One of the newer nonablative techniques introduced into the market is fractional photothermolysis (FP). This is a laser-based platform that utilizes an arrayed laser network to cause microscopic treatment zones (MTZ) of heat-induced damage that extends through the epidermis and into the dermis [62]. The level of injury on a macroscale is relatively small and the micro zones of damaged skin is surrounded by larger areas of undamaged skin, which serves as a source of cells and signaling components for the wound-healing repair process at the injured sites. While referred to as a nonablative technique, there is some degree of compromising of the skin’s barrier, albeit the laser paths are essentially cauterized by the thermal energy, and the healing occurs quite rapidly. One perspective is to view it as a subfraction of an ablative laser peel, albeit into the dermis.
The general mechanism is essentially a controlled wound-healing response induced by the MTZ. This has been evaluated histologically and shown to include such changes as elevation in hsp70 expression patterns and elevated Type III collagen synthesis [63]. The net gain in collagen as well as other cascades of stimulated wound healing leads to a significant improvement in fine lines and wrinkles.
Clinical results have shown that fractional photothermolysis can lead to significant, and sometimes robust improvements in fine lines and wrinkles [64]. The patient experiences significantly less side effects and downtime as compared to the more ablative laser techniques in laser peels. It has been reported that patients undergoing fractional photothermolysis do undergo transient erythema as well as varying degrees of edema and also dryness and flaking of skin, but overall do not experience anything as significant as side effects from more invasive techniques [65]. As a general rule, patients are advised to be prepared to have at least a day or two of recovery before being able to apply makeup or spend time in direct sunlight.