Middle Meningeal Artery Embolization in Chronic Subdural Hematoma: Implications of Pathophysiology in Trial Design

Abstract

Background: Chronic subdural hematoma (cSDH) is a debilitating condition with a high rate of recurrence after surgical evacuation. Summary: This review is focused on middle meningeal artery (MMA) embolization to treat cSDH. We discuss the underlying pathophysiology of chronic subdural hematoma and how cessation of arterial flow may resolve a venous hemorrhage. We also present the current evidence for MMA embolization and the roadmap for future trials. Conclusion: Frequent multimodal imaging and cSDH sampling would enable us to understand mechanisms of MMA embolization in cSDH treatment and therefore improve our ability to offer MMA embolization to the eligible population.

The Mini-Craniotomy for cSDH Revisited: New Perspectives

“…The recent findings with MMA embolization suggest that the mechanism is via devascularization of the outer membranes. The finding of embolization material in the inner membrane raises the question of whether or not devitalization of this membrane may also be important in decreasing the size of the cSDH ( 14 , 39 ).…”

“…This may include headaches, weakness, cognitive decline, and seizures. The outer subdural membrane is very active and has been shown to have high levels of VEGF, inflammatory factors, and autophagy signaling factors (12)(13)(14).…”

Outpatient management of chronic expanding subdural hematomas with endovascular embolization to minimize inpatient admissions during the COVID-19 viral pandemic

“…2 A patient with a small collection and minor or resolving symptoms may be managed expectantly with serial imaging, as in many cases these collections will resolve, on their own while those with large symptomatic lesions are typically offered surgical drainage. 1 In some cases, patients with SDHs that were initially small will demonstrate growth of the collection over time rather than resolution, requiring treatment. The source of growth is attributed to microhemorrhages from the fragile vascular network found in the outer membrane.…”

“…The source of growth is attributed to microhemorrhages from the fragile vascular network found in the outer membrane. 1,15,16 The events that lead to the formation of a chronic SDH are still debated (we prefer the model proposed by Haines et al 17 ), but one thing is certain: every expanding chronic SDH is made up of two parts, (1) the initial, evolving hemorrhage and (2) the continuing hemorrhage. 1 Surgical drainage -via either a burr hole craniotomy or mini-craniotomy -can leave behind most, if not all, of the vascular outer membrane.…”

“…Chronic subdural hematomas (SDH) are typically found on follow-up imaging of known acute SDHs or through evaluations for headaches or falls, particularly in elderly patients. 1 – 3 Expanding collections often require inpatient management in symptomatic patients. However, with the current SARS-CoV-19 (COVID-19) pandemic, our practice has increasingly shifted the management of mildly symptomatic patients with minimal hematoma expansion to the outpatient setting to avoid inpatient hospitalization.…”