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.

Clinical efficacy of silk sericin dressing with collagen for split-thickness skin graft donor site treatment

“…The different absorption rates of melanin pigments indicate the melanin index determined by the red and infrared wavelengths. The result presents arbitrary Mexameter units (0-999) for both melanin and erythema levels [186]. Mexameter ® is one of the devices used to measure erythema and pigmentation in several studies.…”

“…Mexameter ® is one of the devices used to measure erythema and pigmentation in several studies. It shows the intraclass correlation coefficient (ICC) between 0.82 and 0.97 [161,186,187].…”

“…The absolute parameters, measured in millimeters, are influenced by skin thickness varying with age, sex, and body region. Among parameters, maximal skin extension (R0 or Uf) or elasticity (Ue), which are least affected by variations in force, are recommended for use as a reliable parameter in scar elasticity assessment [186]. High ICCs of R0 (>0.78) were found for the measurement in the donor site [190].…”

“…Cutometer was used for determining the skin elasticity by providing the negative pressure to deform the scar, and the noncontact optical measuring system detects the deformation of the scar. The output from Cutometer ® contains different parameters representing the different aspects of scar deformation [186,192]. The Cutometer parameters obtained from the SDC group, Bactigras ® group, and normal skin were compared.…”

“…The vascular cells and myofibroblasts in granulation tissue also undergo apoptosis during the remodeling phase [225]. The lower elasticity of donor sites scar at 6 months might attribute to the incomplete re-establishing of elastin [186], the increased collagen synthesis [186], and the multiple direction arrangement of collagen fibers [157]. Furthermore, the R6 parameter (ratio of viscoelastic to elastic distension; Uv/Ue) was indicated as the most sensitive parameter to the epidermal hydration level [226].…”