Neoperitoneal formation after implantation of various biomaterials for the repair of abdominal wall defects in rabbits

Objective: To study the interfaces between the visceral peritoneum and some of the biomaterials used to repair defects in the abdominal wall. Design: Animal study. Setting: School of medicine, Spain. Material: 48 New Zealand white rabbits divided into 4 groups of 12 each. Interventions: Full thickness defects 50 x 70 mm were created in the abdominal wall and repaired with polytetrafluoroethylene (PTFE, Soft Tissue Patch(R)), one of two polypropylene patches (Marlex(R) and Prolene(R)), or lyophylised dura mater (LyoDura(R)). 3 animals from each group were killed at 14, 30, 60 and 90 days and specimens examined by light microscopy, scanning electron microscopy, and immune histochemistry by labelling of macrophages with RAM-11, a specific monoclonal antibody (MoAb). Main outcome measures: Infection, healing, development of adhesions, and histological appearance of the interface. Results: Tissues responded similarly to materials of similar structures. Layered prostheses (PTFE and Lyo-Dura(R)) caused formation of a well organised neoperitoneum with few adhesions to the abdominal viscera (loose adhesions in. animals in each group), whereas the mesh prostheses generated a disorganised neoperitoneum with many adhesions (Marlex(R) loose adhesions 3, firm 8, and integrated 1; Prolene(R) loose adhesions 2, firm 8, and integrated 2). Lyo-Dura(R) was associated with the formation of areas of calcification. Labelling of macrophages with the MoAb showed that they were in direct contact with all materials studied. Conclusions: Layered biomaterials with Little or no porosity (PTFE and Lyo-Dura(R)) are the most suitable of the four for implantation in sites where the prosthesis is in contact with the visceral peritoneum, because they induce minimal adhesions.