Investigating the Flow Dynamics in the Obstructed and Stented Ureter by Means of a Biomimetic Artificial Model

Clavica, Francesco; Zhao, Xuefeng; ElMahdy, Motaz; Drake, Marcus; Zhang, Xunli; Carugo, Dario

doi:10.1371/journal.pone.0087433

Cited by 45 publications

(62 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This higher friction might create a pressure loss, which reduces the flow outside the stent. Therefore, we account that urine flow dynamics is a more complex mechanism than only a difference in stent and ureter diameters, as observed in the work of Clavica et al We observed indeed that the used procedures here lead to results (i.e., encrustation compositions and morphologies of the crystals found on the stent surfaces) similar to what reported in other in vitro case studies . In addition, the obtained data seem to well simulate the behavior of what reported in real‐case in vivo studies and in particular for even longer indwelling times of the stents .…”

Section: Discussionsupporting

confidence: 87%

Ureteral double‐J stents performances toward encrustation after long‐term indwelling in a dynamic in vitro model

et al. 2016

View full text Add to dashboard Cite

Three different single-lumen double-J ureteral stents of different materials were studied and compared after the insertion into a dynamic in vitro model with sterile artificial urine up to 6 months. The aim was to evaluate, at selected time steps of 1, 3, and 6 months, the material performances of the stents in preventing the formation of inorganic encrustations. Morphological, compositional, and qualitative analyses were carried out both before stent insertion and after stent permanence for the different time steps, showing an increasing level of encrustation which remains particularly low in the case of two polyurethane stents. Mechanical tests show that both the polyurethane stents and the chitosan one do not decrease the tensile strength after 6 months of indwelling. Evaluation of the wetting behavior of the stent outer surfaces indicates a hydrophilic behavior in most of the cases, which is generally preserved after immersion in artificial urine for the different time steps. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2244-2253, 2017.

show abstract

Section: Discussionsupporting

confidence: 87%

Ureteral double‐J stents performances toward encrustation after long‐term indwelling in a dynamic in vitro model

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The volumetric inlet flow rate was set to 1 mL•min −1 , while a 0 gauge pressure boundary condition was imposed at the device outlet. The imposed value of volumetric flow rate was chosen to replicate a physiologically relevant condition, in accordance with previous studies [20][21][22][23]. A no-slip boundary condition was set at the channel walls.…”

Section: Cfd Simulations Of the Flow Field Within Soc Modelsmentioning

confidence: 99%

A Microfluidic-Based Investigation of Bacterial Attachment in Ureteral Stents

et al. 2020

Self Cite

View full text Add to dashboard Cite

Obstructions of the ureter lumen can originate from intrinsic or extrinsic factors, such as kidney stones, tumours, or strictures. These can affect the physiological flow of urine from the kidneys to the bladder, potentially causing infection, pain, and kidney failure. To overcome these complications, ureteral stents are often deployed clinically in order to temporarily re-establish urinary flow. Despite their clinical benefits, stents are prone to encrustation and biofilm formation that lead to reduced quality of life for patients; however, the mechanisms underlying the formation of crystalline biofilms in stents are not yet fully understood. In this study, we developed microfluidic-based devices replicating the urodynamic field within different configurations of an occluded and stented ureter. We employed computational fluid dynamic simulations to characterise the flow dynamic field within these models and investigated bacterial attachment (Pseudomonas fluorescens) by means of crystal violet staining and fluorescence microscopy. We identified the presence of hydrodynamic cavities in the vicinity of a ureteric occlusion, which were characterised by low levels of wall shear stress (WSS < 40 mPa), and observed that initiation of bacterial attachment occurred in these specific regions of the stented ureter. Notably, the bacterial coverage area was directly proportional to the number of cavities present in the model. Fluorescence microscopy confirmed that the number density of bacteria was greater within cavities (3 bacteria·mm−2) when compared to side-holes of the stent (1 bacterium·mm−2) or its luminal surface (0.12 bacteria·mm−2). These findings informed the design of a novel technological solution against bacterial attachment, which reduces the extent of cavity flow and increases wall shear stress over the stent’s surface.

show abstract

“…A few studies have reported a numerical simulation of urine flow in a straight, stented ureter model [4][5][6][7][8], while other studies have analyzed urine flow in a curved, stented ureter model [9,10] were performed for mild or no ureteral stenosis, and they demonstrated that the flow through the side holes either could not be visualized or was very small. However, the studies did not evaluate the flow through the side holes in a stented ureter model for various severities of ureteral stenosis.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of urine flow through the side holes of a double J stent in a ureteral stenosis

Kim

Choi

Lee

et al. 2017

THC

View full text Add to dashboard Cite

Ureteral stenosis presents with a narrowing in the ureter, due to an intrinsic or extrinsic ureteral disease, such as ureter cancer or retroperitoneal fibrosis. The placement of a double J stent in the upper urinary system is one of the most common treatments of ureteral stenosis, along with the insertion of a percutaneous nephrostomy tube into the renal pelvis. The effect that the side holes in a double J stent have on urine flow has been evaluated in a few studies using straight ureter models. In this study, urine flow through a double J stent's side holes was analyzed in curved ureter models, which were based on human anatomy. In ureteral stenosis, especially in severe ureteral stenosis, a stent with side holes had a positive effect on the luminal and total flow rates, compared with the rates for a stent without side holes. The more side holes a stent has, the greater the luminal and total flow rates. However, the angular positions of the side holes did not affect flow rate. In conclusion, the side holes in a double J stent had a positive effect on ureteral stenosis, and the effect became greater as the ureteral stenosis became more severe.

show abstract

Investigating the Flow Dynamics in the Obstructed and Stented Ureter by Means of a Biomimetic Artificial Model

Cited by 45 publications

References 38 publications

Ureteral double‐J stents performances toward encrustation after long‐term indwelling in a dynamic in vitro model

Ureteral double‐J stents performances toward encrustation after long‐term indwelling in a dynamic in vitro model

A Microfluidic-Based Investigation of Bacterial Attachment in Ureteral Stents

Numerical analysis of urine flow through the side holes of a double J stent in a ureteral stenosis

Contact Info

Product

Resources

About