New composite patches and biologic patches for repair of contaminated abdominal wall defect in dogs:A comparative study

Objective To compare the characteristics of two compound patches made of collagen and polypropylene（PP） and the feasibility of their application in repair of contaminated wounds. Methods Twenty-four adult male dogs,weighing 16-20kg,were included in this study.A dog model with 3 contaminated defects at the upper,left and right abdominal wall was established.The 3 abdominal wall defects were repaired by implanting 3 kinds of patches into them.The patches were divided into PP and collagen compound patch group（group A）,porcine cross-linked biologic patch group（group B）,and cattle cross-linked biologic patch group（group C）.A dog abdominal hernia model was established.A segment of small intestine was removed,into which 10ml 0.9% sodium chloride solution was injected and then aspirated to contaminate the abdominal cavity,abdominal wall and patches.The abdominal wall defects were closed with 5cm×5cm patches.The dogs were killed on day 90 after operation to observe the adhesion of organs in abdominal cavity.The patches and their adjacent tissue were cut into sections for histological study. Results No death occurred while patch and omentum adhesion was observed in different groups 90 days after operation.Histological study showed that the scores of proliferating fibroblasts,inflammatory reaction and formation of new blood vessels were higher in group A than in groups B and C. Conclusion The effect of PP and collagen compound patch and biological patch is similar in preventing adhesion under contaminated environment.However,it leads to severer proliferation of fibroblasts,inflammatory reaction and formation of new blood vessels than biologic patch.