Coil-based middle meningeal artery embolization for chronic subdural hematoma: a scoping review

Chronic subdural hematoma (cSDH) is a common neurosurgical condition with meaningful recurrence after conventional treatment. Middle meningeal artery embolization (MMAE) has emerged as an adjunctive and, in selected cases, a treatment strategy. Although liquid embolic agents and particles have been more extensively studied, coil-only MMAE is used in practice and may be particularly useful in anatomically challenging cases. We aim to synthesize the available evidence on coil-only MMAE for cSDH. This scoping review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR). Searches of PubMed, Ovid Medline, Web of Science, and Scopus identified 158 records. 55 studies underwent title and abstract screening, 29 studies received full-text review, and 9 studies met the inclusion criteria. Results were summarized descriptively. 9 studies comprising 367 patients and 459 embolization procedures were included. Coil strategies varied from proximal MMA trunk occlusion to distal branch-level coiling. Recurrence was reported in 7 of 9 studies and ranged from 0-17.6%. Reintervention was reported in 8 of 9 studies and ranged from 0-15.4%. Complications ranged from 0-5%. Where reported, radiographic outcomes generally trended toward hematoma improvement, although reporting was heterogeneous. The current literature suggests low reported complication rates and generally favorable radiographic directionality where measured. However, the current literature is limited by retrospective designs and heterogeneous techniques. Prospective studies with standardized outcome reporting are needed to define the role of coil-only MMAE better.