Abstract 031: Onyx versus nBCA in MMA Embolization for cSDH: A Single Center Experience of 234 hemispheres

Introduction There is growing evidence supporting endovascular treatment with middle meningeal artery embolization (MMAE) for the treatment of chronic subdural hematoma (cSDH). We aimed to compare Onyx vs. N‐Butyl cyanoacrylate (n‐BCA) as liquid embolic materials for MMAE. Methods We included all eligible patients undergoing MMAE for cSDH at University of Pittsburgh Medical Center from April 2019 to December 2022. The main outcomes included radiographic resolution of cSDH with at least 50% reduction of hematoma thickness as a surrogate for treatment success in addition to the need for rescue surgical intervention. Additional outcomes including complication rates and hematoma thickness at the last available follow up. Results A total of 195 patients underwent embolization of 234 hemispheres including 39 bilateral procedures and had available data for final analysis (168 (71.8%) in Onyx group vs. 66 (28.2%) in n‐BCA group). There were no significant differences in age, sex, co‐morbidities, prior SDH/evacuation, pre‐operative cSDH thickness, or use of antithrombotic therapy(P>0.05) while concurrent surgical intervention and midline shift showed a statistically significant difference (P<0.05). On last follow‐up imaging, radiographical treatment success defined as ≥ 50% reduction in hematoma thickness was comparable in Onyx and the n‐BCA groups (50.9% vs 54.8%, P=0.6). Similarly, there was no statistically significant difference in the proportion of patients requiring rescue surgery between both groups (4.8% vs. 7.6%, P=0.4). Excluding concurrent surgical intervention patients yielded similar comparable results. Hematoma thickness at late follow‐up was not statistically significant between both group (8.25 (4.8‐12) mm vs 6.9 (3.1‐11) mm, P =0.11). There was no statistically significant difference in procedural complications between both groups (1.2% vs 1.5%, P=0.84). Conclusion Onyx and n‐BCA in MMAE seem to have comparable outcomes when used in the endovascular treatment of cSDH treatment. Further prospective studies with larger sample sizes are needed to confirm these findings.