Embolization of Middle Meningeal Artery in Patients with Chronic Subdural Hematoma: A Systematic Review and Meta-Analysis of Randomized-Controlled Clinical Trials

Background: Chronic subdural hematoma (cSDH) is a common neurosurgical condition, particularly among elderly patients. Middle meningeal artery (MMA) embolization has emerged as a minimally invasive adjunctive treatment aimed at reducing recurrence. However, its comparative efficacy and safety remain under investigation. Methods: In this systematic review and meta-analysis, randomized-controlled clinical trial (RCT) data evaluating MMA embolization combined with best medical therapy (BMT) versus BMT alone in adult patients with symptomatic cSDH were pooled. The primary efficacy outcome was recurrence or progression of hematoma at follow-up. Secondary efficacy outcomes included good functional outcome modified Rankin Scale (mRS) score ≤ 2, independent ambulation (mRS score ≤ 3), and hematoma thickness at follow-up. The primary safety outcome was all-cause mortality. Procedure-related complications were assessed as a secondary safety outcome. Results: Six RCTs were included, comprising 760 patients treated with MMA embolization and 788 patients treated with BMT alone. MMA embolization significantly reduced recurrence compared to BMT alone (RR: 0.50; 95% CI: 0.37-0.69; six studies; I2 = 0%; number-needed-to-treat = 13). No significant differences were observed in good functional outcome (RR: 1.01; 95% CI: 0.97-1.05; three studies; I2 = 0%), independent ambulation (RR: 1.01; 95% CI: 0.99-1.04; three studies; I2 = 0%), or hematoma thickness at follow-up (SMD: -0.1; 95% CI: -0.3 to 0; four studies; I2 = 42%). All-cause mortality was similar between the two groups (RR: 1.01; 95% CI: 0.42-2.40; five studies; I2 = 44%). The pooled rate of procedure-related adverse events in the MMA embolization-group was 1% (95% CI: 0-3%; two studies; I2 = 35%). Conclusions: MMA embolization significantly reduced cSDH recurrence when used as an adjunct to BMT. However, it did not demonstrate a significant impact on functional outcomes or mortality in this meta-analysis. Further research is needed to identify patient subgroups that benefit most from MMA embolization and to evaluate its impact on cognitive function and quality of life using longer follow-up periods.