Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass versus Occipital Artery-Posterior Inferior Cerebellar Artery Bypass for Treating Posterior Circulation Aneurysms: A Systematic Review and Comparative Meta-Analysis

<black square> BACKGROUND: When traditional therapies are unsuitable, revascularization becomes essential for managing posterior inferior cerebellar artery (PICA) or vertebral artery aneurysms. Notably, the PICA-PICA bypass has emerged as a promising option, overshadowing the occipital artery-PICA (OA-PICA) bypass. The objective was to compare the safety and efficacy of OA-PICA and PICA-PICA bypasses. <black square> METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review and meta- analysis to evaluate the safety and efficacy of OA-PICA and PICA-PICA bypasses for treating posterior circulation aneurysms. <black square> RESULTS: We analyzed 13 studies for the PICA-PICA bypass and 16 studies on the OA-PICA bypass, involving 84 and 110 patients, respectively. The median average follow-up for PICA-PICA bypass was 8 months (2-50.3- 50.3 months), while for OA-PICA, it was 27.8 months (6-84- 84 months). The patency rate for OA-PICA was 97% (95% confidence interval [CI]: 92%-100%)- 100%) and 100% (95% CI: 95%-- 100%) for PICA-PICA. Complication rates were 29% (95% CI: 10%-47%)- 47%) for OA- PICA and 12% (95% CI: 3%-21%)- 21%) for PICA-PICA. Good clinical outcomes were observed in 71% (95% CI: 52%-90%)- 90%) of OA-PICA patients and 87% (95% CI: 75%-- 100%) of PICA-PICA patients. Procedure-related mortality was 1% (95% CI: 0%-- 6%) for OA-PICA and 1% (95% CI: 0%-10%)- 10%) for PICA-PICA. <black square> CONCLUSIONS: Both procedures have demonstrated promising results in efficacy and safety. PICA-PICA exhibits slightly better patency rates, better clinical outcomes, and fewer complications, but with a lack of substantial follow-up and a smaller sample size. The choice between these procedures should be based on the surgeon's expertise and the patient's anatomy.