Chronic subdural hematoma (cSDH) causes a significant burden of disease with a growing incidence secondary to an aging population and increased use of antithrombotics [1]. It is anticipated that by the end of the decade there will 60,000 cases of cSDH in the United States annually [2]. Standard treatment for symptomatic patients involves drainage via twist drill craniostomy, burr holes, or craniotomy [3], [4]. Yet, surgical evacuation has been plagued by high rates of hematoma recurrence and reoperation of about 10 – 20% leading to worse outcomes [5]. The pathogenesis of cSDH involves a split of the dural cell border and an inflammatory cascade resulting in the development of inflammatory membranes and neovasculature. The fragile neovessels of the membranes are thought to contribute to progression of the hematoma through recurrent hemorrhages and fluid exudation [6]. There is a spectrum of hematoma architecture [7], with septations representing more dense membranes and a further progression along the cSDH disease course. Septations have been shown to be an independent risk factor for failure of conservative management and recurrence after surgery [8], [9], [10], [11], [12]. In addition, septations pose a surgical challenge as they are often highly vascular and result in loculated collections that may extend beyond the surgical exposure.

Middle meningeal artery embolization (MMAE) has emerged as a promising treatment of cSDH, both as an adjunct to surgery and as a stand-alone procedure [13], [14]. The efficacy of MMAE in cSDH is currently being investigated in multiple randomized control trials [15]. Due to the inherent vascularity of hematoma membranes, it has been proposed that MMAE may be of particular benefit in patients with septated cSDH [16]. The objective of this study was to evaluate the efficacy of adjuvant MMAE following surgery in patients with septated cSDH compared with surgery alone.