ABSTRACT
Introduction Radiofrequency (RF) energy is a wavelength situated in the range of electromagnetic rays. Propagation of RF through the cutaneous tissue rapidly oscillates electromagnetic elds causing a movement of charged ions within the tissue which subsequently creates an electrical current generating heat proportional to the dermis’ and subcutaneous tissues’ electrical resistance. e application of RF has been extensively used in surgery for hemostasis and tissue ablation (electro-surgery) [1-3], but more recently RF has been applied as a means of shrinking redundant or lax connective tissues through the mechanism of collagen denaturation [4-6]. Collagen molecules are produced by broblasts which synthesize three polypeptide chains that wrap around one another in a triple helix. e phenomenon of thermal shrinkage of collagen begins with denaturation of the triple helix of the collagen bers. When collagen is heated, the heat-labile intramolecular cross-links are broken, and the protein undergoes a transition from a highly organized crystalline structure to a random, gel-like state (denaturation). Collagen shrinkage occurs through the cumulative e ect of the “unwinding” of the triple helix, due to the destruction of the heat-labile intramolecular cross-links, and the residual tension of the heat-stable intermolecular cross-links. Heated broblasts are also implicated in new collagen formation and collagen remodeling which also contribute to the nal cosmetic outcome. e precise heat-induced behavior of connective tissues and the extent of tissue shrinkage are dependent on several factors which include the maximum temperature reached, exposure time, tissue hydration and tissue age [7].
