Biomechanical Behavior of an Aged Synthetic Hernia Mesh Under a Cough-Simulating Protocol

Hernia meshes are repeatedly subjected to physiological loading caused by fluctuations in intra-abdominal pressure during daily activities. This study aimed to investigate the effects of prolonged cyclic loading simulating repetitive severe coughing on the mechanical properties of expired, non-implanted Microval polypropylene mesh. Uniaxial cyclic tensile tests were performed on aged Microval mesh specimens in the two principal material directions. The loading protocol simulated repetitive coughing by applying six loading sessions per day over three consecutive days. Residual strain, elastic modulus, and loading duration were evaluated throughout the experiment. After the loading protocol, the specimens were tested to failure. Cyclic loading affected the mesh. Strain was within 12-20% in the longitudinal (L) direction and up to 25% in the transverse (T) direction after the third testing day. The elastic modulus increased significantly with repetitive loading, indicating pronounced material stiffening, while the ultimate tensile strength remained within the range measured for the unused specimens. In addition, the first loading cycle was approximately 20% longer than the subsequent cycles. Prolonged cyclic loading caused significant permanent deformation and pronounced material stiffening in the aged Microval mesh, whereas its ultimate tensile strength was only slightly affected. These findings enhance understanding of the mechanical behavior of hernia meshes under repetitive physiological loading.