Middle meningeal artery embolization for chronic subdural hematoma with wedging technique

Abstract

Abstract Background Chronic subdural hematoma (CSDH) commonly recurs after burr-hole evacuation or conservative management. Middle meningeal artery embolization (MMAE) using ethylene–vinyl alcohol copolymer (Onyx) aims to devascularize the subdural membranes; however, incomplete distal penetration and proximal reflux can limit efficacy and safety. We evaluated a wedging microcatheter technique with large-caliber catheters to enhance distal delivery while minimizing reflux. Methods We retrospectively analyzed consecutive adults with CSDH treated with MMAE by Onyx (March–July 2025). Angiographic success was complete occlusion of both frontal and posterior branches of the middle meningeal artery (MMA). Clinical outcomes were recurrent symptomatic CSDH and repeat surgical evacuation. Neurological status by National Institutes of Health Stroke Scale (NIHSS) and functional outcome by modified Rankin Scale (mRS) were recorded at baseline and follow-up. Results Thirty patients underwent MMAE (50.0% stand-alone; 43.3% adjunct; 6.7% rescue). Wedging technique succeeded in all cases with 100% dual-branch occlusion; super-selection of the distal frontal branch alone sufficed in 76.7%. Onyx reached the midline in 83.3%, the subdural hematoma membrane in 20.0%, and crossed midline in 6.7%; mean fluoroscopy time was 25 ± 19 minutes. No cranial nerve palsy, vision loss, or ischemic stroke occurred. At 1 month, no symptomatic recurrence or progression was observed; hematoma thickness decreased in 96.7% (− 14.4 ± 7.9 mm) and midline shift in 93.3% (− 7.4 ± 4.6 mm); 83.3% achieved mRS 0–2 with mean NIHSS improvement of 0.6 ± 2.2. Conclusions Wedgeing technique with Onyx achieved universal dual-branch occlusion, deep distal penetration into subdural membranes, low fluoroscopy times, and early clinical and radiographic outcomes without ischemic or cranial nerve complications. These findings support the technique as a feasible, safe, and efficacious strategy for CSDH and motivate prospective comparisons with conventional microcatheter approaches.