Comparison of cross-linked and non-cross-linked porcine acellular dermal matrices for ventral hernia repair

BACKGROUND: Porcine acellular dermal matrices (PADMs) have been used clinically for abdominal wall repair. The newer non-cross-linked PADMs, however, have not been directly compared with cross-linked PADMs. We hypothesized that chemical cross-linking affects the biologic host response to PADMs used to repair ventral hernias. STUDY DESIGN: Fifty-eight guinea pigs underwent inlay repair of surgically created ventral hernias using cross-linked or non-cross-linked PADM. After animals were sacrificed at 1, 2, or 4 weeks, the tenacity of and surface area involved by adhesions to the repair sites were measured. Sections of the repair sites, including the bioprosthesis- musculofascia interface, underwent histologic analysis of cellular and vascular infiltration plus mechanical testing. RESULTS: Compared with cross-linked PADM repairs, non-cross-linked PADM repairs had a significantly lower mean tenacity grade of adhesions at all timepoints and mean adhesion surface area at week 1. Mean cellular and vascular densities were significantly higher in non-cross-linked PADM at all timepoints. Cells and vessels readily infiltrated into the center of non-cross-linked PADM, but encapsulated cross-linked PADM, with a paucity of penetration into it. Mechanical properties were similar for the two PADMs (in isolation) at all timepoints; however, at the bioprosthesis-musculofascia interface, both elastic modulus and ultimate tensile strength were significantly higher at weeks 1 and 2 for non-cross-linked PADM. CONCLUSIONS: Non-cross-linked PADM is rapidly infiltrated with host cells and vessels; cross-linked PADM becomes encapsulated. Non-cross-linked PADM causes weaker adhesions to repair sites while increasing the mechanical strength of the bioprosthesis-musculofascia interface at early timepoints. Non-cross-linked PADM may have early clinical advantages over cross-linked PADM for bioprosthetic abdominal wall reconstruction.