Page 113 - Postoperative Intra-Abdominal Adhesions- New insights in prevention and consequences

Biological and synthetic meshes in ventral hernia repair
In addition to adhesion prevention on the visceral side of the mesh, a fundamental characteristic of a mesh for intraperitoneal use should be a
good incorporation on the ventral side. A macroporous surface and a (mild)
foreign body reaction might be necessary for sufficient incorporation,
although Petter-Puchner et al showed that macroscopical perforation
of different biological meshes did not improve incorporation[31]. At
30 days no significant differences in incorporation were seen between
the meshes as a result of large variation in all the groups. At 90 days
however, Parietex Composite showed a significantly higher percentage
of incorporation than Strattice, Prolene and Permacol. At this time
point, Surgisis mesh resulted in a wide variation of results regarding
all parameters. Five meshes were well incorporated and completely
covered with adhesions, resulting in excessive shrinkage. In contrast the
other two meshes showed no incorporation and adhesion formation at
all, with less shrinkage. Further analysis showed a significant correlation
between incorporation and adhesion formation. The cause of this 6 correlation is a matter of speculation, although an explanation might be
found in the foreign body reaction. This reaction necessary for ingrowth on the ventral side can also induce the formation of adhesions on the visceral side since this mesh does not have a specific anti-adhesive layer. As a consequence limited adhesion formation goes with insufficient incorporation. The literature clearly shows that Surgisis manifests enhanced shrinkage and is absorbed completely by the body. However, the speed of degradation is a matter of discussion [19, 31-33]. One advantage attributed to biodegradable meshes is their ability to support regeneration of the original tissue, but when the mesh degrades before adequate cellular infiltration, differentiation, collagen deposition, and neo- vascularization, the overall quality and strength of the newly formed tissue probably will be insufficient for abdominal hernia repair [19, 34]. Histological examination of Surgisis after picrosirius red staining showed a transition layer with collagen fibers organised in different directions crossing the border between Surgisis and surrounding tissue. Together with degradation of the mesh this suggests an ongoing remodelling process. Unfortunately, from the results of this study it is not possible to conclude what influence the remodelling process has on the strength of the mesh and underlying tissue.
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