Page 104 - Postoperative Intra-Abdominal Adhesions- New insights in prevention and consequences

Chapter 6
Incorporation
Mesh incorporation was defined as the amount of the mesh edge (in millimetres) incorporated into the abdominal wall as a percentage of the circumference. In case of interobserver variance, the mean was scored.
Mesh shrinkage
Mesh shrinkage was defined as the projection of the mesh surface and measured with a calliper by two independent observers. By measuring projection, curling and wrinkling of the mesh were included in addition to the actual size of the mesh. Shrinkage was defined as the relative loss of surface (%) compared with the original size of the mesh.
Tissue reaction
For each group, five meshes with the adjacent abdominal wall were fixed in 4% neutral buffered formalin. After routine tissue processing, sections were cut and stained with hematoxylin and eosin (HE) or picrosirius red (PSR).
H&E staining
Paraffin sections were dewaxed and stained with hematoxylin (Sigma- Aldrich, Germany). After washing in tap water and demiwater, the sections were stained with eosin (Sigma-Aldrich, Germany). Subsequently the sections were dehydrated in alcohol and xylene and mounted with Entallan (Merck, Darmstadt, Germany). Slides were analyzed with a light microscope (Olympus, Tokyo, Japan).
Picrosirius red staining
Paraffin sections were dewaxed, rehydrated and stained with 0.1% Sirius Red F3BA (Direct Red 80; Fluka Chemie, Zwijndrecht, The Netherlands) in a saturated picric acid solution for 1 h. Brief washing in 0.1% acetic acid was followed by rapid dehydration in 100% alcohol. After a xylene bath slides were mounted with Entellan (Merck, Darmstadt, Germany). Subsequently they were analyzed using a polarized light microscope (Olympus, Japan) with polarization filters, whereby the collagen fibers show birefringence. This technique allows visualization of the orientation of collagen fibers giving an indication for the amount of collagen new formation [23].
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