656 Inter- and Intra-user Reliability of Skin Graft Thickness as a Function of Instrument

Abstract

Abstract Introduction The most popular powered dermatomes (both electric and pneumatic) have a linear blade which oscillates at high speeds. Though the thickness of skin graft being elevated can be controlled by the depth-adjustment dial on the side of the instrument, factors, such as applied pressure, angle between the instrument and the surface, and curvature of the harvest site, can cause deviations from the target depth. As a result, the same depth setting can result in significantly different thicknesses of excised tissue among operators. A newer, powered dermatome has been developed which pneumatically rotates a circular blade at a fixed angle to the surface of the skin and does not require additional downward pressure. The goal of this study was to assess inter- and intra-user uniformity of graft thickness using conventional and newly designed dermatomes and assess the accuracy of the excised thickness. Methods Split thickness skin grafts were collected from the dorsum of Yorkshire pigs using a conventional dermatome and a newly designed test dermatome. Three different users collected three 2-inch wide by 4-inch long strips of skin using both instruments. Skin thickness at the center and edges of each strip were measured using a digital micrometer. Additionally, grafts were laser scanned to create a map of thickness for the entire piece of tissue. Reliability of the harvest was assessed using inter- and intra-class correlation coefficient. Results Both instruments were set to collect grafts 0.012” thick. Grafts harvested using the conventional dermatome ranged from 0.020–0.038” thick while grafts harvested with the test instrument ranged from 0.008–0.016” thick. On average, the conventional dermatome harvested grafts that were 2.16-fold thicker than the instrument setting while the test instrument collected grafts 0.91-fold the target thickness. Intra-user reliability was similar between instruments with greater reliability observed when users has substantial prior experience. Additionally, inter-user reliability was significantly increased with the test instrument. Conclusions Many factors control the uniformity and overall thickness of a skin graft including applied pressure and angle of attack, and how much tension is applied to the elevated graft. Using a conventional dermatome, variability in thickness was observed with greater average measured thickness versus depth setting. Grafts harvested using the newly designed instrument were on average closer to the desired thickness and more reproducible among users. Applicability of Research to Practice New instruments for skin harvesting may enhance uniformity of skin grafts.