Shrinking of polypropylene mesh in vivo: An experimental study in dogs

Objective: To assess the extent of shrinkage of meshes used for hernia repa ir. Design: Experimental study in dogs. Setting: University hospital, Germany and University Research Centre, Mosco w. Animals: 10 dogs had monofilament polypropylene meshes that weighed 95 g/m( 2) (Marlex(R)) or multifilament reduced polypropylene meshes combined with polyglactin 910 that weighed 55 g/m(2) (Soft Hernia Mesh(R)) implanted for either 3 or 6 months. Main outcome measures: Histological appearance and radiological assessment of the position and area of the mesh. Results: After 4 weeks the area of mesh in the monofilament group was reduc ed from to 139 (11) to 75 (8) cm(2) (54%) and that of the multifilament fro m 116 (18) to 77 (20) cm(2) (66%). The multifilament mesh with the reduced amount of polypropylene showed less inflammatory response and less shrinkag e. The mesh did not seem to have moved. Conclusion: Meshes that contain a lot of polypropylene shrink to about 30%- 50% of their original size after 4 weeks, requiring an overlap of at least 3 cm if implanted subfascially. Reduction in the polypropylene content decr eases both the inflammatory response and the shrinkage. Meshes with big por es are less likely to fold and improve compatibility.