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Use of nonporous polytetrafluoroethylene prosthesis in combination with polypropylene prosthetic abdominal wall implants in prevention of peritoneal adhesions.

One of the drawbacks of using macroporous polypropylene prostheses in the repair of the abdominal wall is the formation of adhesions with the viscera. However, polytetrafluoroethylene (PTFE) has low adhesion formation, although it provides less resistance to traction in the repaired zone. The aim of the present study was to reduce the formation of adhesions to a polypropylene implant Prolene (PL) by introducing a nonporous expanded PTFE layer (Preclude Dura-Substitute) (PR) between the polypropylene prosthesis and the abdominal viscera. The scarring process and resistance to traction in the repaired zone were also evaluated. Thirty-six rabbits were divided into three groups and were treated as follows: group I, a PR patch (7 x 5 cm) was secured to the parietal peritoneum; group II, an abdominal wall defect (7 x 5 cm) was created and repaired using a PL patch; group III, an abdominal wall defect was as in group II and was repaired using a combined PR/PL prosthesis. Specimens were evaluated at 14, 30, 60, and 90 days postimplant for extent of adhesion formation and morphological analysis was performed using light and scanning electron microscopy. Biomechanical resistance of the implant was evaluated using strips comprising prosthetic material and anchorage tissue. Group I and group III prostheses showed loose adhesions only, but group II adhesions were firmly attached. The mean surface areas covered by adhesions were 0.08 cm2 (group I), 7.67 cm2 (group II), and 0.1 cm2 (group III). PR implants (group I) were encapsulated by organized tissue. In group II the formation of disorganized tissue invading the prosthesis was observed. In group III the PR impeded the growth of disorganized scar tissue and the lower surface of the implant was covered by an orderly neoperitoneum. Resistance to traction of the double implants (group III) (mean +/- SD, 33.32 +/- 0.9 N) was similar to that of the Prolene implants (group II) (33.76 +/- 0.46 N) (Mann-Whitney U test, p < 0.05). We concluded the presence of a PR layer between the PL implant and viscera greatly reduced the incidence of adhesion formation without affecting the high resistance to traction provided by the PL implant or the evolution of the scarring process.