International urogynecology journal vol:17 pages:171-172
IUGA edition:31 location:Athens, Greece date:2006
Objective: A fast growing range of implants is used in
pelvic floor surgery. Silk, although used for decades, was
never studied as mesh material. We present the data from a
comparison of mesh characteristics between two silk
constructs and a polypropylene mesh.
Materials and Methods: The tested materials were two macroporous constructs of silk with different densities (respectively, 0.000135 and 0.0002 g/mm2, manufactured by BARD and not available on the market) and a standard monofilament type I polypropylene mesh (Surgipro SPMM™,
TycoHealthcare). A rat model for abdominal fascia wall
repair was used. This was done by creating full thickness
abdominal wall defects in 72 male Wistar rats and repairing
these defects with the tested meshes. Animals were sacrificed on day 7, 14, 30 and 90 after implantation. At sacrifice the explants were evaluated macroscopically for infections, herniations and adhesions, mechanically for tensile strength, and histopathologically, to evaluate collagen deposition and inflammatory response.
Results: None of the animals developed herniation or
infection, and seromata were present only at day 7 around
the silk implants. Amount and density of peritoneal
adhesions, initially higher with the silk, progressively
decreased over the time to be comparable for all materials
at 90 days. The tensile strength of the explants showed a
gradual and similar increase for silks and SPMM at all time
points. All implants uniformly shrank around one fifth by
day 90. In the silk implants the inflammatory reaction
showed a remarkable higher number of foreign body giant
cells that characteristically spread from the periphery to the central part of the mesh. Collagen deposition was comparable in amount, composition and organisation for all tested materials. In both of the two silk materials a higher grade of neovascularisation was observed.
Conclusion: The two tested silk constructs induced a
similar level of intraperitoneal adhesions after surgery when compared to a standard macroporous polypropylene mesh.
Tensile strength of the explants was also comparable over
the 3 months observation period. Microscopically this
coincided with a strong foreign body reaction and intense
fibrosis process, that took place deeply between individual
silk filaments, with obvious architectural degradation of the initial construct, a phenomenon not observed in polypropylene explants. Density of the silk material did not appear to affect the mesh characteristics.