A Case Report of Stent-Assisted Coiling with One-and-a-Half-Lap Approach for Basilar Artery Fenestration Aneurysm.

Objective: Fenestrated basilar artery aneurysms (fBA-ANs) typically arise at the proximal bifurcation of the fenestration limb. It is reported that endovascular treatment with conventional coil embolization or balloon-assisted embolization techniques is often challenging and associated with a high complication rate, especially for wide-neck fBA-ANs. We present a case of fBA-AN successfully treated with stent-assisted coil (SAC) embolization using a novel one-and-a-half-lap approach with an open-cell stent, ensuring reliable neck coverage while preserving parent artery patency. Case Presentation: A 33-year-old man with a history of an unruptured fBA-AN, previously treated with coil embolization via the double-catheter technique 6 years ago, presented with coil compaction and aneurysm recurrence. DSA revealed an fBA-AN measuring 8.7 mm in diameter, requiring retreatment. Under general anesthesia, SAC was performed using a one-and-a-half-lap approach. A Neuroform Atlas stent (Stryker Neurovascular, Fremont, CA, USA) was deployed via a 2.4 Fr microcatheter, positioned in a clockwise direction from the left loop fenestration to the right loop across the aneurysm neck, followed by coil embolization. Postoperatively, the patient remained free of ischemic complications, and follow-up imaging showed no recurrence of the fBA-AN. Conclusion: This case demonstrates the efficacy of SAC with a one-and-a-half-lap approach using an open-cell stent for the treatment of complex fBA-ANs. This technique provides a viable treatment option for wide-neck fBA-ANs, ensuring durable aneurysm occlusion while maintaining parent artery patency.