The use of composite meshes in laparoscopic repair of abdominal wall hernias: are there differences in biocompatibily?

In recent years, laparoscopic repair of abdominal wall hernias has become increasingly established in routine clinical practice thanks to the myriad advantages it confers. Apart from the risk of intestinal damage following adhesiolysis, to date no information is available on the best way of preventing the formation of new adhesions in the vicinity of the implanted meshes. Numerous experimental investigations, mainly conducted on an open small-animal model, have demonstrated the advantages of coating meshes, inter alia with absorbable materials, compared with uncoated polypropylene meshes. In our established laparoscopic porcine model we set about investigating three of these meshes, which are already available on the market. In total, 18 domestic pigs underwent laparoscopic surgery and three different composite meshes were tested in each case on six animals (Dynamesh IPOM, Proceed, Parietene Composite). At 4 months, postmortem diagnostic laparoscopy was carried out, followed by full-wall excision of the specimens. Planimetric analysis was conducted to investigate the size of the entire surface area and the extent of adhesions. Histological investigations were performed on five sections for each specimen. These focused on the partial volumes of inflammatory cells, the proliferation marker Ki67, apoptotic index, inflammatory cell marker CD68 and transforming growth factor beta (TGF-beta) as a marker of the extracellular matrix. A similar value of 14% was obtained for shrinkage of Dynamesh IPOM and Parietene Composite, while Proceed showed a 25% reduction in its surface area. Markedly lower values of 12.8% were obtained for Parietene Composite in respect of adhesions to the greater omentum, compared with 31.7% for Proceed and 33.2% for Dynamesh IPOM (p = 0.01). Overall, Parietene Composite performed best in the histological and immunhistochemistry tests. On the whole, all composite meshes showed evidence of good biocompatibility. However, none of the coatings was completely able to prevent adhesions. Coating of polypropylene meshes with collagen appears to confer significant advantages compared with other coatings.