Tissue Reaction to Polypropylene Mesh: A Study of Oedema, Blood Flow, and Inflammation in the Abdominal Wall

Abstract

The purpose of the present work was to study the tissue reaction to polypropylene mesh (Marlex®) implanted in three different layers of the abdominal wall, comparable to common clinical practices. The reaction to mesh was compared in terms of tissue oedema, blood flow, and histological appearance in rats. When mesh was placed between muscle layers, blood flow in the abdominal wall was high during the first 4 days after implantation but similar to flow in nonoperated rats 14 and 140 days after implantation. When mesh was placed under skin or on the peritoneum, there was no hyperaemia early after implantation, and flow rate was clearly lower than in non-operated controls 140 days after implantation. The operative procedure produced increased tissue water content, declining from the 1 st to the 14th day after operation. Mesh induced additional oedema in adjacent muscle tissue irrespective of localization of the implant (p < 0.01, vs. sham). Except when separated by peritoneum, mesh caused hyperaemia in muscle tissue in direct contact with mesh the 1st and the 4th day after implantation. After 14 and 140 days no mesh-induced hyperaemia was present. The inflammatory response to mesh was similar in the peritoneum and between muscles, less pronounced in the subcutis. It was characterized by the accumulation of macrophages and the formation of inflammatory granulation tissue in the subacute phase, later followed by the formation of fibrous tissue around mesh fibres. This study suggests that mesh implants should be placed in apposition to muscles in order to obtain well-vascularized healing.

Mesh Implants in Hernia Repair

“…Together with highest values of proliferation (PCNA) at both implantation periods in the PP-mesh group, these findings again underline a more pronounced inflammatory reaction and cell turnover around heavy-weight and small-pored PP-mesh implants. This is consistent with other investigations describing an accented foreign body reaction and fibrosis for heavy-weight polypropylene meshes [14,15,31]. Similar to our previous results [16] and to the observed timedependent decrease of the macrophage index (ED3) in this study, the material-reduced (low-weight) PP + PGcompound mesh was accompanied with a lowered inflammatory activity and decreased rates of cell proliferation.…”

Macrophage Response to Experimental Implantation of Polypropylene Prostheses

“…In the Results section, we have men tioned the formation of considerable granulo mas around the polypropylene monofilaments as well as the increase in the number of foreignbody giant cells. This has also been observed by Dabrowiecki et al [8]. Therefore, we do not agree with the results of Law and Ellis [11] who affirm that the Marlex mesh provokes a weak foreign-body reaction between 8 and 22 weeks after being implanted into the abdominal wall of Sprague-Dawley rats.…”

“…Dabrowiecki et al [8], in a similar model using the Sprague-Dawley rat, found a greater number of macrophages on day 7 than on day 14 after implantation. This first decrease in the number of macrophages is presumably due to the progression from the acute phase of scar formation to the chronic phase.…”

“…Our experience has shown that macrophages are indeed present, although they show a tendency to disappear, in contrast to the giant cells which become more abun dant with time. In a study in rats, Dabro wiecki et al [8] found that, after 140 days, the Marlex monofilaments are covered by a layer of epithelioid cells and surrounded by scar tis sue rich in giant cells. By contrast, the number of macrophages falls by 80% with respect to the 2-week stage.…”

Evaluation of healing prosthetic materials polyester mesh resorbable film and collagen elastin matrix /polypropylene used in rabbits abdominal wall defects

“…The reduction of hernia occurrence on the abdominal wall, after mesh introduction, not only stimulated its use in clinical practice but also stimulated experimental studies in search of a material that would produce less adherence, especially when in visceral contact 14,15,16,17 The classical tissue reaction to prosthesis placement in the peritoneal cavity is characterized by intense inflammatory response which results in the disordered collagen deposition around the prosthesis and in the interstice of the prosthesis's fibers. Fibroblastic reaction provokes mesh encapsulation that is denser in the peritoneal face when compared to the interposed face with the subcutaneous tissue.…”