COMPLEMENT study (ChrOnic subdural hematoMa Patients suppLemented with Embolization of Middle mENingeal artery Trial) is a prospective, open label, blinded endpoint (PROBE), Japanese, two-arm, randomized, controlled, post-market study to assess the efficacy and safety of middle meningeal artery embolization for chronic subdural hematoma.

Inclusion Criteria:

1. Age >=18
2. pre-mRS 0-3
3. Hematoma thickness >=10mm
4. Having at least one risk factor Risk factor: Age >=75, Antithrombotic therapy, DM, Bilateral hematoma, Markwalder grading score >3, Preoperative volume >=130ml, Preoperative midline shift >=8mm, CT appearance (Homogeneous, laminar or separated)

Exclusion Criteria:

1. Cr >=1.8
2. Plt <50,000, PT-INR >2
3. Life expectancy <6 months