Comparative effectiveness of standalone middle meningeal artery embolization versus surgical evacuation in noncritical patients with nonacute subdural hematomas.

Objective: Middle meningeal artery embolization (MMAE) has emerged as an alternative to surgical treatment of nonacute subdural hematoma (NASDH). When used in conjunction with surgery, it has been shown to reduce recurrence, but its effectiveness as a standalone therapy remains to be established. The aim of this study was to investigate the comparative effectiveness of standalone MMAE (sMMAE) versus surgical evacuation in patients with NASDH.

Methods: This retrospective propensity score-matched cohort study included consecutive patients with NASDH who underwent either sMMAE or surgical evacuation at a single institution from January 2017 to June 2024. The primary outcome was reintervention due to hematoma recurrence. Secondary outcomes included the hospital length of stay (LOS), new neurological deficits, and cardiorespiratory, neurological, and other medical adverse events.

Results: Overall, 265 patients (median age 73 years) with NASDH were included. After matching, the sMMAE and surgical evacuation groups each included 85 patients. There was no baseline difference in clinical characteristics at presentation. During a median follow-up of 72 days in the sMMAE group and 59 days in the surgical group, the incidence rate of reintervention did not differ between the two treatments (incidence rate ratio [IRR] 1.38, p = 0.41). The median hospital LOS was shorter in the sMMAE group compared with the surgical evacuation group (4 days vs 6 days, p = 0.003). No differences were observed between groups in terms of new neurological deficits at 30 days (RR 0.85, p = 0.717) or the risk of cardiorespiratory (RR 0.50, p = 0.327) or neurological (RR 0.66, p = 0.657) adverse events. Patients treated with sMMAE had a lower risk of other medical adverse events compared with those treated with surgery (1.1% vs 15.2%; RR 0.07, p = 0.013).

Conclusions: Patients who underwent sMMAE had shorter hospital stays and a lower risk of medical adverse events, without increased risk of recurrence, compared with patients who underwent open surgical treatment. Larger studies are warranted to establish the effectiveness of sMMAE in the management of NASDH.