Risk factors of postprocedure seizures following standalone middle meningeal artery embolization of chronic subdural hematomas: a bi-institutional retrospective analysis.

Background: Seizures have been reported to arise after middle meningeal artery embolization (MMAE) for the treatment of chronic subdural hematomas (cSDH). However, the rates and factors influencing their development have been poorly established in the literature. Herein, we assess for risk factors for seizures post-MMAE.

Methods: A retrospective review of patients with cSDH treated with standalone MMAE from 2017 to 2021 was conducted at two academic institutions in the United States. Seizures were documented using the definition set by the International League Against Epilepsy. Medical charts and imaging were evaluated to assess risk factors associated with postprocedure seizures.

Results: A total of 113 patients, mostly males (57.5%) with 132 cSDH, were included in this analysis. The median thickness of collections was 13.1 mm, and the midline shift was 3 mm. Seizures occurred in five patients (4.4%) and resulted in longer hospitalizations (9 vs. 4 days; p = 0.03) and in-hospital mortality (20.0% vs. 0.9%; p < 0.01). Univariate analysis demonstrated that a midline shift ≥ 5 mm (OR = 6.47; 95% CI = 1.25-33.56; p = 0.03) and a pre-procedure GCS ≤ 12 (OR = 20.33; 95% CI = 2.43-170.15; p < 0.01) were risk factors for developing seizures following MMAE.

Conclusions: Seizures, although uncommon, can occur following MMAE, substantially impacting the length of hospitalization and hospital mortality, with variables such as a GCS score below 13 and a midline shift ≥ 5 mm associated with their development. The role of prophylactic AEDs post-MMAE still needs further evaluation.