Mechanics of mesh implanted into abdominal wall under repetitive load. Experimental and numerical study

There are a number of papers discussing medical and mechanical aspects of ventral hernia management. Despite intensive work on the problem understanding, recurrences of the sickness still happen too often. For that reason, new aspects of the problem must be considered. In this article, a change in the abdominal implant's stiffness is discussed, which is caused by cyclic loading. Such loading influence abdominal implant, for example, while patient is coughing or exercising. For the first time, this stiffness change is quantitatively described for a selected knitted mesh. The influence of mesh stiffness changes on repaired hernia persistence is studied. Then, ex vivo experiments on a repaired hernia model under cyclic pressure loading are performed. Finally, numerical simulations of the experiments are made in which stresses and forces in the system are calculated. The two following cases are considered. In the first case, the mesh has its baseline stiffness, and in the second case, the mesh is preconditioned by former loading; thus, it is stiffened. Reaction forces at the mesh fixation points appear to be approximately twofold higher in the second case than in the first case. That may be a reason for a fixation damage in operated hernia system. The results presented shed new light on the necessary strength of mesh fixation in the abdominal wall. They enlarge the state of the art on laparoscopic hernia management with the use of a synthetic implant. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1400-1409, 2019.