Chronic Subdural Hematoma Treatment with Embolization Versus Surgery Study (CHESS): Trial Rationale and Protocol.

Background: Current treatment paradigms for Chronic Subdural Hematoma (CSDH) include either medical management for mildly symptomatic patients or surgical evacuation for severely symptomatic patients. Middle Meningeal Artery Embolization (MMAE) has demonstrated potential to reduce rate of recurrence and rescue surgery as an adjunctive or standalone treatment for CSDH. However, there currently lacks randomized trial data to support the safety and efficacy of standalone MMAE in CSDH patients. Objective: The objective of Chronic Subdural Hematoma Treatment with Embolization versus Surgery Study (CHESS) is to compare standalone MMAE to conventional surgery for treatment of moderately symptomatic CSDH. Methods: CHESS is a prospective, multi-center, open-label randomized controlled trial. Eligible CSDH patients will be randomized 1:1 to either conventional surgery (burr holes or craniotomy) or standalone MMAE with either polyvinyl alcohol particles or microspheres. The follow-up duration will be for 180 days following randomization. Results: The primary endpoint is a composite measure, comprising of the centrally-adjudicated need of rescue surgery and/or mortality, assessed from randomization through 180 days. Safety outcomes include symptomatic ischemic stroke, serious/life threatening adverse events, worsening neurological status, seizures, and cranial neuropathy. Exploratory endpoints include hematoma volume reduction (at least 50%), functional outcome, as well as changes in quality of life, cognition, and headache severity. Conclusions: CHESS is the first randomized controlled trial to characterize the safety and efficacy of standalone MMAE compared to conventional surgery in a moderately-symptomatic CSDH patient population. Results of this trial will further advance the role of endovascular approaches to CSDH treatment.