Comprehensive Thermoregulation for the Purpose of Skin Tightening Using a Novel Radiofrequency Treatment Device: A Preliminary Report

February 2014 | Volume 13 | Issue 2 | Original Article | 185 | Copyright © February 2014

Douglas J. Key MD

Key Laser Institute for Cosmetic Regenerative Medicine, Portland, OR

BACKGROUND: Radiofrequency-induced heating of dermal and subdermal tissue promotes skin contracture; however, the temperature threshold for inducing an epidermal burn is lower than the therapeutic temperature thresholds required for collagen remodeling, and therefore, there is the possibility of epidermal burn. Herein, we evaluate a radiofrequency treatment that provides novel real-time subdermal and epidermal temperature monitoring.
METHODS: A retrospective chart review of 18 subjects undergoing thermistor-controlled subdermal skin tightening via percutaneous radiofrequency was conducted. During the treatment, epidermal temperature was concurrently monitored by a handheld infrared laser thermometer and a forward looking infrared camera system and peak temperatures readings were reported and evaluated.
RESULTS: Mean temperatures of 43.6 and 38.2oC were reported for the infrared camera and infrared thermometer. The Bland-Altman plot analysis reported a bias of 5.38oC and 95% limits of agreement between 0.60 and 10.15oC. Additionally, the mean difference or bias of 5.38oC was statistically significant (P less than 0.0001).
CONCLUSION: Our preliminary data supports a superior form of thermoregulation for the purposes of skin tightening that integrates continuous subsurface and epidermal temperature monitoring.

J Drugs Dermatol. 2014;13(2):185-189.


The gradual loss of skin quality overtime often becomes a barometer of age, which in turn, fosters the immense patient demand for skin restoration procedures. In 2012, facial rejuvenation treatments, including surgical and minimally- invasive procedures, accounted for an astonishing 74% of all cosmetic procedures performed.1 Considerations for the cause of skin aging and loss of quality include, but are not limited to, loss of subcutaneous fat, prominence of platysmal banding through muscle laxity, jowling along the mandibular border, and excess skin laxity resulting from a decline in collagen and elastin.2 Treatments range from botulinum toxin injections to more invasive surgical procedures. A widely used non-invasive skin tightening solution has been transcutaneous radiofrequency, which exerts a thermomechanical effect to induce neocollagenesis, denaturation of multi-chain collagen crosslinks, immunological and wound healing responses, collagen contraction, and collagen fibril size increase.3-5 Additionally, shorter, heat-stable intermolecular cross-links are established, which increase rubber-elasticity of the collagen polymer.3
Transcutaneous radiofrequency, through an external applicator, permeates the tissue generating an alternating electromagnetic field that increases the kinetic activity of ions.6,7 Increased ion kinetics and oscillations, in turn, facilitates resistive tissue thermogenesis.7 However, resistance-induced thermogenesis mandates that an appropriate quantity of energy reach the target tissue without imposing ill-effects on the epidermis.8 Accordingly, a major disadvantage of transcutaneous radiofrequency is the poor penetration of radiofrequency energy into deeper dermal and hypodermal layers, which can result in tissue arcing and subsequent scar formation.8 Additionally, and of great importance, the temperature threshold for inducing an epidermal burn is lower than the therapeutic temperature thresholds required for collagen remodeling. Accordingly the epidermis and outer dermal layers must be appropriately monitored and cooled to prevent untoward effects. Presently, temperature monitoring is done via a handheld infrared laser thermometer, without proper subdermal temperature monitoring and control.
Based on limited thermoregulation, broad, or volumetric, transcutaneous heating is limited in its ability to effectively treat superficial subdermal layers as well as deep adipose and subcutaneous tissue, without affecting skin integrity.8 This is an important limitation because Paul et al, (2011) described tissue contracture as a result of treating subcutaneous collagenous tissue, rather than dermal collagen only.9 Subcutaneous collagenous tissue includes the papillary and reticular layer of the dermis; fascia layer between muscle and skin; septal connective tissue segmenting fat lobules and linking the dermis and fascia; and reticular fibers encapsulating adipocytes.8
A treatment strategy that may deliver the appropriate subcutaneous heating for optimal skin contracture is thermistor- controlled subdermal skin tightening (ThermiTight) via