Page 110 - Postoperative Intra-Abdominal Adhesions- New insights in prevention and consequences

Chapter 6
Tissue reaction
At 30 days histological evaluation after hematoxylin and eosin staining of the meshes demonstrated a grade 1 (mild) foreign body reaction to all the meshes except Permacol. This mesh showed a grade 2 inflammatory reaction resulting in a thick fibrous layer between mesh and abdominal wall. Additionally in some cases a fibrous layer was visible on the abdominal side of the mesh, generally combined with strong adhesions (Fig 5).
At 90 days a grade 1 mild foreign body reaction was visible around all meshes, with limited numbers of giant cells and lympocytes present. Parietex Composite meshes showed a larger influx of fibroblasts. Strattice and Parietex Composite showed a new mesothelial layer on the visceral side of the mesh. On the Permacol mesh a new mesothelial layer was alternating with a small layer of fibrous tissue.
Histological samples after picrosirius red staining at 90 days are shown in figure 6. Tissue surrounding the Prolene mesh indicated complete incorporation of the mesh by a layer of collagen around the Prolene fibers. All these collagen fibers have the same orientation and thickness. The collagen layer between mesh and muscles was also highly organized but in a different direction and different thickness since it is mostly of the same colour. In the case of Parietex Composite the mesh was completely covered with collagen in different orientations. Collagen directly surrounding the fibers has a different direction than the collagen of the layer between the mesh and muscles. In particular the layer between material and muscles appeared very organized based on the homogeneity of colour. The collagen fibers of Permacol mesh itself showed a structured orientation of collagen fibers. The mesh and the muscle layer had almost no collagen between themas indicated with a ‘c’ in figure 6. Furthermore, this layer was very organized in one direction. A small layer of collagen with fibers in several different orientations separated Strattice mesh from the abdominal muscles. Surgisis mesh was completely incorporated into connective tissue with collagen fibres crossing the surrounding tissue and the Surgisis mesh (indicated by * in figure 6) .
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