Deformation of Transvaginal Mesh in Response to Multiaxial Loading

Synthetic mesh for pelvic organ prolapse (POP) repair is associated with high complication rates. While current devices incorporate large pores (>1 mm), recent studies have shown that uniaxial loading of mesh reduces pore size, raising the risk for complications. However, it is difficult to translate uniaxial results to transvaginal meshes, as in vivo loading is multidirectional. Thus, the aim of this study was to (1) experimentally characterize deformation of pore diameters in a transvaginal mesh in response to clinically relevant multidirectional loading and (2) develop a computational model to simulate mesh behavior in response to in vivo loading conditions. Tension (2.5 N) was applied to each of mesh arm to simulate surgical implantation. Two loading conditions were assessed where the angle of the applied tension was altered and image analysis was used to quantify changes in pore dimensions. A computational model was developed and used to simulate pore behavior in response to these same loading conditions and the results were compared to experimental findings. For both conditions, between 26.4% and 56.6% of all pores were found to have diameters <1 mm. Significant reductions in pore diameter were noted in the inferior arms and between the two superior arms. The computational model identified the same regions, though the model generally underestimated pore deformation. This study demonstrates that multiaxial loading applied clinically has the potential to locally reduce porosity in transvaginal mesh, increasing the risk for complications. Computational simulations show potential of predicting this behavior for more complex loading conditions.