Dynamic Simulation of Male Bladder Outlet Obstruction: Flow Characteristics and Novel Quantitative Indicators

Bladder outlet obstruction (BOO) is diagnosed through clinical urodynamics, an invasive method with many limitations, including side effects or surgical complications. This study introduces evaluation strategies for BOO recognition based on uroflowmetry test. In this study, a catheter-free male lower urinary tract (LUT) model was developed for hydrodynamics simulation. The pressure and velocity distributions in urethras with different obstruction degrees were analyzed under a fixed vesical pressure, and the effect of obstruction on urine flow under transient vesical pressure input was investigated. Dynamic analysis revealed that the assignments of urethral pressure and velocity were substantially influenced by the extent and location of obstruction. The global maximum pressure and velocity differences between obstructed and healthy urethra models reached 28.8 cm H2O and 2.41 m/s, respectively, at a constant bladder pressure input of 50 cm H2O. Vortices emerged at different segments along the obstruction, resulting in energy loss in the urine stream. Based on uroflowmetry data from 300 subjects, four dimensionless evaluation parameters were designed to distinguish healthy individuals from those with BOO, with p-values of < 0.001, 0.05, 0.001, and 0.02, respectively. The distributions of pressure, velocity, and vortex provide significant guidance for customized BOO surgery. In addition, the means and indicators of dimensionless evaluation have a crucial contribution to identify male BOO by uroflowmetry examination. Trial Registration: This experiment was certified by the Chinese Clinical Trial Registry (ChiCTR2200063467).