Clinical Comparison of Flow Diversion and Microsurgery for Retreatment of Intracranial Aneurysms

Introduction: The goal of aneurysm retreatment is effective, durable obliteration. Flow diversion and microsurgical clipping generally represent two aggressive aneurysm treatment options with high obliteration rates. However, their relative efficacy in aneurysm retreatment has been infrequently evaluated. The purpose of this study was to compare the radiographic and neurological outcomes of microsurgery and FD for retreatment of intracranial aneurysms (IAs).

Methods: A single institution database was reviewed to identify patients undergoing retreatment of IAs over a two-year period via either FD or microsurgery. Angiographic obliteration rates and neurological outcomes were compared between the two treatment modalities and across subgroups. Impact of treatment modality was adjusted via multivariate logistic regression analyses.

Results: 67 retreatments were identified, 60% via microsurgery and 40% via FD. Microsurgery was more commonly performed for anterior communicating artery (Acom) aneurysms (p=0.036), residual size < 10mm (p=0.023), and aneurysms initially treated endovascularly (p=0.021). FD was more commonly performed for ICA aneurysms (p=0.01) and residual size >10mm (p=0.023). Angiographic obliteration rates and neurological outcome were similar overall between the two retreatment modalities at a median follow-up of 26 months. Raymond I or II obliteration rate was 100% after microsurgery and 91.3% after FD. Good neurological outcome (mRS 0-2) was 85% after both microsurgery and FD. Comparable outcomes were observed across several subgroups, including previously ruptured aneurysms and aneurysms requiring retreatment within 6 months.

Conclusion : FD is an appropriate endovascular option for IA retreatment, with comparable radiographic efficacy and neurological outcome to microsurgery at 2-year follow-up.