J AM ACAD DERMATOL
VOLUME 59, NUMBER 4
The Er:YAG laser is a more gentle ablative therapy than the carbon-dioxide laser. Its targeted chromophore is also water but there is 16 times more energy absorption. There is more superficial penetration, which leads to less collateral damage and more rapid healing but that also makes it less efficacious for dermal remodeling and collagen stimulation. Again, this may be of benefit for hypertrophic scars, rarely keloids, and shallower boxcar scars. There are available short-, variable-, and dual-pulsed modes. Each of these was evaluated in a study of 158 patients (70 male, 88 female; age 18-46 years, average age 26.4 years; Fitzpatrick III-V) with icepick, rolling, and shallow or deep boxcar scars. In all, 83 were treated with short-pulsed Er:YAG, 35 were treated with variable-pulsed Er:YAG, and 40 were treated with dual-mode Er:YAG. All 3 modes resulted in good to excellent results for icepick and shallowboxcar scars. Rolling scars achieved good to excellent results only with dual-mode treatment.
The best result for deep boxcar scars was rated as good and was also after treatment with the dual-mode laser. The authors reasoned that the rolling and deep boxcar scars required ‘‘a long-pulse duration for a thermal effect’’ for successful treatment.77 Potential side effects again may include delayed healing, erythema, milia, acne, edema, hyperpigmentation or hypopigmentation, infection, or scarring but equal or less so than with the carbon-dioxide laser. A comparison study of postoperative healing and short- and long-term side effects was done between the carbon-dioxide laser and the Er:YAG laser. This retrospective review was of 50 consecutive patients (49 female, 1 male; mean age 51 years; Fitzpatrick I-V) treated with single pass carbon-dioxide resurfacing and 50 consecutive patients (47 female, 3 male; mean age 47 years; Fitzpatrick I-V) treated with multiple pass, longpulsed Er:YAG resurfacing. The average time to reepithelialization, postoperative erythema, hyperpigmentation, acne, milia, superficial bacterial infection, and patient satisfaction were all similar. There were no occurrences of hypopigmentation or scarring. The conclusion was that these two procedures were of comparable postoperative period and complication profile.78
A newer concept, fractional photothermolysis, introduced and discussed in 2004,79 may be a very important development for use in the improvement of acne scarring. Fractional photothermolysis ablates tissue and stimulates collagen remodeling and neocollagenesis in a columnar fashion leaving surrounding rings of viable tissue, sparing the noninvolved, intertreatment epidermal and dermal regions. As its value and potential are being realized, there are new fractionated devices being developed and tested constantly. One study used a 1550-nm erbium-doped fractional laser to create microscopic thermal zones as described above on facial skin with mild to moderate atrophic acne scars. In all, 53 patients (39 women, 14 men; age 19-78 years, mean age 39.6 years; Fitzpatrick I-V) were treated with several sessions. Blinded assessments of photographs revealed 91% to have 25% to 50% improvement after a single treatment whereas 87% of patients undergoing 3 treatments had 51% to 75% improvement. Age, sex, and skin type did not alter the outcome. At the 6- month follow-up, the results were maintained.80 Chiu and Kridel81 note that energy levels of 25 to 40 mJ are chosen for deeper skin lesions that include scars such as those from acne. It is discussed that those authors’ most impressive results have included those with deep acne scarring and they summarize that fractional technology ‘‘represents a particularly useful modality for difficult-to-treat conditions, such as melasma and acne scarring.’’81 There are similar side-effect concerns as other ablatives but there tend to be less problems overall because of the selective sparing of skin rather than total ablation.82 There is still the possibility for transient erythema or edema, dryness, scabbing, milia or acne, hyperpigmentation or hypopigmentation, prolonged healing, or infection. As with other aggressive or ablative procedures, isotretinoin is often stopped 6 to 12 months before treatment and the retinoids, glycolics, or other acids are stopped 2 weeks prior. Fractionated technology may be one of the groundbreaking developments for the treatment of acne scarring and future studies using this mechanism should be eagerly anticipated and studied.
The second category consists of the nonablative therapies, which include multiple wavelength lasers, pulsed light, and other forms of energy delivery. Because these modalities are less aggressive as a whole, they are more useful for atrophic, rolling, or possibly hypertrophic scars rather than icepick, boxcar, or keloid scars. The morphology of the scar seems to be more predictive of results than the extent or amount. In addition, these therapies are more often used with darker skin types because ablative management tends to have a higher risk of pigmentary alterations.83 In general, there is selective thermal stimulation of dermal collagen to increase local proliferation while the epidermis is spared, although cooling is often required to ensure superficial protection.
Acne Scarring Light, Laser, and Energy Therapy page 2
Acne Scarring A review and current treatment modalities BACKGROUND and ACNE SCARS ACNE SCARS page 2 ACNE SCAR TREATMENT and MEDICAL MANAGEMENT SURGICAL MANAGEMENT PROCEDURAL MANAGEMENT PROCEDURAL MANAGEMENT page 2 TISSUE AUGMENTATION TISSUE AUGMENTATION page 2 TISSUE AUGMENTATION page 3 TISSUE AUGMENTATION page 4 Light, laser, and energy therapy Light, laser, and energy therapy page 2 Light, laser, and energy therapy page 3 Light, laser, and energy therapy page 4 Conclusion and REFERENCES Manufacturers of brand name drugs mentioned in this article