Page 235 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

5. Carboxymethylcellulose–sodium hyaluronate coated polypropylene (Sepramesh®; Bard, New Providence, New Jersey, USA)
6. Expanded polytetra uoroethylene (PTFE) (Dualmesh®; Gore, Flagsta , Arizona, USA)
7. Condensed PTFE (Omyramesh®; B. Braun)
Measurements
Half of the surviving animals were killed after 28 days and half after 90 days. The abdomen was shaved, disinfected and opened through a U-shaped incision extending laterally and caudally to the mesh. Directly after opening the abdomen, a swab of the abdominal cavity was taken for culture. Mesh infection was de ned as the presence of abscesses of the mesh, and parts of the mesh were cultured for microbiological evaluation. Adhesions were scored using a grid placed over the mesh, dividing it into 30 equal squares. The tenacity of the adhesions was graded using the Zühlke score, a four-degree classi cation of adhesions based on histological and morphological criteria(13). Pictures of the abdominal wall with mesh and any adhesions were taken with a 5.0-megapixel digital camera. The abdominal cavity was inspected for abscesses; when present, these were scored and cultured at four sites: the liver, abdominal wall, bowel and omentum(14). Mesh incorporation was de ned as the percentage of the mesh edge incorporated into the abdominal wall, taking into account any shrinkage. Shrinkage was de ned as the relative loss of surface compared with the original size of the mesh, measured with a caliper. The animals were killed by cardiac cut. All measurements were carried out by two independent observers and disagreements reconciled by discussion.
Histological evaluation
At least two representative samples of macroscopically non infected meshes with adjacent abdominal wall were excised by full-thickness (mesh and abdominal wall muscle) biopsy punches of 5 mm diameter. The samples were embedded in Tissue-Tek® (Sakura, Alphen aan den Rijn, The Netherlands) and immediately frozen in liquid nitrogen. Frozen sections of 6 μm were made using a cryostat (Leica; Davis Instruments, Vernon Hills, Illinois, USA). Sections were stained with either haematoxylin and eosin or picrosirius red (Direct Red 80; Fluka Chemie, Zwijndrecht, The Netherlands)(15). Samples were assigned a random number before evaluation and scored by two observers blinded to
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Meshes in a contaminated environment
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