Onyx Versus Particles for Middle Meningeal Artery Embolization in Chronic Subdural Hematoma

BACKGROUND: Middle meningeal artery (MMA) embolization has recently emerged as a treatment option for chronic subdural hematoma (cSDH). It is considered a simple and potentially safe endovascular procedure. OBJECTIVE: To compare between 2 different embolic agents; onyx (ethylene vinyl alcohol) and emboparticles (polyvinyl alcohol particles-PVA) for endovascular treatment of cSDH. METHODS: A retrospective analysis of all patients who underwent MMA embolization for cSDH treatment in 2 comprehensive centers between August 2018 and December 2021. Primary outcomes were failure of embolization and need for rescue surgical evacuation. RESULTS: Among 97 MMA embolizations, 49 (50.5%) received onyx and 48 (49.5%) received PVA. The presence of acute or subacute on cSDH was higher in the PVA group 11/49 (22.5%) vs 30/48 (62.5%), respectively, P < .001. There were no significant differences between both groups regarding failure of embolization 6/49 (12.2%) vs 12/48 (25.0%), respectively, P = .112, and need of unplanned rescue surgical evacuation 5/49 (10.2%) vs 8/48 (16.7%), respectively, P = .354. Hematoma thickness at late follow-up was significantly smaller in the PVA group 7.8 mm vs 4.6 mm, respectively; P = .017. CONCLUSION: Both onyx and PVA as embolic agents for cSDH can be used safely and have comparable clinical and surgical outcomes.