Embolization of the Middle Meningeal Artery for Chronic Subdural Hematoma

BACKGROUND: Patients receiving standard treatment for chronic subdural hematoma have a high risk of treatment failure. The effect of adjunctive middle meningeal artery embolization on the risk of treatment failure in this population remains unknown. METHODS: We randomly assigned patients with symptomatic chronic subdural hematoma to undergo middle meningeal artery embolization as an adjunct to standard treatment (embolization group) or to receive standard treatment alone (control group). Either surgical or nonsurgical standard treatment had been chosen for each patient before randomization. The primary efficacy outcome was a composite of the following events: recurrent or residual chronic subdural hematoma (measuring >10 mm) at 180 days; reoperation or surgical rescue within 180 days; or major disabling stroke, myocardial infarction, or death from neurologic causes within 180 days. The primary safety outcome was a composite of major disabling stroke or death from any cause within 30 days. RESULTS: Among 310 enrolled patients, 149 were randomly assigned to the embolization group and 161 to the control group; 189 patients were to receive surgical standard treatment and 121 nonsurgical standard treatment. The mean age of the patients was 73 years, and 70% were men. In the primary efficacy analysis, a primary-outcome event occurred in 19 of 120 patients (16%) in the embolization group, as compared with 47 of 129 patients (36%) in the control group (odds ratio, 0.36; 95% confidence interval, 0.20 to 0.66; P = 0.001). In the primary safety analysis, 4 of 144 patients (3%) in the embolization group and 5 of 166 patients (3%) in the control group either had a major disabling stroke or died within 30 days. Through 180 days, 12 patients (8%) in the embolization group and 9 patients (5%) in the control group had died, with death from neurologic causes occurring in 1 patient (1%) in the embolization group and in 3 patients (2%) in the control group. CONCLUSIONS: Among patients with symptomatic chronic subdural hematoma, adjunctive middle meningeal artery embolization resulted in a lower risk of treatment failure than standard treatment alone, without resulting in an increased incidence of disabling stroke or death in the short term. Further study of longer-term safety outcomes is warranted. (Funded by Balt USA; STEM ClinicalTrials.gov number, NCT04410146.).