Urine Flow Dynamics Through Prostatic Urethra With Tubular Organ Modeling Using Endoscopic Imagery

Abstract

Voiding dysfunction is common in the aged male population. However, the obstruction mechanism in the lower urinary tract and critical points for obstruction remains uncertain. The aim of this paper was to develop a system to investigate the relationship between voiding dysfunction and alteration of the shape of the prostatic urethra by processing endoscopic video images of the urethra and analyzing the fluid dynamics of the urine stream. A panoramic image of the prostatic urethra was generated from cystourethroscopic video images. A virtual 3-D model of the urethra was constructed using the luminance values in the image. Fluid dynamics using the constructed model was then calculated assuming a static urethra and maximum urine flow rate. Cystourethroscopic videos from 11 patients with benign prostatic hyperplasia were recorded around administration of an alpha-1 adrenoceptor antagonist. The calculated pressure loss through the prostatic urethra in each model corresponded to the prostatic volume, and the improvements of the pressure loss after treatment correlated to the conventional clinical indices. As shown by the proposed method, the shape of the prostatic urethra affects the transporting urine fluid energy, and this paper implies a possible method for detecting critical lesions responsible for voiding dysfunction. The proposed method provides critical information about deformation of the prostatic urethra on voiding function. Detailed differences in the various types of relaxants for the lower urinary tract could be estimated.

Prostatic collagen architecture in neutered and intact canines

“…In the resting state, the lumen of the prostatic urethra is collapsed. Micturition causes the urethra to expand and accommodate urine passage . A lack of urethral compliance due to urethral fibrosis could underlie the obstructive phenotype seen in some men with LUTS.…”

“…Micturition causes the urethra to expand and accommodate urine passage. 26 A lack of urethral compliance due to urethral fibrosis could underlie the obstructive phenotype seen in some men with LUTS. Our study did not find any changes in urethral collagen with age or castration, however changes in urethral collagen could be specific to human, or only occur in the most severe LUTS cases.…”

Experimental investigation of the biomechanics of urethral tissues and structures

“…Experimental investigation on humans is complex and must take into account an extended group of subjects of similar age, body conformation and health conditions. At present, experimental testing on human urethrae is performed in vivo (Griffiths, 1971a,b;Thind, 1995;Bagi et al 2002;Comiter et al 2003;Mijailovich et al 2007;Ishii et al 2014).…”

Role for intravesical prostatic protrusion in lower urinary tract symptom: a fluid structural interaction analysis study

“…Diameter for prostatic urethra during voiding process was a parameter paramount for accurate simulation. The value should be between 1 mm and the diameter of anterior urethra [ 14 ]. Five candidate diameters (1, 1.5, 2, 3 and 4 mm) were proposed for initial diameter of prostatic urethra (d prostate ).…”