Comparing Five New Polymer Barriers for the Prevention of Intra-abdominal Adhesions in a Rat Model

Background: Intra-abdominal adhesions affect up to 93% of the patients after abdominal surgery, causing small-bowel obstruction, infertility, chronic abdominal pain, and iatrogenic bowel injury at reoperation. The efficacy of five new polymer antiadhesive barriers to avoid adhesion formation is evaluated in an ischemic button model in rats. Materials and methods: Five new, biodegradable polyurethane and copolyester-based, anti-adhesive barriers (A1, A2, A3, B1, and B2) were evaluated in separate experimental groups and compared with two control groups (hyaluronate carboxymethylcellulose barrier and no antiadhesive barrier) in an ischemic button model (n = 11 per group operated). After 14 d, the quantity and quality of the adhesions were scored macroscopically. The Kruskal-Wallis with ManneWhitney U post hoc and the Fisher's exact tests were used for data analysis. The Bonferroni correction method was applied, and a P-value < 0.007 was considered significant. Results: Two animals died during surgery and follow-up. A significant reduction of adhesions to ischemic buttons was found in the A2 group (median, 3.5; interquartile range, 2.25) compared with no adhesive barrier (median, 8.0; interquartile range, 2.0) (P = 0.001). The remaining groups did not differ significantly regarding adhesion quantity or quality. Adverse events were observed in the A2, A3, and B2 groups. Conclusions: The A2 antiadhesive barrier reduced the adhesion formation significantly compared with no anti-adhesive barrier, but applicability is questionable because of extensive adverse events observed due to implantation of the anti-adhesive barrier. The Nair score appears not to be sensitive enough to detect differences in adhesion formation in this model. Future research should focus on anti-adhesive barriers that are self-adhering. (C) 2019 Published by Elsevier Inc.