We read with interest the recent article by Dr. Roostaeian and colleagues regarding anatomic considerations to prevent facial nerve injury.1 The authors provided a state-of-art analysis of the facial nerve branches to improve the understanding of facial soft-tissue anatomy when applied to face lift procedures, in order to outline safe planes of dissection for each branch during surgical undermining. They underscored that the precise location and the number of peripheral rami of each of the five main facial nerve trunks are variable but their anatomical course is relatively constant. Understanding of the clear anatomical plane in which facial nerves course is paramount to identify safe planes of dissection during face lift.
Even though there is no compromise between any face lift technique and potential facial nerve injury, it is widely accepted that injuries to peripheral rami of zygomatic and buccal branches may not be clinically relevant, as there are numerous interconnections that explain the spontaneous recovery of motor functions following most of the peripheral injuries. The cervical branch is mainly responsible for platysma innervation, and thus its injury may be not clinically relevant. Also for this reason, the cervical branch has been reported as donor nerve for motor reinnervation procedures.2 However, cervical branch injury may be responsible in some cases for marginal mandibular pseudoparalysis, a transient but frustrating condition for both surgeon and patient after a face lift. This complication can be experienced in the setting of anatomic variation of the cervicofacial trunk (5 percent of cases), where the ascending branch of the cervical branch contributes to lower lip muscle innervation along with the marginal mandibular branch.3 The frontal and marginal mandibular branches, however, have received more attention in the face lift literature because these branches show no to minimal interconnections, and their injury may result in permanent and visible stigmata.
Even though the bidimensional anatomy (its projection on skin) of the frontal branch is quite established, its three-dimensional (relationship with anatomical spaces) anatomy has been misunderstood because of the incorrect description given by anatomy books and by some papers. According to those sources, the frontal branch is situated just below the superficial musculoaponeurotic system (SMAS)/temporoparietal fascia layer at the level of the zygomatic arch. Interestingly, Barton4 and Connell and Marten5 popularized the high-SMAS technique, in which they demonstrated clinically that it is technically safe to transect the SMAS at the level of zygomatic arch since the frontal branch is not at risk because it is situated in a deeper plane than the SMAS layer. Subsequent anatomical studies confirmed their statements.
With this Letter, we would like to provide our cadaveric images of high-SMAS face lift with dissection of the facial nerve branches, with particular focus on the frontal branch and cervicofacial branches (Fig. 1). Figure 1 may provide a nice adjunct to the comprehensive and excellent article by Dr. Roostaeian and colleagues. It may help in further understanding the three-dimensional course of the frontal branch across the zygomatic arch, especially when applied to the high-SMAS procedure, as well as the complexity of the cervicofacial branch anatomy, with its potential clinical implication in case of injury.
The authors thank professor P. M. N. Werker, Mr. Hepke Gjaltema, and Mr. Sip Zwerver, Wenckebach Institute, Skill Center, University Medical Centre Groningen, Groningen, The Netherland,s for their assistance, receptiveness, and hospitality.
The authors have no financial interest to declare in relation to the content of this communication.
Giuseppe Visconti, M.D.
Marzia Salgarello, M.D.
Department of Plastic and Reconstructive Surgery and
Catholic University of “Sacro Cuore”
University Hospital “A. Gemelli”
1. Roostaeian J, Rohrich RJ, Stuzin JM. Anatomical considerations to prevent facial nerve injury. Plast Reconstr Surg. 2015;135:1318–1327.
2. Bertelli JA. Platysma motor branch transfer in brachial plexus repair: Report of the first case. J Brachial Plex Peripher Nerve Inj. 2007;2:12.
3. Daane SP, Owsley JQ. Incidence of cervical branch injury with “marginal mandibular nerve pseudo-paralysis” in patients undergoing face lift. Plast Reconstr Surg. 2003;111:2414–2418.
4. Barton FE Jr. The SMAS and the nasolabial fold. Plast Reconstr Surg. 1992;89:1054–1057. discussion 1058..
5. Connell BF, Marten TJ. The trifurcated SMAS flap: Three-part segmentation of the conventional flap for improved results in the midface, cheek, and neck. Aesthetic Plast Surg. 1995;19:415–420.