Chronic Subdural Hematoma Treatment With Embolization Versus Surgery Study

Inclusion Criteria:

1. Age 40-90 years inclusively.

2. Per CT of the head, (one of the following): Unilateral convexity CSDH measuring atleast 10 mm in thickness OR Bilateral CSDH if only one side is considered fortreatment and the contralateral side is asymptomatic and < 5 mm in thickness.

3. CSDH at least 2/3 isodense or hypodense, verified on axial CT slice used to measurethe thickness of the qualifying CSDH.

4. Qualifying baseline head CT performed within the 7 days prior to randomization.

5. Able to undergo assigned treatment within 72 hours after randomization.

6. Patient or legally authorized representative agrees to be randomized, and provideswritten informed consent and Health Insurance Portability and Accountability Act (HIPAA) authorization.

Exclusion Criteria:

1. Secondary cause apart from trauma for the qualifying SDH, such as an underlyingvascular abnormality or tumor.

2. Tentorial or interhemispheric SDH.

3. Secondary to CSDH, MRC of 0, 1, 2, or 3 in any muscle group contralateral to theside of the CSDH 4.

4. Pre CSDH mRS of 5 or higher.

5. Secondary to CSDH, patient is unable to complete TUG (i.e.,TUG > 120 seconds, unableto walk, or tries TUG but quits in ≤ 120 seconds). Note: This criterion does notapply if the patient does not complete TUG for reason other than CSDH.

6. Secondary to CSDH, ASR of 0, 1, or 2.

7. Emergent surgical evacuation such as open craniotomy, burr hole drainage, orSubdural Evacuating Port System (SEPS) is required for the patient.

8. Unable to withhold all antiplatelet agents or OACs for the first 7 days afterrandomization.

9. Indication that withdrawal of care will be implemented for the qualifying SDH.

10. Prior surgical treatment for CSDH if the surgery is less than 30 days prior torandomization.

11. On tranexamic acid.

12. Platelet count of <100,000 per microliter refractory to transfusion.

13. Coagulopathy that cannot be corrected to an INR of ≤1.5.

14. Known contraindications to angiography.

15. Known intolerance to occlusion procedures.

16. Known vascular anatomy (small artery size) or blood flow (high vascular resistanceperipheral to the feeding arteries) that precludes catheter placement or embolicagent (Embosphere Microspheres or CONTOUR particles) injection.

17. Known presence of collateral vessel pathways potentially endangering normalterritories or cranial nerves during embolization.

18. Known large diameter arteriovenous shunt, i.e., where the blood does not passthrough an arterial/capillary/venous transition but directly from an artery to avein or presence of patent extra-to-intracranial anastomoses (where studyembolization devices could pass directly into the internal carotid artery, vertebralartery, or intracranial vasculature) that cannot be addressed with coilembolization.

19. Patient has a known active systemic infection or sepsis.

20. Patient is pregnant, planning to become pregnant, or lactating.

21. Life expectancy of less than 6 months due to comorbid terminal conditions.

22. Concurrent participation in another research protocol for investigation of anexperimental therapy.

23. Known or suspected to not be able to comply with the study protocol.

24. No measurable deficit secondary to the CSDH on the Timed Up and Go [TUG], AphasiaSeverity Rating [ASR], or MRC. At baseline, a measurable deficit on the TUG isdefined as: time >10 seconds. At baseline, a measurable deficit on the ASR isdefined as: a score<4. At baseline, a measurable deficit on the MRC is defined as: ascore < 5 in any muscle group contralateral to the site of the CSDH.