Characteristics and usage of different ureteral stent catheters.

Presuming that complications associated with ureteral stenting vary in type and occurrence depending on the material and cross-section of the stent, six types of stents immersed in 48 different preparations of artificial urine for 1 month to observe surface changes with a scanning electron microscope. As a result, there was less encrustation on the silicone material compared with other material types, probably due to the smoothness of the surface. This may be related with higher frequency of spontaneous removal or migration to the bladder of this catheter type. Because silicone catheters have softer and thicker walls with a narrow lumen, they may be appropriate for long-term stenting, but not for urinary drainage. In alkaline bacteriuria, struvite encrustation was observed on all stents. This reaction was especially intense with Towers peripheral stents, which had most irregular and uneven surfaces. In aseptic alkaline urine, calcium phosphate crystals partly covered with proteinaceous debris were noted on catheter surfaces. Although in some patients encrustation of uric acid occurred in the bladder portion of the stents, there was no uric acid encrustation in this experimental study.