Abstract WP212: Evolution of Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: Institutional Experience from 2018–2024

Background: Middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH) progressed rapidly from early adoption to an established treatment to prevent recurrence in cSDH. To evaluate changes in practice patterns, we compared institutional techniques and outcomes between the early adoption period and a recent practice period. Methods: We analyzed a prospectively maintained database to identify consecutive patients undergoing MMAE at a single institution, comparing demographics and outcomes in “early” cases between 2018–2020 and “contemporary” cases in 2024. Technique selection and radiographic outcomes were analyzed, including choice of embolic agent, recurrence of SDH, complete radiographic resolution or improvement at last follow-up image, necessity of reintervention (repeat embolization or surgical evacuation after the index procedure), fluoroscopy time, contrast volume, and complications. Continuous variables were compared with t-tests; categorical with Chi-Square/Fisher’s exact (alpha=0.05). Results: Sixty MMAE cases were included in the analysis, 39 in the “early” group and 21 in the “contemporary” group. Groups included patients of similar mean age (72.7 vs. 73.0, p=0.95), sex (% male 64.1 vs 61.9, p=0.87), and mean thickness (13.3 vs 15.4mm, p=0.23). Embolic agents were used with similar frequency in both groups, with n-BCA being the most common ( Table 1 ). The use of triaxial access increased in recent cases (from 12.8% to 47.6%, p=0.003). Adjuvant surgical evacuation trended lower in 2024 (from 38.5% to 14.3%, p=0.08). Contemporary cases showed more complete resolution (47.6% vs 18.0%, p=0.02) and fewer partial improvement (38.1% vs 69.2%, p=0.02). Recurrence was similar (8.1% vs 15.8%, p=0.40), however reintervention after the index procedure was more frequent in 2024 (21.1% vs 2.6%, p=0.02). Conclusions: In this interrupted time series study, we found similar occlusive agent utilization amongst cases in 2018-2020 and 2024 within our institution. Recent cases of MMAE adopted triaxial access more commonly and achieved higher complete resolution. A higher reintervention rate in 2024 may reflect reduced reliance on adjuvant evacuation or limitations of moderate sample size. Larger prospective studies will be useful in clarifying the relationship between technique selection and outcomes.