Mechanical response of human abdominal walls ex vivo: Effect of an incisional hernia and a mesh repair.

The design of meshes for the treatment of incisional hernias could benefit from better knowledge of the mechanical response of the abdominal wall and how this response is affected by the implant. The aim of this study was to characterise the mechanical behaviour of the human abdominal wall. Abdominal walls were tested ex vivo in three states: intact, after creation of a defect simulating an incisional hernia, and after reparation with a mesh implanted intraperitonally. For each state, the abdominal wall was subjected to air pressure loading. Local strain fields were determined using digital image correlation techniques. The strain fields on the internal and external surfaces of the abdominal wall exhibited different patterns. The strain patterns on the internal surface appeared to be related to the underlying anatomy of the abdominal wall. Higher strains were observed along the linea alba than along the perpendicular direction. Under pressure loading, the created incision increased the strain of the abdominal wall compared to the intact state in 5 cases of a total 6. In addition, the mesh repair decreased the strains of the abdominal wall compared to the incised state in 4 cases of 6. These results suggest that the intraperitoneal mesh restores at least partially the mechanical behaviour of the wall and provides quantification of the effects on the strains in various regions.