Ureteral tunnel length versus ureteral orifice configuration in the determination of ureterovesical junction competence: A computer simulation model

Villanueva, Carlos; Tong, Junfei; Nelson, Carl A.; Gu, Linxia

doi:10.1016/j.jpurol.2018.01.009

Cited by 15 publications

(5 citation statements)

References 13 publications

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“…They additionally may explain that shorter tunnel lengths with ratios less than 5:1 are still capable of preventing reflux when this is all that is available surgically. These findings somewhat oppose that of Villueneva et al who found that the length‐to‐diameter ratio had minimal effect on closure 16,17 . We attribute this difference mainly to the fact that they consider the pressure as a primary factor for UVJ closure as opposed to the deformation of the bladder wall.…”

Section: Discussioncontrasting

confidence: 88%

“…These findings somewhat oppose that of Villueneva et al who found that the length-to-diameter ratio had minimal effect on closure. 16,17 We attribute this difference mainly to the fact that they consider the pressure as a primary factor for UVJ closure as opposed to the deformation of the bladder wall.…”

Section: Discussionmentioning

confidence: 99%

“…The FE model we developed does not take into consideration many other contributing factors to the UVJ function. Specifically, this single layer model does not acknowledge the effects of the highly elastic mucosa, 20 UO configuration, 2,17 and the UO's association with the trigone. 21,22 This also does not explain the success of suburetereic injection bulking agents that alter UO configuration more than the length-to-diameter ratio.…”

Section: Discussionmentioning

confidence: 99%

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The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation

Kalayeh

Fowlkes

Schultz

et al. 2020

Neurourology and Urodynamics

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Aims: Paquin asserts that in order for ureterovesical junctions (UVJs) to prevent reflux, the ureteral tunnel length-to-diameter ratio needs to be 5:1. We hypothesize that the surgical implementation of this observation results in an overestimation of the needed length-to-diameter ratio to prevent vesicoureteral reflux. Methods: With finite elements, we model the urine storage phase of the bladder under nonlinear conditions. In the reference state, the bladder is assumed to be a sphere with an oblique straight elliptical hole as the UVJ. Broad parametric studies on different length-to-diameter ratios are performed as the bladder volume increases from 10% to 110% capacity. Results: The capability of the UVJ to prevent reflux during storage depends on its length-to-diameter ratio. UVJs with larger length-to-diameter ratios lengthen and narrow as the bladder volume increases, causing the closure of the UVJ and rise in its flow resistance. Our model shows that the UVJ length-to-diameter ratio decreases as the bladder volume increases. The 5:1 ratio implemented at 80% capacity-approximate volume or bladder wall stretch during ureteroneocystostomy (UNC)-corresponds to 7:1 at the reference state-used by Paquin. The 5:1 ratio implemented at the reference state corresponds to 3:1 at 80% capacity. Conclusions: Our modeling results are consistent with Paquin's original observation on the significance of the UVJ length-to-diameter ratio in preventing reflux. They, however, indicate that the surgical implementation of this rule during UNC results in an overestimation of the requisite tunnel length-todiameter ratio to prevent reflux. They also suggest that the UVJ closure is due to the bladder wall deformation rather than the pressure.

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Section: Discussioncontrasting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation

Kalayeh

Fowlkes

Schultz

et al. 2020

Neurourology and Urodynamics

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“…To include further components of the urinary system, one may also prescribe a BC to include the functionality of UVJ, which acts like a valve to close the ureter during the voiding phase and prevent reflux (Juskiewenski et al, 1984). Villanueva et al (2015Villanueva et al ( , 2018 studied the UVJ competence, where the ureter wall is modeled as a viscoelastic material after Yin and Fung (1971). The pressures needed to collapse the ureter tube with different diameter, wall thickness, and length are studied.…”

Section: Fluid-structure Interaction Modelsmentioning

confidence: 99%

Fluid mechanical modeling of the upper urinary tract

Zheng

Carugo

Mosayyebi

et al. 2021

WIREs Mechanisms of Disease

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The upper urinary tract (UUT) consists of kidneys and ureters, and is an integral part of the human urogenital system. Yet malfunctioning and complications of the UUT can happen at all stages of life, attributed to reasons such as congenital anomalies, urinary tract infections, urolithiasis and urothelial cancers, all of which require urological interventions and significantly compromise patients' quality of life. Therefore, many models have been developed to address the relevant scientific and clinical challenges of the UUT. Of all approaches, fluid mechanical modeling serves a pivotal role and various methods have been employed to develop physiologically meaningful models. In this article, we provide an overview on the historical evolution of fluid mechanical models of UUT that utilize theoretical, computational, and experimental approaches. Descriptions of the physiological functionality of each component are also given and the mechanical characterizations associated with the UUT are provided. As such, it is our aim to offer a brief summary of the current knowledge of the subject, and provide a comprehensive introduction for engineers, scientists, and clinicians who are interested in the field of fluid mechanical modeling of UUT. This article is categorized under: Cancer > Biomedical Engineering Infectious Diseases > Biomedical Engineering Reproductive System Diseases > Biomedical Engineering

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“…Following ureteral reimplantation, achieving ureteric access for retrograde diagnostic and therapeutic manoeuvres (such as, for example, in cases of urolithiasis, urothelial cancer or ureteral stenosis) may be challenging or even impossible. In fact, the location and shape of the ureteral neo-orifice, as well as the characteristics of the intravesical tunnel (in antireflux techniques), may be at the basis of anatomical alterations of the ureterovesical neojunction that hinder retrograde manoeuvres 3. In these cases, antegrade ureteroscopy may represent an intermediate step before proceeding to more invasive, transabdominal approaches 4…”

Section: Introductionmentioning

confidence: 99%

Antegrade left ureterolithotripsy in a patient with previous psoas-hitch ureteral reimplantation

et al. 2022

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A standard surgical treatment of distal ureteric defects is represented by the ureteroneocystostomy-ureteric reimplantation. However, the procedure involves an anatomical alteration of the ureterovesical (neo)junction that often hinders the retrograde catheterisation of the reimplanted ureter.We describe a case of antegrade ureterolithotripsy (AULT) in a psoas-hitch reimplanted ureter. A woman with severe left hydronephrosis supported by a subcentimetric proximal ureteral stone in a psoas-hitch reimplanted ureter was referred to our unit. Retrograde ureteroscopy was unsuccessful due to impossibility in incannulating the ureteral neo-orifice. Following the placement of a percutaneous nephrostomy, percutaneous AULT through ureteral sheath was successfully performed with complete treatment of the stone.AULT may represent a viable alternative in the management of ureteral stones when the upper urinary tract is not amenable to retrograde ureteroscopy. In experienced hands, the procedure is straightforward and may avoid the adoption of transabdominal approaches.

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Ureteral tunnel length versus ureteral orifice configuration in the determination of ureterovesical junction competence: A computer simulation model

Cited by 15 publications

References 13 publications

The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation

The 5:1 rule overestimates the needed tunnel length during ureteral reimplantation

Fluid mechanical modeling of the upper urinary tract

Antegrade left ureterolithotripsy in a patient with previous psoas-hitch ureteral reimplantation

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