Page 236 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 11
the speci c type of mesh. Fibrosis, lymphocyte in ltration and angiogenesis were scored macroscopically at 200× magni cation using a light microscope (Olympus, Center Valley, Pennsylvania, USA). The following grading scale was used: 0, none present; 1, little; 2, moderate; and 3, extensive. The picrosirius red-stained sections were analysed for collagen and scored by means of the same scale for the presence of collagen around the mesh and abdominal wall.
Statistical analysis
Results are presented as median (interquartile range). Mesh infection, tenacity and percentage of adhesions, histological score, abscess formation, survival and weight were compared using Kruskal–Wallis, Mann–Whitney U, χ2 and Fisher’s exact tests as the data did not show a normal distribution. If the overall test showed di erences, pairwise tests were done to determine the groups causing the overall signi cance. Exact methods for signi cance were used when computational limits allowed these. All reported P values are two-sided and P < 0.050 was considered statistically signi cant. In view of the numbers, it was not possible to adjust the P values using Bonferroni’s correction. Statistical analysis was performed using PSAW® statistical software package version 17 (IBM, Armonk, New York, USA).
Results
During the rst 2 days of the experiment 22 (15.3%) of the 144 rats died. Necropsy was performed and septicaemia was found to be the cause of death in all rats (Table 1). On day 13 one rat in the C-Qur® group died from intestinal obstruction due to severe adherence of the bowel to the infected mesh. Abdominal cultures on day 1 con rmed bacterial contamination in all animals with Gram-positive (Enterococcus, Staphylococcus, Streptococcus) and Gram-negative (Escherichia coli and Proteus) microorganisms. All animals exhibited symptoms of sepsis including apathetic behaviour, ocular exudates, piloerection, diarrhoea and weight loss. The maximum percentage weight loss varied between 11.1 and 14.2%, and was more pronounced in the C-Qur® group (P ≤ 0.048 compared with other groups).
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