The Retroperitoneum Protects Prosthetic Graft Material from Intraperitoneal Contamination: An Experimental Study

ObjectivesTo evaluate the ability of the retroperitoneum to serve as a barrier, against bacterial contamination, between the peritoneal cavity to the retroperitoneal space.MethodsSeventy rats had a small piece of knitted Dacron graft placed in the retroperitoneal space and 106–109 colony forming unit (cfu) Enterococcus faecalis was injected into the peritoneal cavity. In half the retroperitoneal (RP) group, the retroperitoneum was preserved and in the remainder, the open peritoneal (OP) group, needle holes were created. Grafts were harvested after 1, 4, or 7 days and cultured for E. faecalis. A blood sample was collected from three rats in each group for culture before the graft was harvested.ResultsGraft infection did not develop in any rat injected with 106 or 107 cfu in the RP group, while seven out of the 10 graft cultures of the OP group grew E. faecalis (P=0.003). In rats injected with 108 or 109 cfu, five out of the 10 graft cultures in the RP group and eight out of 10 in the OP group grew E. faecalis. All blood cultures were negative when the injected bacterial count was 107 cfu or less. One out of the three blood cultures was positive at 108 cfu, and all were positive at 109 cfu.ConclusionsThese results suggest that an intact retroperitroneum acts as a protective barrier against intraperitoneal bacterial contamination, particularly when blood cultures are negative.