2006 - UZ Leuven

esistant to degradation, but at 365d half of the implants demonstratedsigns of degradation, the other half remaining intact. We wanted tofollow up the latter process in a 2-year follow up study in the rabbitmodel.Material and methods: Four 2.5 x 2.5 cm full thickness abdominal walldefects were created in 8 New Zealand rabbits, resulting in 32 implantsites. In a random fashion the defects were primarily closed with oneeither Prolene (Ethicon), SIS or Pelvicol. At 545 and 720 days fourrabbits were sacrificed providing minimally 5 implants for eachmaterial and for each time group. The macroscopic appearance of theimplant was noted and freshly harvested explant strips (1 cm wide)were tested by tensiometry (Instron). Microscopic evaluation consistedof quantification of polymorphonuclear cells, mononuclear cells(MNC), foreign body giant cells and newly formed vessels onHematoxylin and Eosin (H&E) and Movat stained parafin sections.Results: Three of the 8 rabbits, all from the 545 group, died fromunknown reasons, before sacrifice could take place. Macroscopically80% of all Pelvicol implants remained nearly intact except that thematerial showed 3 to 4 bursts spread over the implant area and half ofthem. These implants felt hard, rigid and stiff. The remaining 20%Pelvicol implants had a moth-eaten aspect with 90% of the meshsurface remaining intact. SIS implants were macroscopically notrecognisable anymore and replaced by a connective tissue scar. Ontensiometry all biopsies were tearing at the interface with nosignificant difference in strength between the different materials. Therewere two clinical herniation sites at sacrifice, one in the SIS (545d)and Pelvicol (545d) group. Pelvicol explants showed a strong chronicinflammatory infiltrate (100 MNC/hpf), limited to the interface. Theconnective tissue deposition was parelleling the implant(encapsulation), except from rare small islands of connective tissueinvading the implant. SIS was entirely replaced by slightly organisedconnective tissue consisting of collagen, fat and muscle tissue withalmost no inflammatory cells (5MNC/hpf). Prolene explants had amilder chronic inflammatory cell infiltrate (10MNC/hpf) and fibrosiswith an intermediately dens collagen deposition.Conclusion: Pelvicol implants remain virtually intact up to two yearsafter implantation. They are encapsulated by the host but become stiffand non compliant. SIS is entirely replaced by a mix of connectivetissue.CLAES H., VAN POPPEL H.: Thoughts and views on erectiledysfunction in the 50+ population in Belgium. Eur. Urol. Suppl., 2006;5(2): 102 (320).133