Combined biaxial and uniaxial mechanical characterization of prosthetic meshes in a rabbit model
Röhrnbauer, B × Ozog, Y Egger, J Werbrouck, E Deprest, Jan Mazza, E #
Journal of Biomechanics vol:46 issue:10 pages:1626-32
The present experimental study is aimed at a combined uniaxial and biaxial mechanical characterization of the deformation behavior of two types of prosthetic meshes, SPMM (heavy-weight) and Gynemesh M (light-weight, partly absorbable), after integration in the host tissue. Explants from a full-thickness-abdominal-wall-defect-rabbit-model were tested in the two loading conditions. Corresponding protocols and data analysis procedures for biaxial inflation tests and uniaxial tensile tests were developed. Biaxial responses were observed to be by factor 2-4 stiffer compared to corresponding uniaxial experiments, depending on the material tested. In biaxial loading conditions, SPMM explants were stiffest. Gynemesh M explants and native tissue were similarly compliant at low membrane tensions (<5N/cm) (abdominal wall: 40±23N/cm, Gynemesh M: 59±44N/cm, SPMM: 145±36N/cm). At high membrane tensions (>5N/cm), there were distinct differences in the stiffness of the three groups, SPMM explants being the stiffest, followed by Gynemesh M explants and native tissue being the most compliant. In uniaxial loading conditions, the two explants were similarly stiff and distinctly stiffer than native tissue at low membrane tensions (<5N/cm) (abdominal wall: 9±1N/cm, Gynemesh M: 21±5N/cm, and SPMM: 24±5N/cm). At high membrane tension (>5N/cm), differences between all groups vanished. Biaxial and uniaxial tests yield different results with respect to the mechanical behavior of mesh explants. These findings demonstrate that an evaluation of the mechanical biocompatibility of prosthetic meshes should be based on an experimental configuration (uniaxial or biaxial tension) which reproduces the expected in vivo conditions of mechanical loading and deformation.