Comparative immunohistochemical study of tissue integration of macroporous and laminar surgical meshes.

Intraperitoneal surgical mesh implantation is required for laparoscopic ventral hernia repair. Composite meshes are well known in animal models and human practice. The aim of our study is to compare the biological behaviour of two different textured silicone-covered polypropylene meshes. Transmural abdominal wall defect was created in 40 rabbits and treated as follows: In 20 animals a polypropylene mesh with a laminar silicone covering (LSPP) and in the rest a macroporous textured mesh knitted of silicone-impregnated polypropylene filaments (MSPP) was applied. One and three weeks after implantation we evaluated the intraperitoneal adhesion formation of the mesh macroscopically, histologically and immunohistochemically to detect the reactive cells, especially inflammatory, endothelial and mesothelial cells, as well as their proliferative activity, and with Scanning Electron microscopy to visualize the surface of the meshes. The adhesion formation caused by the composites showed no statistical difference after one week although in the three weeks old samples the LSPP adhesion was significantly weaker than that of MSPP. As complications, serome formation in both groups, fistulas, abscesses, and sc. haematoma in the LSPP group were found. Only in MSPP containing tissues was the decrease of Ki-67 positive proliferating cells significant. A significant increase in VEGF expressing cells was observed only in MSPP containing three week old samples, suggesting better regulation of vascular growth in tissues surrounding the implants. In one week old specimens we observed an irregular proliferation of cytokeratin containing mesothelial cells in both group. The intraperitoneal surface of MSPP mesh was covered with neoperitoneum, while it was not regularly seen on LSPP mesh after three week.