A case of recurrent subdural hematoma after unilateral MMA embolization that resolved after contralateral MMA embolization.

Middle meningeal artery embolization (MMAe) is rapidly emerging as a valuable intervention to decrease the risk of recurrent subdural hematoma (SDH) after surgical evacuation. The role of upfront bilateral MMAe for unilateral SDH and the value of contralateral MMAe after SDH recurrence post evacuation and ipsilateral MMAe are still unknown. Here, we report the case of an elderly patient that presented with a large acute on chronic SDH and underwent surgical drainage and ipsilateral MMAe (with Contour PVA particles, 150-250 µm). At one month follow-up, he was found to have a significant radiographic recurrence of the SDH with interval acute hemorrhage. Angiography revealed complete occlusion of the trunk of the previously embolized ipsilateral MMA, and the presence of robust anastomotic branches from the contralateral MMA crossing the midline to collateralize patent distal branches of the previously embolized MMA. Decision was made to proceed with contralateral MMAe, which resulted in near complete SDH resolution at 6 months follow-up.