Long-Term Efficacy, Safety, and Recurrence Rates of Coiling, Stent-Assisted Coiling, and Flow Diversion in Unruptured Intracranial Aneurysms: A Systematic Review

Abstract

Background : Unruptured intracranial aneurysms (UIA) affect approximately 2%–3% of adults, and their management must balance rupture prevention against periprocedural risk. This systematic review compares the long-term efficacy, safety, and recurrence of coiling, stent-assisted coiling (SAC), and flow diversion (FD).

Methods : Following PRISMA guidelines, a comprehensive search yielded 18 eligible studies (RCTs, prospective/retrospective cohorts, and propensity-score matching) covering more than 5,000 procedures. Risk of bias, assessed with RoB 2, NOS, ROBINS-I, and MINORS, ranged from moderate to high.

Results : Coiling achieved 63.0%–76.8% complete occlusion with the lowest permanent morbidity (0.27%) but the highest recurrence (37.1%), reduced by 8.4% with hydrogel coils. SAC gave superior occlusion (90%–94.1%) in wide-neck aneurysms and stable long-term recanalization (8.0% at >24 months) but higher first-year ischemic complications (8.8% vs 2.2%). FD provided the best progressive durability (80.7%–81.81%) with near-zero recanalization and only 1.2% periprocedural neurological morbidity using new-generation coated devices.

Conclusion : Optimal UIA management is individualized by aneurysm size and morphology: coiling for small aneurysms (high safety, high recurrence), SAC for wide-neck aneurysms (improved efficacy, moderate first-year ischemic risk), and FD for complex or giant aneurysms (durable occlusion, near-zero recurrence, minimal morbidity).