The Fate of the Middle Meningeal Artery in Patients with Chronic Subdural Hematoma Treated with Embolization

Background: Middle meningeal artery embolization (MMA) is a mainstay in treatment for chronic subdural hematoma (cSDH). The fate of the MMA and the territory it supplies after embolization remains unknown. Methods: We conducted a retrospective review of patients who underwent repeat delayed digital subtraction angiograms after MMA embolization. Angiograms were retrospectively reviewed to assess patency of MMA branches prior to, immediately after embolization and at follow-up. Results: Between 3 centers, 17 patients were identified that underwent MMA embolization and repeat angiograms. This entailed 28 total sides and 47 total branches; bilateral embolization was performed in 11 cases. In all, 14 patients underwent an evacuation procedure. A total of 16 (31%) MMA branches were embolized with N-butyl cyanoacrylate, 16 (31%) with Onyx, 16 (31%) with coils, and 4 (7.7%) with particles, respectively. A total of 44 (94%) branches were completely obliterated immediately after treatment and 3 branches showed persistent but delayed opacification. Of the 44 branches obliterated on initial procedure, only 30 remained obliterated (68%) and 14 (32%) recanalized. Coils were significantly associated with recanalization compared to liquid embolic agents (P < 0.001). There was no significant difference between liquid embolic agents though n-BCA trended towards an association with recanalization (P = 0.10). Branch obliteration at follow-up was not associated with cSDH improvement. Conclusions: After embolization, the MMA can undergo remodeling which may depend on embolization technique used. Coils appear to result in a high rate of vessel recanalization whereas liquid embolic tends to result in more permanent occlusion. However, it remains unclear whether this affects hematoma resolution.