Computational fluid dynamics analysis of ureteral constrictions: Impact on flow dynamics and potential clinical implications

This study investigated the effects of anatomical constrictions on ureteral flow dynamics using computational fluid dynamics (CFD). Constrictions such as those at the ureteropelvic junction (UPJ), vesicoureteral junction (VUJ), and external compression by the iliac artery are common clinical issues associated with significant morbidity. However, their impact on ureteral fluid flow remains insufficiently understood. Using patient-specific computed tomography (CT) data, a constant-diameter ureter model was reconstructed. Three constriction scenarios—UPJ, VUJ, and iliac artery compression—were developed and incorporated into this baseline model. CFD simulations were conducted in ANSYS CFX to evaluate flow patterns, pressure distribution, velocity profiles, and wall shear stress in both normal and constricted geometries. Results showed clear deviations in constricted models compared to the constant-diameter ureter, including localized upstream pressure increases and elevated flow velocities within narrowed regions. These findings provide quantitative insight into altered ureteral fluid dynamics and their role in conditions such as hydronephrosis and ureteral calculi. Overall, this study demonstrates the value of CFD in analyzing ureteral flow physiology and supports its potential for improving clinical diagnosis, prediction, and development of targeted therapeutic interventions for ureteral obstructions.