Development of a new visual analogue scale for the assessment of area scars

Clinical scar assessment lacks standardized methodology and consensus on the most appropriate evaluation instrument. This study empirically evaluated whether area scars could be validly assessed by naive observers with the objective to develop and validate a novel multidimensional visual analogue scale (VAS) for the assessment of area scars.

Standardized digital photographs of radial forearm free flap (RFFF) donor sites were obtained. Naive observers evaluated the images in three sequential psychophysical experiments, which led to the development of the new scar scale. These experiments involved initial evaluation of four dimensions (pigmentation, vascularity, observer comfort, acceptability) using a paired comparison (PC) paradigm and correlation with ratings of overall severity using a VAS, and initial VAS test phase followed by formal debriefing, and, subsequently, evaluation of a VAS for the four dimensions in addition to contour. Validation involved determination of intra- and interrater reliability and correlational analysis.

Across all three experiments, 56 observers evaluated 101 images, generating 12 720 observations for analysis. PC data demonstrated that observers could assess scars with high reliability and internal consistency for all dimensions (> 95%). Overall (VAS) severity correlated highly with all dimensions, including contour. The new VAS yielded high levels of correlation (r = .72-.98, p < .01).

Comprehensive VAS analysis demonstrates high reliability in mirroring PC results for multiple dimensions of area scars. These data support our novel multidimensional VAS method as a valid, reliable, simple, and time-efficient instrument for clinical and research use. We introduce the Western Scar Index as a new measurement tool with many potential applications.