Middle Meningeal Artery Embolization With n-Butyl Cyanoacrylate in Patients With Chronic Subdural Hematoma

Importance: Middle meningeal artery embolization (MMAE) is a minimally invasive adjunctive treatment for chronic subdural hematoma (cSDH). The TRUFILL n-butyl cyanoacrylate (n-BCA) liquid embolic system is indicated for embolization of cerebral arteriovenous malformations for presurgical devascularization and may be appropriate for MMAE in patients with cSDH. Objective: To evaluate safety and effectiveness of the study device for MMAE plus standard of care vs standard of care alone in patients with cSDH. Design, Setting, and Participants: The Middle Meningeal Artery Embolization for the Treatment of Subdural Hematomas With TRUFILL n-BCA (MEMBRANE) trial was a prospective, multicenter, open-label, randomized clinical trial conducted from May 27, 2021, to February 6, 2024, at 30 hospitals (28 in the United States and 2 in China). Participants aged 18 to 90 years with symptomatic cSDH and a modified Rankin Scale score of 3 or less were enrolled. Interventions: Site physicians determined whether each patient required surgical or nonsurgical management. Participants in the surgical and nonsurgical cohorts were then randomized 1:1 to receive MMAE plus standard of care or standard of care alone. Main Outcomes and Measures: The primary effectiveness end point was residual or re-accumulation of hematoma (>10 mm; assessed by an independent core laboratory) at 6 months or requiring a surgical procedure on the cSDH within 6 months (conducted as an intention-to-treat analysis). The primary safety end point was incidence of adverse events through 6 months (conducted as an as-treated analysis). Results: A total of 376 participants (188 in MMAE plus standard of care and 188 in standard of care alone) were included. In the MMAE plus standard of care and standard of care alone groups, the mean (SD) age was 70.9 (10.6) and 70.3 (12.1) years, and 45 (23.9%) and 49 (26.1%) were female, respectively. Primary effectiveness end point events occurred in 17 of 146 participants receiving MMAE plus standard of care (11.6%) and 29 of 131 receiving standard of care alone (22.1%) (final estimate of common odds ratio: 0.53 [90% CI, 0.31-0.91]; P = .04), indicating statistically significant benefit for MMAE plus standard of care vs standard of care alone. Adverse events occurred in 130 of 181 participants in the MMAE plus standard of care group (71.8%) and 124 of 190 in the standard of care alone group (65.3%) through 6 months. MMAE plus standard of care treatment was noninferior to standard of care alone based on analysis of good functional outcome at 3 months, as assessed by the modified Rankin Scale. Conclusions and Relevance: In this randomized clinical trial, MMAE plus standard of care significantly reduced rates of recurrence and reoperation vs standard of care alone, without a significant increase in adverse events. Trial registration: ClinicalTrials.gov Identifier, NCT04816591.