BACKGROUND AND OBJECTIVES: Laser treatment in the early phases of wound healing may reduce scar formation. However, little is known on when in the early wound healing phases laser exposure most optimally should be provided and at which fluence levels. This study investigates the clinical effect of non-ablative-fractional-laser (NAFL) performed at three early time points at a range of fluence levels versus untreated control scars.

MATERIALS AND METHODS: A randomized, controlled, intra-individual trial with erbium-glass 1,540 nm NAFL versus no laser treatment on sixteen subjects receiving 10 standardized full-thickness punch-biopsy wounds. A single NAFL-exposure was applied to test-wounds 1 day before, immediately after, or 2 weeks after wounding. Three fluence levels provided deep and superficial energy depositions (range 30-70 mJ/microbeam). Primary outcome comprised the total-score of the observer part of Patient-Observer-Scar-Assessment-Scale (POSAS), performed by blinded on-site assessment at 3 months follow-up. Secondary outcomes were clinical evaluation on visual-analogue-scale (VAS), reflectance measurements, and histology.

RESULTS: NAFL-treatment applied 1 day before, immediately after or 2 weeks after wounding had the potential to offer subtle but detectable improvement in clinical scar appearance compared to untreated controls. Thus, NAFL-exposure 1 day before wounding (POSAS-total: median of 15 vs. control-median of 16, P = 0.03, VAS: median 4.1 vs. control-median 5.5, P = 0.03, medium-fluence), as well as immediately-, and 2 weeks after wounding (POSAS-total: P ≤ 0.05, low-fluence) induced improvement compared to untreated controls. No significant differences in dyschromia were detected between NAFL-treated and control scars. Histology showed subtle changes towards more mature interwoven bundles of collagen in NAFL-treated scars as compared to controls.

CONCLUSIONS: This study indicates that a single NAFL-treatment at low to medium fluence performed 1 day prior, or in the early phases of wound healing, may have the potential to optimize scar formation in full thickness wounds. Lasers Surg. Med. 50:28-36, 2018. © 2017 Wiley Periodicals, Inc.