Comparative Efficacy and Safety of Coil Versus Onyx Embolization in Middle Meningeal Artery Embolization as an Adjunct to Burr Hole Drainage for Chronic Subdural Hematoma

AIM: To investigate the differences in efficacy, safety, and health economic outcomes between coils and the Onyx liquid embolic agent in middle meningeal artery embolization (MMAE) as an adjunct to burr hole drainage for chronic subdural hematoma (cSDH).METHODS: This single-center retrospective cohort study included patients with cSDH who underwent burr hole drainage combined with MMAE between April 2024 and October 2025. Patients were divided into a coil group and an Onyx group based on the embolic material used. Propensity score matching (PSM) was used to balance baseline characteristics across groups. The primary outcome was hematoma volume absorption at 90 days postoperatively. Secondary outcomes included imaging parameters, clinical outcomes, recurrence and reoperation rates, safety events, and health economic indicators.RESULTS: A total of 184 patients were enrolled, with 66 patients in each group after PSM. Post-matching analyses demonstrated no statistically significant differences between the two groups in hematoma absorption volume at 90 days postoperatively or in other imaging parameters. Regarding clinical outcomes, the proportions of patients with modified Rankin Scale (mRS) scores of 0–2, as well as the recurrence and reoperation rates, were comparable between the groups. In terms of safety, the overall incidence of serious adverse events (SAEs) was comparable; however, cases of facial nerve palsy occurred in the Onyx group, whereas no such complications were observed in the coil group. Perioperative assessments showed that the coil group had a shorter operative time and lower hospitalization costs (all p < 0.05), whereas the length of hospital stay did not differ significantly between the groups.CONCLUSIONS: In the adjunctive treatment of cSDH with burr hole drainage, coils and Onyx liquid embolic agent demonstrate comparable short-term efficacy and overall safety.