Experimental assay of a Dual Mesh polytetrafluoroethylene prosthesis (non-porous on one side) in the repair of abdominal wall defects.

The porosity of the prosthetic biomaterials used to repair defects in the abdominal wall seems to influence the tissue repair process insofar as tissue integration of the prosthetic material and the formation of adhesions with abdominal viscera are concerned. We studied the behaviour of a new type of polytetrafluoroethylene prosthesis used for the repair of abdominal wall defects. Dual Mesh (DM), which has two different faces; one face has a porosity between 30 and 60 microns, while the other is non-porous. In 20 New Zealand White rabbits, a full-thickness (except skin) 7 cm x 5 cm defect was created in the anterior abdominal wall that was repaired with DM. At 14, 30, 60 and 90 days, samples were obtained and studied by light and scanning electron microscopy. An immunohistochemical study was made with antibody anti-rabbit macrophages (RAM-11). Tensile strength was measured with an Instron tensiometer using 2-cm-wide strips obtained parallel to the shorter axis of the implant. DM induced little tissue adhesion to the material on the visceral peritoneum interface and was surrounded by organized repair tissue. The biomaterial was integrated in the repair tissue on the subcutaneous interface, but not on the peritoneal interface. The macrophage response decreased between days 14 and 90 (P < 0.001). Tensile strength increased significantly (P < 0.05) at every study period. We conclude that the DM prosthesis has little tendency to formation of visceral adhesions, the DM prosthesis was well tolerated by the receptor organism and the tensile strength of the prosthesis/receptor tissue interface increased with time.