Page 259 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

In ammatory response in a contaminated environment
Discussion
Surgeons often hesitate to use biomaterials in a contaminated environment, like fascial defects after bowel resection, near stomas or after removal of an infected mesh. Nowadays, most used biomaterials in this environment are biologic materials, which are very expensive compared to synthetic biomaterials. However, a critical review describes that there is not enough evidence to state that biologic biomaterials perform better than synthetic biomaterials(1). Therefore a close look to synthetic biomaterials in a contaminated environment is needed. Little is known about the mesh-speci c phenotypes and presence of macrophages after implantation of a mesh in a contaminated environment.
In this study, di erent meshes were implanted in a rat model in a contaminated environment. The attractors of macrophages, namely T-cells and mast cells, and the di erent phenotypes of macrophages were analyzed. In these experiments mesh-speci c cellular responses were seen. All meshes induced the in ux of T-cells and macrophages, still present after 90 days compared with the control group without a mesh. High levels of T-cells and macrophages indicate a chronic in ammatory reaction when meshes were implanted in a contaminated environment(3, 4). Both PTFE-meshes were surrounded by the most T-cells whereas the polypropylene biomaterials Parietene® and Parietene Composite® had the lowest number of T-cells. The latter is indicative for resolution of the in ammatory reaction, possibly leading to a brotic reaction for Parietene® which is often seen in vivo. This macroscopically represents in a rm incorporation and shrinking of this mesh suggesting brosis(3, 13, 18, 19). Parietene Composite® performed well macroscopically with a low amount of adhesions and a low percentage of infection in a contaminated environment(13), most likely due to the collagen layer which is known to reduce adhesions(14).
We found high numbers of CD206-positive and iNOS-positive macrophages around C-Qur®-and Dualmesh®-samples after 28 days, indicative for a chronic in ammation reaction. Indeed macroscopically these meshes had the highest infection rate and a bad incorporation in the abdominal wall(13). This might be explained by the presence of endotoxins released by bacteria during the infection, which are known to delay the foreign body reaction(12). Dualmesh® is a partially microporous mesh with a higher risk of infection than PP and polyethylene(15, 20). This can be explained by the small pore size
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