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. W e hypothesized that a bioprosthetic collagen patch would reduce these compl ications and be remodeled into autogenous tissue over a short period of tim e. Thirty-two New Zealand White rabbits had two 2 x 2-cm left diaphragmatic defects created. One of these defects was repaired with a collagen biopros thetic patch (n = 20) and the other with a polytetrafluoroethylene (PTFE) p atch (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 f or adhesion formation, and tensiometrically tested. The PTFE patch was note d to have a significantly higher average adhesion grade than the collagen p atch. The tensile strength of the two repair methods was statistically equi valent at both time intervals. On histologic examination the collagen patch es were surrounded by an increased number of macrophages and fibroblasts. T he PTFE patch exhibited no neovascularization or fibroblast deposition at t he periphery, but had a much greater surrounding inflammatory response. Thu s, 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, w hile the PTFE patches exhibited a more severe grade of adhesions.