Mechanical Characterization of Animal Derived Grafts for Surgical Implantation

Abstract

Bioprostheses obtained from animal models are often adopted in abdominal surgery for repair and reconstruction. The functionality of these prosthetic implants is related also to their mechanical characteristics that are analyzed here. This work illustrates a constitutive model to describe the short-term mechanical response of Permacol TM bioprostheses. Experimental tests were developed on tissue samples to highlight mechanical non-linear characteristics and viscoelastic phenomena. Uni-axial tensile tests were developed to evaluate the strength and strain stiffening. Incremental uni-axial stress relaxation tests were carried out at nominal strain ranging from 10% to 20% and to monitor the stress relaxation process up to 400 s. The constitutive model effectively describes the mechanical behavior found in experimental testing. The mechanical response appears to be independent on the loading direction, showing that the tissue can be considered as isotropic. The viscoelastic response of the tissue shows a strong decay of the stress in the first seconds of the relaxation process. The investigation performed is aimed at a general characterization of the biomechanical response and addresses the development of numerical models to evaluate the biomechanical performance of the graft with surrounding host tissues.

Regulatory science for hernia mesh: Current status and future perspectives

“… Physical properties [ 97 , 98 ] Risk of hernia recurrence due to insufficient mechanical properties. Appearance, physical dimensions (thickness) [ 23 ], monofilament diameter [ 22 ], pore properties [ 23 , 99 ] (pore size, pore density, porosity), weight per unit area/Density [ 23 , [100] , [101] , [102] ], uniaxial tensile strength [ 23 , 100 , [103] , [104] , [105] , [106] ], tensile elongation [ 106 , 107 ], burst strength [ 23 , 100 , 104 ], suture retention [ 23 , 100 , 104 ], suture pullout strength [ 108 ], connection strength between components and layers (when applicable), tear resistance [ 23 , 100 , 104 ] (when applicable), fading test (when applicable), stiffness [ 109 ]. Chemical properties Toxic reaction due to chemical residues.…”

Biomaterial Implants in Abdominal Wall Hernia Repair: A Review on the Importance of the Peritoneal Interface

“…Biological meshes-usually referred to as grafts or biomeshes-consist of materials derived from animal (xenograft) tissue like Surgisis® [103], Permacol TM [104,105] CollaMend TM [106], Tutomesh®and Strattice® [12,107] or human (allograft) tissue like Alloderm TM [87]. The first tissue-based implant composed of porcine intestinal submucosa for use in abdominal wall reconstruction (Surgisis®) was approved in 1998 [103].…”

“…Due to this, concerns regarding this issue have restricted their use to infected environments. The use of some chemically cross-linked meshes like Permacol TM (a porcine-derived acellular dermal sheet) contributed to an increase in graft stability and durability that led to lower hernia recurrence rates while still being incorporated successfully [12,104,105]. However, some authors [9] concluded that cross-linking does not significantly impact the tensile strength or stiffness of the graft-tissue composites in the long term.…”

Synthetic surgical meshes used in abdominal wall surgery: Part II—Biomechanical aspects

“…Pavan et al developed a numerical model of the abdominal wall on a solid model reconstructed from MRI, comprising rectus abdominis muscle and linea alba . They included an ellipsoidal hernia defect in the upper region of the linea alba , according to plausible pathological conditions, and repaired it with a biological prosthesis.…”