Hyperelastic characterization of synthetic mesh for abdominal wall hernia repair

Synthetic polypropylene meshes are widely used in abdominal wall hernia repair, but complications such as chronic pain and recurrence have been linked to poor biomechanical compatibility between the implanted mesh and host tissue. This study mechanically characterized two commercial polypropylene meshes used clinically for hernia repair (Prolene mesh by Ethilon and Premilene mesh by B. Braun) and developed hyperelastic constitutive fits suitable for finite-element simulation of mesh behavior. Rectangular specimens were cut and tested in uniaxial tension along two perpendicular directions (longitudinal and transverse) to capture anisotropy arising from mesh yarn architecture and inter-yarn interactions. Force–strain responses showed direction-dependent, nonlinear behavior, confirming anisotropic hyperelasticity. The authors then evaluated several hyperelastic models and identified a five-parameter Mooney–Rivlin formulation as providing the best fit to the experimental data in both directions for both meshes. The resulting fitted parameters are proposed as a practical input set for computational modeling workflows aimed at improving mesh selection, predicting deformation, and reducing mechanical mismatch-driven postoperative complications.