Endovascular Treatment of Large Proximal Basilar Artery Fenestrated Aneurysms: Overlapping Stent with Coil Embolization-A Case Report.

This detailed case report presents and discusses the endovascular treatment of a large proximal basilar artery fenestrated aneurysm (PBAFA). Aneurysms occur rarely at the vertebrobasilar junction, with a moderate proportion of cases presenting fenestrations. Considering the high risk associated with posterior circulation aneurysms, including estimated rupture risk, periprocedural complications, or treatment difficulties in surgical procedures, endovascular treatment options are becoming increasingly favored, particularly considering the advancements in stent and flow diverter techniques. Our report focuses on a case of a 58-year-old male with a large unruptured PBAFA, treated using overlapping stent with coil embolization (OSCE) and triple catheter technique. This method was selected considering the size of the aneurysm, its complex vascular structure, and the risk of recurrence and complications. Our findings emphasize that a comprehensive understanding of vascular anatomy, hemodynamics, and the characteristics of endovascular treatment devices is essential for the treatment success. In addition, they demonstrate that the OSCE using low-profile visible intraluminal support devices combined with the triple catheter technique are an effective treatment option for large PBAFAs.