Comparative finite element modelling of surgical meshes at macro and mesoscale: assessing the role of morphology on mechanical behavior.

Synthetic meshes are widely used in abdominal wall surgery, yet recurrences remain common. Understanding how mesh morphology evolves under physiological loads is therefore crucial. In this work, a mesoscale finite element approach was developed and compared against the conventional macroscale approach to investigate the mechanical response of lightweight and standard weight polypropylene meshes using previously performed experimental tests. The new mesoscale approach reconstructed the porous architecture from high-resolution images, allowing anisotropy to emerge from geometry while using an isotropic hyperelastic material formulation. Macroscale models were implemented for comparison, modelling meshes as homogeneous surfaces with an anisotropic hyperelastic formulation. Material properties in both approaches were calibrated on uniaxial tensile tests and evaluated through ball burst simulations. Both strategies showed comparable agreement with experiments at the surgical mesh-level. However, mesoscale models provided insights into pore-level mechanisms, including deformation and collapse, confirmed through image-based tracking. They also confirmed that the observed anisotropy can be reproduced numerically by reconstructing the textile architecture. In conclusion, while the macroscale approach is faster to implement, mesoscale models better capture how structural features influence pore-level mechanical response. Integrating this approach into more complex simulations could help predict in vivo performance and guide the design of next-generation surgical meshes.