Surgical and Endovascular Treatment of Saccular Posterior Inferior Cerebellar Artery Aneurysms: Systematic Review and Meta-Analysis

Objective: The optimal treatment modality for saccular aneurysms of the posterior inferior cerebellar artery (PICA) remains unclear. A previous meta-analysis on the topic included a heterogenous study population, limiting the conclusions that can be drawn from its results. The aim of this study was to perform a systematic review and meta-analysis to compare outcomes of microsurgical and endovascular treatment (EVT) of these aneurysms. Methods: A search of 4 online databases was performed for studies describing the management of saccular PICA aneurysms. The primary outcome was complete aneurysm occlusion. Data were also collected on neurologic outcomes, cranial nerve palsies, and requirement for re-treatment. A random effects model was used for calculation of pooled proportions. Our protocol was registered with PROSPERO (CRD42021232784). Results: A total of 17 studies were included in the final analysis, reporting the treatment outcomes of 455 aneurysms, with a mean follow-up of 20 months. The pooled occlusion rates were 94.8% (95% confidence interval [CI] 90.6%–97.8%) for surgical treatment and 69.1% (95% CI 55.0%–81.7%) for EVT. Pooled rates of good neurologic outcome (modified Rankin scale score ≤2, Glasgow Outcome Scale score ≥4) at last follow-up were 78.1% (95% CI 67.4%–87.1%) for surgery and 77.6% (95% CI 67.9%–86.0%) for EVT. Conclusions: This meta-analysis demonstrates that in the treatment of saccular PICA aneurysms, microsurgical clipping results in superior angiographic outcomes, similar functional outcomes, but higher rates of lower cranial nerve palsy compared with EVT. Further studies are required to assess the duration and severity of cranial nerve palsies following surgical treatment, and long-term aneurysm occlusion and the requirement for re-intervention following EVT.