Long-Term Durability and Recurrence Patterns After Endovascular Treatment for Basilar Tip Aneurysms

Abstract

Treating recurrence after coil embolization of basilar tip aneurysm remains challenging even with the development of endovascular procedures. The present study evaluated long-term durability and recurrence patterns after endovascular treatment of basilar tip aneurysms. Data of 116 consecutive patients treated with endovascular therapy at 3 regional hospitals from 2002-2019 were retrospectively analyzed. Aneurysms were ruptured in 51 cases and unruptured in 65 cases, with a mean maximal diameter of 7.8mm (>15mm in 14 patients) and a mean follow-up period of 5.8±4.3years. Recurrence was observed in 24 of the 116 patients (21%), and 14 patients were retreated. The 5-year recurrence-free survival rate was 75.3%. Cox proportional hazards analysis found that recurrence correlated significantly with maximal aneurysm diameter >10mm (P=0.001; hazard ratio: 3.95, 95% confidence interval: 1.76-8.90) and incomplete occlusion (P=0.003; hazard ratio: 4.43, 95% confidence interval: 1.63-12.00). Recurrence pattern was classified into 3 types: neck type (9 patients), regrowth type (10 patients), and regrowth type of initially thrombosed aneurysms (3 patients). Rerupture occurred in neck type with de novo aneurysm formation adjacent to the neck (n= 3) and regrowth type with dome filling (n= 4). Recurrence after coil embolization for basilar tip aneurysms is associated with large aneurysms and incomplete occlusion at initial embolization. Understanding the patterns of recurrence is useful for predicting recurrence and selecting treatment strategies.