Normal preoperative urodynamic testing does not predict voiding dysfunction after Burch colposuspension versus pubovaginal sling.

PURPOSE

Urodynamic studies have been proposed as a means of identifying patients at risk for voiding dysfunction after surgery for stress urinary incontinence. We determined if preoperative urodynamic findings predict postoperative voiding dysfunction after pubovaginal sling or Burch colposuspension.

MATERIALS AND METHODS

Data were analyzed from preoperative, standardized urodynamic studies performed on participants in the Stress Incontinence Treatment Efficacy Trial, in which women with stress urinary incontinence were randomized to undergo pubovaginal sling surgery or Burch colposuspension. Voiding dysfunction was defined as use of any bladder catheter after 6 weeks, or reoperation for takedown of a pubovaginal sling or Burch colposuspension. Urodynamic study parameters examined were post-void residual urine, maximum flow during noninvasive flowmetry, maximum flow during pressure flow study, change in vesical pressure at maximum flow during pressure flow study, change in abdominal pressure at maximum flow during pressure flow study and change in detrusor pressure at maximum flow during pressure flow study. The study excluded women with a preoperative post-void residual urine volume of more than 150 ml or a maximum flow during noninvasive flowmetry of less than 12 ml per second unless advanced pelvic prolapse was also present.

RESULTS

Of the 655 women in whom data were analyzed voiding dysfunction developed in 57 including 8 in the Burch colposuspension and 49 in the pubovaginal sling groups. There were 9 patients who could not be categorized and, thus, were excluded from the remainder of the analysis (646). A total of 38 women used a catheter beyond week 6, 3 had a surgical takedown and 16 had both. All 19 women who had surgical takedown were in the pubovaginal sling group. The statistical analysis of urodynamic predictors is based on subsets of the entire cohort, including 579 women with preoperative uroflowmetry, 378 with change in vesical pressure, and 377 with change in abdominal and detrusor pressure values. No preoperative urodynamic study findings were associated with an increased risk of voiding dysfunction in any group. Mean maximum flow during noninvasive flowmetry values were similar among women with voiding dysfunction compared to those without voiding dysfunction in the entire group (23.4 vs 25.7 ml per second, p = 0.16), in the Burch colposuspension group (25.8 vs 25.7 ml per second, p = 0.98) and in the pubovaginal sling group (23.1 vs 25.7 ml per second, p = 0.17). Voiding pressures and degree of abdominal straining were not associated with postoperative voiding dysfunction.

CONCLUSIONS

In this carefully selected group preoperative urodynamic studies did not predict postoperative voiding dysfunction or the risk of surgical revision in the pubovaginal sling group. Our findings may be limited by the stringent exclusion criteria and studying a group believed to be at greater risk for voiding dysfunction could alter these findings. Additional analysis using subjective measures to define voiding dysfunction is warranted to further determine the ability of urodynamic studies to stratify the risk of postoperative voiding dysfunction, which appears to be limited in the current study.