Ablative fractional laser resurfacing is more effective than nonablative therapy for the treatment of acne scaring, albeit, with greater side effects and pain, according to a new review.
Ms. Michal Wen Sheue Ong and Dr. Saquib Bashir, of King’s College Hospital NHS Foundation Trust in London, conducted literature searches using the PubMed and Scopus databases for English-language articles published between 2003 and January 2011 that reported on "acne scars" and "fractional photothermolysis."
A total of 26 papers, published between 2008 and 2011, met the criteria – 13 papers on ablative fractional lasers and an equal number on nonablative fractional lasers (Br. J. Dermatol. 2012 Feb. 1 [doi: 10.1111/j.1365-2133.2012.10870.x]).
"Most ablative studies reported a percentage of improvement within the range of 26% to 75%," they wrote. In two cases, studies claimed 79.8% and 83% mean improvement, although the reviewers questioned the appropriateness of using mean values rather than medians, given that "the properties of the ordinal scales were unknown and points on the scale were not necessarily equidistant."
The nonablative studies reported an improvement range of 26% to 50%.
Only four studies were split-face randomized controlled trials, and most had follow-up criteria of just 1 to 6 months; only one study included a 2-year follow-up. Moreover, the methods and rating scales for measuring improvement varied widely.
Only five studies analyzed the histological degree of scar improvement, but in these, new collagen formation was noted with both ablative and nonablative fractional photothermolysis.
In one of the nonablative studies included in the review, an increase in elastic fibers framework in the papillary dermis, as well as the upper and mid dermis, was noted 12 weeks after final treatment (Photodermatol. Photoimmunol. Photomed. 2009;25:138-42).
Similarly, using 3D optical profiling, a study of ablative laser resurfacing showed a marked, statistically significant improvement in skin smoothness and scar volume 1 month after treatment. "However, there were no further improvements of skin smoothness or scar volume at 3- and 6-months follow-up," wrote the authors (J. Am. Acad. Dermatol. 2010;63:274-83).
Looking at side effects, "A higher proportion of patients (up to 92.3%) who undertake ablative FP [fractional photothermolysis] experience post inflammatory hyperpigmentation (PIH) than those who have nonablative FP (up to 13%)," wrote the reviewers, with a maximum duration of PIH of up to 6 months in ablative FP, vs. 1 week in nonablative treatment.
Pain ratings for nonablative procedures were also lower, compared with ablative procedures. "The mean pain score reported across ablative FP studies ranged from 5.9-8.1 (scale of 10)," reported the authors. In contrast, the mean pain scores for nonablative FP procedures were rated 3.9-5.7.
The authors pointed out that they found no evidence regarding the effects of FP lasers on patients’ psychological status and quality of life. "This information can be useful and should be obtained before and after treatment," they wrote.
Limitations of the review included the fact that none of the methods of assessing clinical outcome had had its validity or reliability investigated, wrote the reviewers. For the most part, however, the results were promising.
"Most studies had clinicians/dermatologists to assess overall scar improvement, and there were some studies which had patient assessment," they wrote. In many cases the evaluators were blinded, but at least three studies used evaluators who were not.
Fractional photothermolysis laser resurfacing improves facial acne scarring, despite dramatic methodological variability in efficacy studies. Nevertheless, more studies are needed, especially split-face, randomized controlled trials using objective assessment measures of improvement, like histological or 3D optical profiling, they concluded.
The review authors reported having no outside funding and stated that they had no conflicts of interest to declare.