A double J stent (DJS) is used to alleviate the congestion of urine in the upper urinary tract when there is ureteral stenosis, which causes the interruption of normal urine flow and results in renal failure. The purpose of placing DJSs is to ensure sufficient urine flow in the ureter, but the DJS acts as a foreign body in the urinary system and sometimes acts as an obstacle in achieving sufficient urine flow. Here, to evaluate the performance of various sizes of DJSs, 5Fr (1.666 mm) to 8Fr (2.666 mm), in the ureter, silicon ureter models without stenosis, and a circulation setup were constructed. The total flow rates (TFRs) in the stented ureters were evaluated with an in vitro experiment. The TFRs in the 5Fr DJS were larger than those in the other sizes of DJS. As the size of DJS increased, the TFR decreased. Computational fluid dynamics was also applied to validate the experimental results. It was shown that the experimental results agreed well with the numerical results.

中文翻译：

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在体外输尿管模型中使用各种尺寸的双J支架进行尿流分析。

当存在输尿管狭窄时，使用双J支架（DJS）缓解尿液在上尿路的充血，这会导致正常尿流中断并导致肾衰竭。放置DJS的目的是确保输尿管中有足够的尿流，但是DJS在泌尿系统中起异物的作用，有时还成为实现足够尿流的障碍。在这里，为了评估5Fr（1.666 mm）至8Fr（2.666 mm）各种尺寸DJS的性能，在输尿管中，构建了没有狭窄的硅输尿管模型，并建立了循环装置。带支架输尿管中的总流速（TFR）通过体外实验进行评估。5Fr DJS中的TFR大于其他大小的DJS中的TFR。随着DJS大小的增加，TFR减小。计算流体动力学也被用于验证实验结果。结果表明，实验结果与数值结果吻合良好。