Expanded polytetrafluoroethylene and polypropylene in the repairing of abdominal wall defects in Wistar rats: comparative study

Abstract

PURPOSE: To compare the use of polypropylene and PTFE meshes in the treatment of incisional hernias made experimentally on Wistar rats. METHODS: The experiment used 24 Wistar rats divided into three cohorts: C-A (ressection of a segment of abdominal wall), E-A (ressection and placement of PTFEe mesh), E-B (resection and placement of polypropylene mesh). After 28 days, the mesh and the surrounding tissue were removed and submitted to macroscopic analysis (assessment of the abdominal wall for presence of abscess in the surgical wound and/or skin necrosis, and adhesions) as well as microscopic analysis (presence of fibrosis, necrosis and abscess, counting of macrophages, mononuclears and polymorphonuclears). RESULTS: Adhesions and abscesses in the surgical wound were observed more commonly associated to the group treated with PTFEe. The size of the fibrous tissue was greater in the group treated with polypropylene. Cohort E-A showed PTFEe mesh enveloped by organized fine connective tissue. No groups presented necrosis on the site of the insertion. The highest mononuclear inflammatory reaction occurred in association to PTFEe when compared to the control group, but the findings for the polypropylene mesh were also significant when compared to the control group. In the analysis of the results obtained for cohorts E-A and E-B, a minimal occurrence of polymorphonuclears was noticed in both groups, which indicates low tissue reactivity to both materials used in the present experiment. CONCLUSION: Even with epithelization and proliferation of connective tissue, anchorage between PTFEe and abdominal wall is insufficient, which can result in reherniations.

Fibroplasia after polypropylene mesh implantation for abdominal wall hernia repair in rats

“…In the literature, several studies have assessed the body's reaction to polypropylene mesh implantation, which is widely used for the repair of abdominal wall defects of different etiologies. However, most studies seek to assess the rates of recurrence, infection and inflammatory response, and the presence of adhesions associated with the use of different mesh types available in the market [7][8][9] . According to the literature, since polypropylene mesh acts as a foreign body in the surgical wound, it could cause a prolonged inflammatory response (chronic inflammatory reaction) retarding progression to the proliferative phase of healing, which is responsible for the tensile strength of the scar 8,22,23 .…”

“…Anesthesia was performed using a solution of 10% ketamine chlorhydrate (Ketalar® Agener União 100 mg/ml) and 2% xylazine chlorhydrate (Calmium® Agener União 20 mg/ml), in doses of 100 mg/kg and 10 mg/kg IM, respectively 8,18 .…”

“…Most of these studies seek to determine the rates of recurrence, infection and inflammatory response, and the presence of adhesions associated with the use of different mesh types currently available in the market [7][8][9] .…”

“…It has been shown that the polypropylene mesh becomes intensely covered by dense fibrotic tissue 8 , and that fibrosis results from the local reaction to tissue damage and to the mesh used. The fibroplasia process consists of a harmonious and coordinated sequence of cellular and molecular events which interact to promote the repair and reconstruction of damaged tissue [10][11][12][13] .…”

Análise da rejeição do transplante de aponeurose em coelhos

“…To deal with these wall defects the aim is to achieve the functional and aesthetic recovery of organs and affected tissues (2,3) . In some cases of intestinal and multivisceral transplantation, for example, the abdominal wall closure is a major technical challenge.…”