Laser Treatments in Early Wound Healing Improve Scar Appearance

A Randomized Split-wound Trial With Nonablative Fractional Laser Exposures vs. Untreated Controls

K.E. Karmisholt; C.A. Banzhaf; M. Glud; K. Yeung; U. Paasch; A. Nast; M. Haedersdal


The British Journal of Dermatology. 2018;179(6):1307-1314. 

In This Article


Thirty-two patients were recruited and 30 completed the study. Two patients dropped out after the first treatment; one passed away due to conditions considered unrelated to study treatment, and one had a surgery-related abscess and did not want to continue study procedures. Table 3 shows the baseline demographics.

Clinical Response

Excisional wounding and scar remodelling over the course of time is illustrated in Figure 1, along with the study procedures and immediate skin response to NAFL exposures. Regarding the primary outcome, the NAFL-treated scar halves improved compared with the control halves on POSAS total: NAFL-treated median 11, interquartile range (IQR) 9–12 vs. control median 12, IQR 10–16; P < 0·001. Nevertheless, considerable variation in the effect of NAFL treatment was illustrated on POSAS total: improvement on the NAFL-treated scar halves compared with the control halves was shown in 63% of patients, there was no difference in 26% of patients, and in 10% of patients the untreated control scars rated better than the corresponding NAFL-treated scar. In the three patients where the NAFL-treated scar halves received inferior ratings, only a 1-point difference on POSAS total separated the NAFL-treated and untreated control scar halves. Conversely, the three best responders showed improvement on the NAFL-treated scar halves vs. controls with a POSAS total difference ranging from 8 to 11 points (Figure 2).

Figure 2.

The spectrum of clinical response to nonablative fractional laser (NAFL) treatment at the 3-month follow-up. (a) Study patient #4, a representative patient scoring worse on the NAFL-treated scar according to Patient and Observer Scar Assessment Scale (POSAS) total (1-point difference favouring the control side). (b) Study patient #32, a representative average responder (POSAS total difference 3 points favouring the NAFL-treated scar section). (c) Study patient #7, a representative from the best responders (POSAS total, 11-point difference favouring the NAFL-treated scar section). t, NAFL-treated scar side; c, untreated control scar side.

With regard to the anatomical regions of the scars, the largest NAFL improvement in median POSAS total was observed for scars located on the thorax, showing a median difference of 3 points (P ≤ 0·001). Based on POSAS total, patients aged < 50 years and > 50 years responded similarly. Thus, improvement in the NAFL-treated scars vs. the untreated control scars was observed both in patients aged ≤ 50 years (P = 0·008) and in those aged > 50 years (P = 0·015) (Table 1). No correlation was found between the change in POSAS total at the 3-month follow-up and scar length (P = 0·83). On the separate POSAS observer items the NAFL-treated scar halves showed significantly less vascularity and erythema, smoother relief, improved pliability, lower surface area and improved overall opinion compared with controls, whereas no difference was found in pigmentation and thickness (Table 1).

Secondary outcomes, with regard to VSS total, supported a subtle but statistically significant benefit of NAFL compared with control: NAFL-treated, median 2, IQR 1–2·5 vs. controls, median 2, IQR 1·75–3; P = 0·007. Furthermore, less erythema/vascularity but no difference in pigmentation was detected on the NAFL-treated scars compared with controls on VSS (Table 4).

In the standardized assessment comparing the NAFL-treated and corresponding untreated control halves, a 'no difference' rating was given by on-site evaluation in eight patients, by photo evaluation in 20 patients and in one patient evaluation (Table 5). Among the control halves rated better than their corresponding NAFL-treated halves (on-site evaluation n = 7, photo evaluation n = 2, patient evaluation n = 7), complete agreement among all evaluation methods was shown in only one patient. Thus, large inconsistencies were demonstrated between the three evaluation methods.

Patient-reported Outcomes

According to the POSAS patient evaluations, patients scored the NAFL-treated scar halves as having normalized colour, less stiffness, less thickness and a less irregular surface compared with the untreated control halves (Table 2). The patients' VAS evaluations showed that the NAFL-treated scar halves rated better (median 3·0 cm, IQR 1·4–5·7) than the untreated control scars (median 4·15 cm, IQR 2·0–5·9). All patients reported that they would recommend the treatment procedure to friends and family.

Adverse Events

Three participants had an infection after the surgery, one of whom dropped out of the study. The two other patients were treated sufficiently with oral antibiotics and continued the study procedures. NAFL did not induce any dyschromia.