Abstract Body (Do not enter title and authors here): Background:
Middle Meningeal Artery Embolization (MMAE) has gained attention as a minimally invasive standalone or adjunct treatment for chronic subdural hematoma(cSDH), although its comparative efficacy and safety remain unclear cSDH often recurs after conventional surgery prompting interest in adjunctive strategies like MMAE.

Methods:
PubMed, MEDLINE and CENTRAL were searched up to March 2025 for studies involving involving adult cSDH patients undergoing MMAE or surgery. Efficacy outcomes were recurrence, reoperation while safety endpoints were mortality and complications. A random-effects model was used in R (version 4.4.0), to pool risk ratios (RR) and mean differences (MD) with their respective 95% confidence intervals (CI). Certainty of evidence was assessed using the GRADE approach.

Results:
Eight studies (N = 8,948) were included. MMAE significantly reduced recurrence risk compared to surgery alone (RR = 0.38; 95% CI: 0.26–0.55; I² = 27.2%; p < 0.0001). Subgroup analysis by treatment strategy showed reduced recurrence with both adjunct MMAE (RR = 0.29; 95% CI: 0.22–0.39; I² = 0%) and standalone MMAE (RR = 0.33; 95% CI: 0.12–0.91; I²= 60.7%) versus surgery. No significant difference was observed between the two approaches (p = 0.747). Subgroup analysis by hematoma thickness showed benefit across sizes. MMAE reduced recurrence in hematomas RR = 0.31; 95% CI: 0.13–0.75) and ≥20 mm (RR = 0.52; 95% CI: 0.20–1.33) without significant interaction (p = 0.147). By study design, MMAE reduced recurrence in both observational studies (RR = 0.29; 95% CI: 0.22–0.39) and RCTs (RR = 0.53; 95% CI: 0.01–25.10), with no significant subgroup difference (p = 0.0673), supporting consistency of effect.

Conclusion:
Adjunct MMAE significantly lowers recurrence risk in chronic subdural hematoma, with consistent benefit across hematoma sizes and study designs. These findings support its use as a safe, effective option, particularly in patients at high risk for surgical recurrence or complications. While RCTs are limited, current evidence supports its integration into surgical decision making.