Anatomical study and modified incision of the infrahyoid myocutaneous flap.

Skin paddle necrosis and neck function damage, particularly rotation, are two problems associated with the infrahyoid myocutaneous flap clinical application. The aim of this study was to investigate vessel supply and drainage of the skin paddle and to report our modified flap incision technique. In this work, we conducted a cadaveric study and reviewed our experience with the modified incision and describe the surgical procedure. We confirmed the platysma muscle branch feeds the skin paddle overlying the infrahyoid myocutaneous flap. The length between the platysma muscle branch entry point and its originating point measured 3.38 (min 2.51, max 4.52) cm. The flap has two drainage systems. The skin paddle of the flap was drained by the anterior jugular vein and external jugular vein, respectively, or both. The infrahyoid muscles were drained by the superior thyroid vein. In the early four cases, where the platysma muscle branch was not protected, skin paddle necrosis appeared in two cases. In the later seven cases, which involved preservation of the platysma muscle branch, all flaps successfully survived. Patients in whom a modified incision was used all achieved both satisfactory rehabilitation of neck function and an adequate esthetic result. We conclude that the necrosis rate of the skin paddle of the flap can be reduced by carefully protecting its supply and drainage vessels. The modified incision can improve neck function postoperatively.