Novel CFD modeling approaches to assessing urine flow in prostatic urethra after transurethral surgery

Bin Zhang,Bo Wu,Xin Wang,Shuang Liu,Dongwen Wang,Xuezhi Liang,Xiaoming Cao,Xuhui Zhang,Chin-Lee Wu,Yinxia Liu

doi:10.1038/s41598-020-79505-6

Abstract

Assessment of the pressure and velocity of urine flow for different diameter ratios of prostatic urethra (RPU) after transurethral surgery using computational fluid dynamics (CFD). A standardized and idealized two-dimensional CFD model after transurethral surgery (CATS-1st) was developed for post-surgery mid-voiding. Using CATS-1st, 210 examples were amplified according to an array of size [3][5][14], which contained three groups of longitudinal diameters of prostatic urethra (LD-PU). Each of these groups contained five subgroups of transverse diameters of the bladder neck (TD-BN), each with 14 examples of transverse diameters of PU (TD-PU). The pressure and velocity of urine flow were monitored through flow dynamics simulation, and the relationship among RPU-1 (TD-PU/TD-BN), RPU-2 (RPU-1/LD-PU), the transverse diameter of the vortex, and the midpoint velocity of the external urethral orifice (MV-EUO) was determined. A total of 210 CATS examples, including CATS-1st examples, were analyzed. High (bladder and PU) and medium/low (the rest of the urethra) pressure zones, and low (bladder), medium (PU), and high (the rest of the urethra) velocity zones were determined. The rapid changes in the velocity were concentrated in and around the PU. Laminar flow was present in all the examples. The vortices appeared and then gradually shrank with reducing RPU on both the sides of PU in 182 examples. In the vortex examples, minimum RPU-1 and RPU-2 reached close to the values of 0.79 and 0.02, respectively. MV-EUO increased gradually with decreasing RPU. In comparison to the vortex examples, the non-vortex examples exhibited a significantly higher (p < 0.01) MV-EUO. The developed CFD models (CATS) presented an effective simulation of urine flow behavior within the PU after transurethral surgery for benign prostatic hyperplasia (BPH). These models could prove to be useful for morphological repair in PU after transurethral surgery.

Highlights

Assessment of the pressure and velocity of urine flow for different diameter ratios of prostatic urethra (RPU) after transurethral surgery using computational fluid dynamics (CFD)
Morphological deformation of prostatic urethra (PU) is a significant factor contributing to benign prostatic hyperplasia (BPH), which leads to voiding dysfunction in elderly males
In the present study, computational fluid dynamics (CFD) modeling focusing on PU was employed to determine the pressure and velocity of urine flow with different diameter ratios of PU (RPU) mid-voiding after transurethral surgery

Summary

Introduction

Assessment of the pressure and velocity of urine flow for different diameter ratios of prostatic urethra (RPU) after transurethral surgery using computational fluid dynamics (CFD). The developed CFD models (CATS) presented an effective simulation of urine flow behavior within the PU after transurethral surgery for benign prostatic hyperplasia (BPH). Abbreviations BN Bladder neck BPH Benign prostatic hyperplasia CATS Two-dimensional CFD model after transurethral surgery CATS-1st Standardized and simplified two-dimensional CFD model after transurethral surgery CFD Computational fluid dynamics LD-PU The longitudinal diameters of prostatic urethra MV-EUO The midpoint velocity of the external urethral orifice PU Prostatic urethra RPU Ratio of prostatic urethra RPU-1 The first diameter ratio of prostatic urethra RPU-2 The second diameter ratio of prostatic urethra RU The rest of the urethra TD-BN The transverse diameters of the bladder neck. In the present study, computational fluid dynamics (CFD) modeling focusing on PU was employed to determine the pressure and velocity of urine flow with different diameter ratios of PU (RPU) mid-voiding after transurethral surgery

Methods

Results

Conclusion