Efficacy and safety of middle meningeal artery embolization for chronic subdural hematoma: an updated systematic review and meta-analysis focusing on time of intervention.

INTRODUCTION: Chronic subdural hematoma (cSDH) is increasingly prevalent among older adults due to population aging and widespread antithrombotic use. Although burr-hole drainage remains the standard treatment, recurrence rates are substantial. Middle meningeal artery embolization (MMAE) has emerged as an adjunctive strategy to disrupt dural neovascularization and prevent rebleeding. OBJECTIVES: To assess the efficacy and safety of MMAE combined with standard therapy versus standard therapy alone, with stratification by timing of intervention. METHODS: Randomized controlled trials (RCTs) were searched in PubMed, Scopus, and Cochrane Central up to July 2025. Adults with confirmed cSDH were included. The primary outcome was hematoma recurrence or persistence. Secondary outcomes were reoperation, hematoma resorption, serious adverse events, neurological death, mortality, functional independence, and hospital stay. Risk of bias was assessed with RoB-2, and analyses followed PRISMA guidelines (PROSPERO CRD420251112841). RESULTS: Seven RCTs (1,889 patients) were included. Compared with standard therapy, MMAE significantly reduced recurrent or residual cSDH (RR 0.63; 95% CI 0.46-0.85) and reoperation (RR 0.39; 95% CI 0.28-0.56) without increasing serious adverse events (RR 0.87; 95% CI 0.72-1.06), neurological death, mortality, or poor functional outcomes. Hematoma resorption did not differ significantly. Subgroup and sensitivity analyses confirmed the robustness of the results across age, intervention timing, and follow-up duration. CONCLUSION: MMAE combined with standard therapy significantly reduces recurrence and reoperation in cSDH without increasing adverse events or mortality. Benefits appear independent of procedural timing, though larger RCTs with extended follow-up are warranted to define long-term outcomes and optimal use.