Sternohyoid flap for facial reanimation: a comprehensive preclinical evaluation of a novel technique

Neuromuscular reanimation of the face provides the correct specific neural functional input and thereby prevents synkinesis. Unfortunately, this ideal situation is rarely encountered in the clinical setting.

To assess the technical feasibility of and define the surgical procedure for harvesting the sternohyoid muscle as a novel free flap for use in facial reanimation indications.

Fresh, postmortem, nonfixed cadavers were used to define the anatomy and perform the flap harvest procedures. Twenty-four flap harvests were performed. Angiography was performed on the pedicle of the harvested flaps to assess potential flap perfusion. Adenosine triphosphatase staining was performed on the muscle specimens to establish fiber type.

The harvest technique, pedicle (arterial or venous), nerve length, and flap geometry parameters were characterized.

The sternohyoid muscle was found to be reliably vascularized by the superior thyroid artery in all cases with an appropriate arterial and venous pedicle for vascular anastomosis. The mean arterial (5.5 cm) and venous (5.9 cm) pedicle lengths are comparable with gracilis flaps. The mean motor nerve length was 10.7 cm. The inclusion of the hyoid bone allows rigid fixation, and the muscle size, fiber type, and volume profiles all compare favorably to the gracilis flap for use in the indication of facial reanimation. Mock surgical procedures were performed to define inset parameters. This flap potentially allows single-stage cross-facial neurorrhaphies to be performed.

This is the first article, to our knowledge, of the sternohyoid muscle as a potential donor site for free-tissue transfer. This muscle has a predictable vascular pedicle and neural innervation along with size and fiber type parameters that make it an ideal potential free flap for facial reanimation.

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