Background Chronic subdural hematomas (cSDH) are traditionally managed by close observation with repeat neuroimaging or surgical evacuation. In recent years, middle meningeal artery embolization (MMAE) has emerged as minimally invasive treatment for cSDH. There are ongoing trials evaluating the safety and effectiveness of MMAE. Some of the ongoing debates include the timing of MMAE in relationship surgery as well as which embolic material is most effective. The relationship of MMAE to surgical infections has not been extensively studied.

Methods This is a retrospective review of patients who underwent MMAE for treatment of cSDH during the time period of May 2019 to November 2022. Data collection includes patient side(s) of treatment, embolization material, pre-embolization and post-embolization neurological exams, surgical interventions, and, if any, subsequent infections. Relationship between MMAE timing/embolic material with infections was evaluated.

Results A total of 80 patients were included in the analysis who had 101 MMAEs for treatment of cSDH. Thirty-seven (46.25%) patients had stand-alone MMAE, 34 (42.5%) post-surgical MMAE, 5 (6.25%) pre-surgical MMAE, and 4 (5%) pre/post-surgical MMAE. Surgeries included SEPS, burr holes, and mini craniotomies. Embolic material included polyvinyl alcohol particles (PVA) (67, 66.3%), Onyx18 (27, 26.7%), a combination of PVA with Onyx18 (6, 5.94%), and N-butyl-2-cyanoacrylate (NBCA) glue (1, 0.99%). There were a total of 5 (6.25%) infections, 3 of which were ipsilateral subdural empyema (SDE) and included and 2 of which were excluded (scalp infection and contralateral infection). The infection rate of patients with MMAE only, post-surgical MMAE, pre-surgical MMAE, and pre/post-surgical MMAE were 0/37, 0/34, 2/5, and 1/4, respectively. All 3 infections (100%) occurred in patients who had a craniotomy following MMAE. Two infections (67%) occurred with Onyx18 use and one infection (33%) occurred with PVA. No infections occurred with SEPS or burr holes.

Conclusion Within the limitations of a small single center retrospective study, there may be an association with pre-surgical MMAE with Onyx18 and SDE potentially caused by extensive permanent devascularization of the dura. This finding should be examined in a larger multicenter cohort.

Disclosures M. Farrell: None. K. Russell: None. M. Webb: None. F. Al-Saiegh: None. P. Rodriguez: None. L. Birnbaum: None. R. Morton: None. J. Mascitelli: None.