Abstract:
" Effect of Material Properties on Predicted Vesical Pressure During a Cough in a Simplified Computational Model of the Bladder and Urethra"
Stress urinary incontinence (SUI) arises from involuntary urine loss due to elevated abdominal pressure without active bladder contraction. To probe the underlying biomechanics, we created a simplified three-dimensional finite element model of the bladder, urethra, and supporting pelvic bowl—meshed with hexahedral solid and fluid elements—and driven by time-dependent abdominal pressure data recorded during coughs in continent women. Two sets of tissue definitions were compared: nonlinear hyperelastic (Mooney–Rivlin for bladder, Blatz–Ko for urethra) versus linear elastic properties; a sensitivity study then varied stiffness and compliance of bladder wall, urethra, and support structure. Explicit dynamic simulations in LS-DYNA showed that predicted vesical pressures closely matched urodynamic measurements (within 5 cmH₂O, <10%), regardless of material model. While pressure predictions were insensitive to tissue property variation, resulting displacement patterns and magnitudes (≤2 cm) depended on stiffness changes, underscoring level-dependent biomechanical response. These findings highlight that vesical pressure alone is insufficient as a singular validation metric, but its robustness to uncertain material properties makes it a reliable early criterion for computational model development in urinary tract biomechanics.
