Delineation and histological examination of the intramuscular innervation of the platysma: Application to botulinum neurotoxin injection.

This study aimed to identify the whole innervation pattern of the platysma using the Sihler's staining, and the axonal composition profile of the sensory-motor anastomosis identified by immunofluorescence assays. The findings provide a comprehensive understanding of the neural anatomy of the platysma and facilitate efficient and safe manipulation for neurotoxin injection. Ten fixed and two fresh hemifaces were included in this study. Sihler's staining was used to the study 10 fixed hemifaces and two fresh hemifaces were used for immunofluorescence assays. In all cases, the cervical branch of facial nerve (Cbr) broadly innervated the platysma, and the marginal mandibular branch of facial nerve (MMbr) provided supplementary innervation to the uppermost part of the platysma. The transverse cervical nerve (TCN), great auricular nerve (GAN), and supraclavicular nerve (SCN) were observed in the lower half of the platysma. In 30% of all cases, there was a communicating loop between the Cbr and TCN. In 20% of all the cases, a communicating branch joined between the Cbr and GAN. For successful esthetic rejuvenation procedures, a clinician should consider the Cbr distribution to the overall platysma and additionally innervation by individual nerves (MMbr, GAN, TCN, and SCN) to the middle and lower portions of the platysma muscle.

Platysma and the cervical superficial musculoaponeurotic system - Comparative analysis of facial crease and platysmal band development.

OBJECTIVE: The superficial musculoaponeurotic system connects the mimic muscles to the skin, allowing mimic expressions with regional morphological architectural differences. The aim of this study was to perform an architectural analysis of the cervical platysma-skin interaction, determine the morphological implications in platysmal band development and compare the findings to the facial SMAS architectural types. METHOD: Full-thickness blocks of skin, SMAS and platysma from seven hemifaces (three male and two female) and full-thickness blocks of skin, SMAS and mimic muscles of the periorbital, perioral, forehead and midfacial regions from six hemifaces (three male and three female) of donor bodies were collected postmortem. Serial histological sections were cut and stained with Azan. After the morphological analysis, three-dimensional reconstruction of the tissue block was performed with AutoCAD. The morphological and mechanical properties of the different facial SMAS types were compared with those of the cervical SMAS. RESULTS: The architecture of the cervical SMAS (type V) consists of parallel, aligned septum fibrosus profundus and septum fibrosus superficialis tissue connected by vertical, aligned septa fibrotica commisurales tissue delimiting fatty tissue compartments transferring platysmal contractions to the skin. The facial morphological dynamic mimic pattern (SMAS types I, II and III) describes the point-by-point transfer of mimic muscle bundle contractions to the skin, explaining facial crease formation. The cervical morphological dynamic mimic pattern (SMAS type V) can be explained by dual traction force collimation over the septum fibrosus superficialis and profundus in platysmal band development. CONCLUSIONS: The cervical SMAS (type V) description supports the hypothesis that the SMAS and platysma have different morphological origins. The two different facial and cervical morphological dynamic mimic patterns support the phenotypical difference between facial fold and platysmal band development.

Deep Plane Facelift: An Evaluation of the High-SMAS versus Standard Incision Points.

In surgery of the aging face, operative adjustments of the superficial musculoaponeurotic system (SMAS) enhance facial contours. The senior author has observed that the standard deep plane face lift entry points on the SMAS do not provide as much tissue movement in a vertical direction as high-SMAS deep plane face lift entry points. In this study, tissue movement was measured comparing the conventional SMAS entry point with a high-SMAS entry point for deep plane face lifts. Institutional review board approval was obtained. Fourteen facelift patients were enrolled, 10 female and 4 male. Average age was 63.4 (50-81) years. Tissue movement at three points along the jaw line was measured intraoperatively. Standard SMAS entry point suspension resulted in average vertical movements of 6.4, 10.3, and 13.8 mm and average horizontal movements of 3.5, 5.7, and 6.5 mm. High-SMAS entry point resulted in average vertical movements of 11.8, 17.9, and 24.1 mm and average horizontal movements of 5.8, 9.8, and 9.9 mm. This resulted in a 77.3% increase (p = 0.03) in vertical movement and a 61.4% increase (p = 0.02) in horizontal movement with a high-SMAS entry compared with standard SMAS entry. The high-SMAS entry point for a deep plane facelift resulted in a significant increase in lift for both the horizontal and vertical vector on the facial skin flap when compared with the conventional entry.

The Utility of Superficial Musculoaponeurotic System Flaps in Facelift Procedures.

Facelift techniques widely vary with known individual surgeon modifications of and preference for particular techniques. This article provides an overview of the history of the superficial musculoaponeurotic system (SMAS), the changes of aging related to the soft tissues of the face, and the history of facelift procedures, including techniques to address the SMAS. In addition, a description of past studies and literature analyzing techniques of facelift procedures, safety of interventions involving the SMAS, low, extended, and high SMAS techniques, and evaluations of patient satisfaction with facelift outcomes including use of the FACE-Q are discussed. After review of the existing literature, a knowledge of the process of aging, and its effect on facial soft tissues, there is data to support SMAS flaps as a safe, effective, and logical means to handle the SMAS in facelifts. There is a paucity of the literature directly comparing differing techniques, particularly regarding SMAS flaps, leading to a challenging review but significant opportunity for additional study.

Are There Differences Between the Upper and Lower Parts of the Superficial Musculoaponeurotic System? A Preliminary Biomechanical Study.

BACKGROUND: The superficial musculoaponeurotic system (SMAS) becomes thinner and gradually disappears from the midface. In rhytidectomy, manipulation of the SMAS occurs in the lateral area, and previous research has focused primarily on the SMAS region as a whole. OBJECTIVES: In this preliminary study, the authors compared the viscoelasticity of the upper and lower regions of the SMAS using biomechanical techniques. METHODS: Two adjacent projection regions of the SMAS were designated: region 1 and region 2, representing the upper and lower parts, respectively. The SMAS tissues from 8 fresh-frozen cadaver heads were cut into 64 samples before biomechanical testing, and the following variables were recorded for subsequent analysis: stress-strain curve, elastic modulus, ultimate strength, and elongation at break. RESULTS: The stiffness of region 1 was markedly greater than that of region 2. Energy dissipation was greater in region 2. Elastic modulus and ultimate strength were significantly higher for region 1, and elongation at break was longer in region 2. The fit curve of the 2 regions deviated markedly. CONCLUSIONS: The biomechanical properties of the upper and lower regions of the lateral SMAS are functionally different. Such knowledge will help refine the planning and design of facial surgery and improve outcomes for patients who undergo rhytidectomy.