Lasers for Skin Resurfacing
To understand the mechanism behind laser skin resurfacing for rejuvenation of photo-aged skin, it is helpful to understand how chronic sun exposure alters normal components of skin.
Collagen is the main structural extracellular matrix component of skin. Elastic fibers, while composing a relatively small portion of skin (1-2%), are critical to the ability of skin to stretch and recoil.
Glycosaminolglycans, proteoglycans and fibronectin are widely distributed in skin, and while they compose only a small percentage of dry weight of skin, they bind a large amount of water and thus regulate skin hydration which in turn affects cellular mobility. Proteoglycans and fibronecin also play a role in cell migration necessary for skin remodeling or wound healing.
Aging of the skin occurs as a result of 2 distinct processes – chronologic aging is related to our “biologic clock” and continues with less influence from outside agents. Chronologically aged skin demonstrates thinning of the dermis and decrease cellularity, including loss of elastic fibers and collagen. This results in loss of resiliency and a slower healing response. Photo-aging however, is a direct result of continued exposure to UV rays and our ability to fight this damage with melanin pigment synthesis and antioxidant capabilities of our skin. In contrast to the more subtle changes from chronologic aging, the changes from chronic sun exposure can be quite pronounced. The normal fine meshwork of elastic fibers superimposed on a background of dense, well-organized collagen fibers is replaced with a massive accumulation of elastic fibers in an abnormal and haphazard arrangement against a backdrop of poorly organized collagen strands. In contrast to the large increase in abnormal elastic tissue is the decrease in collagen fibers.
To achieve an improvement in photo-aged skin, the skin must be injured in order to promote dermal wound healing and regeneration. To simplify a complex process, after tissue injury occurs, repair takes place in a series of interrelated steps including cell migration and collagen production and deposition forming the final matrix in the evolving scar. The collagen network matures, contracts and strengthens over months; normal elastic fibers may or may not appear or reform only partially in a mature healed wound.
What this means is that to achieve more dramatic improvements in photo-damaged skin, modalities that destroy the surface of the skin will promote more “wound healing” with skin regeneration. The deeper one treats the skin, the more dramatic the result, the longer lasting the result, but with longer healing time, and greater sequelle and potential risks. Dr. Rasmussen offers 2 levels of laser skin resurfacing – FRAXEL™ and the CO2 laser.
The CO2 laser is the most effective tool for improving sun-induced wrinkles and pigmentation changes and smokers-damaged skin. After healing, the facial skin looks like a “baby’s butt”. But there is significant downtime and it will result in a persistent pink tinge to the skin, often lasting several months. It will also result in a lightening of the skin resulting in a line of demarcation below the jaw line. This limits treatment to the face.
The FRAXEL™ laser results in only 2 to 4 days of social downtime, but requires several ( 3 – 5 ) sessions to attain the best results. Unlike the CO2 laser, it will not result in “baby’s butt” skin, but the results can be very satisfying without the sequelle and potential risks. Plastic surgeons like Dr. Rasmussen who perform FRAXEL™ usually report that it attains approximately 75% of the CO2 laser results. Another significant advantage is that it can be used on body sites other than the face, such as the neck, décolleté and hands.