Page 224 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 10
supported by our study showing major alterations in the results after 90 days compared with 30 days. The amount of adhesion formation to the Strattice and the Prolene meshes was signi cantly diminished, whereas the extent of adhesions to the Surgisis mesh increased at 90 days.
The fact that the anti-adhesive collagen layer of the Parietex composite mesh is absorbed within 30 days is not congruent with our ndings that very few adhesions on this mesh occur even in the long term(28). These data support recent long-term studies in which Parietex composite resulted in minimal adhesion formation(29, 30). The mechanism of this phenomenon is not completely understood, but perhaps the formation of a new mesothelial layer plays a pivotal role in this process. Histologic examination of tissue samples after H&E supports this hypothesis showing a new mesothelial layer on the Parietex composite and Strattice meshes. On Permacol mesh, a new mesothelial layer was alternating with a small brous layer, the latter most probably the result of adhesion formation.
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 su cient incorporation, although Petter- Puchner et al.(31) showed that macroscopic perforation of di erent biologic meshes did not improve incorporation. At 30 days, no signi cant di erences 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 signi cantly higher percentage of incorporation than Strattice, Prolene, or 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 or adhesion formation at all, with less shrinkage.
Further analysis showed a signi cant correlation between incorporation and adhesion formation. The cause of this 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 also can induce the formation of adhesions on the visceral side because this mesh does not have a speci c anti-adhesive layer. As a consequence, limited adhesion formation goes with insu cient incorporation.
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