Cutera

In a simple answer, Cutera selected YSGG (Pearl and Pearl Fractional) for thermal control with the desire to maximize ablation and control, but not eliminate coagulation (thermal damage). A little thermal damage during ablative procedures is a benefit, but too much can be a liability. Laser wavelength is the primary determinant of thermal damage. Power determines how deep an ablative laser vaporizes – and necessary power is determined by water absorption. At the edges of the ablation column though (sides and bottom) there is not sufficient power to continue ablating tissue. From this point outward, the zone of thermal damage is determined by how far sub-ablative intensity light penetrates through tissue – creating a coagulation zone. Cutera selected YSGG because this zone is 40-60 microns thick. Conversely, Er:YAG is about 10-20 microns and CO₂ is about 75-150 microns.

The coagulation zone (thermally denatured tissue) with YSGG is thick enough to coagulate normal microvasculature in dermal tissue, thus preventing significant operative bleeding. It is small enough though to be able to maximize ablation area without unduly increasing the size of the lesion. Note: thermally denatured tissue is dead / necrotic tissue that the body must also clear for the wound to heal. Additionally, excess thermal damage is associated with increased risks of pigmentary complications. With the thermal control of YSGG, Pearl fractional can maximize treated area and tissue vaporization beyond that of CO₂, yet still provide coagulation and thermal stimulation that is lacking with Er:YAG.