[Approximation of uroflowmetrograms using micturition model]

One hundred and two uroflowmetric curves obtained from adult men were approximated to investigate the individual micturition quantitatively. We obtained a differential equation under the hypothesis that the factors concerned with micturition are the vesical pressure as the driving force and inertia of urine, friction resistance and elasticity of urethra as resistance. Using one of the solutions of this differential equation, we could approximate the uroflowmetric curves for normal and abnormal micturition. Furthermore, we could describe the calculated vesical pressure curve from the differential equation. There was a lag in the phase of the calculated vesical pressure curve against the uroflowmetric curve, which was considered to appear according to the resistance due to both inertia of urine and elasticity of urethra. The mean value of the difference of the calculated vesical pressure during micturition in normal cases was larger than that in abnormal cases. This suggests that it is necessary to maintain a high vesical pressure during micturition in abnormal cases, to maintain a small difference of the vesical pressure. In conclusion, we approximated the uroflowmetric curves, described the calculated vesical pressure curves and estimated them quantitatively.