Physical and surgical principles governing carbon dioxide laser surgery on the skin

Although the physical principles governing the safe delivery of coherent radiation are well established, these rules are broken as often as they are followed. Few surgeons take advantage of the increased precision afforded by the rapid superpulse mode. Through a misdirected sense of caution, many surgeons use dangerously low power outputs and choose power densities in the carbonization range. Surface ablation is often undertaken with a beam geometry suited only to thermal incision, thereby producing an array of ridges and gutters that must be flattened by a raster technique. Each sequential pass of the laser adds to the amount of unnecessary thermal injury. Finally, some surgeons still try to control the laser in delicate situations through turning down beam power rather than through the strategy of prolonging reaction time with gated pulses. Of course, simple observation of correct physical principles does not guarantee a successful outcome. Strategies are also required to ensure dextrous beam delivery and to minimize thermal injury within adjacent tissue. As in other forms of surgery, the dermatologic surgeon must learn how to control bleeding, gain exposure, delineate geographic margins, and control the depth of destruction. When these lessons are assimilated, wounds heal rapidly, and results are indistinguishable from normal tissue.