Middle meningeal artery embolization as standalone treatment versus combined with surgical evacuation for chronic subdural hematomas: systematic review and meta-analysis

OBJECTIVE Middle meningeal artery embolization (MMAE) is a novel treatment for chronic subdural hematomas (cSDHs) with high variability of use across practitioners and institutions. This study sought to investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgery for select patients with cSDH. METHODS The authors searched the Medline and Embase databases for studies reporting outcomes specific to standalone MMAE and combined MMAE and surgery. The Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool was used to assess risk of bias in each included study. Patient characteristics were compared between cohorts, and rates of surgical recurrence of standalone MMAE and combined MMAE and surgery were pooled using random-effects models. RESULTS Four hundred two unique patients (156 with standalone MMAE and 246 with combined MMAE and surgery) were identified across 8 studies. Overall, the subdural thickness for the standalone MMAE group was modestly but statistically significantly smaller (16.8 vs 18.8 mm, estimated p value 0.002), and the mean follow-up time was significantly longer for the standalone MMAE group (5.4 vs 2.3 months, estimated p value < 0.001); there were no significant differences between age, sex, and anticoagulant use. The surgical recurrence rates were not significantly different between the two groups (estimated p value 0.63). Using random-effects models, the surgical recurrence rates were estimated at 6.8% (95% CI 3.5%–11.2%) and 4.6% (95% CI 2.3%–7.7%) for standalone MMAE and combined MMAE and surgery, respectively. CONCLUSIONS Standalone MMAE for cSDH may yield a low rate of surgical recurrence, which may be comparable to that of combined MMAE and surgery. However, studies in this systematic review and meta-analysis were primarily single-arm studies prone to treatment bias. Future studies are needed to further investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgical treatment for cSDH in select patients.