Posterior auricular artery-to-middle cerebral artery side-to-side microvascular anastomosis

In rare cases, the superficial temporal artery (STA) is not the optimal donor vessel for extracranial-intracranial (EC-IC) bypass procedures. This situation can arise due to factors such as congenital abnormalities, hypoplastic development, trauma-related alterations, or prior surgical interventions. In such scenarios, a well-developed robust and sizable posterior auricular artery (PAA) can be considered a viable alternative for facilitating EC-IC revascularization surgeries. To assess the feasibility of the surgical technique for posterior auricular artery (PAA) and middle cerebral artery (MCA) side-to-side (S-S) microvascular anastomosis, and to explore the blood flow distribution patterns following the establishment of PAA-MCA S-S anastomosis. A PAA-MCA S-S microvascular anastomosis was successfully performed. Intraoperatively, indocyanine green videoangiography (ICG-VA) confirmed immediate anastomotic patency, which was further validated by digital subtraction angiography (DSA). The recipient MCA received blood flow from two directions: antegrade blood flow originated from the proximal preanastomotic PAA, whereas retrograde blood flow traveled from the distal postanastomotic PAA via the ipsilateral and contralateral OAs. Side-to-side microvascular anastomosis between the posterior auricular artery and middle cerebral artery is an effective alternative revascularization strategy in moyamoya disease. This approach optimizes the blood supply to the recipient MCA territory through dual-directional flow from the donor PAA, enhancing hemodynamic augmentation.