We conducted a systematic review and meta-analysis of studies that compared the efficacy and safety of MMA embolization to conventional treatment alone for CSDH.

Chronic subdural hematoma (CSDH) is characterized by the collection of blood beneath the dura mater. Traditional treatments involve surgical drainage of the hematoma, but recurrence rates can be high. A highly vascularized neo-membrane irrigated by the middle meningeal artery (MMA) may be involved in CSDH re-accumulation.

A systematic search of PubMed, Embase Ovid, and ClinicalTrials.gov identified observational and randomized clinical studies comparing MMA embolization to conventional treatment for chronic subdural hematoma. The efficacy outcomes were hematoma recurrence and good functional outcome (as defined by a modified Rankin Scale score (mRS) of 0-2). Safety outcomes were the rate of major complication and mortality. Heterogeneity among studies were evaluated using the I² statistic. Analyses were conducted using Cochrane Review Manager software, with risk ratios (RR) and 95% confidence intervals (95% CI) presented for key outcomes. Absolute risk reduction (ARR, 95% CI) 1000 patients were also calculated using GRADEpro software.

The analysis included data from 13 studies (4 RCTs and 9 observational studies) with a total number of 2960 patients (35.3% in the MMA group and 64.7% in the conventional treatment group). Compared to conventional treatment, MMA embolization decreased risk of hematoma recurrence by 59% (13 studies, RR=0.41, 95% CI 0.26-0.65; I²=49%), for an absolute effect of 116 fewer events/1000 patients (95% CI 69-145), with similar risk of major complications (13 studies, RR=0.88, 95% CI=0.67-1.15; I² = 43%) and mortality risk (13 studies, RR=1.05, 95% CI=0.67-1.65). In subgroup analyses by study type, pooled results from RCTs showed similar direction effects as those from observational studies for both efficacy and safety outcomes.

MMA embolization in CSDH management is a safe and effective approach for CSDH.