IMPROVEMENT OF THE TISSUE INTEGRATION OF A NEW MODIFIED POLYTETRAFLUOROETHYLENE PROSTHESIS - MYCRO MESH(R)

We studied the behaviour of the different tissue interfaces formed on a new type of prosthesis used for the repair of abdominal wall defects , Mycro Mesh(R) (W. L. Gore and Ass., Flagstaff, AZ, USA), which consi sts of perforated layers of polytetrafluoroethylene (PTFE). In 20 New Zealand white rabbits, a full-thickness (except skin) 7 cm x 5 cm defe ct was created in the anterior abdominal wall. The defects were repair ed with a prosthetic implant (Mycro Mesh(R)) that was placed in direct contact with abdominal viscera and subcutaneous tissue. At 14, 30, 60 and 90 d post-implantation, samples were obtained from the tissue int erfaces formed between the prosthesis and subcutaneous tissue, viscera l peritoneum and receptor tissue, respectively. Samples were studied b y optical microscopy and scanning electron microscopy. The immunohisto logical study was made with RAM-11, a monoclonal antibody specific for rabbit macrophages. Tensile strength was measured with an Instron ten siometer using 2 cm wide strips obtained parallel to the shorter axis of the implant. Strips included the prosthesis and two anchor zones on the receptor tissue. Macroscopically, the prosthesis induced little a dhesion formation on the Visceral peritoneum interface. Microscopicall y, an organized neoperitoneum and abundant tissue formed on the subcut aneous interface. In the prosthesis perforations, bridges of tissue li nked the peritoneal and subcutaneous sides. The macrophage response de creased significantly in intensity between day 14 and day 90 (Student- Newman-Keuls test, P = 0.01). Tensile strength increased significantly (Wilcoxon test, P < 0.05) at every study period. To conclude: the Myc ro Mesh(R) prosthesis proved suitable for implantation in sites where it comes in contact with abdominal viscera and it provided good suppor t for the formation of an organized neoperitoneum; the perforations in the prosthetic material improved implant integration; the macrophage response was not altered by the biomaterial and the tensile strength o f the prosthesis increased as scar tissue formation and tissular integ ration of the prosthesis progressed. Copyright (C) 1996 Elsevier Scien ce Limited