Modified mesh for hernia repair that is adapted to the physiology of the abdominal wall

Objective: To develop a new mesh for hernia repair that is adapted to the p hysiological forces. Design: Animal experiment. Setting: Surgical Department of the RWTH-Aachen. Animals: Wistar rats. Main outcome measures: Textile analysis, tensile strength, bending stiffnes s, histology and morphometry. Results: After textile analysis of commercially available meshes in clinica l use we defined the physiological forces and constructed a new mesh (Soft Hernia Mesh(R), SHM) based on a combination of non-absorbable polypropylene and absorbable polyglactin 910. The amount of non-absorbable material coul d be reduced to < 30% compared with Marlex(R) while still guaranteeing the necessary pulling force of 16 N/cm. Improvements of the hosiery structure i mproved the symmetrical distribution of the retaining forces in all directi ons. Compared with the considerable restriction of the abdominal wall mobil ity by Prolene(R) (polypropylene) and Mersilene(R) (polyester) meshes there was no increase in the bending stiffness after the implantation of the new mesh. Histological examination showed a pronounced reduction of the inflam matory reaction in the tissues, and the collagen bundles were orientated me rely around the mesh filaments instead of forming a scar plate that complet ely embedded the mesh. Conclusion: Different meshes caused specific histological reactions with ch anges of their mechanical properties after implantation in rodents. A new m esh with a reduced amount of polypropylene showed both less inflammation an d less restriction in the mobility of the abdominal wall though it exceeded the required tensile strength of 16 N/cm.