Assessment of equivalence of adipose tissue treatment with a noncontact field RF system delivering 200 W for 30 min and 300 W for 20 min: An in vivo porcine study

Background and aims: Abdominal circumferential reduction with noncontact high frequency apoptosis-inducing field RF (AiRF) is becoming very popular. The present study compared the treatment results from two different sets of parameters giving the same dose from the same system in an in vivo porcine model.

Materials and methods: Two 10 cm × 10 cm areas were symmetrically marked on both sides of the midline (total of 4 areas) over the rectus abdominis muscle of two anesthetized female micropigs. In Animal A (G1), 27.12 MHz AiRF treatment was given at 200 W for 30 min, and 300 W for 20 min in Animal B (G2). Four sessions were performed at weekly intervals. Gross observation by a veterinary specialist was performed on a daily basis. Temperature measurements (fat and skin), clinical photography and ultrasound imaging were carried out at each session. In addition, blood chemistry was performed before each session to check lipid levels, any adverse changes in markers for liver damage in addition to an enzyme-linked immunosorbent assay (ELISA) for raised levels of TNF-α and IL-1β. Biopsies were taken and routinely processed for hematoxylin and eosin, Toluidine blue and oil red O stains to examine for tissue damage at baseline and after each treatment. TUNEL assays were performed to check of apoptotic-related DNA damage. Follow-up assessments included photography, ultrasound, ELISA tests and biopsies which were taken regularly up to 90 days after the final treatment.

Results: The maximum adipose tissue temperatures at and over the apoptotic threshold of 43°C were reached and maintained in both G1 and G2. The skin surface temperature was slightly higher in G2 after 20 min than in G1 after 30 min, but was still below 43°C. Gross and magnified observation revealed no appreciable differences or thermally-mediated damage between the skin of either of the two groups after the treatments or during the 90-day follow-up period. No lasting erythema or any other adverse event was seen in either group. The liver enzyme markers showed very similar patterns over the 4 weeks of treatment compared with baseline with no levels outside of the normal range. Triglycerides were all within normal rage with no significant differences between the groups. Remarkably similar patterns were noted for the ELISAs in both groups performed over the 4 weeks of treatment and at periods during the 90-day follow-up with no notable abnormal changes in levels. Staining patterns for both G1 and G2 specimens were similar for all stain types during treatment and the 90-day follow-up, showing decreased numbers of adipocytes by the 90-day point. The ultrasound findings revealed a 44.8% and 55.6% decrease in the adipose layer for G1 and G2, respectively, at the 90-day assessment.

Conclusions: The 200 W AiRF treatment for 30 min (G1) and the 300 W AiRF treatment for 20 min (G2) produced very similar results in the porcine model for all assessments and at all assessment points during and up to 90 days after treatment, with slightly better findings suggested for G2. Based on the above findings, the two different settings, delivering the same dose, produced good results with no skin damage and no adverse events. This has implications in busy clinics for AiRF treatment, where the shorter treatment time could represent time saving for the clinic and the patient without compromising safety and giving equal if not better efficacy.