A new instrument for serial measurements of elasticity in hypertrophic scar

The "elastometer," a hand-held device, was designed and constructed to permit noninvasive quantification of the elastic properties of normal skin or hypertrophic scar. The instrument utilizes a constant-tension spring and a sensitive strain gauge to distract two loci of skin. Normal skin from 15 dogs was measured in vivo with the elastometer and in vitro using standard tensometry. The results correlated significantly by regression analysis (r = .87, p less than .01, 1/Young's Modulus of Elasticity v percent stretch in vivo). Normal dorsal hand skin was tested elastometrically in six volunteers of both sexes. Values (units: percent stretch) ranged from 29 to 43 with a small standard error (+/- 4%). In nine patients with hypertrophic burn scars, the mean percent stretch was 16.2 +/- 1.8 v 37.9 +/- 6.5 in the mirror-image normal skin. There was no overlap between the two groups. There was a trend towards higher values in older scars. Elastometric measurements have increased appreciably in some burn scars undergoing treatment. The elastometer should be useful in documenting objectively the spontaneous maturation of burn scars and/or their response to treatment.