Effects of Subdermal Monopolar RF Energy on Abdominoplasty Flaps

January 2016 | Volume 15 | Issue 1 | Original Article | 55 | Copyright © January 2016


John Ferguson MD

The Ferguson Clinic, Honolulu, HI

Abstract
BACKGROUND: Radiofrequency has long been successfully employed for medical and, more recently, aesthetic indications due to its ability to cause tissue contraction by thermal induction of neocollagenesis and the subsequent wound healing cascade, leading to collagen remodeling and a tightening effect. Percutaneous RF treatment provides therapeutically relevant thermal stimulation directly to the tissue target in a minimally invasive manner, which is therapeutically ideal because of limitations inherent in transcutaneous RF heating. A novel device combines percutaneous RF with thermistor-controlled temperature regulation and external tissue temperature monitoring, providing the ability to safely deliver RF energy.
METHODS: Percutaneous subdermal RF treatment was performed on 48 samples of abdominoplasty tissue; samples were marked to standardize measurement of surface area in the treatment zones, and a subdermal temperature target of 51°C was preprogrammed into the treatment device. The treatment cannula was inserted parallel to the dermal plane at four points with a single pass per insertion. Surface area was then re-measured.
RESULTS: Approximate average reduction in surface area was 91.23±19.33 mm2, ranging between 124.45 mm2 and 35.39 mm2 (median 96.83 mm2). Results were statistically significant (P<0.0001). Statistical analysis via analysis of variance (ANOVA) plus Tukey post-hoc testing revealed no statistically significant difference between the sides in all comparisons, demonstrating symmetry in contracture.
CONCLUSION: Percutaneous subdermal monopolar RF creates dramatic, immediate tissue contraction in vitro and is a viable technology for tissue tightening.

J Drugs Dermatol. 2016;15(1):55-58.

INTRODUCTION

The use of radiofrequency (RF) energy in medicine dates back to the 1920s and went virtually unchanged until the late 1960s. Today, RF is in wide use in the medical and aesthetic fields. In aesthetic medicine RF is harnessed to create a therapeutic thermal effect (thermogenesis) for tissue remodeling and related indications. The mechanism of action includes collagen cross-link denaturation, partial fibril denaturation, and an inflammatory response inducing the activation of the healing cascade. While there is an immediate contraction effect, the subsequent inflammatory wound healing response leads to collagen remodeling and more tightening over a period of months, with additional improvement in quality and elasticity. Histologic study by Zelickson and colleagues1 thoroughly documented these effects; work by Meshkinpour et al.2 revealed upregulated collagen production at 12 months post-treatment with monopolar RF, highlighting the progressive nature of outcomes as well as their persistence. Work by Paul et al.3 surmised that fuller tissue contracture was the result of deeper thermogenic treatment of the subcutaneous collagenous tissue, versus only superficial treatment of dermal collagen.
Monopolar RF employs a single electrode but requires a return pad to complete the circuit, while bipolar RF uses pair electrodes and no return pad is needed. Both cause heating of tissue via impedance with thermal profiles that differ somewhat. RF has been widely studied for aesthetic indications including wrinkles, facial laxity, brow lifting, nasolabial folding, acne, and scarring as well as general skin tightening,4 with emerging investigation for use on the body for recontouring.3,5
Most RF treatments involve external application of energy; for transcutaneous methods cryogen cooling is often used to protect the epidermis while heat is deposited more deeply for a therapeutic effect. Percutaneous radiofrequency tightening allows practitioners to deliver energy directly to the target tissue; as long as nearby tissue and tissue structures remain relatively undamaged and discomfort is tolerable, this is therapeutically ideal because outcomes using transcutaneous methods are limited to the upper dermis and epidermis, failing to address the complex network of collagenous tissues of the dermis and hypodermis, down to the fascia.6-7 Demonstrable efficacy for submental recontouring has been noted using a novel RF technology for percutaneous subdermal heating5 which delivers energy directly to the dermis and subdermis. The device, called ThermiRF (Thermi, Irving, TX), combines monopolar RF with real-time thermistor feedback control and the option of using concurrent external infrared tissue temperature monitoring shown effective for thermoregulation in a previous study,8
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