A Comprehensive Ultrasound Investigation of Lower Facial and Neck Structure.

[BACKGROUND] The jawline and neck significantly influence facial aesthetics. Botulinum toxin and filler are highly favored as minimally invasive jawline rejuvenation procedures. However, little evidence exists on the age-related skin and superficial fat tissue transformations in healthy individuals to guide targeted interventions.

[METHODS] A quantitative sonographic assessment was conducted on 51 patients. Total soft tissue thickness (the skin and superficial fat compartments) was measured at eight sites along the jawline and four sites at the neck. Among them, 21 patients received botulinum toxin A (BTX-A) injections for jawline lift. Three-dimensional images and questionaries were obtained before and after the treatment.

[RESULTS] In this ultrasound study, total superficial soft tissue thickness decreased significantly from the prejowl sulcus to the lateral cheek, with the jowl showing the greatest thickness. Vertically, significant differences in thickness were noted between superior and inferior points, especially at the inferior prejowl sulcus for the middle-aged and the jowl for the elderly group when comparing across age groups. Soft tissue thickness at the neck decreased from zones 1 to 3, consistent in all age groups. BMI and age positively correlated with soft tissue thickness at the jawline and neck. Regarding BTX-A injections, participants described a pain-free injection process, of which 85.7% reported substantial aesthetic improvement and sharpening of the submental-cervical angle.

[CONCLUSIONS] This study quantified age-related changes in superficial soft tissues at the jawline and neck regions with ultrasound imaging. With aging, soft tissue thickness alters with high region-specificity. Tailoring interventions to the specific alterations within each age group can achieve optimal results with enhanced safety. This study provided a quantitative analysis of skin and superficial fat compartment thicknesses for the young, middle-aged, and elderly groups. This study illustrated how skin and superficial fat compartments change with age in a regionally specific manner for both the jawline and neck regions. This study revealed a positive association between BMI and age with skin and superficial fat tissue thicknesses, especially in areas like the jowl, submental, and neck. This study provided guidance for a safe and effective botulinum toxin. A injection method focusing on the injection depths and regions to achieve optimal jawline rejuvenation outcomes and patient experience.

[LEVEL OF EVIDENCE IV] This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .