Document resource
Background Chronic subdural hematoma (cSDH) is increasingly prevalent in older adults and is associated with high recurrence rates following conventional management. Middle meningeal artery embolization (MMAE) has emerged as an effective adjunctive or stand-alone therapy, with recent randomized trials demonstrating reduced treatment failure and hematoma progression. Given that cSDH membranes are primarily supplied by distal MMA branches, distal embolization may allow improved penetration of pathologic neovasculature; however, proximal embolization is technically simpler and may be safer. The optimal embolization strategy remains unclear. We therefore evaluated the comparative efficacy and safety of proximal versus distal MMA embolization.Methods PubMed, Embase, and Scopus were systematically searched from inception through 2026 for studies evaluating MMAE in cSDH. Studies reporting outcomes of either proximal or distal embolization were included, while those performing both techniques in the same patient or using adjunct coiling with other embolic agents were excluded. Proximal embolization was defined as coiling of the main MMA trunk, and distal embolization as liquid embolization of distal branches. Primary outcomes included hematoma improvement or resolution, and recurrence. Secondary outcomes included need for surgical rescue, major morbidity or mortality, and periprocedural complications. Random-effects models were used to generate pooled estimates.Results Fifty-seven studies comprising 6,826 patients were included. Overall, hematoma improvement or resolution occurred in 79% (95% CI: 71-86%; I 2=86.4%), with recurrence in 10% (95% CI: 7-13%; I2=81.0%). Surgical rescue was required in 8% (95% CI: 6-10%; I2=63.4%), and major morbidity or mortality occurred in 5% (95% CI: 3-7%; I2=62.7%). Periprocedural complications were observed in 4% (95% CI: 3-5%; I2=15.3%). Subgroup analysis demonstrated comparable outcomes between proximal and distal embolization for hematoma improvement (80% vs. 79%, p=0.977), recurrence (7% vs. 11%, p=0.103), surgical rescue (6% vs. 8%, p=0.180), and major morbidity or mortality (5% vs. 5%, p=0.963). Proximal embolization was associated with significantly lower periprocedural complications (2% vs. 4%, p=0.002).Conclusion Proximal and distal MMA embolization techniques demonstrate comparable efficacy across major clinical outcomes. However, proximal embolization is associated with significantly fewer periprocedural complications, suggesting a potential safety advantage without compromising effectiveness. Prospective head-to-head studies are warranted to confirm these findings and guide optimal technique selection.Disclosures M. Jatty: None. D. Hijazi: None. L. Saada: None. R. Khelo: None.Abstract E-046 Figure 1