Pressure-to-cross-sectional area relationships in the proximal urethra of men with bladder outlet obstruction.

ABSTRACT

PURPOSE: Related values of pressure and cross-sectional area in the proximal urethra were measured in patients with bladder outlet obstruction. Urethral opening pressure and elastance (the inverse of compliance) were estimated. MATERIALS AND METHODS: We studied 15 men with standard urodynamic examinations. The pressure-to-cross-sectional area relationship in the prostatic urethra was determined using a special probe. RESULTS: Elastance varied significantly along the studied portion of the urethra, with higher values found in the sphincter area. The estimated urethral opening pressure appeared high compared to that in unobstructed cases and without variation along the prostatic urethra. CONCLUSIONS: The most important effect of prostatic obstruction appears to be the increased urethral opening pressure.