Goals/Purpose: Noninvasive devices for body contouring, such as radiofrequency, laser- and light-based therapies, cryolipolysis, mesotherapy, and ultrasound, provide an alternative to surgical interventions for appropriate patients. However, there have been few studies of the long-term safety of such technologies. High-intensity focused ultrasound (HIFU) may be used to ablate subcutaneous adipose tissue via a thermomechanical process. HIFU energy is focused in a small area; application is precisely controlled and the dermis and other collateral tissues are not damaged. Within the treated area, a wound-healing response ensues in which macrophages engulf and transport free lipids and cellular debris away from the treatment area, and the destroyed adipocytes are resorbed. This randomized controlled clinical trial evaluated the effectiveness (12 wks) and safety (24 wks) of a HIFU device for noninvasive body contouring.
Methods/Technique: Men and women 18–65 years of age with body mass index ≤30 kg/m2 and subcutaneous adipose tissue ≥2.5 cm in thickness in the abdominal region were randomized to 1 of 3 groups for HIFU treatment of the anterior abdomen and flanks with different energy levels. Patients in each group were administered 3 passes at an energy level (total dose) of 47 (141), 59 (177), or 0 (0, sham) J/cm2 and focal depth of 1.3 cm. Patients were required to abstain from changes in diet and exercise during the trial. The primary assessment was change from baseline waist circumference (CBWC) at the level of the iliac crest 12 weeks posttreatment. Waist circumference was measured using a validated technique with standardized positioning, dress, posture, and breathing. Secondary endpoints were CBWC at 4 and 8 weeks posttreatment, physician ratings of appearance using the Global Aesthetic Improvement Scale (GAIS), and a nonvalidated patient satisfaction questionnaire. Safety assessments were adverse events (AEs), laboratory parameters, physical examinations, and patient ratings of discomfort during posttreatment week 1 using a 100-mm visual analog scale (VAS). Differences between sham and active treatments were evaluated using analysis of covariance (change in waist circumference, patient satisfaction), the Cochran-Mantel-Haenszel test (GAIS), or descriptive statistics (discomfort, safety endpoints). Least squares (LS) mean was used to account for additional factors in the model (e.g., weight).
Results/Complications: 180 patients were treated and composed the intent-to-treat (ITT) group (per protocol [PP] group, n=168); mean±SD age was 42±11 years, mean body mass index was 25±3 kg/m2; 85% (n=153/180) were women, and 87% (n=156/180) were white. Weight fluctuations during the study were minimal (≤0.6 kg). Using the predefined significance criteria of p<0.05 for both active treatments or p<0.025 for any 1 active treatment vs. sham, success on the LS mean CBWC at 12 weeks posttreatment was achieved for the ITT population for both active treatments vs. sham, as well as for 59 J/cm2 (-2.44 cm [p=0.01]) but not 47 J/cm2 (-2.06 cm [p=0.13]) vs. sham (-1.43 cm). For the PP population, significance was achieved for both active treatments at 12 weeks posttreatment (59 J/cm2, -2.52 cm [p=0.002]; 47 J/cm2, -2.10 cm [p=0.04]) vs. sham (-1.21 cm). Significant CBWC vs. sham was observed as early as 4 weeks posttreatment (ITT, 59 J/cm2: -1.86 cm [p<0.001]; PP, 47 J/cm2: -0.88 cm [p=0.04], 59 J/cm2 -1.81 cm [p<0.001]) and with both active treatments at week 8 (p≤0.005). Significantly higher percentages of patients receiving active treatments vs. sham were rated as improved on the GAIS at weeks 4–8 (p>0.001). Figure 1 shows baseline/ posttreatment photographs of the abdomen and flanks in 2 patients. At 12 weeks posttreatment, investigators rated GAIS as improved or much improved in 78% (59 J/cm2) and 72% (47 J/cm2) vs. 16% (sham). Overall satisfaction was reported by 58% of patients treated with 47 J/cm2 (p=0.3) and 67% of patients treated with 59 J/cm2 (p=0.03) vs. 48% of patients in the sham group. ≥67% of patients in the active-treatment groups reported mild or no discomfort (VAS = 0-44), and 40 patients (22%) used an analgesic before, during, or after treatment. The most common treatment-related AEs were procedural pain (47 J/cm2, 85%; 59 J/cm2, 95%; sham, 12%) postprocedural pain (61%, 52%, 14%), bruising/ecchymosis (66%, 67%, 0), and edema/swelling (8%, 10%, 0), all of which had a mean time to resolution of 10.9-16.6 days. Safety assessments through week 24 posttreatment showed no unanticipated adverse device effects, no unexpected AEs, and no treatment-related serious AEs. No burns occurred, and there were no clinically meaningful physical findings or fluctuations in laboratory parameters, including lipid profiles, inflammatory markers, and bilirubin over 24 weeks.
Conclusion: This HIFU device for noninvasive ablation of subcutaneous adipose tissue demonstrated safety similar to sham after 24 weeks and was generally well tolerated and effective for body sculpting at energy levels of 47 J/cm2 and 59 J/cm2.
Supported by Medicis Technologies Corporation, Scottsdale, AZ.
Figure 1. Patient Photographs at Baseline (Left) and Posttreatment Week 12 (Right) (A) 47 J/cm2 CBWC=-2.45 cm (B) 59 J/cm2 CBWC=-2.55 cm
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