Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: Preliminary Results of a Systematic Review of Interventional Studies

Abstract

Background. Chronic subdural hematoma is one of the most common neurosurgical conditions. Although burr-hole trepanation remains the conventional therapeutic strategy, it has important limitations, including hematoma recurrence, which may lead to repeat surgical interventions, increased healthcare costs, complications, clinical deterioration, morbidity, and mortality. Collectively, these factors may delay or interrupt comprehensive rehabilitation processes, limit functional recovery, and increase the overall burden of disease. Middle meningeal artery embolization has emerged as a minimally invasive therapeutic alternative associated with a substantial reduction in hematoma recurrence and the need for reintervention. However, there is still no consensus regarding which patients are most likely to benefit from this procedure, at what stage of the therapeutic algorithm it should be implemented, or under which clinical objectives it may provide greater value than trepanation alone. Objective. To evaluate the impact of middle meningeal artery embolization on chronic subdural hematoma recurrence. Methods. A literature search was conducted in PubMed using search algorithms based on the following Medical Subject Headings (MeSH) and search terms: ("Chronic Subdural Hematoma" OR "Subdural Hematoma") AND ("Middle Meningeal Artery Embolization" OR "Middle Meningeal Artery Embolisation" OR "MMA Embolization"). Randomized controlled trials comparing middle meningeal artery embolization combined with conventional treatment versus conventional treatment alone were included. Study selection was performed independently by two reviewers in two stages (title/abstract screening and full-text review). A narrative synthesis was conducted according to PRISMA guidelines. Risk of bias for the recurrence outcome was assessed using the RoB 2 tool, and certainty of evidence was evaluated using the GRADE approach. For the primary outcome (hematoma recurrence), a random-effects model was applied to estimate relative risks (RRs) and 95% confidence intervals (95% CIs). Results. Four randomized controlled trials published in 2024 were included, comprising a total of 1,467 patients. Risk-of-bias assessment using RoB 2 for the recurrence outcome identified one trial at high risk of bias due to concerns regarding the allocation process, whereas the remaining three multicenter trials presented some concerns. Certainty of evidence assessed with the GRADE approach was rated as moderate because of limitations related to risk of bias, with no major concerns regarding inconsistency, indirectness, or imprecision. Middle meningeal artery embolization was associated with a 52% relative reduction in the risk of recurrence (RR=0.48; 95% CI, 0.33–0.69). The confidence interval suggests that the true effect may correspond to a risk reduction ranging from 31% to 67%. Heterogeneity was low (I²=19.9%), indicating good consistency among the included studies. Conclusions. In conclusion, this preliminary analysis suggests that middle meningeal artery embolization may reduce the risk of chronic subdural hematoma recurrence. However, the available evidence remains limited by the small number of randomized clinical trials and the need for additional analyses of secondary outcomes to more precisely establish the effectiveness of this intervention.