Influence of the Dermis Thickness on the Results of the Skin Treatment with Monopolar and Bipolar Radiofrequency Currents

The Influence of Skin Parameters and Body Composition on the Tolerance of Pain Stimulus Generated During Electrical Muscle Stimulation (EMS) in Women - Pilot Study

Purpose

This pilot study aims to explore how skin parameters and body composition impact the tolerance to EMS (Electrical Muscle Stimulation) stimuli in women, particularly focusing on pain tolerance in response to varying intensities of EMS. This research seeks to understand what is essential for optimizing EMS applications.

Patients and Methods

The study involved 16 females (age 35.9 ± 12.3). Body composition and anthropometric measurements were taken, including BMI (Body Mass Index), weight percentage, WHtR (Waist to Height Ratio), WHR (Waist-Hip Ratio), and Bioelectrical Impedance Analysis. High-frequency ultrasound scans were conducted to assess skin parameters. The EMS stimulation was performed using an Evolvex (InMode, Israel), with applicators placed around the abdomen and intensity adjusted according to patient tolerance, recorded at the pain threshold.

Results

The maximum tolerated EMS stimulus varied from 12V to 55V, with a median of 33V. Body weight showed a strong positive correlation (R=0.76, p<0.001) and hip circumference (R=0.66, p<0.001) with EMS intensity. Body fat mass (R=0.61, p=0.012) and visceral fat area (R=0.55, p=0.029) were positively correlated with EMS intensity. However, no significant correlations were observed between EMS tolerance and muscle tissue parameters or total body water content. The study also found that skin structure parameters showed no significant impact on EMS tolerance.

Conclusion

The study reveals that women's tolerance to EMS stimuli is influenced by various factors. Anthropometric parameters like hip circumference, body weight, skinfold, and BMI are strongly correlated with EMS tolerance. Body composition factors, particularly adipose tissue characteristics such as body fat mass and percentage, also significantly impact EMS intensity requirements, with no notable correlation to muscle tissue or water content. However, variations in skin structure, including thickness and density, do not significantly affect EMS tolerance. These insights are crucial for tailoring personalized EMS therapy to enhance effectiveness and comfort in both aesthetic and rehabilitative applications.

A Split-face Study on Rejuvenation Efficacy According to Monopolar Radiofrequency Tip Size

Monopolar radiofrequency (RF) non-invasively tightens and rejuvenates the skin by stimulating collagen fiber production. Since the introduction of the monopolar RF device in the early 2000's, RF devices have advanced and they can rejuvenate of periorbital and forehead wrinkles, as well as skin laxity of the lower face and neck. We compared the differences in the treatment effects based on the tip size. This randomized split-face study comprised 31 participants aged 29 to 75 years old (three males and 28 females) who underwent one session of monopolar RF; one side of the face was treated with a 3cm2 tip and the other with a 4cm2 tip. Facial wrinkle scores were measured on the upper face and the lower face before and after treatment for up to three months. Significant improvement was observed in the periorbital area (p<0.001), forehead (p=0.72), and glabellar (p=0.63) treated with a smaller tip. However, nasolabial folds (p=0.8) and marionette lines (p=0.13) showed better improvement when treated with a larger tip.

Evaluation of Skin Biophysical Parameters and Angiogenesis Using CD34 as a Biomarker in Older Diabetic Women Treated with Radiofrequency

Background

The prevalence of type 2 diabetes mellitus (t2DM) has been steadily increasing. Patients with t2DM need to slow down the skin ageing processes and to obtain a rejuvenating effect. Treatments that do not damage the superficial layers of the epidermis could be a promising solution for those patients.

Purpose

The aim of this study was to evaluate the effects of radiofrequency therapy on the biophysical parameters and angiogenesis of facial skin, using CD34 as a biomarker in older diabetic women treated with metformin.

Patients and Methods

A total of 45 subjects with phototype 2 or 3 (Fitzpatrick scale) were investigated (25 t2DM – study group, 20 – healthy controls). A series of 6 treatments (once a week) with a Radio Frequency Skin Rejuvenation System device was used on facial skin. Measurements of skin hydration, transepidermal water loss (TEWL), melanin and erythema index, temperature, and pH, at baseline and after radiofrequency therapy were performed with the Courage + Khazaka MPA-9 device. Immunohistochemistry on paraffin-embedded sections was used to evaluate the intensity of CD34 expression.

Results

Radiofrequency treatment significantly improved facial skin hydration (p < 0.0001). Enhancement of the epidermal barrier observed, by reduced TEWL as a result of a series of treatments with radiofrequency on the facial skin (p < 0.0001), was observed. CD34 was more abundantly expressed after radiofrequency treatment. No side effects were observed.

Conclusion

Treatment with radiofrequency is an effective and non-invasive method of facial skin rejuvenation in older women with t2DM, with a relatively short post-procedure recovery time and low potential for severe adverse effects.

Effect of changes in Skin Thickness on pain-relief Transcutaneous Electrical Nerve Stimulation (TENS)

Transcutaneous Electrical Nerve Stimulation (TENS) suppresses chronic pain by stimulating deep nerves near the fascia from electrodes on the skin's surface. TENS has different effects on patients of different ages due to the variation of the thickness of skin layers when one becomes older.In this paper, we aim to optimize the stimulation effectiveness of TENS for patients of different ages through investigation of TENS stimulations of three different skin types categorized by age, Young, Old, and Older. In this investigation, the skin layer (stratum corneum, epidermis layer, dermis layer) in each model was created, and the thickness was varied. The effect of sin wave stimulation at 1 Hz, 100 Hz, and 10 kHz on the nerve stimulation effect near the fascia was examined.It is found that besides the well-known effect of stratum corneum, the thickness of the dermis layer significantly affects the stimulating effect. In addition, by using a lumped circuit model, it is showed that the change in the current path causes a mitigation in the stimulation effect in the dermis layer.

Assessment of Mechanical Stress Induced by Radiofrequency Currents on Skin Interfaces

The epidermal-dermal (ED) and dermal-subcutaneous (DS) junctions are the most prominent skin interfaces, which are known to be of primary importance in different dermatological and aesthetic conditions. These interfaces are strongly modified in aging skin, and their effective targeting can lead to improvement of skin appearance in aging and by cellulite. Application of radiofrequency (RF) currents to the skin can selectively produce mechanical stress on these interfaces. Here, we assess the stresses induced by RF currents of different frequencies on EDJ and DSJ and discuss possible applications of the interfacial therapy in aesthetic medicine.

Skin aging as a mechanical phenomenon: The main weak links

From a mechanical point of view, human skin appears as a layered composite containing the stiff thin cover layer presented by the stratum corneum, below which are the more compliant layers of viable epidermis and dermis and further below the much more compliant adjacent layer of subcutaneous white adipose tissue (sWAT). Upon exposure to a strain, such a multi-layer system demonstrates structural instabilities in its stiffer layers, which in its simplest form is the wrinkling. These instabilities appear hierarchically when the mechanical strain in the skin exceeds some critical values. Their appearance is mainly dependent on the mismatch in mechanical properties between adjacent skin layers or between the skin and sWAT, on the adhesive strength and thickness ratios between the layers, on their bending and tensile stiffness as well as on the value of the stress existing in single layers. Gradual reduction of elastic fibers in aging significantly reduces the skin's ability to bend, prompting an up to 4-fold reduction of its stability against wrinkling, thereby explaining the role of these fibers in skin aging. While chronological and extrinsic aging differently modify these parameters, they lead to the same end result, reducing the critical strain required for the onset of instabilities. Comparing of mechanical properties of the skin presented as a bi-, tri- or tetra-layer structure demonstrates the particular importance of the papillary dermis in skin aging and provides the arguments to consider the undulations on the dermal-epidermal and dermal-sWAT interfaces as the result of mechanical bifurcation, leading to structural instabilities inside of the skin. According to this model, anti-aging strategies should focus not as much on the reinforcement of the dermis, but rather aim to treat the elastic mismatch between different adjacent layers in the skin and sWAT as well as the adhesion between these layers.

General theory of skin reinforcement

Macroscopic mechanical properties of human skin in vivo cannot be considered independent of adjacent subcutaneous white adipose tissue (sWAT). The layered system skin/sWAT appears as the hierarchical structural composite in which single layers behave as fiber-reinforced structures. Effective macroscopic mechanical properties of such composites are mainly determined either by the properties of the skin or by those of the sWAT, dependent on the conditions of mechanical loading. Mechanical interactions between the skin and the adjacent sWAT associated with a mismatch in the mechanical moduli of these two layers can lead to production of the skin wrinkles. Reinforcement of the composite skin/sWAT can take place in different ways. It can be provided through reorientation of collagen fibers under applied loading, through production of new bonds between existing collagen fibers and through induction of additional collagen structures. Effectiveness of this type of reinforcement is strongly dependent on the type of mechanical loading. Different physical interventions induce the reinforcement of at least one of these two layers, thus increasing the effective macroscopic stiffness of the total composite. At the same time, the standalone reinforcement of the skin appears to be less effective to achieve a delay or a reduction of the apparent signs of skin aging relative to the reinforcement of the sWAT.

Effects of Multipolar Radiofrequency and Pulsed Electromagnetic Field Treatment for Face and Neck Rejuvenation

Skin aging is a gradual process that leads to wrinkle formation, laxity, and overall changes in skin appearance. In recent years, the demands to noninvasive treatments for facial rejuvenation increased, along with a variety of technologies and devices, such as radiofrequency. The present study aimed to evaluate the clinical effects of a multipolar radiofrequency and pulsed electromagnetic field treatment for face and neck rejuvenation. Eleven patients with mild to moderate grades of photoaging underwent eight radiofrequency and pulsed electromagnetic field treatment sessions, once a week. Clinical photographs were taken before and a week after the end of the treatment, and improvement of facial skin parameters was evaluated by two different investigators. Significant improvement in skin laxity was observed in all eleven patients (100%). Improvement in facial contour was noted in 73% and 100% of patients when analyzed by investigators A and B, respectively. The score for overall improvement in skin condition was 3 ± 0.78 for investigator A and 3.6 ± 0.67 for investigator B. All patients were satisfied with the procedure and noted significant improvement in the skin. The combined multipolar radiofrequency and pulsed electromagnetic field device is effective and safe for treatment of aged skin in Brazilian patients.