The real expansion rate of meshers and micrografts: things we should keep in mind

Skin graft expansion techniques (mesh and micrograft) are widely used, but there is ample evidence that skin graft meshers do not provide their claimed expansion rates. Although this finding might not be new for the majority of surgeons, less is known about surgeons' actual knowledge of expansion rates. The aim of this study was to evaluate the true expansion rates of commonly used expansion techniques with regard to claimed, achieved, and polled results. In the first part of the study, 54 surgeons were polled during an annual burns meeting regarding the most commonly used expansion techniques and expansion ratios; in the second step the true (achievable) expansion rates of the most widely used meshers and micrografts were analysed; and in third step, a poll involving 40 surgeons was conducted to estimate the true expansion rates of the most frequently used skin expansion techniques. The skin meshers (1:1.5 / 1:3) did not achieve their claimed values: (1:1.5) 84.7% of the claimed expansion (mean ± SD: 1:1.27 ± 0.15) and (1:3) 53.1% of the 1:3 (1:1.59 ± 0.15) mesher. The use of the micrografting technique resulted in 99.8% of the 1:3 (1:2.99 ± 0.09), 93.6% of the 1:4 (1:3.74 ± 0.12) and 93.8% of the 1:6 (1:5.63 ± 0.12) claimed expansion rates, respectively. In general the surgeons overestimated the achievable expansion rates. In general the achieved expansion rate was lower than the estimated and claimed expansion rates. The micrografting technique provided reliable and valid expansion rates compared to the skin meshers. We recommend using the micrograft technique when large expansion ratios are required, for example in severe extensive burns.