Bacterial clearance of biologic grafts used in hernia repair: an experimental study

Abstract

Background Biologic grafts used in ventral hernia repair are derived from various sources and undergo different post-tissue-harvesting processing, handling, and sterilization techniques. It is unclear how these various characteristics impact graft response in the setting of contamination. We evaluated four materials in an infected hernia repair animal model using fluorescence imaging and quantitative culture studies. Methods One hundred seven rats underwent creation of a chronic hernia. They were then repaired with one synthetic polyester control material (n = 12) and four different biologic grafts (n = 24 per material). Biologic grafts evaluated included Surgisis (porcine small intestinal submucosa), Permacol (crosslinked porcine dermis), Xenmatrix (noncrosslinked porcine dermis), and Strattice (noncrosslinked porcine dermis). Half of the repairs in each group were inoculated with Staphylococcus aureus at 104 CFU/ml and survived for 30 days without systemic antibiotics. Animals then underwent fluorescence imaging and quantitative bacterial studies. Results All clean repairs remained sterile. Rates of bacterial clearance were as follows: polyester synthetic 0%, Surgisis 58%, Permacol 67%, Xenmatrix 75%, and Strattice 92% (P = 0.003). Quantitative bacterial counts had a similar trend in bacterial clearance: polyester synthetic 1 × 106 CFU/g, Surgisis 4.3 × 105 CFU/g, Permacol 1.7 × 103 CFU/g, Xenmatrix 46 CFU/g, and Strattice 31 CFU/g (P = 0.001). Fluorescence imaging was unable to detect low bacterial fluorescence counts observed on bacterial studies. Conclusion Biologic grafts, in comparison to synthetic material, are able to clear a Staphylococcus aureus contamination; however, they are able to do so at different rates. Bacterial clearance correlated to the level of residual bacterial burden observed in our study. Post-tissue-harvesting processing, handling, and sterilization techniques may contribute to this observed difference in ability to clear bacteria.

Bacterial adhesion to biological versus polymer prosthetic materials used in abdominal wall defect repair: do these meshes show any differences in vitro?

“…According to some authors, crosslinks confer advantages to a biomesh in the face of infection through an increased resistance to bacterial metalloproteinases [25]. However, clinical evidence exists indicating that cross-linked biomaterials show greater rates of infection and explantation than non-crosslinked materials [26,27], as suggested by the present results. The use of a biomesh in a contaminated field is still a matter of debate given the disparate experimental data and the lack of prospective clinical studies performed [28][29][30].…”

Use of Biologic Grafts in Surgery

“…Reconstruction of major abdominal walls with modifi ed tissues that is harvested from human or pigs has become a common practice. In an experimental study examining biologic grafts in comparison to synthetic material, biologic grafts are able to clear a Staphylococcus aureus contamination; however, they do so at different rate [ 18 ]. The authors created a chronic hernia model in rats and then used various meshes (one synthetic polyester as control material ( n = 12) and four different biologic grafts ( n = 24 per material)).…”

A Modified Approach to Component Separation Using Biologic Graft as a Load-Sharing Onlay Reinforcement for the Repair of Complex Ventral Hernia

“…6 These characteristics include intact extracellular matrix, low antigenic response, and the ability to support tissue regeneration through revascularization and cell repopulation, which may contribute to improved resistance to infection demonstrated by some biologic materials, such as noncrosslinked PADM. 6,[12][13][14][15][16] An expert panel (The Ventral Hernia Working Group) has stratified hernia patients into 4 grades to assist surgeons in the prediction of a patient's risk for SSO after hernia repair. 6 Patients in grades 3 and 4 have contamination or infection of their wounds, respectively; biologic repair materials are recommended for these patients, as biologic materials generally do not require removal in the setting of SSO such as infection.…”

“…Elevated risk of infection is a reasonable contraindication to the implantation of synthetic repair materials, whereas biological materials such as noncrosslinked PADM have been shown to develop a vascular supply and thus more reliably resist infection. 9,13,15,[17][18][19][20][21][22] We hypothesized that noncrosslinked PADM would be safe and effective when used as an onlay reinforcement of components separation repair of ventral hernias in obese patients at high risk for hernia recurrence and/or SSO.…”