The pedicled masseter transfer for facial nerve palsy reconstruction—an anatomical study

Dynamic facial reanimation is one of the key treatment goals for lower facial palsy patients. Currently, temporalis myoplasty is the only non-free flap muscle transfer option considered feasible with good outcome. Although masseter transfer has been attempted, it was associated with poor results or considered to be technically challenging. This cadaveric study aimed to re-evaluate the feasibility of masseter transfer by looking at its geometry and offer a new approach to the muscle. Twenty-four masseter muscles were dissected in 12 fresh frozen cadavers through a preauricular rhytidectomy incision and a pre-parotid approach. The muscle’s insertion and origin attachments were divided to allow for rotation toward the modiolus. The angle of rotation, vector of pull, transfer distance, and length of the muscle were measured. The mean angle of rotation was 40.1 degrees, and the mean vector of pull was 66.7 degrees. The mean transfer distance from the muscle’s origin and insertion attachments was 30 and 62.5 mm, respectively. The mean lengths of the muscle’s anterior, posterior, superior, and inferior borders were 55.3 mm, 46.3 mm, 42.6 mm, and 42 mm, respectively. The distance, angle of transposition, and vector of pull measurements support the feasibility of pedicled masseter transfer in achieving optimal contraction vector with less risk of pedicle injury in lower facial palsy reconstruction. Tendon and fascial grafts can be adjuncts in cases where the masseter muscle length is short. The pre-parotid approach to the pedicled masseter transfer allows for a shorter operative time, which is desirable, particularly in the infirm. Level of evidence: Not ratable .