Objectives To quantify the degree of submental platysmal tightening that can be accomplished with superficial musculoaponeurotic system (SMAS) plication vs deep-plane rhytidectomy techniques in a cadaveric anatomical study to help dictate the need for midline platysmal surgery when using different rhytidectomy techniques.
Methods The lateral distraction of the medial edge of the platysma muscle was measured during tightening of the SMAS-platysmal complex on 5 cadaver heads. The measurements were taken after the following 3 rhytidectomy techniques: SMAS-platysmal plication, deep-plane rhytidectomy, and extended deep-plane rhytidectomy continuing the flap below the angle of the mandible into the neck with release of the platysma and cervical retaining ligaments.
Results The medial edge of the platysma muscle was distracted laterally 427% more with deep-plane rhytidectomy compared with SMAS-platysmal plication (P < .001). Extending the deep-plane rhytidectomy flap into the neck to release the cervical retaining ligaments resulted in 554% greater lateral distraction of the medial edge of the platysma muscle compared with SMAS-platysmal plication (P < .001). This represents 30% greater advancement compared with the traditional deep-plane technique (P = .05).
Conclusions Extending a traditional deep-plane rhytidectomy inferiorly to release the lateral platysma and cervical retaining ligaments to the sternocleidomastoid muscle achieves the greatest lateral motion of the midline platysma, theoretically obviating the need for midline platysmal plication except in cases of severe platysmal laxity and banding. Because of the limited platysmal motion during SMAS plication, midline platysmal plication should routinely be used as an adjunct procedure except in cases of no or minimal platysmal laxity.