The auricle is supplied by 2 main arterial sources arising from the external carotid artery: the superficial temporal artery (STA) supplying the anterior auricle and the posterior auricular artery (PAA) supplying the posterior auricle and the concha.1 Anastomoses between these 2 blood supplies occur through perforating arteries and vascular arcades.
As the STA courses cranially, it moves from a deep position—deep to the parotidomasseteric fascia—to the superficial temporal fascia approximately 1 cm anterior and superior to the tragus. In approximately 80% of patients, 3 perpendicular branches stem from the STA—the upper, middle, and lower anterior branches—which supply the ascending helix, tragus, and lower margin of the earlobe, respectively.2 The upper anterior branch of the STA joins other branches to form 2 dominant arcades: the first with the nonperforating branches of the PAA forming the upper third of the helical arcade, and the second with the lower anterior branch of the STA forming the middle portion of the helical arcade.3,4 In 75% of patients, the middle helical arcade was identified as a single connecting artery, whereas in the remaining 25% of patients, a robust capillary network was formed.2 In patient 2, the middle helical arcade was likely disrupted during closure, resulting in the helical necrosis seen postoperatively.
The second main blood supply of the auricle is the PAA, which enters in a more superficial position after traversing superiorly from the meatal cartilage, between the mastoid process and the posterior surface of the concha. From this point, the PAA runs in the deep subcutaneous tissue in the groove formed by the conchal cartilage and the mastoid process. Near the midpoint of the postauricular groove, it passes inferior to the postauricular muscle. The PAA has multiple radial branches that anastomose with helical branches; it also sends perforating branches (there were 2–4 branches in a recent study2) through the cartilage to the anterior surface of the concha. The 2 primary perforating arteries most commonly are located at the level of the antihelix and the antitragus.5 These arteries transverse through a vascular foramen located approximately 11 mm from the tragus in the horizontal plane and supply blood to the conchal bowl.6 In patient 1, the PAA itself, or the perforating arteries that course anteriorly through the vascular foramen, was likely disrupted, resulting in the conchal defect.
Special Considerations Before Surgery—As evidenced by these cases, special attention is needed during operative planning to account for the external ear vascular arcades. Damage to the helical arcades (patient 2) or the perforating arteries within the conchal bowl (patient 1) can lead to unintended consequences such as postoperative tissue necrosis. Tissue manipulation in these areas should be approached cautiously and with the least invasive treatment and closure options available. In doing so, blood flow and tissue integrity can be maintained, resulting in improved postoperative outcomes. Further research is warranted to identify the best intervention in cases involving these watershed regions.