Optimal Timeline and Hematoma Size Parameters for Middle Meningeal Artery Embolization in Acute-On-Chronic Subdural Hematomas

Background and Purpose Chronic subdural hematomas (cSDH) are subdural collection of blood for which the current treatment option remains as surgical evacuation due to recurring focal inflammation and angiogenesis. An adjunctive therapeutic intervention is endovascular embolization of the middle meningeal artery (MMA) to cease the prolific cycle of angiogenesis. Few investigations have been made into the indications of this treatment modality regarding the intervention timeline and hematoma size for non-surgical candidates with acute-on-chronic subdural hematomas. Methods We examined the clinical outcomes of 19 patients with 31 acute-on-chronic SDHs undergone MMA embolization and highlighted preliminary trends in radiological and morbidity outcomes. Results Primary outcomes identified a 57.6% success rate for MMA embolization of acute-on-chronic SDHs defined as significantly reduced hematoma size (i.e. >50%) without recurring bleeds, peri-procedural complications, post-procedural neurological deficits, and need for post-procedural surgical evacuation. Subgroup analysis demonstrated a success rate of 90.9% in patients undergone embolization after a minimum 3-week delay from initial CT head study compared to 33.3% with early intervention as well as a success rate of 75% in patients presenting with a large (i.e. >10 mm) SDH compared to 30% for small SDH. Conclusion Our preliminary data in this retrospective cohort study demonstrates significantly improved outcomes of MMA embolization in patients presenting with large (>10 mm) acute-on-chronic SDHs and in patients undergone embolization after >3 weeks from initial CT head and symptomatic presentation.