Authors: Leonardo B. C. Brasiliense, MD; Manuel Granja, MD; Pedro Aguilar-Salinas, MD; Travis Dumont, MD (Tucson, AZ)

Introduction: Embolization of middle meningeal artery (MMA) has been proposed as a potential treatment for chronic subdural hematomas (cSDH) by cutting off the blood supply to the subdural membrane, preventing microhemorrhages, and enabling hematoma resorption. We sought to investigate its safety and efficacy in the treatment of recurrent and newly-diagnosed cSDHs. Methods: A systematic review of the literature was performed searching multiple databases for reports on the treatment of cSDHs with embolization of MMA. Outcomes investigated included procedure-related complications, mortality, rate of hematoma recurrence, and rate of rescue surgery after embolization. The odds of recurrence after embolization were compared between recurrent and newly-diagnosed cSDHs. Results: A total of 11 studies were included, involving 128 patients and 136 cSDHs. All patients had successful embolization of the frontal and parietal branches of the MMA. Mean age was 70 years ( ± 6.2 years) and 70% of patients (89) were males. Forty percent of patients (48) were taking antiplatelets or anticoagulants. Mean hematoma size was 19mm ( ± 1.8mm). The rate of procedure-related complications was 1.4% (95% CI, 0.5% - 3.4%). There were no neurological complications or mortalities. Seventy-eight (57%) hematomas were treated upfront with MMA embolization and 58 (43%) were treated with embolization after one or more recurrences from drainage. The rate of recurrence was similar in both groups 1.2% and 3.4%, respectively (odds ratio of recurrence, 0.36; 95% CI 0.03 – 4.11, p=0.41) during a mean follow up of 5.1 months ( ± 2.5 months). The rate of rescue evacuation after embolization was 0.7% (95% CI, 0.002% - 1.4%). Conclusion: Our systematic reviewed showed that treatment of cSDHs with embolization of the MMA is extremely safe with low rates of morbidity and no mortalities. We also found that MMA embolization was effective not only for newly-diagnosed cSDH but also for recurrent cSDHs. A prospective, randomized study is warranted.