Calibrated Microspheres versus Liquid Embolic Agents for Chronic Subdural Hematoma: A Single-Center Clinicoradiologic...

Middle meningeal artery embolization (MMAe) is an effective treatment for chronic subdural hematoma (cSDH), but the optimal embolic agent remains debated. Landmark randomized trials predominantly used liquid embolics, although calibrated microspheres remain widely used. We compared clinicoradiologic outcomes after MMAe with 75 μm Embozene microspheres versus liquid embolics (n-butyl cyanoacrylate or Onyx 18).

We retrospectively reviewed single-agent MMAe for cSDH at a tertiary center (January 2019-January 2025). The embolized MMA was the unit of analysis; agent choice was discretionary. The efficacy cohort required 2-8 week imaging (n = 66); the safety cohort included all single-agent procedures (n = 67; 35 particle, 32 liquid). Primary outcomes were embolization failure and unplanned surgical evacuation. Secondary outcomes included early SDH thickness, midline shift, and latest modified Rankin scale (mRS).

Fifty patients underwent 66 embolizations (16 bilateral): 34 particle and 32 liquid. Embolization failure occurred in 5/34 versus 4/32, and unplanned evacuation in 3/34 versus 1/32; events were few and the comparison underpowered. Female patients were more frequent in the particle group (47% vs 19%, P = 0.020). Early SDH thickness was 8 (6) versus 6 (6) mm (P = 0.340). The safety cohort had one fatal posterior-circulation infarct after Embozene (1/35 vs 0/32) and no other periprocedural complications.

Embolization failure was similar between 75 μm Embozene and liquid embolics, while unplanned evacuation was numerically higher with particles. Given infrequent events, limited sample size, and baseline imbalances, agent selection may be individualized by anatomy, visualization, and operator experience.