Influence of implantation interval on the long-term biocompatibility of surgical mesh

Background: The aim was to study the long-term tissue response to polypropylene mesh. Methods: This was a retrieval study that investigated 76 polypropylene meshes with a median implantation interval of 18 (range 2-180) months. Mesh was explanted following hernia recurrence, infection or pain. The median implantation interval was 20 (range 4-180) months in the recurrence group, 30 (range 5-48) months in the pain group and 10 (range 2-56) months in the infection group (P < 0.05, infection versus pain or recurrence). The inflammatory response was determined by immunohistochemistry of macrophages (CD68), polymorphonuclear granulocytes (CD15) and T and B lymphocytes (CD3 and CD20). The cell turnover within the interface mesh fibre-recipient tissue was measured by TUNEL for apoptosis or DNA strand breaks, Ki67 for cell proliferation and heat-shock protein (HSP) 70 for cell stress. Results: With the exception of HSP-70, levels of all variables decreased over time. Sex, age, type of previous operation or location of the mesh did not have a significant influence. Conclusion: Long-term incorporated polypropylene mesh in humans has a more favourable tissue response with increasing implantation interval.