Multi-directional mechanical analysis of synthetic scaffolds for hernia repair

Hernias remain one of the most common ailments to affect men and women worldwide. Surgical mesh materials were first used to reinforce hernia defects during surgery in the late 1950s (Laker, n.d.). Today, there are well over 50 prosthetic meshes available for hernia repair (Brown and Finch, 2010; Bryan et al., 2014; Hope and El-hayek, 2014). With the multitude of available options, surgeons are faced with the challenging task of optimizing mesh selection for each patient. If the mechanics of the mesh are not compatible with the surrounding tissue, mismatch can occur, which can lead to complications such as mesh failure and/or hernia recurrence. Unfortunately, many aspects of synthetic mesh mechanics remain poorly described. Therefore, the purpose of this study was to provide a more complete mechanical analysis of a variety of commercially available prosthetic meshes for hernia repair, including evaluation of meshes in a variety of orientations. Twenty different meshes were subjected to biaxial tensile tests at both 90° and 45° orientations, and results were analyzed for relative strength, strain behavior, and anisotropy. Peak tension and strain values varied dramatically across all mesh types for all directions, ranging between 4.08 and 25.74N/cm and -5% to 10% strain. Anisotropy ratios for the evaluated meshes ranged from 0.33 to 1.89, demonstrating a wide range in relative direction-dependence of mesh mechanics. While further study of prosthetic meshes and better characterization of properties of the human abdominal wall are needed, results of this study provide valuable data that may aid clinicians in optimizing mesh selection for specific patients and repair conditions.