Factors Affecting Chronic Subdural Hematoma Recurrence after Middle Meningeal Artery Embolization

Abstract Although the predictors of chronic subdural hematoma (SDH) recurrence after surgical evacuation are well known, there is limited evidence available on factors affecting its recurrence after middle meningeal artery (MMA) embolization. The objective of this study was to determine the factors influencing the risk of recurrence in patients with chronic SDH undergoing MMA embolization. A prospective study was performed between September 2022 and October 2024 on patients with chronic SDH who underwent MMA embolization with or without surgical evacuation. The primary outcome was clinical recurrence of SDH within 90 days after the embolization, defined as new onset or worsening of existing neurological symptoms, associated with a residual or recurrent SDH with hyperdense contents on computed tomography (CT). The association of demographic, clinical, imaging, and angiographic parameters with SDH recurrence was analyzed. For variables that showed a significant association with recurrence, relative risks were ascertained. All statistical tests were two-sided, and a p-value of less than 0.05 was considered significant Seventy-four patients (mean age, 67.3 ± 11 [standard deviation] years; males, 66/74 [89.2%]) with 96 SDHs were included in the study. Clinical recurrence of chronic SDH was observed in 6 patients (8.1%). Membrane enhancement on pre-embolization CT was less common in hematomas that recurred than those that did not (2/8, 25% vs. 61/88, 69.3%; p = 0.018). The absence of membrane enhancement was a significant risk factor for clinical recurrence after MMA embolization (relative risk, 5.7 [95% confidence interval, 1.2–26.8], p = 0.01). Out of the 33 SDHs with no membrane enhancement, 6 recurred (18.2%). The absence of enhancement on pre-embolization CT is a risk factor for SDH recurrence after MMA embolization. The high recurrence rate in hematomas without membrane enhancement indicates that MMA embolization may not reduce the risk of recurrence in these patients.