A simple fluid-mechanical model for the prediction of the stress-strain relation of the male urinary bladder.

The non-linear, viscoelastic behavior of the male urinary bladder complicates the formulation of suitable stress-strain relations for the quasi-static filling process and the unsteady voiding process. In particular, the voiding process-which, in addition, is affected by contraction of muscles leading to generation of bladder wall tension-makes it difficult to obtain quantitative results. In the present study, a simple model is developed that uses certain urological data from cystometry and uroflowmetry to determine the stress-strain relations of the bladder wall during both filling and voiding.