INTRODUCTION
A well contoured jawline is a key factor in the perception of facial attractiveness and youthfulness in both men and women.1-3 Patients are increasingly interested in non-invasive methods with little to no downtime to improve jowling and sagging of the lower face and neck. These changes are caused by loss of bone, subcutaneous fat repositioning, loosening of facial ligaments, and a decrease in collagen and elastin fibers within the dermis and subcutis.4 Microfocused ultrasound with visualization system (MFU-V) (Ulthera Inc., Ultherapy, Merz North America, Inc., Raleigh, NC) delivers ultrasound energy below the epidermis creating precise 1 mm3 microthermal lesions at approximately 65 degrees C in specific anatomical layers of the skin including the dermis at 1.5 mm of depth, deep dermis at 3.0 mm of depth and the sub-dermal plane including the superficial musculo-aponeurotic system (SMAS) and fibrous septae at 4.5 mm.5,6 MFU-V has the ability to bypass the epidermis, therefore; eliminating the downtime created by many non-ablative and ablative devices used for neocollagensis.7 MFU-V is based on principles of wound healing to produce robust neocollagenesis which creates lifting and tightening of the treated tissue.
Treating all patients with a one size fits all standard protocol does not take into consideration variances in facial anatomy and skin tissue thickness and may result in suboptimal results and poor patient satisfaction.8 Customizing the dual depth treatment protocol to the anatomy of each patient by visualizing the superficial muscular aponeurotic system (SMAS) and fibrous septae of the lower face and upper neck, which in some subjects can be found at 4.5 mm deep and in others at 3.0 mm deep, and then selecting the appropriate depth transducers may result in a more efficacious treatment with higher patient satisfaction as all coagulation point placement is being optimized.9
Treating all patients with a one size fits all standard protocol does not take into consideration variances in facial anatomy and skin tissue thickness and may result in suboptimal results and poor patient satisfaction.8 Customizing the dual depth treatment protocol to the anatomy of each patient by visualizing the superficial muscular aponeurotic system (SMAS) and fibrous septae of the lower face and upper neck, which in some subjects can be found at 4.5 mm deep and in others at 3.0 mm deep, and then selecting the appropriate depth transducers may result in a more efficacious treatment with higher patient satisfaction as all coagulation point placement is being optimized.9
MATERIALS AND METHODS
This was a single center, prospective, randomized, investigator blinded clinical trial. Institutional review board approval was obtained to ensure the study was conducted in accordance with the Declaration of Helinski and the International Conference on Harmonization. After obtaining informed consent, 51 female subjects were enrolled in the trial, with a median age of 55, and Fitzpatrick skin types II-V. Subjects had moderate to severe sagging of the jawline area (grade II-III on the Merz Jawline Assessment Scale). Subjects were excluded if they were pregnant, breastfeeding, or planning pregnancy for the duration of the trial. Additionally, subjects were excluded if they were using any opioids for pain control. Exclusions also included the presence of active or local systemic skin disease that may affect wound healing, history of Bell's palsy, significant scarring in the area, open wounds, severe or cystic acne in the treatment area, active implants (pacemakers or defibrillators) or metallic implants in the area (dental implants not included). History of microdermabrasion or glycolic acid peel to the treatment area within two weeks prior to study participation. History of any energy-based device procedure for skin tightening within the past 12 months, injectable filler of any type in the treatment area within the past 24 months, neurotoxin treatment in the area within the past six months, fractional and fully ablative resurfacing laser treatment within the past 6 months, surgical dermabrasion or deep facial peels within the past 6 months, history of facelifts, neck surgery within the past two years, any history of deoxycholic acid or cryotherapy to the treatment area, history of contour threads in the past year or the initiation of retinoids 14 days prior to the start of the study, use of antiplatelet/anticoagulants, systemic immunosuppressants, and/or autoimmune connective tissue disease.
Subjects were randomized to receive 1 MFU-V treatment of the lower face and upper neck utilizing either the standard or custom dual depth treatment protocol. The standard treatment protocol included 360 lines with the 4.5 mm transducer followed by 310 lines with the 3.0 mm transducer, both at the default energy level setting of 2. The custom dual depth treatment protocol was based on the patient's unique anatomical depth of the SMAS of the lower face and the platysma of the upper neck using visualization on the device. 360 lines were delivered with either the 4.5 mm or the 3.0 mm transducer, depending on the depth of the SMAS and platysma followed by 310 lines with the 3.0 mm depth transducer, or the 1.5 mm transducer depending on the depth of the fibrous septae. Prior to treatment, subjects were offered oral pre-medication of 5-10 mg of diazepam, 800 mg of ibuprofen, and/or 1 gram of acetaminophen. Immediately post treatment, subjects were asked to rate their level of discomfort during treatment using a 10-point visual pain scale (0 = no pain, 10 = worst pain). Subjects returned for follow up visits at month 3 and month 6 for evaluations. Vectra 3D photographs (Canfield Scientific Inc., Parsippany, NJ) were taken at baseline, month 3, and month 6. 3D photographs were then analyzed with Mirror Photofile Software (Canfield Scientific Inc., Parsippany, NJ) to measure submental lift. The following evaluations were also conducted: Blinded Evaluator Merz Jawline scale (0 = no sagging, 1 = mild sagging, 2 = moderate sagging, 3 = severe sagging, 4 = very severe sagging; Figure 1) at day 0, month 3 and month 6; and Investigator Global Aesthetic Improvement Scale (I-GAIS) (1 = Very Much Improved, 2 = Much Improved, 3 = Improved, 4 = No change, 5 = Worse), Subject Global Aesthetic Improvement Scale (S-GAIS) (1 = Very Much Improved, 2 = Much Improved, 3 = Improved, 4 = No change, 5 = Worse) and Subject Satisfaction Questionnaire (0 = Completely Dissatisfied, 1 = Moderately Dissatisfied, 3 = Neither Dissatisfied Nor Satisfied, 4 = Mildly Satisfied, 5 = Moderately Satisfied, 6 = Completely Satisfied), were conducted at month 3 and month 6. Any adverse events were recorded.
Statistical Analyses
All statistical tests were two-sided and interpreted at a 5% significance level. Descriptive statistics (ie, mean standard deviation, etc) were provided for all continuous variables and frequencies for all categorical variables. In order to track changes for individual variables across all relevant visits,
single-factor Analysis of Variance (ANOVA) tests were used, while comparisons between two individual visits were done using two sample t-tests assuming equal variance. P-values < 0.05 were considered clinically significant.
RESULTS
Forty-one subjects completed the trial, Fitzpatrick II-V skin types, with a mean age of 55 (37 to 65 years old). 19 subjects were randomized to the standard treatment group and 22 subjects were randomized to the custom treatment group. Of the subjects randomized to the custom treatment group, 13 subjects still had platysma identified at 4.5 mm and were treated with the 4.5 mm and 3.0 mm depth transducers. 9 subjects had a more superficial platysma at 3.0 mm and were treated with the 3.0 mm and 1.5 mm depth transducers. Seven subjects were lost to follow up and three subjects withdrew consent, as this study took place during the COVID-19 pandemic.
Primary Endpoint
Standard and custom treatment groups both demonstrated improvement with regards to the degree of submental lift as measured by 3D photography (Table 1, Figures 2-4). No statistical significance was noted between groups with regards to submental lift. The mean submental area for the standard group was 185.083 mm2 +/- 101.44 at baseline decreasing to 164.78 mm2 +/- 85.11 at month 3 with further reduction at month 6, 129.11 mm2 +/- 75.06. For the custom group, the mean submental area at baseline was less at 167.85 mm2 +/- 87.20. Reduction in mean submental area was also seen in the custom group with month 3 mean submental area of 152.6 mm2 +/- 80.34 and month 6 being 132.28 mm2 +/- 68.56.
