The Role of Middle Meningeal Artery Embolisation in the Management of Refractory Chronic Subdural Haematoma: A Systematic Review of Randomised Controlled Trials and Primary Studies

Abstract

Introduction. Chronic subdural haematoma (cSDH) is among the most frequent conditions encountered in contemporary neurosurgical practice and is projected to become the commonest cranial operative indication in ageing populations. Conventional surgical evacuation relieves mass effect but does not address the pathophysiological substrate of the disease—an inflammatory, angiogenic and hyperfibrinolytic neomembrane perfused by fragile, leaky branches of the middle meningeal artery (MMA). Consequently, recurrence rates of 2–37% persist after apparently adequate evacuation. Middle meningeal artery embolisation (MMAE) is a minimally invasive endovascular technique that devascularises the neomembrane and, in principle, interrupts the recurrence cycle at its source.

Methods. The study strictly adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. Eligible: RCTs, prospective and retrospective cohorts, case-control, cross-sectional, and observational studies; systematic reviews excluded from characteristics tables. Risk of bias assessed with RoB 2 and ROBINS-I; certainty with GRADE.

Results. Forty primary reports (10 RCTs, 2,552 participants; 30 non-RCT studies, 204,509 patients). Adjunctive or standalone MMAE halved symptomatic recurrence (RR 0.51; 95%CI 0.38–0.68; 9 RCTs; P<0.001; I²=29%), with ARR 9.0% and NNT 11. Effect on reoperation was larger and homogeneous (RR 0.33; 95%CI 0.20–0.53; 6 RCTs; P<0.001; I²=0%; NNT 11). Radiographic recurrence or residual >10 mm was reduced by 60% (RR 0.40; 95%CI 0.29–0.57; P<0.001; I²=24%). Observational studies confirmed direction and magnitude (RR 0.35; 95%CI 0.18–0.70; P=0.003; I²=68%). Pooled surgical rescue after MMAE was 7.8% (95%CI 6.9–8.9; I²=0%). Mortality (RR 1.57; 95%CI 0.86–2.87; P=0.14) and serious adverse events (RR 0.80; 95%CI 0.43–1.51; P=0.50) did not differ significantly. Aggressive distal penetration reduced surgical rescue to 2.6%. The CSDH grading scheme prediction model achieved AUC 0.85.

Discussion. Randomised evidence now converges on a robust conclusion: MMA devascularisation halves recurrence risk and reduces reoperation by two-thirds, with no procedural harm signal. Apparent discordance between trials is explained by differing endpoint definitions, proportions of surgical patients, and embolic agent/penetration technique. Liquid agents with distal penetration produced the largest effects. Safety is reassuring but complications such as cranial nerve palsy and non-target embolisation remain.

Conclusion. Middle meningeal artery embolisation is an effective and acceptably safe intervention that substantially reduces recurrence, reoperation, and radiographic treatment failure in refractory cSDH without compromising functional recovery. It should be offered as an adjunct to evacuation in patients with recurrent haematoma or established high-risk features, and considered as standalone therapy in neurologically stable patients who are poor surgical candidates. Future trials should adopt harmonised endpoint definitions, mandate distal penetration, extend follow-up, and incorporate cognitive, quality-of-life, and health-economic outcomes.