Middle meningeal artery embolization in chronic subdural hematoma: bridging surgical innovations and molecular mechanisms

Background: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions in the elderly. Despite advances in burr-hole craniotomy, up to one-third of patients experience clinically significant recurrences, and most are not suitable candidates for repeat surgery. Objective: To summarize current surgical concepts and clinical evidence for middle meningeal artery embolization (MMAE) in CSDH and integrate this data with our current understanding of the molecular and cellular mechanisms that drive disease persistence and response to treatment. Methods: We detail the epidemiology and standard surgical management of CSDH, discuss prospective and randomized evidence for the use of MMAE as adjunctive, primary, or salvage therapy, and synthesize experimental and clinical data on inflammation, angiogenesis, and coagulation in the CSDH neomembrane. We then summarize mechanistic hypotheses regarding how MMAE alters this microenvironment and highlight future directions, including biomarker development and AI-assisted precision therapy. Unlike previous reviews that focused primarily on clinical outcomes, this article highlights the biological mechanisms underlying MMAE efficacy and their impact on precise patient selection. Results: Recent randomized controlled trials of MMAE have yielded mixed but encouraging results. Some trials have shown a reduction in relapse or treatment failure with adjunctive MMAE, whereas others have failed to achieve primary endpoints. Heterogeneity in study design, patient selection, and outcome definitions limits direct comparison. Mechanistic studies demonstrate that CSDH is a vascularized and inflamed microenvironment nourished by fragile MMA-derived vessels. Embolization may reduce microbleeding, dampen inflammation, and promote hematoma resorption. Conclusion: By targeting underlying vascular and inflammatory processes, MMAE is a promising adjunct and, in selected cases, an alternative strategy for CSDH. However, current evidence is heterogeneous, and further studies are needed to define its safety, efficacy, and cost-effectiveness. Integration of mechanistic information with biomarker and imaging-based approaches may improve patient selection and treatment strategies.