Effect of Bladder Anatomy on Vesicoureteral Reflux Through Computational Modeling

Vesicoureteral reflux (VUR) is a condition common in young children where urine in the bladder flows backward toward the kidneys–allowing for passage of bladder bacteria to the kidneys and potentially resulting in urinary tract infection (UTI) and in severe cases, permanent kidney damage. In this project, using computational techniques, we set out to better understand the effects of different ureterovesical junction (UVJ) anatomical parameters---which cannot be measured non-invasively---on VUR. As a part of this study, we investigate the effect of UVJ deformation during urine storage on VUR using a bladder finite element (FE) model. We dissect the well known 5:1 rule---proposed by Albert Paquin in 1959---stating that for reimplanted UVJs to be able to prevent reflux their length-to-diameter ratio needs to be at least 5 to 1. We then highlight its current surgical implications.

Finite element model of the bladder during urine storage

(a) A three-dimensional domain for the finite element (FE) simulations. (b) The symmetry plane of the FE domain showing different model parameters. The major axis of the ureterovesical junction (UVJ) cross-section, not shown in the figure, is perpendicular to the minor axis. (c) A typical FE mesh and (d) its magnified view around the UVJ.

How the UVJ insertion angle controls its closure during urine storage

The elongation and contraction of the bladder wall in its circumferential and radial directions during urine storage. The deformation of the bladder wall and ureterovesical junction (UVJ) is shown on the symmetry plane for the UVJ initial length‐to‐diameter ratios of 2.5:1, 3:1, 5:1, and 7:1. The finite element simulation results are shown for different bladder volume ratios, as indicated

Related Publications

[1] K. Kalayeh, J. B. Fowlkes, W. W. Schultz and B. S. Sack, “Ureterovesical junction deformation during urine storage in the bladder and the effect on vesicoureteral reflux.,” J Biomech, vol. 113, pp. 110123-110121, 2020. https://www.ncbi.nlm.nih.gov/pubmed/33242822

[2] K. Kalayeh, J. B. Fowlkes, W. W. Schultz and B. S. Sack, “The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation,” Neurourol Urodyn, vol. 40, no. 1, pp. 85-94, 2021. https://www.ncbi.nlm.nih.gov/pubmed/33017072

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