Postoperative recruitment and remodeling of middle meningeal artery collaterals in adult moyamoya disease: implications for preservation during combined revascularization.

BACKGROUND

The middle meningeal artery (MMA) may provide pre-existing transdural flow and postoperative collateral recruitment in adult moyamoya disease (MMD). We evaluated MMA remodeling, recruitment, and the safety relevance of preserving visible branches during combined revascularization.

METHODS

This retrospective hemisphere-level study included 110 operated hemispheres from 85 adults undergoing superficial temporal artery-middle cerebral artery bypass with encephaloduromyosynangiosis. Preoperative angiography showed visible MMA collaterals in 38 hemispheres and none in 72. Outcomes included vessel diameters, MMA caliber change ratio (MMA-CCR), Matsushima grade, and perioperative infarction. Groups were further classified by intraoperative MMA preservation or injury and by postoperative recruitment.

RESULTS

Hemispheres with visible preoperative collaterals had more advanced Suzuki stages (P < 0.001), larger postoperative MMA diameters (P = 0.006), and smaller postoperative donor superficial temporal artery diameters (P < 0.001). Among collateral-absent hemispheres, 56/72 (77.8%) developed postoperative MMA collaterals. Recruited hemispheres had better Matsushima grades (P = 0.001), larger preoperative (3.05 ± 1.14 vs 2.23 ± 1.19 mm; P = 0.016) and postoperative MMA diameters (P < 0.001), and higher MMA-CCR values (P < 0.001). Perioperative infarction occurred in 3/10 hemispheres with MMA injury and 0/28 with preservation (P = 0.014); this three-event association was exploratory.

CONCLUSION

The MMA showed postoperative recruitment and caliber remodeling. Visible branches should be preserved when technically feasible, although the observed association between injury and infarction requires validation.