Abstract 265: Beyond The Burr‐Hole: Evaluating Middle Meningeal Artery Embolization for Chronic Subdural Hematoma Recurrence

Introduction/Purpose Chronic subdural hematoma (cSDH) is common in older adults driven in part by aging and widespread antithrombotic use and carries significant morbidity and mortality. Standard surgical management, typically burr‐hole (BH) drainage, is effective but limited by procedure‐related risks and recurrence reported up to ∼30%. Middle meningeal artery embolization (MMAE) has emerged as a promising alternative and adjunctive treatment for cSDH. MMAE involves the endovascular occlusion of the middle meningeal artery, which supplies the outer membrane (dura) of the hematoma cavity. This minimally invasive approach aims to reduce the vascular supply to the hematoma membrane, potentially minimizing its expansion and promoting resolution. Several studies have suggested that MMAE has a positive therapeutic effect on cSDH, demonstrating lower recurrence rates (ranging from 2‐10%) and fewer complications compared to conventional surgical treatments. However, long‐term safety and effectiveness versus surgery alone remains incompletely defined. This study evaluates the effectiveness and safety of MMAE compared with standard surgical management in adults with cSDH. Specifically, we compare 6‐month recurrence SDH rates and key complications such as blindness, facial nerve palsy, non‐target embolization, and stroke between adjunctive MMAE and BH alone to guide clinical decision‐making. Materials/Methods Retrospective cohort of adults with radiologically confirmed cSDH treated between January 1, 2019‐June 30, 2025. Patients were categorized as MMAE (n‐BCA) + BH or BH alone. The primary endpoint was 6‐month recurrence based on neuroimaging. Secondary endpoints included 30‐day in‐hospital mortality and 6‐month stroke, non‐target embolization, blindness, and facial nerve palsy. Baseline variables included age, sex, and antithrombotic and anticoagulation use at admission and upon discharge. Group event rates were summarized, and an unadjusted odds ratio (OR) with 95% confidence interval (CI) for recurrence was estimated using 2×2 methods (Fisher's exact). Results N=123 (MMAE+BH n=24; BH alone n=99). Six‐month recurrence: 2/24 (8.3%) after MMAE+BH vs 10/99 (10.1%) after BH alone (OR 0.81, 95% CI 0.17‐3.96, p=1.000). 30‐day in‐hospital mortality: 0/24 (0.0%) vs 13/99 (13.1%). Six‐month stroke: 0/24 (0.0%) vs 1/99 (1.0%). Non‐target embolization: 0/24 (0.0%) vs 0/99 (0.0%). Blindness and facial nerve palsy: 0 events in both groups. Conclusion In this interim analysis, adjunct n‐BCA MMAE + BH showed similar 6‐month recurrence to BH alone, with no excess neurologic complications observed. Ongoing accrual under IRB amendment to include two more years of patients will increase sample size and statistical power.