Elimination of the influence of intravesical pressure on the micturitional urethral pressure profile by calculation of urethral cross-sectional area: an experimental study.

OBJECTIVE

To determine whether it is possible to eliminate the influence of intravesical pressure on the pressure drop recorded between the bladder and prostatic urethra during the micturitional urethral pressure profile (MUPP).

MATERIALS AND

METHODS

An experimental study using an artificial bladder/urethral model and computerized urethral pressure profile measurement system.

RESULTS

By simultaneous measurement of the flow rate and MUPP it is possible to calculate a theoretical cross-sectional area, based on Griffiths' theory of flow through distensible tubes. The calculated cross-sectional area for a given constriction remains the same despite changes in the driving pressure.

CONCLUSION

The effect of changes in intravesical pressure on the MUPP can be eliminated by calculation of the urethral cross-sectional area. This parameter forms part of the Schäfer model of obstruction and this technique may therefore be useful in quantifying bladder outlet obstruction.