Efficacy and Safety of High-Intensity Focused Ultrasound (HIFU) on Reduction of Unwanted Submental Fat in Asian Patients.

[BACKGROUND] There are several treatment options to improve a double chin, such as contour injections, thread lifting, and double chin liposuction. However, the results of these treatments can be minimal or have a short-lasting effect. Additionally, these treatments may lead to worsened scarring due to repeated skin penetration and can cause prolonged discomfort. The high-intensity focused ultrasound (HIFU) is a non-invasive ultrasound lifting treatment that can improve a double chin without the need for surgical procedures, so the HIFU is considered a very safe way to reduce the submental volume.

[OBJECTIVE] This study aimed to identify the clinical and photographic changes observed among patients who received HIFU treatment and to evaluate the efficacy and safety of HIFU for submental fat reduction.

[METHODS] Thirty patients, aged from 25 to 60 years (20 females and 10 males), participated in a 4-week follow-up (n=30). High-intensity focused ultrasound treatment was performed on submental fat using two different focal depth transducers, 4.5 mm and 6.0 mm, with MP (Micro Pulsed) mode. We assessed the treatment effects using Vectra for volume measurement, CR-SMFRS (Clinician Report-Submental Fat Rating Scale) on a 5-point scale (0-4), SSRS (Subject Self-Rating Scale) on a 4-point scale (0-3), as well as monitoring weight and photography. Adverse events were evaluated using questionnaires.

[RESULTS] A total of 30 patients were enrolled in this evaluation at the follow-up visit (4 weeks). The proportion of treatment patients satisfied with appearances and significant submental fat reduction was apparent when comparing the initial CR-SMFRS ratings to the final CR- SMFRS ratings. Initially, CR-SMFRS ratings were categorized as 10 mild, 10 moderate, 8 severe, and 2 extreme. After one session of treatment, the final ratings showed improved submental fat conditions, with 16 mild, 8 moderate, 5 severe, and 1 extreme. This change indicated a significant improvement, with a p-value of <0.000005. The SSRS showed an 82% improvement level, and most patients experienced immediate improvements. No significant side effects or adverse events were reported. Expected common side effects were noted but resolved within 2 weeks.

[CONCLUSION] The HIFU treatment using the 4.5 and 6.0 mm focal depth transducers was safe and effective in reducing the submental fat based on the results.

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