Introduction Middle meningeal artery (MMA) embolization has been recognized as a promising treatment for patients with subdural hematoma (SDH). Prior studies reported a variable rate of SDH volume reduction (HVR) ranging between 0.5 to 1 cc/day. We examined whether bilateral embolization (BE) offered HVR benefit when compared to unilateral embolization (UE).

Methods We retrospectively reviewed prospectively collected data for patients presenting with a unilateral SDH and treated with MMA embolization using diluted n-butyl cyanoacrylate (n-BCA). The BE and UE cohorts were compared with respect to baseline clinical characteristics, pre-embolization baseline hematoma volume, and follow-up hematoma volume.

Results In our cohort of 65 patients with unilateral SDH undergoing embolization with n-BCA, 29 patients (44.6%) underwent BE and 36 patients (55.4%) underwent UE. The cohort was 73.9% (N=48) male with median age 71 years (IQR 65-82). There were no significant differences between UE and BE with respect to hypertension, hyperlipidemia, diabetes, anticoagulant use, antiplatelet use, coagulopathy, cirrhosis, alcohol abuse, or trauma (all p>0.05). There was no significant difference in baseline hematoma volume (BE 73.2cc [IQR 59-103] vs UE 60.9cc [IQR 33-86], p=0.08) or pre-embolization evacuation (BE 18 vs UE 17, p=0.23). Follow-up CT was performed a median of 71.5 days post-embolization (IQR 34-97). There was no significant difference in follow-up times between BE and UE (59.5 days BE vs 73 days UE, p=0.99). Rate of reduction in SDH volume/day was significantly greater in BE compared to UE (BE 1.0 cc/day [IQR 0.2-1.28] vs UE 0.7cc/day [IQR 0.3-72], p=0.02). In a regression model adjusting for pre-operative evacuation, volume reduction remained significantly greater in BE (p=0.04). There was no difference in retreatment (BE 2 events vs UE 3 events, p=0.8)

Conclusion We observed a significantly higher volume reduction in bilateral embolization of unilateral SDH using nBCA glue when compared to unilateral embolization. Larger randomized studies are warranted to further investigate bilateral vs unilateral embolization.

Disclosures M. Al-Kawaz: None. C. Rossitto: None. J. Scaggiante: None. K. Yaeger: None. J. Bose: None. M. Bazil: None. T. Young: None. S. Ratna: None. A. Devarajan: None. S. Majidi: None. J. Fifi: 2; C; Microvention, Stryker, Cerenovus. 4; C; Bendit tech. J. Mocco: 2; C; Serves as a consultant for Cerebrotech, Viseon, Endostream, Vastrax, RIST, Synchron, Viz.ai, Perflow, CVAid. 4; C; Investor in Cerebrotech, Imperative Care, Endostream, Viseon, BlinkTBI, Myra Medical, Serenity, Vastrax, NTI, RIST, Viz.ai, Synchron, Radical, and Truvic. 6; C; PI on research trials funded by: Stryker, Microvention, and Penumbra. C. Kellner: 1; C; Research Funding for Penumbra and Siemens.