Efficacy and safety of flow diverters in small intracranial aneurysms: a systematic review and single-arm meta-analysis

Objective This study aimed to evaluate the efficacy and safety of flow diverters (FDs) in the treatment of small intracranial aneurysms (≤10 mm). Methods PubMed, Embase, Web of Science, and Cochrane Library were comprehensively searched up to July 2025. Eligible studies included retrospective cohort studies reporting angiographic and clinical outcomes of FD treatment in small intracranial aneurysms. Data analysis was conducted using STATA 15.0. Pooled proportions and 95% confidence intervals (CIs) were calculated using Freeman–Tukey double arcsine transformation. Publication bias was evaluated using funnel plots and Egger’s test. Results Ten retrospective studies comprising 2,275 patients with 1,938 aneurysms were included. The pooled complete or near-complete occlusion rate was 86% (95% CI: 80–92%). The treatment-related mortality rate was 1% (95% CI: 0–2%), and the hemorrhagic event rate was 1% (95% CI: 1–2%). The ischemic event rate was 2% (95% CI: 1–3%), and the stroke rate was 3% (95% CI: 1–5%). The overall complication rate was 9% (95% CI: 5–12%), while 98% (95% CI: 94–100%) of patients achieved favorable functional outcomes. Egger’s test showed no significant publication bias ( p = 0.791). Conclusion FDs appear to be both effective and safe for the treatment of small intracranial aneurysms, achieving high occlusion rates and favorable functional outcomes with low rates of mortality and complications. However, given the high heterogeneity and retrospective nature of the included studies, further large-scale prospective studies are warranted to confirm these findings and refine treatment strategies.