Embolization of the middle meningeal artery for chronic subdural hematoma: The OTEMACS multicenter, randomized, clinical trial protocol

Background: The role of middle meningeal artery (MMA) embolization as an adjunct to standard treatment in chronic subdural hematoma (CSDH) is debated. Further randomized trials are needed to establish MMA embolization as an essential therapeutic option for CSDH. The OTEMACS study aims to assess the adjunctive benefit of MMA embolization in patients undergoing either conservative or surgical treatment for CSDH. Methods: OTEMACS is a multicenter, prospective, randomized controlled clinical trial with an open-label and blinded endpoint evaluation (PROBE) design. Patients with symptomatic CSDH treated either with conservative or surgical treatment are randomized 1:1 to receive MMA embolization within 72 h (experimental arm) or standard of care alone (control arm). The primary efficacy outcome is a composite of clinical and radiological events, including surgical rescue or revision surgery within 90 +/- 14 days postrandomization or radiological remaining of the CSDH thickness >10 mm at 90 +/- 14 days postrandomization. The primary safety outcome included all-cause mortality. Secondary outcomes included the modified Rankin scale, Barthel index, EuroQol-5, and Mini Mental State Examination. The number of patients to be included is 440. Results: The trial debuted in October 2021 in six centers, in France. A preplanned interim analysis was performed after the enrollment and completion of the follow-up of 220 patients, and the Data Safety Monitoring Board decided to stop the trial for efficacy. The final results will be made available upon completion of the enrollment. Conclusions: OTEMACS will provide additional evidence for the clinical and radiological efficacy and safety of MMA embolization in patients with CSDH.