Middle meningeal artery embolization as an adjunct to surgery for non-acute subdural haematoma: an updated meta-analysis of randomized and prospective studies on efficacy, safety, and clinical utility.

Middle meningeal artery embolization (MMAE) combined with surgery has emerged as a promising option for treating non-acute subdural haematomas (non-aSDH). This meta-analysis aimed to evaluate the efficacy, safety, and clinical utility of adjunctive MMAE and compare them with conventional surgery alone for non-aSDH. Seven English and Chinese databases were searched to identify eligible randomized controlled trials (RCTs) and prospective cohort studies (PCSs) from inception to June 2025. The primary efficacy outcome was treatment failure, and the primary safety outcome was complications. The secondary outcomes included favourable outcomes, mortality, changes in SDH thickness, and length of hospital stay (LOS). Ten RCTs and three PCSs were analysed. Compared with surgery alone, adjunctive MMAE significantly reduced the risk of treatment failure (RR = 0.53, 95% CI: 0.40-0.69, high certainty). Adjunctive MMAE was also associated with a non-significant trend towards fewer complications (RR = 0.86, 95% CI: 0.71-1.04, moderate certainty) and lower mortality (RR = 0.72, 95% CI: 0.43-1.21, moderate certainty), with these trends being more pronounced in Chinese studies. However, no significant differences were observed in favourable outcomes (mRS 0-2; RR = 1.00, 95% CI: 0.96-1.04, moderate certainty), haematoma-thickness change (MD = -0.22 mm, 95% CI: -0.96 to 0.53, moderate certainty), or length of hospital stay (MD = -0.59 days, 95% CI: -2.49 to 1.31, low certainty). Adjunctive MMAE significantly reduces treatment failure and is associated with a non-significant trend towards fewer complications and lower mortality. No significant improvements are observed in favourable outcomes, haematoma-thickness change, or length of hospital stay.