Neoperitoneal formation after implantation of various biomaterials for therepair 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 abdomi nal wall and repaired with polytetrafluoroethylene (PTFE, Soft Tissue Patch (R)), one of two polypropylene patches (Marlex(R) and Prolene(R)), or lyoph ylised 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 e lectron microscopy, and immune histochemistry by labelling of macrophages w ith RAM-11, a specific monoclonal antibody (MoAb). Main outcome measures: Infection, healing, development of adhesions, and hi stological appearance of the interface. Results: Tissues responded similarly to materials of similar structures. La yered prostheses (PTFE and Lyo-Dura(R)) caused formation of a well organise d neoperitoneum with few adhesions to the abdominal viscera (loose adhesion s in. animals in each group), whereas the mesh prostheses generated a disor ganised neoperitoneum with many adhesions (Marlex(R) loose adhesions 3, fir m 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 calcificatio n. Labelling of macrophages with the MoAb showed that they were in direct c ontact 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 ind uce minimal adhesions.