Salvage STA–MMA anastomosis for intraoperative middle meningeal artery in moyamoya disease: a technical note

BACKGROUND: In numerous cases of Moyamoya disease (MMD), the middle meningeal artery (MMA) develops as a spontaneous collateral prior to surgery, providing an extracranial-intracranial compensatory pathway. However, the MMA is vulnerable to iatrogenic injury during surgery. There is a lack of literature regarding managing iatrogenic injuries to the MMA which has collateral supply to the cerebral hemisphere. CASE DESCRIPTION: We report a case of a 61-year-old woman with MMD with collateral flows from the MMA. During a right-sided direct revascularization surgery, the MMA was inadvertently ruptured. After the bleeding is controlled, a salvage bypass was created by anastomosing the frontal branch of the superficial temporal artery (STA) end-to-end to the MMA, while the parietal branch of STA branch was anastomosed to a cortical middle cerebral artery (MCA) branch in an end-to-side fashion. Intraoperative indocyanine green video angiography (ICG-VA) confirmed good patency of the bypasses. Follow-up cerebral computed tomography angiography (CTA) confirmed the patency of the STA-MMA and STA-MCA anastomosis. Magnetic resonance imaging (MRI) showed no cerebral infarction. CONCLUSION: A remedial STA-MMA anastomosis can be a technically feasible salvage strategy when the MMA with collateral flow to the brain is injured intraoperatively. This approach preserves cortical collateral flow and expands the surgical options for complex revascularization cases.