Chronic Subdural Hematoma: A Review of Current Knowledge, Treatment Modalities, and Clinical Trials of Middle Meningeal Artery Embolization.

Purpose of Review: While chronic subdural hematoma (cSDH) has been considered a neurosurgical disease, conventional management with surgical evacuation has been associated with high rates of disease recurrence and long-term patient morbidity and mortality. In this narrative review, we summarize the current knowledge regarding the epidemiology, pathophysiology, and treatment modalities for cSDH with a particular focus on middle meningeal artery embolization (MMAE) and other novel treatment modalities. Recent Findings: A growing body of literature has suggested that inflammation and angiogenesis may play a central role in cSDH pathophysiology, and major advances have been made on nonsurgical treatment modalities for cSDH such as MMAE and antiangiogenic agents. Furthermore, recent studies, including several large randomized controlled trials, have confirmed that MMAE is generally an effective treatment for promoting cSDH resorption and reducing recurrence rates. Summary: Chronic SDH is a common neurovascular disease that is expected to increase in incidence because of global population aging and widespread use of antithrombotic medications. The current pathophysiologic understanding suggests that cSDHs may form because of a positive feedback loop of inflammation, angiogenesis, and persistent exudation of blood into the subdural space. Surgical management is the standard treatment for relieving acute neurologic deficits; however, rates of cSDH recurrence are high and risks of perioperative morbidity and mortality are substantial. Conservative medical management options for cSDH are limited. MMAE is a novel treatment with high-quality data from multiple randomized trials suggesting efficacy regarding preventing cSDH recurrence and promoting hematoma resorption.