Harvesting the Middle Temporal Artery for Bypass: Microanatomical Description and Surgical Technique

Background: The middle temporal artery (MTA) is the proximal medial branch of the superficial temporal artery (STA). It mainly irrigates the temporalis muscle along with the deep temporal arteries. Prior literature about its anatomical characteristics is limited. In the clinical setting, it has been occasionally described as a donor in vascularized flaps for reconstructive surgery and otolaryngological procedures.

Objective: To present a novel isolation technique of the MTA using a conventional curvilinear incision for an anterolateral approach, and to evaluate its morphological characteristics with the aim of using it in cerebrovascular bypass surgery.

Methods: Ten specimens were prepared using our laboratory’s embalming protocol. Each specimen was positioned in a 3-pin head clamp with a 15- to 20-degree rotation contralateral to the side of approach and with a 20-degree extension. A curvilinear skin incision was performed beginning at the zygomatic arch and ending at midline, slightly behind the hair line. The STA was identified and dissected from distal to proximal, and the horizontal portion of the MTA was located posterolateral to the posterior edge of the zygomatic root. It was then followed proximally until its origin, and distally until the visualization of two terminal branches (anterior, and posterior). The total length, visible branches, and calibers of MTA were recorded.

Results: The average length of exposure for MTA was 29.45 ± 6.48 mm, with an average of 4.9 ± 0.87 branches. The origin of MTA was visible 16.87 ± 4.88 mm inferior to the posterior edge of the zygomatic root. The average distance from the posterior edge of the zygomatic root to the most inferior proximal visible point of the ECA was 29.61 ± 4.54 mm. On average, the total length of MTA exposure was 29.45 ± 6.4 mm, and after being freed from the surgical dissected area and stretched, the total length of MTA was 31.71 ± 5.10 mm, with a proximal caliber of 1.68 ± 0.39 mm and a distal caliber of 1.27 ± 0.50 mm.

Conclusion: We were able to safely isolate the MTA until its origin in all our specimens; its medial origin decreases the risk of facial nerve or parotid transection. The constant horizontal portion of MTA at the level of zygomatic root facilitates its localization during an anterolateral approach. The MTA could be considered as a potential donor or interposition graft for use in extracranial-intracranial bypass cases where distal STA has been injured or has been already used in a previous procedure.