A comparison of stress leak-point pressure and maximal urethral closure pressure in patients with genuine stress incontinence.

OBJECTIVE: To determine the correlation between the maximal urethral closure pressure and the stress leak-point pressure in patients with genuine stress incontinence, and to define a critical stress leak-point pressure value to detect patients with a low-pressure urethra, as defined by a maximal urethral closure pressure less than 20 cm H2O.
METHODS: Fifty-nine patients with genuine stress incontinence were evaluated prospectively with multichannel urodynamics. Maximal urethral closure pressures and stress leak-point pressures were determined and correlated. Several stress leak-point pressure values were evaluated by contingency tables to detect a critical level for detecting a low-pressure urethra.
RESULTS: There is a statistically significant relationship (P < .0001) between the stress leak-point pressure and the maximal urethral closure pressure. However, a correlation coefficient of 0.56 demonstrates poor clinical relationship. A stress leak-point pressure less than or equal to 45 cm H2O was found to be 80% sensitive and 90% specific in diagnosing a low-pressure urethra. A stress leak-point pressure less than or equal to 60 cm H2O was 90% sensitive and 64% specific in detecting a low-pressure urethra.
CONCLUSIONS: The stress leak-point pressure has poor clinical correlation to the maximal urethral closure pressure. A stress leak-point pressure less than or equal to 45 cm H2O has adequate sensitivity and specificity to diagnose a low-pressure urethra. A value less than or equal to 60 cm H2O would be an appropriate cutoff level to screen for those patients at risk of having a low-pressure urethra in need of further evaluation.