Outcomes after middle meningeal artery embolization using coils alone for chronic subdural hematoma: A systematic...

Coil-only middle meningeal artery embolization (MMAE) remains less well characterized in the literature compared to liquid or particulate embolization for chronic subdural hematoma (cSDH). This systematic review and single-arm meta-analysis summarized clinical, radiographic, procedural, and safety outcomes after coil-only MMAE for cSDH. This systematic review followed PRISMA guidelines. PubMed, Ovid MEDLINE, Web of Science Core Collection, and Scopus were searched for English-language studies evaluating coil-only MMAE for cSDH with ≥ 5 patients and ≥ 1 predefined endpoint. Risk of bias was assessed using ROBINS-I. Single-arm random-effects meta-analyses were performed for clinical and radiographic outcomes when sufficient data were available. Anesthetic approach was summarized descriptively. Ten studies comprising 397 patients and 502 embolizations were included. Recurrence was reported in 7 studies comprising 252 patients, with a pooled rate of 4.6% (95% CI, 1.7%-12.1%). Reintervention was reported in 9 studies comprising 345 patients, with a pooled rate of 7.5% (95% CI, 4.5%-12.3%). Procedure-related complications were reported in all 10 studies, with a pooled rate of 1.3% (95% CI, 0.5%-3.0%). Radiographic reduction > 50% was reported in 6 studies comprising 220 patients, with a pooled rate of 76.7% (95% CI, 55.0%-89.8%). Heterogeneity ranged from absent to substantial across outcomes, and 9 of 10 studies were judged to have serious risk of bias. In this meta-analysis based on studies with substantial risk of bias, coil-only MMAE for cSDH was associated with low pooled rates of recurrence, reintervention, and procedure-related complications; however, these estimates should be considered hypothesis-generating rather than definitive evidence. Most included studies were retrospective and nonrandomized, treatment contexts and outcome definitions were heterogeneous, and prediction intervals were wide for several endpoints. Coil-only MMAE may represent a potential anatomy-selective embolization strategy, but current evidence does not establish equivalence, noninferiority, or superiority relative to liquid or particulate embolic agents.