A comparison of collagen and PTFE patch repair in a rabbit model of congenital diaphragmatic hernia

The use of prosthetic material in severe cases of congenital diaphragmatic hernia is complicated by infection, bowel adhesion, and patch dehiscence. We hypothesized that a bioprosthetic collagen patch would reduce these complications and be remodeled into autogenous tissue over a short period of time. Thirty-two New Zealand White rabbits had two 2 × 2-cm left diaphragmatic defects created. One of these defects was repaired with a collagen bioprosthetic patch (n = 20) and the other with a polytetrafluoroethylene (PTFE) patch (n = 20). Members of a control group (n = 12) had their defects closed primarily. The animals were then placed in either a 6- or 12-week survival cohort. At necrosectomy the repairs were assessed histologically, graded for adhesion formation, and tensiometrically tested. The PTFE patch was noted to have a significantly higher average adhesion grade than the collagen patch. The tensile strength of the two repair methods was statistically equivalent at both time intervals. On histologic examination the collagen patches were surrounded by an increased number of macrophages and fibroblasts. The PTFE patch exhibited no neovascularization or fibroblast deposition at the periphery, but had a much greater surrounding inflammatory response. Thus, there was evidence of early remodeling of the collagen with no increase in the amount of adhesions or loss of strength when compared to the PTFE, while the PTFE patches exhibited a more severe grade of adhesions.