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

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. To compare the safety and efficacy of OA-PICA and PICA-PICA bypasses. Following PRISMA 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. 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 months), while for OA-PICA, it was 27.8 months (6 - 84 months). The patency rate for OA-PICA was 97% (95% CI: 92% - 100%) and 100% (95% CI: 95% - 100%) for PICA-PICA. Complication rates were 29% (95% CI: 10% - 47%) for OA-PICA and 12% (95% CI: 3% - 21%) for PICA-PICA. Good clinical outcomes were observed in 71% (95% CI: 52% - 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%) for PICA-PICA. 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.