A Numerical Study to Precise the Estimation of the “Good” Mound Height in Endoscopic Treatment of VUR

Mehdi Shirazi,Alireza Mehdizadeh,Mojtaba Taherisadr,Zahra Jahanabadi,Zeinab Hooshyar,Zahra Mortazavinia

doi:10.4236/jbise.2014.711091

Mehdi Shirazi, Alireza Mehdizadeh + Show 4 more

Open Access

https://doi.org/10.4236/jbise.2014.711091

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Abstract

Objective: To ascertain the technique and volume of injection increasing the success rate of endoscopic VUR treatment, we develop a novel method to numerically describe the relationship between intramural ureter anatomy, intravesical pressure, and the theoretical mound height needed for adequate treatment. Methods: The main purpose of this study is to construct a finite element simulation of intramural ureter and injected mound which aims to numerically define the relationship between indexes which have influence in VUR endoscopic treatment. Using linearization software and numerically simulation data, the relationship between effective indexes has been derived. Results: By linearization of the effective parameters of different finite element models, the relationship between effective parameters in filling phase is derived as: H (m) = ﹣0.003467 (m) + 0.7864D (m) + 0.000233. This equation depicts adequate injected mound height as a function of internal diameter and intramural length, H = f(L, D). Conclusion: Using numerical simulation, we introduced the novel formula to predict the height of injected mound in endoscopic VUR treatment. As a result of this study, in order to increasing the success rate of this treatment, the ratio of mound height to intramural ureter diameter should be approximately 78%.

Highlights

Vesico ureteral reflux (VUR) is a major disorder of childhood declared by retrograde urine flow from the bladder toward the kidney, predisposing patients to UTI and renal scarring and in long term leading to renal insufficiency and hypertension [1]
The aim of this study is to develop a novel method to numerically describe the relationship between intramural ureter anatomy, intravesical pressure, and the theoretical mound height needed for adequate treatment
Keeping the intramural ureter length constant by changing the intravesical pressure and internal diameter parameters, the adequate injected mound height leading to tight closure of the intramural ureter was obtained

Summary

Introduction

Vesico ureteral reflux (VUR) is a major disorder of childhood declared by retrograde urine flow from the bladder toward the kidney, predisposing patients to UTI and renal scarring and in long term leading to renal insufficiency and hypertension [1]. The prophylactic antibiotic approach is proper for uncomplicated reflux (grade I-III without significant renal scarring or breakthrough infection) [3]. This type of treatment has some problems such as patient noncompliance and increased antibiotic resistance [4]. Surgical reimplantation of the ureter is an invasive method [5] and already used for patients with high grade reflux, children with breakthrough UTI and children with reflux and developed renal scarring [6]. Endoscopic subureteral injection of bulking agents was introduced by Matouscheck as an evolution in treatment of reflux with a high success rate and minimal invasion [6] [7]. The proper shape was demonstrated by adequate coaptation of the ureteral orifice and by its location in the bladder below the ureteral orifice and/or along the waldeyer’s sheat [12] [13]

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Conclusion