Current tools for noninvasive objective assessment of skin scars.

BACKGROUND: Cutaneous scarring is affected by genetic, physiologic, and biochemical factors. These produce a continuum of scar types (i.e., keloid, hypertrophic, atrophic, contracted, and fine line) that can be symptomatic, aesthetically unsatisfactory, psychologically distressing, and functionally restrictive to the affected individual. Accurate scar assessment allows for quantification of scar evolution and management, and is key to evaluating the effectiveness of applied modulating therapies and treatments. Numerous objective instruments exist for the evaluation of different scar characteristics, but no consensus has been reached as to the most appropriate device. This review aims to explore the current range of noninvasive objective assessment tools available for cutaneous skin scarring, with specific emphasis on their application to research trials and clinical practice. METHODS: An extensive search of the literature was completed to assemble comprehensive data surrounding the objective assessment of skin scars by both validation studies and clinical trials. RESULTS: A wide range of tools exist to monitor cutaneous scar physical characteristics. Primarily, there are four parameters explored by these instruments: (1) color, including pigmentation and vascularity (e.g., laser Doppler); (2) surface area (e.g., three-dimensional scanning); (3) height/depth (e.g., ultrasonography); and (4) pliability (e.g., tonometry). Many studies appraise single instruments in specific scar patient groups with subjective comparator tools. CONCLUSIONS: There is no overall valid and reliable noninvasive objective assessment tool for measurement of cutaneous skin scar characteristics. Further studies are warranted that compare multiple, parameter-specific instruments in a single-sample group and across a range of scar types.