Middle Meningeal Artery Embolization for Membranous Versus Nonmembranous Subdural Hematomas: A Retrospective and Multicenter Cohort Study

-BACKGROUND: Middle meningeal artery (MMA) embolization is a treatment option for chronic subdural hematomas (SDHs). The theorized mechanism of MMA embolization is devascularization of membranes that contribute to recurrence. In the present study, we aimed to determine whether MMA embolization is more efficacious for SDHs with radiographically visible membranes.-METHODS: A multicenter, retrospective cohort study was performed of patients with SDHs who underwent MMA embolization alone or with burr hole drainage. The SDHs were categorized as membranous or nonmembranous according to the radiographic appearance. The patient characteristics and outcomes were compared between the 2 groups.-RESULTS: A total of 99 patients with 117 MMA embolization procedures were included. Of the 99 patients, 73.7% with a membranous SDH and 61.0% with a nonmembranous SDH underwent MMA embolization alone. The remaining patients underwent MMA embolization in conjunction with burr hole evacuation. The overall recurrence rate was 10.7%. No significant differences were found in complications (P = 0.417), recurrence (P = 0.898), or retreatment (P = 0.999) among the membranous and nonmembranous groups.-CONCLUSIONS: To the best of our knowledge, this is the first multicenter study evaluating the effect of membrane presence in SDHs undergoing embolization. Membrane presence in patients undergoing MMA embolization did not correlate with recurrence or retreatment, suggesting that membrane presence should not be used as the sole selection criterion for MMA embolization. Although prospective studies of larger cohorts are needed, the results from the present study provide information on the potential implications of membranes in determining the optimal treatment paradigm for SDHs.