Abdominal wall reinforcement: biologic vs. degradable synthetic devices

New biodegradable synthetic and biologic hernia implants have been promoted for rapid integration and tissue reinforcement in challenging repairs, e.g. at the hiatus or in contaminated wound fields. Interestingly, experimental data to support or falsify this assumption is scarce.

Synthetic (BioA^®) and biologic implants (porcine and bovine collagen matrices Strattice^® and Veritas^®) have been tested in experimental onlay hernia repair in rats in observation periods of 30 and 60 days. The key outcome parameters were mesh integration and reinforcement of the tissue at the implant site over sutured and sealed defects as well as comparison to native abdominal wall. Macroscopic assessment, biomechanical analysis and histology with haematoxylin/eosin staining, collagen staining and van Willebrand factor staining for detection of neovascularization were performed.

BioA^® was well integrated. Although the matrices were already fragmented at 60 days follow-up, hernia sites treated with synthetic scaffolds showed a significantly enhanced tissue deflection and resistance to burst force when compared to the native abdominal wall. In porcine and bovine matrices, tissue integration and shrinkage were significantly inferior to BioA^®. Histology revealed a lack of fibroblast ingrowth through mesh interstices in biologic samples, whereas BioA^® was tightly connected to the underlying tissue by reticular collagen fibres.

Strattice^® and Veritas^® yielded reduced tissue integration and significant shrinkage, prohibiting further biomechanical tests. The synthetic BioA^® provides little inherent strength but reticular collagen remodelling led to an augmentation of the scar due to significantly higher burst force resistance in comparison to native tissue.