Occult meningeal arterial bleeding in recurrent and postoperative subdural hemorrhage: implications for surgical decision-making and adjunctive middle meningeal artery embolization.

Subdural hemorrhage is generally managed according to established surgical pathways, which are appropriate for most patients. The aim of this review was to distinguish 2 mechanistically different settings in which meningeal arterial pathology may matter: chronic subdural hematoma (cSDH), where the middle meningeal artery (MMA) supplies a pathologic membrane, and uncommon recurrent or postoperative cases in which focal MMA injury may represent one actionable arterial source. We performed a structured narrative review of PubMed, Embase, and the Cochrane Library through March 2026. For cSDH, we prioritized randomized trials, meta-analyses, and multicenter studies. For acute or postoperative focal arterial injury, where direct evidence is limited, we synthesized angiographically characterized case reports, small case series, and concept-level evidence from epidural hematoma literature. Two arterial phenotypes emerged. In cSDH, the MMA sustains the pathologic outer membrane, and embolization functions as membrane devascularization to reduce recurrence. Evidence for this phenotype is supported by randomized trials, meta-analyses, and multicenter studies. In contrast, direct angiographically confirmed evidence for focal MMA injury in acute or postoperative subdural hemorrhage remains anecdotal and is limited to isolated cases of extravasation, pseudoaneurysm, or dissection. Early clinically significant postoperative reaccumulation, recurrent hemorrhage without a convincing cortical or venous source, repeated recurrence despite adequate drainage, and discordance between intraoperative findings and postoperative progression may justify vascular reassessment in selected patients. MMA-related pathology should not be considered a dominant explanation for problematic acute subdural hematoma, nor should cSDH trial evidence be extrapolated to acute lesions. A phenotype-based framework may help identify selected recurrent or postoperative cases in which CTA/DSA and adjunctive MMA embolization are clinically actionable, while standard management remains appropriate when no arterial lesion is identified.