Daoud 2019.

Study characteristics
Methods	Study design: prospective randomised intra‐individual (split‐scar) controlled trial with 3 treatment arms conducted in the USA. Scar segment as the unit of randomisation. Duration of the study: not reported Follow‐up time: 6 months (intermediate‐term follow‐up) Protocol was published before recruitment of participants: the study was board‐approved but there is no mention about protocol publishing. Details of trial registration: not reported Funding sources: this trial received funding from the Lumenis corporation.
Participants	Number of participants assigned: 23 participants (with a total of 69 scar segments enrolled) Group 1 (fractional CO2 laser): 23 segments Group 2 (fractional CO2 laser plus Intense Pulsed Light ‐ IPL) : 23 segments Group 3 (control ‐ no treatment): 23 segments Loss: 4 participants. Number of participants assessed: 19 participants Group 1: 19 segments Group 2: 19 segments Group 3: 19 segments Inclusion criteria: presence of at least a 12‐month history of either one large (> 100 cm2) erythematous, hypertrophic scar, or 3 similar hypertrophic scars measuring ≥ 30 cm2; adults. Exclusion criteria: not specified. Age (years): 18 to 60 Gender: not specified Scar Location: not specified Skin phototypes: I‐IV Duration of scars (months): at least 12 months
Interventions	Scars were divided into 3 segments of equal area and randomised into either single laser, multi‐laser, or control (no laser treatment). Analgesia was achieved topically with BLT (20% / 8% / 4%). Group 1: submitted to a total of 4 treatment sessions at 6 to 8‐week interval, with single laser CO2 AFL (Lumenis UltraPulse Encore™, Yokneam, Israel, 15 to 20 mJ, 10% Density, 200 to 300 Hz, 120 μm spot). Group 2: submitted to a total of 4 treatment sessions at 6 to 8‐week interval, with IPL (Lumenis M22 IPL, Yokneam, Israel, 15 mm × 35 mm footprint, settings varied based on scar) immediately followed by CO2 AFL (same parameters of group 1). Group 3: no treatment.
Outcomes	Primary outcomes Manchester Scar Scale (MSS): The MSS considered 5 categories (colour, matte versus shiny, contour, distortion and texture) and was assessed by a blinded observer. Lower scores indicate a better scar character profile. The average decrease in MSS score was reported and means scar severity (improvement). Patient and Observer Scar Assessment Scale (POSAS): The POSAS is a scar assessment scale that combine participant and blinded observer evaluation of 5 components: appearance, pigmentation, hypertrophy, vascularity and roughness (results from 5 to 50; the highest score reflects the worst scar). Secondary Outcomes: Digital Photography assessment: Digital photographs (pre‐ and post‐treatment) were evaluated by blinded observers, in order to identify which one was taken before and after treatment; they also analysed if there was improvement of the scars (appearance).
Notes	Statistical analysis: Data were analysed using a parametric analysis of variance (ANOVA) between the 3 groups (control, CO2 alone, CO2 plus IPL) and the 2 time periods (pre‐treatment and post‐treatment). A 2 x 3 ANOVA with repeated measures was used for statistical comparisons. The trial received funding from the Lumenis corporation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation was cited but the method was not described.
Allocation concealment (selection bias)	Unclear risk	Allocation process was not described.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and health professionals performing the treatment were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Results were assessed by a blinded observer.
Incomplete outcome data (attrition bias) All outcomes	High risk	Four lost to follow‐up prior to the third treatment. The reasons were specified (loss of communication). As‐treated analyses were performed.
Selective reporting (reporting bias)	Unclear risk	No trial protocol is available. All parameters listed in the methods section to assess changes in the scars were described, however, the methods used to assess these parameters were not described.
Other bias	Low risk	No other sources of bias were found.