Comparison of Meshed versus MEEK Micrografted Skin Expansion Rate: Claimed, Achieved, and Polled Results

Sir: There has been ample evidence that meshed skin grafts did not provide their claimed expansion rates.1,2 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 (Fig. 1). 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.Fig. 1.: Comparison of the 1:3 mesh carrier and 1:3 micrograft gauze based on achieved expansion rates. A 310-cm2 split-thickness skin graft harvested from the model's right upper thigh (black) can achieve coverage of up to 493 cm2 total body surface area with a mesh graft (left, light gray), or 927 cm2 total body surface area with a micrograft (right, dark gray), respectively. When intending to cover 927 cm2 with a 1:3 mesher, the required donor skin extends to the medial and lateral thigh (area marked in red around the black donor site). Drawings and calculations were based on a male three-dimensional model with 180-cm height and 85-kg weight using BurnCase 3D (RISC Software GmbH, Hagenberg, Austria).The expansion rate depends on a number of factors related to the skin graft's quality itself1,2 and recipient wound bed.3 Nonetheless, the accurate estimation of the required donor site based on the technique used is particularly important when grafting large surface areas4: 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,2 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.5 DISCLOSURE The authors have no financial interest to declare in relation to the content of this article. No outside funding was required. David Benjamin Lumenta, M.D. Lars-Peter Kamolz, M.D., Ph.D. Maike Keck, M.D. Manfred Frey, M.D., Ph.D.