Standalone Middle Meningeal Artery Embolization Versus Surgical Evacuation for Nontraumatic Subdural Hematoma: A Propensity-Matched Multicenter Real-World Study

Objective: The aim of the study was to compare real-world outcomes after standalone middle meningeal artery embolization (MMAE) versus surgical evacuation among adults with inpatient International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM)-coded nontraumatic subdural hematoma.Methods: We conducted a retrospective propensity-matched cohort study using TriNetX Global Collaborative Network reports.Adults aged 18 years or older with inpatient ICD-10-CM-coded nontraumatic subdural hemorrhage were assigned to standalone MMAE or surgical evacuation if the qualifying procedure occurred within one month of diagnosis.Patients were matched 1:1 on demographic, cardiovascular, cerebrovascular, renal, hepatic, metabolic, substance use, medication, and laboratory variables.For outcome analyses, the qualifying intervention served as the analytic index event, with follow-up beginning on day 1 after the procedure.Outcomes were all-cause mortality, incident seizure disorder, and ischemic stroke assessed through 3, 6, and 12 months after the qualifying intervention.Results: After matching, 2,156 patients were included in each cohort.All-cause mortality did not differ significantly at 3 months (245/2,156 (11.4%) vs 283/2,156 (13.1%); risk difference (RD), -1.8%; p=0.08), 6 months (308/2,156 (14.3%) vs 327/2,156 (15.2%);RD, -0.9%; p=0.41), or 12 months (354/2,156 (16.4%) vs 377/2,156 (17.5%);RD, -1.1%; p=0.35).Incident seizures were less frequent after MMAE at 3 months (63/1,888 (3.3%) vs 106/1,798 (5.9%)), 6 months (79/1,888 (4.2%) vs 136/1,798 (7.6%)), and 12 months (97/1,888 (5.1%) vs 157/1,798 (8.7%); all p<0.001); however, this association was not statistically significant in the age >65 years sensitivity analysis.Ischemic stroke risk did not differ significantly at 3 months (90/1,692 (5.3%) vs 81/1,731 (4.7%)), 6 months (103/1,692 (6.1%) vs 97/1,731 (5.6%)), or 12 months (115/1,692 (6.8%) vs 111/1,731 (6.4%)).Conclusions: In this propensity-matched real-world cohort, standalone MMAE was associated with similar mortality and ischemic stroke risk compared with surgical evacuation.Lower incident seizure risk was observed after MMAE in the primary analysis, but this association was not preserved in the age >65 years sensitivity analysis and should therefore be considered hypothesis-generating.These findings support prospective evaluation in selected patients and should not be interpreted as evidence that MMAE replaces urgent surgical decompression.