The Impact of Near-infrared in Plastic Surgery

Abstract

Many studies regarding near-infrared, have used near-infrared resources without a water filter or a cooling system, and have proven its thermal effects. With these methods near-infrared energy is mainly absorbed in the superficial tissues and cannot be delivered sufficiently to deeper tissues. As solar near-infrared is filtered by atmospheric water, a water filter is essential in order to simulate solar near-infrared. Thus, these approaches could not sufficiently evaluate the effects of incident solar near-infrared that reaches the human tissue. We have clarified that the near-infrared that simulates solar near-infrared non-thermally affects subcutaneous tissues, including muscle. Importantly, the biological effects of near-infrared have both beneficial applications and deleterious effects. Near-infrared induces dermal heating thermally and non-thermally induces collagen and elastin stimulation, which results in skin tightening, and induces long-lasting vasodilation that may prevent vasospasm and may be beneficial for ischemic disorders and flap surgeries. Near-infrared also non-thermally relaxes and weakens dystonic or hypertrophic muscles to reduce wrinkles and myalgia. Its long-lasting induction of subcutaneous adipocytes may have an application in volume augmentation. However, continuous near-infrared exposure may induce photoaging and thinning of superficial muscles, which results in skin ptosis. Protection against near-infrared should be strongly considered, as over half of the solar energy is near-infrared. Although plastic surgeons are not familiar with the effects of near-infrared, its potential appears to be high and significant. This paper reviews the effects of near-infrared and introduces the new findings and applications of the biological effects of near-infrared in the field of plastic surgery.