7.      England, L. J.; Egbert, B. M.; and Pope, K.: Wound healing in an animal model following Thermage treatment. Wound Repair and Generation. 2005; 13(2):A28-A48.

BACKGROUND: The ThermaCool TC system (Thermage® Inc., Hayward, CA) is a non-invasive, non-ablative system that combines cryogen cooling and monopolar radiofrequency (RF) energy to volumetrically heat dermal and sub-dermal tissue. Monopolar RF treatment causes collagen contraction resulting in immediate skin tightening. It has also been clinically shown to tighten skin over time. This long-term tightening effect is believed to result from the body’s wound-healing response.

METHODS: We performed studies in a juvenile pig to characterize the wound-healing response after RF treatment in order to elucidate the cellular and molecular events resulting from treatment. RF treatments were performed using a 1 cm2 standard treatment tip and various treatment levels. Tissue responses in histologic specimens were examined over a 1-month period following RF treatment. Results: Mast cells and macrophages are important inflammatory cell types that stimulate fibroblast recruitment, collagen synthesis and blood vessel growth. Three to five days following treatment, immature macrophages were present in the dermis. Between 3 and 14 days post-treatment, alkaline phosphatase-positive mast cells were present in the dermis. Dermal blood vessel density was observed to increase beginning at 7 days post-treatment and persisting throughout the study period. Fibroplasia was observed beginning at 7 days, becoming more pronounced 21 days following treatment. By 14 or 21 days following RF treatment, collagen compaction and new collagen in the dermis were noted.

CONCLUSIONS:  Monopolar RF treatment stimulates dermal remodeling by initiating a wound-healing response. This study demonstrates that RF treatment results in the recruitment of important cellular mediators of wound healing and changes in dermal collagen in an animal model. These events are presumed to be responsible for dermal remodeling and skin tightening over time in human subjects