Evaluation of pressure transmission ratios in women with genuine stress incontinence and low urethral pressure: a comparative study.

OBJECTIVE

To determine whether women with genuine stress incontinence and low urethral closure pressure (20 cm H2O or lower) had more severely impaired pressure transmission to the urethra than women with stress incontinence and normal urethral pressures.

METHODS

Seventy-six women who underwent multichannel urodynamic testing were included for comparative analysis. They were classified into the following groups: genuine stress incontinence with low urethral pressure (N = 20), genuine stress incontinence without low urethral pressure (N = 32), and continent controls (N = 24). Urodynamic indices and pressure transmission ratios were calculated from static and stress urethral pressure profiles, respectively. Multiple demographic cofactors, urethral mobility, and previous surgeries were correlated for associations with urodynamic results.

RESULTS

Women with stress incontinence and low urethral pressure were significantly older (57.6 years, P < .0071). There were no differences with regard to urethral mobility and previous surgeries. Mean maximum urethral closure pressure and the distance from the proximal margin of the urethra to the point of maximum urethral closure pressure were statistically less in women with low urethral pressure. There were no differences in pressure transmission ratios between any of the study groups.

CONCLUSION

Because there are no differences in pressure transmission ratios between women with genuine stress incontinence with and without low urethral closure pressure, the higher risk for surgical failure with low urethral pressure appears to result from another pathophysiologic process.