gms | German Medical Science

There has been ample evidence that meshed skin grafts did not provide their claimed expansion rates. Although for the majority of surgeons this finding might not be new, even less is known about the actual knowledge among them. In the first part of our analysis, we evaluated the true expansion rates for a widely used and claimed 1:3 expansion rate of split-thickness skin grafts harvested by one experienced surgeon using the anterior thigh as the donor site (Air Dermatome; Zimmer, Dover, Ohio) before and after respective meshing (n=21, Dermacarriers II in combination with Meshgraft II; Zimmer) or micrografting (n=7, MEEK Micrograft Gauze; Humeca BV, Enschede, The Netherlands). In the second part, by the use of an anonymized written questionnaire, 40 surgeons were polled for their estimates of expansion rates during an annual meeting. Data are represented at mean ± SD, and values of p<0.05 were considered statistically significant.

The claimed 1:3 expansion rate was achieved by only 53.1 percent using the mesh (1:1.59 ± 0.15) and by 99.8 percent using the micrografting technique (1:2.99 ± 0.09; p=0.0001, Mann-Whitney test), respectively. Regardless of the level of experience, all participants overestimated the achieved expansion rate of the widely used 1:3 mesher by 55 percent (1:2.47 ± 0.69; p=0.0004), and there was no statistically significant difference between senior surgeons’ and residents’ estimates. The expansion rate depends on a number of factors related to the skin graft’s quality itself and recipient wound bed.Nonetheless, the accurate estimation of the required donor site based on the technique used is particularly important when grafting large surface areas: planning an operation with a 1:3 mesher based on a 1:2.47 ratio (polled mean) may result in overestimation of the true expansion rate by 55 percent, and may require consequent adaptation of the operative procedure when addressing large surface areas (e.g., repositioning, redraping, reharvesting). Although meshed skin grafts become even more unreliable beyond 1:6 expansions, micrografting allows for use of even small skin remnants and mimics the true expansion rate used by 86.5 to 99.8 percent when using expansion rates of 1:3 and above (data not shown). Because more than 57 percent of the polled participants with previous experience in micrografting based their indication for switching to this technique on claimed expansion ratios, our results can help to define more accurate cutoff values for the use of either technique, and to improve the economic use of donor sites in the future.