Quantitative Measurement of Hypertrophic Scar: Intrarater Reliability, Sensitivity, and Specificity

TLDR

Scar evaluation over time requires measurement tools that are reliably reproducible and can discriminate skin characteristics. The study aimed to assess the intrarater reliability, sensitivity, and specificity of the Cutometer, Mexameter, and DermaScan C compared to the modified Vancouver Scar Scale across normal skin, donor‑site scar, and hypertrophic scar. Thirty burn survivors were evaluated by a single investigator using the Cutometer, Mexameter, DermaScan C, and mVSS across severe and less severe hypertrophic scar, donor sites, and normal skin, and ROC curves identified optimal cutoffs of 2.034 mm for DermaScan C thickness and 0.387 mm for Cutometer deformation. The Cutometer showed acceptable intraclass correlation for donor site and normal skin but not for hypertrophic scar; the Mexameter and DermaScan C had acceptable ICCs across all sites, with DermaScan C effectively discriminating hypertrophic scar from normal scar and skin, while the Cutometer was less discriminative and the Mexameter erythema index failed to differentiate scar types, indicating that these devices can substitute for mVSS but require caution due to Cutometer ceiling effects and Mexameter erythema limitations.

Abstract

The comparison of scar evaluation over time requires measurement tools with acceptable intrarater reliability and the ability to discriminate skin characteristics of interest. The objective of this study was to evaluate the intrarater reliability and sensitivity and specificity of the Cutometer, the Mexameter, and the DermaScan C relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar (donor sites), and hypertrophic scar (HSc). A single investigator evaluated four tissue types (severe HSc, less severe HSc, donor site, and normal skin) in 30 burn survivors with all four measurement tools. The intraclass correlation coefficient (ICC) for the Cutometer was acceptable (> or =0.75) for the maximum deformation measure for the donor site and normal skin (>0.78) but was below the acceptable range for the HSc sites and all other parameters. The ICC for the Mexameter erythema (>0.75) and melanin index (>0.89) and the DermaScan C total thickness measurement (>0.82) were acceptable for all sites. The ICC for the total of the height, pliability, and vascularity subscales of the mVSS was acceptable (0.81) for normal scar but below the acceptable range for the scar sites. The DermaScan C was clearly able to discriminate HSc from normal scar and normal skin based on the total thickness measure. The Cutometer was less discriminating but was still able to discriminate HSc from normal scar and normal skin. The Mexameter erythema index was not a good discriminator of HSc and normal scar. Receiver operating characteristic curves were generated to establish the best cutoff point for the DermaScan C total thickness and the Cutometer maximum deformation, which were 2.034 and 0.387 mm, respectively. This study showed that although the Cutometer, the DermaScan C, and the Mexameter have measurement properties that make them attractive substitutes for the mVSS, caution must be used when interpreting results since the Cutometer has a ceiling effect when measuring rigid tissue such as HSc and the Mexameter erythema index does not discriminate normal scar from HSc.