Minimally Invasive Sternocleidomastoid Muscle Thinning for Cervical Feminization.

Background: At present, there is no gender-affirming facial surgery that offers feminization of the lateral neck. Objective: To demonstrate reliable relationship between the great auricular nerve point (GAP) and spinal accessory nerve along the sternocleidomastoid muscle (SCM) in human anatomical specimens and demonstrate feasibility of muscle transection in one transgender female patient. Methods: A total of 14 human anatomical specimen dissections were performed to determine if a transection of the SCM perpendicular to the GAP could be performed without potential compromise of the spinal accessory nerve. The surgical course of a patient who underwent transection is discussed. Results: Mean distance from the GAP to the accessory nerve at the posterior border of the sternocleidomastoid was 1.01 ± 0.54 cm, consistent with results from prior studies. In both the human anatomical specimens and the patient, sternocleidomastoid muscles were divided without injury to accessory nerve. The patient's neck girth was reduced by an average of 7 cm at 2 years post-operatively. Conclusion: Transection with distal denervation of the SCM by identifying the relationship between the GAP and accessory nerve is a feasible method of feminizing the lateral neck to improve cosmetic satisfaction while minimizing the risks of cervical neurovascular injury.