Objective Assessment Tools: Physical Parameters in Scar Assessment

Abstract

Objective assessment tools can be used to evaluate whether (new) scar treatment is effective and to monitor the scar’s response to interventions in clinical practice. It is important to take the clinimetric properties of each tool into account, especially when used for the follow-up of an individual patient. An overview is provided for three important physical scar parameters that can be assessed by noninvasive objective tools: color, elasticity, and perfusion. To assess the color of a scar, an array of tools is available, all using reflectance spectroscopy and determining color by measuring the intensity of reflected light of specific wavelengths. The handheld DSM III ColorMeter offers read-out of erythema and melanin index values as well as CIEL∗a∗b values. The interrater reliability is best for the parameter a∗ of the DSM III ColorMeter. To assess scar elasticity, the Cutometer is the most widely used tool. Scar deformation is measured using negative pressure and reflected in relative and absolute elasticity parameters. On the contrary, firmness or hardness of scar tissue can be quantified by tonometry, a technique that works by exerting pressure on the skin. Lastly, it is of interest to measure scar blood flow (i.e., perfusion) as several treatment regimens work by destructing the microvasculature and/or reducing the blood flow to enhance shrinkage of hypertrophic scar tissue. Laser Doppler imaging and laser speckle imaging can be used to quantify and visualize scar blood flow, but a thorough clinimetric evaluation of these tools in scars is not performed yet.