The effect of pre-treatment hematoma size and unilateral vs bilateral MMA embolization on volume reduction in the treatment of chronic subdural hematomas: A retrospective cohort study

Background and purposeDespite a rapidly growing body of literature supporting the treatment of chronic subdural hematoma (cSDH) with middle meningeal artery embolization (MMAE), real-life data is still scarce. This study aimed to evaluate MMAE radiological and clinical outcomes, based on radiological characteristics.Materials and MethodsFifty-two cSDH patients, treated by MMAE as a post-CSDH evacuation therapy in a single tertiary center, were included. Radiological outcome was evaluated with cSDH thickness/volume difference at routine follow-up compared to pre-MMAE CT head imaging. The cohort was divided into groups pertaining to cSDH laterality (bilateral and unilateral cSDH) and pre-MMAE hematoma thickness (>15 mm and ≤15 mm) for analysis. Patients who underwent evacuation <i>after</i> MMAE were not included in the analysis to eliminate bias of surgical effect on hematoma progression.ResultsThirty patients had bilateral, and 22 patients had unilateral cSDH treated with bilateral and unilateral MMAE respectively. Twenty-nine patients had >15 mm pre-MMAE hematoma thickness, and 23 had ≤15 mm pre-MMAE hematoma thickness. Mean cSDH volume was lower at all follow-up intervals when compared to baseline and was reduced by a factor of 10 at the 3-6-month interval. The mean cSDH thickness was significantly lower at all three follow-up intervals when comparing each group (bilateral and unilateral MMAE) (pre-treatment hematoma thickness >15 mm and ≤15 mm). Larger hematomas with a thickness of >15 mm had a significantly greater reduction in mean cSDH volume interval follow-up than hematomas measuring ≤15 mm (1-3 months-63 mm³, 40.6-85.69, <i>P</i> < .001). Unilateral cSDH and MMAE demonstrated greater cSDH volume reduction compared to bilateral cSDH and MMAE at 1-3 months (42, 15.2-68.8, .001) and 3-6 months (33.7, 5.2-72.7, .043). No procedure-related major complications or deaths or recurrences were observed.ConclusionsAdjunctive MMAE after surgical evacuation appears safe and effective. MMAE is particularly effective for larger pre-treatment hematomas >15 mm (compared to ≤15 mm) and for unilateral cSDH and MMAE (compared to bilateral cSDH and MMAE).