Shrinkage of intraperitoneal onlay mesh in sheep: coated polyester mesh versus covered polypropylene mesh

Currently, the laparoscopic placement of intraperitoneal mesh constitutes an acceptable option in the management of ventral hernia. To date, relatively little has been published on the consequences of intra-abdominal placement of a mesh with respect to the decrease of mesh size (shrinkage).

In each of 16 sheep, four meshes (dimensions 10 × 10 cm), two based on polyester and two on polypropylene, were placed laparoscopically on intact peritoneum and fixed with either non-absorbable or absorbable tacks. After 3, 6, 12, and 18 months, four animals, respectively, underwent a new laparoscopy with the harvesting of mesh and fascia. Quantitative measurement of the mesh size was performed and expressed as percentage shrinkage. Random core biopsies of mesh and adjacent tissue were obtained and histologically examined.

There was a significant difference of the two meshes with respect to shrinkage at all time points. The coated polyester-based mesh was exposed to more shrinkage compared to the polypropylene mesh covered with anti-adhesive material. Random biopsies at 3 months showed an increased foreign body reaction to the coated polyester mesh.

This study is the first long-term experimental study on mesh shrinkage after the laparoscopic placement of mesh. The polyester-based mesh induced a more intense foreign body reaction and was exposed to significantly more shrinkage than the covered polypropylene mesh.