Vascular variation of temporoparietal fascia in microtia associated with hemifacial microsomia.

The study analyzed vascular variations in microtia associated with hemifacial microsomia (HFM). A retrospective analysis was conducted on 47 patients with microtia and HFM, who underwent computed tomography angiography between November 2011 and May 2022. The vascular course and branching supplying the TPF were analyzed. Craniometric measurements were conducted to determine the horizontal distance from the porion and fronto-zygomatic suture (F-Z suture) to the vessels. On the affected side, the TPF was primarily supplied by either the superficial temporal artery (STA) or the postauricular artery-originated STA (Po-STA). The Po-STA (n = 29) was more prevalent than the STA (n = 18), and mostly exhibited a single frontal branch (n = 20). Craniometric analysis revealed that the Po-STA was closer to the porion, ear vestige, and F-Z suture than the STA on the non-affected side. Furthermore, a significant correlation was observed between the severity of mandibular hypoplasia and presence of Po-STA variation (Cramer's V = 0.498, p = 0.005). Microtia associated with HFM exhibits vascular variations in the TPF - in particular, a unique Po-STA variation. The Po-STA is prone to injury during ear reconstruction because of its proximity to the external auditory canal and ear vestige. Surgeons should be cautious of these anatomical variations for safer ear reconstruction procedures, and utilize preoperative imaging for meticulous planning.