Liquid embolic penetration of the skull during middle meningeal artery embolization is correlated with chronic subdural hematoma resolution

Background Few studies have explored the role of skull–meninges interaction in outcomes post middle meningeal artery (MMA) embolization. We investigated how the liquid embolic penetration into the skull bone during MMA embolization affects chronic subdural hematoma (cSDH) resolution. Methods All patients undergoing MMA embolization at our institution from January 2019 to November 2024 were included in this single center retrospective study. Bilateral embolizations were counted as two separate cases. The cohort was divided into two groups: those with embolic agent within skull bone, and those without. Baseline characteristics, procedural details, and SDH resolution status were compared. Univariate analysis was performed. Results A total of 132 MMA embolization cases were included within this cohort; 49 (37.1%) had liquid embolic agent within the skull bone, and 83 (62.9%) did not. The presence of liquid embolic agent within the skull bone was significantly correlated with higher rates of resolution for cSDH (P=0.005). The cohort with embolic material within bone was also associated with increased diffuse distal penetration (P<0.001) and increased volume of embolic agent (P<0.001). On multivariate analysis limited to patients with >60 days of follow-up, bony embolic penetration remained significantly associated with cSDH resolution (P=0.038). Conclusions Penetration of liquid embolic agent into the skull during MMA embolization is associated with higher rates of cSDH resolution. Further studies exploring the potential role of skull bone marrow in the inflammatory process involved in cSDH formation are warranted.