Posterior colporrhaphy does not affect the urethral closure mechanism.

INTRODUCTION AND HYPOTHESIS: Studies have suggested that a posterior vaginal wall prolapse might compress the urethra and mask stress urinary incontinence (SUI), much like an anterior vaginal wall prolapse. A recent study with urethral pressure reflectometry (UPR) has shown that the urethral closure mechanism deteriorates after anterior colporrhaphy; this could explain the occurrence of postoperative de novo SUI. We hypothesized that urethral pressure would also decrease after posterior colporrhaphy.

METHODS: This was a prospective, observational study where women with posterior vaginal wall prolapse ≥stage II were examined before and after posterior colporrhaphy. We performed prolapse staging according to the Pelvic Organ Prolapse Quantification system, UPR measurements at rest, during squeezing and straining, and standardized stress tests with 300 ml saline. The women filled out International Consultation on Incontinence-Urinary incontinence (ICIQ-UI) short forms. The sample size was 18, with a power of 99.9% and a level of significance of 5%. Parameters were compared using paired t tests or Fisher's exact test, where appropriate; p values <0.05 were considered statistically significant.

RESULTS: Eighteen women with posterior vaginal wall prolapse ≥stage II were recruited. One woman did not undergo surgery. There were no changes in urethral pressure at rest (p = 0.4), during squeezing (p = 0.2) or straining (p = 0.2), before and after surgery. The results of the stress tests and ICIQ-UI short forms were the same after surgery.

CONCLUSIONS: The urethral closure mechanism is not affected by posterior colporrhaphy. Our study does not support the theory that the posterior vaginal wall prolapse compresses the urethra and masks SUI.