Early biocompatibility of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral hernia repair

Abstract

Purpose: Biologic meshes have unique physical properties as a result of manufacturing techniques such as decellularization, crosslinking, and sterilization. The purpose of this study is to directly compare the biocompatibility profiles of five different biologic meshes, AlloDerm(®) (non-crosslinked human dermal matrix), PeriGuard(®) (crosslinked bovine pericardium), Permacol(®) (crosslinked porcine dermal matrix), Strattice(®) (non-crosslinked porcine dermal matrix), and Veritas(®) (non-crosslinked bovine pericardium), using a porcine model of ventral hernia repair.

Methods: Full-thickness fascial defects were created in 20 Yucatan minipigs and repaired with the retromuscular placement of biologic mesh 3 weeks later. Animals were euthanized at 1 month and the repair sites were subjected to tensile testing and histologic analysis. Samples of unimplanted (de novo) meshes and native porcine abdominal wall were also analyzed for their mechanical properties.

Results: There were no significant differences in the biomechanical characteristics between any of the mesh-repaired sites at 1 month postimplantation or between the native porcine abdominal wall without implanted mesh and the mesh-repaired sites (P > 0.05 for all comparisons). Histologically, non-crosslinked materials exhibited greater cellular infiltration, extracellular matrix (ECM) deposition, and neovascularization compared to crosslinked meshes.

Conclusions: While crosslinking differentiates biologic meshes with regard to cellular infiltration, ECM deposition, scaffold degradation, and neovascularization, the integrity and strength of the repair site at 1 month is not significantly impacted by crosslinking or by the de novo strength/stiffness of the mesh.

Fig. 1

Diagram of mesh placement in the porcine preperitoneal incisional hernia repair. Biologic mesh (8 × 10 cm) was implanted in the preperitoneal plane, secured by eight transfascial sutures, centered under the 4-cm hernia defect

Fig. 2

Uniaxial tensile testing. The mesh–tissue specimen is secured into grips and pulled apart at a constant displacement (0.42 mm/s). The maximum load (N), tensile strength (N/cm), and stiffness (N/mm) are recorded for each specimen

Fig. 3

a Maximum load, b tensile strength per unit width, and c stiffness of de novo mesh (t = 0 months) compared to native abdominal wall without implanted mesh and to mesh–tissue composites after 1 month in vivo

Fig. 4

Histologic scoring of all meshes after 1 month in vivo by subcategory: a cellular infiltration, b cell types present, c extracellular matrix (ECM) deposition, d scaffold degradation, e fibrous encapsulation, f neovascularization. Higher scores represent more favorable outcomes with regard to graft remodeling

Fig. 5

H&E photomicrographs of biologic meshes after 1 month in vivo. Non-crosslinked meshes, top row: a Veritas®, b AlloDerm®, c Strattice®. Crosslinked meshes, bottom row: d Permacol®, e PeriGuard®. Basophilic (blue) staining represents inflammatory infiltrate and eosinophilic (pink) staining represents collagen and ECM deposition

Fig. 6

Histologic scoring of all meshes after 1 month in vivo; composite scores