Rescue management of recurrent or growing non-acute subdural hematoma following standalone or adjunctive middle meningeal artery embolization: A case series and systematic review

ObjectiveRecurrent or growing non-acute subdural hematoma (SDH) following standalone or adjunctive middle meningeal artery embolization (MMAe) present a complex clinical challenge. This study aims to investigate the multifactorial causes of recurrence and growing SDH, including vascular and systemic contributors, and explores management strategies to improve outcomes.MethodsWe conducted a retrospective analysis of 22 patients with non-acute SDH requiring rescue treatment after adjunctive or stand-alone MMAe. Patients with documented trauma deemed responsible for the SDH expansion were excluded. Data were collected on patient demographics, clinical presentations, imaging findings, treatment approaches, and outcomes. A systematic review was also conducted across PubMed, Web of Science, Scopus, and Embase databases, adhering to PRISMA guidelines.ResultsNon-traumatic recurrent or growing SDHs were associated with MMA recanalization (27%), contralateral supply from the contralateral MMA (27%), CSF-venous fistulas (5%), and recruitments of vascular collaterals such as deep temporal artery (5%). Management strategies included, respectively, repeat MMAe using polyvinyl alcohol particles, coils, and liquid agents; contralateral MMAe, transvenous embolization for CSF-venous fistulas; and targeted embolization for other vascular contributors. Follow-up assessments were available for 14 patients (64%). Of these, 10 patients (45%) achieved complete resolution of symptoms, three patients (14%) experienced symptomatic improvement, and one patient (5%) had worsening symptoms. In terms of hematoma resolution, nine patients (41%) had complete or near-complete resolution, three patients (14%) exhibited stable hematoma size, and two patients (9%) demonstrated a reduction in hematoma size. Notably, no recurrences were observed after the final treatment. Two patients (9%) died within 10 days of the final embolization treatment due to malignancies.ConclusionRecurrent or growing SDHs following MMAe are linked to subdural membrane vascularity and intracranial hypotension which must be investigated and addressed. Treatment of these issues results in high cure rates.