Outpatient Middle Meningeal Artery Embolization as Treatment for Uncomplicated Chronic Subdural Hematoma

Introduction: Middle meningeal artery embolization (MMAE) is a minimally-invasive treatment for chronic subdural hematoma (cSDH) that is often performed for select asymptomatic or minimally-symptomatic patients. In such cases, prior hospitalization and prolonged postoperative length of stay (pLOS) may not be required. We compared the outcomes of performing MMAE as an outpatient versus inpatient procedure.

Methods: We reviewed a retrospective institutional dataset for MMAE between 2018 and 2024. Outpatient MMAE (OMMAE) was defined as any electively scheduled MMAE while inpatient was defined as any MMAE performed after admission for cSDH management. Demographic, clinical, and outcome variables were compared with univariate and multivariable analysis.

Results: We identified 78 inpatient and 33 outpatient MMAE cases. The median age was 73 years, 27.9% were female, and 80.6% were white. Patients undergoing OMMAE were more likely white (93.9% versus 74.7%, p = 0.0192), less likely to have symptomatic cSDH at presentation (33.3% versus 69.2%, p = 0.0007), and less likely to have headache at presentation (18.2% versus 38.5%, p = 0.0463) than inpatient cases. Baseline demographics and imaging were otherwise similar. OMMAE were less likely to undergo concomitant evacuation (3.0% versus 26.1%, p = 0.0001), more likely to have same-or-next-day discharge (84.9% versus 33.3%, p < 0.0001), and had a shorter pLOS (median 1.0 versus 3.0, p < 0.0001). There were no differences in rates of recurrence, reoperation, or symptoms at last follow-up, however fewer deaths were recorded for OMMAE (9% versus 24%, p = 0.07). OMMAE also had less midline shift at last follow-up (p = 0.0437). Symptomatic cSDH at presentation (OR: 0.33; p = 0.0272), concomitant evacuation (OR: 0.13; p = 0.0233), and pLOS (OR: 0.89 per day; p = 0.0448) remained independently associated with OMMAE.

Conclusion : OMMAE for the treatment of cSDH in asymptomatic or minimally-symptomatic patients can be performed safely and allow for reduced pLOS.