ABSTRACT
BACKGROUND: Facial skin tightening with wrinkle/fine line reduction is a highly demanded procedure in the aesthetic field. Although there are studies focused on the types of energy sources, the total amount of thermal energy, and the affected depth, there have been no reports examining the relationship between the shape of thermal energy and the directivity of skin tightening. We have developed a specific method to apply thermal energy to the dermis in continuous parallel lines, resembling a thread, perpendicular to the Relaxed Skin Tension Lines (RSTL) for vectorized collagen contraction using synchronous ultrasound parallel beam technology. OBJECTIVE: To evaluate the safety, tightening capability, and directivity of the Thermal Thread Technique™ utilizing a high-intensity, high-frequency, parallel ultrasound beam. MATERIALS AND METHODS: A total of 34 cases, both males and females aged between 30 and 70 years with Fitzpatrick skin types 2-4, exhibiting mild to moderate skin laxity, participated. All subjects received one treatment using the Thermal Thread Technique™ utilizing high-intensity, high-frequency parallel ultrasound beam to cover the full face and submental area. 3D clinical images were captured before, 8 weeks, and 24 weeks after the treatment. A quantitative image analysis of captured 3D images was performed to objectively measure the direction and distance of contraction. RESULTS: The average contraction distance from baseline (0 mm) to 8 weeks and 24 weeks posttreatment were 1.91 ± 0.61 mm (p < 0.001) and 1.96 ± 0.67 mm (p < 0.001) respectively. Regarding the contraction direction at 24 weeks posttreatment, the angle formed between the contraction direction and the base axis, which is perpendicular to the RSTL, was + 9.85° ± 32.94°. Out of 34 cases, 28 met the criteria with the angle within ±22.5° of the base axis (p < 0.001). The average pain score on a 0-5 scale (0 being no pain, and 5 being maximum pain) was 2.63 ± 0.78. No side effects were reported during the treatment or observation period. CONCLUSION: The Thermal Thread Technique™ utilizing a high-intensity, high-frequency, parallel ultrasound beam was proven to be clinically safe and effective for vectorized facial skin tightening.
