Failure of ureteral stents subject to extrinsic ureteral obstruction and stent occlusions.

Autor: Amitay-Rosen T; Department of Physical Chemistry, Institute for Biological Research, 7410001, Ness-Ziona, Israel.; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel., Nissan A; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel., Shilo Y; Department of Urology, Kaplan Medical Center, 7661041, Rehovot, Israel., Dror I; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel., Berkowitz B; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel. brian.berkowitz@weizmann.ac.il.
Jazyk: angličtina
Zdroj: International urology and nephrology [Int Urol Nephrol] 2021 Aug; Vol. 53 (8), pp. 1535-1541. Date of Electronic Publication: 2021 Feb 17.
DOI: 10.1007/s11255-021-02810-0
Abstrakt: Purpose: To quantify the occurrence of stent failure and the dynamic behavior of urine flow in ureter-stent systems, including the relative flow in the ureter and stent lumina, subject to various degrees of ureter and stent blockage.
Methods: Numerical simulations based on computational fluid dynamics (CFD) were used to quantify urine flow behavior in stented ureters, in the presence of extrinsic ureteral obstruction (EUO) and stent occlusions. Two stented ureter configurations were considered, one with circumferential occlusion of the ureter and the second with pressure on one side of the ureter wall. The pressure within the renal unit for different degrees of ureter closure and stent lumen occlusion was determined systematically. Onset of stent failure and the distribution of urine flow between stent and ureter lumina were determined.
Results: In the case of EUO completely encircling the ureter, causing 100% obstruction of the ureter lumen, pressure in the renal unit is essentially unaffected until the stent lumen reaches ~ 90% occlusion, and fails only with > 95% occlusion. Occlusions of 50% in stent side holes in the vicinity of the EUO only alter local flow patterns but have no significant influence on renal unit pressure. For EUO deforming and compressing the ureter from one side, with ~ 50% reduction in ureter lumen, urine drainage proceeds with negligible increase in renal pressure even with 100% occlusion in the stent lumen.
Conclusion: CFD simulations show that stent failure under EUO tends to occur suddenly, only when both ureter and stent lumina become almost fully blocked.
(© 2021. The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.)
Databáze: MEDLINE
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