Tensile strength and host response towards different polypropylene implant materials used for augmentation of fascial repair in a rat model

Abstract

We compared inflammatory response, fibrosis and biomechanical properties of different polypropylene materials from one manufacturer (Tyco Healthcare) in a rat model for primary fascial repair. Full-thickness abdominal wall defects were primarily repaired using 'overlay' technique. Multifilament implants were Surgipro SPM and SPMW, the latter a wider-weave type of the former. Monofilament SPMM implants and polypropylene suture repair (Surgipro II) served as controls. Explants were evaluated macroscopically and changes in thickness, shrinkage and tensile strength were measured. Inflammatory and connective tissue response was assessed on haematoxylin-eosin and Movat stains. Immunohistochemistry was done to localise rat macrophages/monocytes. Multifilament materials induced a shorter acute inflammatory response and more pronounced chronic inflammatory reaction compared to monofilament implants. Macrophages could be found deep in interstices 7.5 by 12.5 microm. No difference in collagen deposition and neovascularisation was observed. At 90 days time point, explants reconstructed with tighter woven multifilament SPM were weaker than sutured or SPMM controls. Overall shrinkage of 10% was comparable for all groups.

Biomechanical findings in rats undergoing fascial reconstruction with graft materials suggested as an alternative to polypropylene

“…We earlier reported that PP containing products had most reassuring observations which was comparable for Pelvitex at 90 days. 29 Pelvitex is covered with collagen coating, supposed to be degraded very fast. 30,31 The clinical rationale for collagen covering is the avoidance of local complications such as erosions, which cannot be tested in this model.…”

A standardized description of graft-containing meshes and recommended steps before the introduction of medical devices for prolapse surgery

“…Prolapse surgery typically involves repair of fascial structures, and the bulk of the studies is being done in models that were borrowed, again, from hernia surgery [15][16][17][18][19][20]. In essence, they involve the repair of a fascial defect, either by primary sutured repair reinforced by the implant or by overlaying the defect.…”

“…Using different staining methods, one can quantify the inflammatory response, eventually also using immunochemistry against cell-specific markers [18,43]. The organization, composition, and amount of connective tissue can be scored [44,45].…”

A preclinical evaluation of polypropylene/polylacticacid hybrid meshes for fascial defect repair using a rat abdominal hernia model

“…The ideal material has been defined as biocompatible, adequately mechanically strong, physical resistant to surrounding tissues, available in a convenient format and affordable for clinical use [7]. Available materials are knitted from monofilament yarn with relatively large pore sizes, in order to allow tissue ingrowth [10]. Poly-propylene (PP) is probably the most widely used synthetic material [9].…”