Tissue Response After Non-absorbable Hernia Mesh Implantation : Effects of Mesh Material and Structure

Abstract

Hernia meshes are often used in the repair of abdominal wall hernias. An abdominal wall hernia refers to the protrusion of intra-abdominal contents through a weak site in the abdominal wall. A hernia is usually observed as a bulge under the skin. The gold standard procedure of abdominal wall hernia repair involves the placement of a non-absorbable surgical mesh over the hernia defect. The purpose of this hernia mesh is to integrate into the native tissues, provide support for the weakened abdominal wall, and prevent the recurrence of the hernia. The implantation of a hernia mesh induces a tissue response, or a foreign body reaction (FBR), in the host. This is an inflammatory reaction that aims at isolating the implant from the surrounding native tissues. Ultimately, the FBR leads to the growth of a foreign body capsule, consisting of immune cells and fibrotic tissue, around the fibers of the mesh. The thickness of this capsule is dependent on the strength of the FBR. Generally, a strong FBR promotes the growth of a thick capsule, which has the potential to encapsulate the entire mesh, impair tissue integration, and compromise mesh performance. Therefore, the strength of the FBR after mesh implantation is an important determinant of the overall success of the hernia repair. The purpose of this bachelor’s thesis was to investigate how the material and structure of the non-absorbable hernia mesh affect the strength of the tissue response. A secondary objective was to find how the tissue response and the mesh design features affect the mesh performance and the risk of postoperative complications in hernia repair. The work was done as a literature review using published literature, such as research and review articles. It was found that the strength of the tissue response is heavily dependent on the structure of the mesh. However, the effects of mesh material on the tissue response could not be accurately determined. The most important structural features were found to be those that affect the overall surface area of the mesh, such as pore size, fiber structure, and textile design. A mesh with a small overall surface area was found to induce a minimal FBR, whereas a large surface area was associated with a pronounced FBR. The majority of postoperative complications, such as infection, mesh shrinkage, visceral adhesions, and hernia recurrence, were found to be related to a strong FBR. Therefore, it seems like the same structural features that promote a severe tissue response increase the risk of postoperative complications. Future studies will have to clarify the connection between the mesh material and the FBR. It should also be investigated whether specific features of the non-absorbable material influence the risk of postoperative complications in hernia repair. This would be important for the development of more advanced non-absorbable hernia meshes.