.