TY - JOUR TI - Viscoelastic property mapping along encrusted polymeric urinary catheters AU - Mouzakis, Dionysios E. AU - Bouropoulos, Nikolaos AU - Kallidonis, AU - Panagiotis AU - Karnabatidis, Dimitrios AU - Katsanos, Konstantinos and AU - Constantinidis, Constantinos AU - Perimenis, Petros AU - Siamblis, AU - Dimitrios AU - Liatsikos, Evangelos N. JO - Journal of Endourology Case Reports PY - 2008 VL - 22 TODO - 8 SP - 1761-1769 PB - MARY ANN LIEBERT INC PUBL SN - null TODO - 10.1089/end.2007.0423 TODO - null TODO - Purpose: Mapping of the material viscoelastic property variation along the length axis of polymeric stents. Materials and Methods: Five pigtail ureteral stents and five percutaneous stents placed in vivo for different periods were studied. Viscoelastic property changes along the length of polymeric stents were measured using the dynamic mechanical analysis technique. The type of encrustations was identified using FT-IR spectroscopy and their morphology by scanning electron microscopy (SEM). Results: Variations in viscoelastic stiffness were confirmed for both types of stents. In a few cases, the variation was quite large (400%). Various encrustation types and/or organic sheathing of the salt were found to be responsible for this effect. In detail, calcium oxalate monohydrate (COM) plaques for percutaneous and COM/organic layer for pigtail stents were recognized by FT-IR spectroscopy and SEM observation to invoke reinforcing effects along the stent axes. Conclusions: The phenomenon of stiffness variation along the stent axes requires further study to understand the mechanism behind it and consequently to improve the biomaterial and design of specific areas of stents as well as to avoid encrustations. This further research might lead in the near future to the development of new types of polymer stents for drug-eluting specialized areas. ER -