Efficacy and safety profiles of single versus multiple pipeline embolization devices for intracranial aneurysms: a systematic review and meta-analysis.

To systematically evaluate the efficacy and safety of single versus multiple PEDs in the treatment of intracranial aneurysms. We performed systematic searches on PubMed, Web of Science, and the Cochrane Library Databases of single versus multiple PEDs through June 10, 2025. Primary outcomes were complete occlusion at 6 months, 1 year, and the latest follow-up; complications (thromboembolic, hemorrhagic, in-stent stenosis); retreatment; and favorable outcome (mRS ≤ 2). Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using Mantel–Haenszel method. Six retrospective cohort studies (846 patients, 869 aneurysms) were included. Of these, 272 patients were treated with multiple PEDs, 597 with a single PED, and 24 received adjunctive coils. Multiple PEDs were more often used in larger or fusiform aneurysms. At the latest follow-up, multiple PEDs achieved a higher occlusion rate than single PEDs (95% vs. 85%; OR 2.30, 95% CI 1.23–4.28; p = 0.009), but this significance disappeared when studies with adjunctive coiling were excluded (93.8% vs. 84.6%; OR 3.75, 95% CI 0.58–24.12; p = 0.164). No significant differences were found at 6 months or 1 year. Overall complication rates, retreatment rates, and favorable outcomes were comparable, but thromboembolic events were more frequent with multiple PEDs (6.88% vs. 2.64%; OR 2.60, 95% CI 1.14–5.93; p = 0.02). This meta-analysis demonstrated that multiple PEDs are preferentially used for complex aneurysms but not provide consistent benefits in occlusion rates, retreatment, or favorable outcomes compared to single PEDs, while increasing thromboembolic risk.