The effect of posterior wall support defects on urodynamic indices in stress urinary incontinence.

OBJECTIVE

To determine if posterior vaginal wall defects affect urodynamic indices and mask stress urinary incontinence.

METHODS

Ninety women with grade 0, 1, 2, or 3 posterior wall defects were evaluated prospectively by complete urodynamics to assess their urinary complaints. None had severe anterior or apical support defects. Urethral pressure profilometry and cough stress test were performed with the posterior wall in the unretracted position and then with the posterior wall retracted using a split speculum. Analysis of covariance was used to compare adjusted mean differences in maximum urethral closure pressure, functional urethral length, and units of leakage volume during the cough stress test in the unretracted and retracted positions among the posterior wall grade groups.

RESULTS

In women with grade 3 posterior wall defects, there were significant changes from the unretracted to the retracted position in maximum urethral closure pressure of -7.0 cm H20, (99% confidence interval [CI] -12.4, -1.6), functional urethral length of -0.3 cm (99% CI -0.5, -0.1), and leak volume units of +0.7 (99% CI 0.4, 1.0) during the cough stress test. There were four women with grade 3 posterior wall defects who demonstrated potential stress incontinence when their posterior wall was retracted.

CONCLUSION

A grade 3 posterior wall defect may artificially raise maximum urethral closure pressure, increase functional urethral length, and mask urinary stress incontinence during a cough stress test. Women with grade 3 posterior wall defects should be tested with the posterior wall retracted during urodynamic evaluation.