Abstract Number ‐ 143: Middle Meningeal Artery Embolization of Septated Chronic Subdural Hematomas

Introduction Chronic Subdural Hematoma (cSDH) is projected to be the most common neurosurgical disease in the US by the end of the decade. MMA embolization is a promising new treatment; however, its efficacy in patients with complex, septated cSDH remains uncertain. Methods From our prospectively maintained registry of patients with cSDH treated with MMA embolization (with or without concurrent surgical drainage), we identified patients with and without septations. Septations were defined as hyperdense septa between the inner and outer membranes on a lower‐density background. The primary outcome was recurrence of cSDH, which was defined as any radiographic evidence of increase in thickness and/or new acute hemorrhage. Secondary outcomes included reduction in cSDH thickness, midline shift and rate of reoperation. Results Among 84 patients with 100 cSDHs, median age was 70 [IQR 59‐77] with 26.2% females. 35 CSDHs (35%) had membranes identified on imaging. Evacuation with burr holes was performed in 45.2% and craniotomy in 16.7% of the total cohort. Baseline characteristics between the patients with no septations (no SEP) and those with septatations (SEP) were similar except for median age (no SEP vs SEP, 66 vs 74, p = 0.006). Recurrence rate was lower in the SEP group (no SEP vs SEP, 21.5 vs 2.9%, p = 0.017) even when adjusting for clinically relevant factors (OR 0.07, p = 0.017). Despite larger baseline thickness in the SEP groups, the mean absolute reduction in thickness was more pronounced (no SEP vs SEP, ‐4.6 vs ‐8.0 mm, p = 0.016) with similar midline shift change. Rate of reoperation did not differ (6.2 vs 2.9%, p = 0.65). Recurrence free survival was significantly improved in patients with septations even after adjustment for age and evacuation strategy (Figure 1, p = 0.04). Conclusions MMAE in traditionally higher risk septated cSDHs appears to be highly effective with an even larger reduction in volume and lower risk of recurrence than non‐septated hematomas. These findings support the mechanistic theory of MMAE as a devascularization procedure of membrane neovasculature and may aid in improved patient selection.