Comparing the behavior of different polypropylene meshes (heavy and lightweight) in an experimental model of ventral hernia repair

New generation prosthetic biomaterials for abdominal wall repair have been designed to be less dense, by having larger pores than that of the standard polypropylene meshes, to improve abdominal wall compliance. The aim of the present study was to analyze the functional and morphologic properties of these new meshes. For this purpose, 7 x 5 cm(2) defects were created in the anterior abdominal wall of 36 male New Zealand White rabbits and repaired using different polypropylene meshes: a heavyweight mesh (HW), Surgipro, and two lightweight meshes (LW), Parietene and Optilene. Six animals each implanted with biomaterial were sacrificed on postoperative days 14 and 90. Histological and morphometric analysis, adhesion assessment, and biomechanical resistance tests were performed. Similar behavior was shown by the LW and HW meshes in terms of the adhesions and macrophage response induced. After 14 days, the tensile strength of Optilene was greater than the strengths recorded for the other two biomaterials, probably because of its high elasticity. By 90 days, however, the tensile strengths of the three biomaterials were comparable. In conclusion, despite an initial tensile strength advantage shown by the mesh with larger pores, at 90 days postimplant, tensile strengths were similar. Compared with HW, LW prostheses have the benefit that less foreign material was implanted, preserving the elasticity of the recipient host tissue.