Background and Objectives
The true target of skin tightening is not just the dermis, but the deeper structures of the hypodermis and fascia. Current methods of laser, ultrasound and radiofrequency (RF) skin tightening are transdermal, and as such are limited as to depth. This study evaluates the safety and efficacy of a method of structural tightening of the skin using a subcutaneous placed radiofrequency (RF) probe guided by Thermal Image Monitoring (TIM).
Study Design and Methods
- A retrospective analysis of 35 patients was completed on patients having undergone the new procedure ThermiTight™ for submental and jowl tightening.
- Treated sites included underchin and jowls. Neck banding and jowl laxity were pre-marked along the points of greatest severity.
- Photographs taken at baseline and between 60 and 180 days post-procedure were assessed by three blinded reviewers. They were randomly asked to sort order of sequence of treatment and to rate the photographs using a 4.0 skin laxity scale*.
- A t-test for paired samples evaluated the mean difference between baseline and post-procedure skin laxity severity scores.
- Bland-Altman statistics analyzed the reported mean change in laxity severity scores between each blinded reviewer.
Of the study population, 72.4% of subjects demonstrated a clinical improvement in skin laxity based on combined reviewer laxity scores. Forty-six percent of subjects reported an improvement of one grade or more.
Blinded reviewers reported a statistically significant improvement in skin laxity severity scores. The procedure is shown to be a safe and effective strategy for comprehensive 3-dimensional skin contracture of the jowl and submentum.
The prior existing approaches to non-invasive treatment for skin laxity are transcutaneous thermogenesis – achieved using ultrasound, radiofrequency, or light. These approaches use heat to promote neocollagenesis, denaturation of collagen cross-links, activation of wound healing pathways, contraction of collagen, and increase in collagen fibril size. The clinical results of current transdermal energy delivery are attenuated by factors such as depth, and variably influenced by pigmentation and water content of the skin. These are critical limitations as the collagenous structure of the subcutaneous and underlying superficial fascial compartments are extremely important in restoring the three-dimensional quality of skin we call tightness.
A newly emerging approach that provides precise and controlled subdermal heating in a 3-dimensional approach is “smart” thermistor-controlled subsurface skin tightening.
This approach uses a percutaneous treatment probe to administer radiofrequency-induced heating to all three structural compartments of the skin - dermis, subcutaneous and fascial. Subsurface temperatures are monitored and controlled by a thermistor integrated at the distal tip of the handpiece. Concurrently, epidermal temperatures are monitored using an infrared camera system. Therefore, both dermal and subsurface collagenous tissue reaches therapeutic temperature thresholds necessary for collagen remodeling.
Treatment entry points were created on the left and right lateral sides of the neck just inferior to the jowl, and left and right paracentral in the submentum, immediately superior to the apex of the platysmal bands. Each patient was infiltrated with preheated tumescent solution (37oC) containing 0.17% lidocaine and 1:600,000 epinephrine. A blunt 10 cm long, 18 gauge, percutaneous treatment probe was inserted at an angle nearly parallel to the dermal plane. The distal end of the treatment probe administered the radiofrequency, which possessed a temperature sensor that initiated an automatic feedback loop to allowed surface heating to occur only with the range of default temperature settings. The probe was guided at a deliberate pace, treating a surface area of 3.0 cm2 every two minutes. The clinical endpoint was an epidermal temperature of 42oC, not to exceed 45oC, as measured by a FLIR infrared imaging system.
Of the total study population, 57.8% has aspiration of excess lipid content. The average volume of aspirant was 3.81mL. For subjects undergoing aspiration, the average change in the skin laxity score was 0.82. For subjects not requiring aspiration, the average change was 0.78. The difference was not found to be significant. Photographs taken at baseline and between 60 and 180 days post-procedure were assessed by three blinded reviewers. They were randomly asked to sort order of sequence of treatment and to rate the photographs using a 4.0 skin laxity scale*.
The treatment was well tolerated with patients experiencing mild erythema, which persisted no more than 12 hours. No pigmentary alterations, blistering, erythematous papules, or scarring was observed. Additionally, there were no reports of a burning, sore, or achy sensation that were sufficient to require analgesics post treatment. Of the study population, 72.4% of subjects demonstrated a clinical improvement in skin laxity based on combined reviewer laxity scores, 46% of subjects showed an improvement of one grade or more. These data demonstrate the clinical effectiveness of the use of subsurface thermistor probe RF heating for jowl and submental skin tightening. Patients demonstrated a statistically significant change based on the 4.0 skin laxity score*. Additionally, comparison of the mean change reported for each blinded reviewer was not statistically significantly different, demonstrating a consistent assessment between reviewers for each patient. Altogether, subsurface smart thermistor probe RF heating is shown to be a safe and effective strategy for comprehensive 3-dimensional skin tightening of the jowl and submentum.