Sternohyoid Flap for Facial Reanimation

Abstract

IMPORTANCE 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.OBJECTIVES 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.DESIGN, SETTING, AND PARTICIPANTS 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. MAIN OUTCOME MEASURESThe harvest technique, pedicle (arterial or venous), nerve length, and flap geometry parameters were characterized. RESULTSThe 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.CONCLUSIONS AND RELEVANCE 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.LEVEL OF EVIDENCE NA.

Sterno-omohyoid Free Flap for Dual-Vector Dynamic Facial Reanimation

“…Second, the strap muscles are grossly more similar to native facial musculature than postural muscles, such as gracilis and serratus anterior, ultimately providing a more naturalappearing smile without adding excess bulk to the face. [12][13] In our case, commissure deviation decreased to 1mm after surgery, which is small enough that it is unlikely to be noticed as asymmetry by the untrained eye. [17][18] Also, the weight of the muscles transferred was 16 g, which is considerably less than that achieved with gracilis, serratus anterior, or latissimus dorsi transfer.…”

“…Strap muscles have been used for free tissue transfer previously, but not for dual-vector facial reanimation. [12][13][14] The sterno-omohyoid may be a preferable option for many reasons. First, it obviates the need for a separate donor site, especially in patients already undergoing a neck dissection.…”

“…[9][10][11] Last, the strap muscles are histologically similar to native facial muscles. [12][13] They are faster twitch muscles than postural muscles. A smile reanimated with a gracilis muscle is temporally asynchronous, meaning the hemiface with intact facial nerve and facial muscles will achieve a smiling position before the reanimated side.…”

“…Alam and Boahene have previously described harvesting the sternohyoid and omohyoid individually, respectively, but both authors reported using the superior thyroid artery and the AC, with Alam having additionally performed angiography to verify perfusion of the sternohyoid by the superior thyroid artery. [12][13][14] Through a hockey stick incision, we were able to harvest both muscles with the superior thyroid artery, its vena comitans, and the AC. Positioning the muscles in the face suggested that the superior thyroid artery could reach the superficial temporal artery, transverse facial artery, or facial artery for anastomosis.…”

Advances and future directions in the care of patients with facial paralysis

“…Limited case reports of alternate free muscle transfers for facial reanimation have aimed at improving facial contour and bulk. Alam et al 47 first reported the use of a novel sternohyoid muscle free flap using the ansa cervicalis for nerve coaptation and the superior thyroid artery as its vascular pedicle in a series of 24 fresh cadaver flap harvest procedures. Vincent et al 48 later described a dual vector transfer technique using the sternohyoid and omo-hyoid muscles together in cadaveric studies and report good outcomes with one patient who successfully underwent a dual-vector sterno-omohyoid flap with the superior thyroid artery, middle thyroid vein, and ansa cervicalis innervated by the nerve to masseter.…”