Defining a Safe Corridor of Cervical Branch Preservation in Lateral Platysmaplasty Surgery During Facial Rejuvenation Surgery.

Abstract

During rhytidectomies, the cervical branch of the facial nerve (CBFN) can easily be encountered, and potentially injured, when releasing the cervical retaining ligaments in the lateral neck. This nerve has been shown to occasionally co-innervate the depressor anguli oris muscle, and damage to it can thus potentially compromise outcomes with a postoperative palsy. The authors sought to examine the lateral cervical anatomy specific to the CBFN to ascertain if the position of the nerve can be predicted, thereby enhancing safety of the platysmal flap separation and dissection from this lateral zone of adhesion. Eleven cadaveric hemifaces were dissected, and the distance between the medial border of sternocleidomastoid muscle (SCM) and the CBFN was measured at 3 key points: (1) superior: the distance between the SCM and the nerve at the level of the angle of the mandible in neutral; (2) narrowest: the narrowest distance measurable between the superior and inferior points as the CBFN descends into the neck medial to the SCM; and (3) inferior: the distance at the most distal part of the cervical nerve identified before its final intramuscular course. The average distances (in mms) were as follows: superior = 12.1 (range, 10.1-15.4), narrowest = 8.8 (range, 5.6-12.2), and inferior = 10.9 (range, 7.9-16.7). There is a narrow range between the nerve and the anterior border of SCM. We thus propose a safe corridor where lateral deep-plane dissection can be performed to offer cervical retaining ligament release, with reduced risk of endangering the CBFN.