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Laser resurfacing
Laser resurfacing
Laser resurfacing is frequently used for acne scar treatment with both ablative CO2 and Er:YAG lasers, at 10,600 and 2,940 nm, respectively. Water in the skin absorbs the infrared wavelengths generated by these laser devices, leading to destruction and ensuing collagen formation. Ablative CO2 lasers have been shown to result in 81% improvement in moderate to severe acne scars.80 The negative effects of these lasers include dyspigmentation, erythema, fibrosis, and scarring. Laser resurfacing may not be ideal for dark-skinned patients, though single-pass CO2 laser can reduce the intensity and duration of hyperpigmentation compared to a multi-pass procedure.80
Although nonablative lasers, such as the long-pulsed 1,450-nm diode and 1,320-nm Nd:YAG are safer than ablative lasers, they generally provide only modest benefit over three to six sessions.67 A 1,550-nm erbium-doped laser was assessed for ice pick, boxcar, and rolling scars. After five treatments the mean improvement ranged from 25% to 50%. The improvement was achieved without scarring or dyspigmentation, although erythema and edema were observed.81
The largest study on nonablative fractional lasers (NAFL) to date was conducted on 500 patients, using a 1,540-nm-fractional laser. After three treatments, the median improvement ranged from 50% to 75%.82,83
Several studies have revealed that ablative fractional lasers (AFL) confer the additional advantage of prolonging collagen remodeling. One study found that two to three monthly treatments with fractional CO2 can lead to a 66.8% mean improvement based on topographic analysis. Although local side effects were still observed, they disappeared within a week. The most important advantage of this technique was that no pigmentary changes occurred, in contrast to using fully ablative resurfacing modalities.84 However, AFL used at low-energy settings, along with nonablative 1,064- nm Nd:YAG, can result in a higher percent improvement with fewer side effects compared to using AFL alone.85 In one study, NAFL was compared to AFL, in which atrophic scars showed equal or greater improvement with AFL treatment. Thus, AFL provides much of the efficacy of ablative lasers without the risk of scarring or dyspigmentation.86