Chap. 44 - OVERVIEW OF CO₂ AND ER:YAG LASERS AND PLASMA DEVICES

Summary

Laser skin resurfacing remains the most effective modality for skin rejuvenation. Indications for treatment include dyschromia, photoaging, rhytids, skin laxity, and acneiform scars. Although numerous nonablative laser and light devices have been developed over the years, none of them is able to deliver results equivalent to ablative devices. The effectiveness of ablative lasers results from their ability to accomplish two major effects: first, complete and total vaporization of the epidermis removes unwanted pigment and solar-damaged cells; second, there is deeper penetration and diffusion of thermal energy that heats dermal tissues, causes tissue contraction, and stimulates new collagen production. The net effect of these two processes is that a new, more uniform epidermis is regenerated, without unwanted pigmentation. Additionally, solar elastosis is removed from the superficial dermis, yielding a brighter, more lustrous skin tone, and immediate tissue contraction plus new collagen production lead to the reduction of wrinkles and tighter skin.

The use of ablative lasers for skin resurfacing goes back to the 1980s. Early devices consisted of continuous wave CO₂ lasers. These lasers provided adequate ablation of tissue; however, longer dwell times resulted in prolonged and unpredictable thermal heating, charring of the tissue, and a high risk of scarring. The true breakthrough occurred in the early to mid-1990s, when CO₂ pulsed lasers with pulse durations in the millisecond domain were introduced for resurfacing. The addition of efficient scanners made these systems even more practical.