Novel Technology for Facial Muscle Stimulation Combined With Synchronized Radiofrequency Induces Structural Changes in Muscle Tissue: Porcine Histology Study

Abstract

Background: With age, facial muscles lose the ability to complete contractions properly, resulting in limitation of facial expressions and fat shifting, and leading to skin creases and wrinkling.

Objectives: The aim of this study was to determine the effects of the novel high intensity facial electromagnetic stimulation (HIFES) technology combined with synchronized radiofrequency on delicate facial muscles, using an animal porcine model.

Methods: Eight (n = 8, 60-80 kg) sows were divided into the active group (n = 6) and the control group (n = 2). The active group underwent four 20-minute treatments with radiofrequency (RF) and HIFES energies. The control group was not treated. Histology samples of muscle tissue were collected by a punch biopsy (6 mm in diameter) from the treatment area of each animal at baseline, 1-month, and 2-month follow-up. The evaluation included staining of the obtained tissue slices with hematoxylin and eosin and Masson's trichrome to determine the changes in muscle mass density, number of myonuclei, and muscle fibers.

Results: The active group showed muscle mass density increase (by 19.2%, P < .001), together with elevated numbers of myonuclei (by 21.2%, P < .05) and individual muscle fibers, which increased from 56.8 ± 7.1 to 68.0 ± 8.6 (P < .001). In the control group, no significant changes were seen in any of the studied parameters throughout the study (P > .05). Finally, no adverse events or side effects were observed in the treated animals.

Conclusions: The results document favorable changes after the HIFES + RF procedure at the level of the muscle tissue, which may be of great importance in terms of maintenance of facial appearance in human patients.

Figure 1.

Visualization of the self-adhesive, hands-free EMFACE applicator intended to treat the forehead area in human patients.

Figure 2.

The temperature development in the muscle tissue during the therapy. The temperature rises to 39.5°C within 2 minutes and stays essentially unchanged for the rest of the therapy time.

Figure 3.

The skin temperature measurements were taken immediately after the treatment. The maximum surface temperature in the treatment area was just above 42°C, not exceeding 42.5°C. A thermal image taken by an infrared camera Fluke Ti300 (Fluke Corporation; Everett, WA).

Figure 4.

A cross-sectional view of the muscle tissue in the active group stained by hematoxylin and eosin, taken at (A) baseline and (B) 2-month follow-up. The pink represents the muscle tissue with dark purple nuclei at the periphery. The muscle tissue is noticeably denser after treatments in the assessed regions of interest.

Figure 5.

A longitudinal view of the muscle tissue stained by Masson's trichrome, taken at (A) baseline and (B) 2-month follow-up. The red color represents the muscle tissue, whereas the green color documents the presence of the intersected collagen fibers with lipid droplets without color. At baseline, the muscle fibers were relatively sparsely distributed, which changed at the 2-month follow-up. There was a noticeable increase in muscle fiber density together with a decrease in the fat tissue infiltration.

Figure 6.

The histogram represents the relative frequency distribution of the muscle fiber sizes in the active group samples. The interval width was chosen to be 10 μm. The muscle fibers of greater diameters were more frequently present at 2-month follow-up.