Bladder neck suspension for stress urinary incontinence: how does it work?

The objective of this study was to compare urethral resistance as determined in pressure-flow studies before and after Burch retropubic urethropexy. Urethral resistance was retrospectively determined from pressure-flow studies in 178 patients before and 1 year after Burch retropubic urethropexy. Results of cotton swab tests, pressure transmission to the proximal urethra, and urethral functional length were also recorded. Results were analyzed statistically using the two-tailed paired t-test. Voiding studies in 176 patients were analyzed before and after Burch retropubic urethropexy. Mean urethral resistance increased significantly over preoperative values after successful surgery, from 0.051 to 0.099. The mean urethral resistance in patients in whom surgery failed to cure stress incontinence was unchanged from the preoperative value of 0.041. There was no direct correlation between stabilizing the bladder base, as evaluated by the cotton swab test, and cure of stress incontinence. When successful in curing genuine stress urinary incontinence, the Burch retropubic urethropexy increases urethral resistance. Creating bladder neck support without affecting urethral resistance does not, by itself, restore continence. Neurourol. Urodynam. 18:623-627, 1999. Copyright 1999 Wiley-Liss, Inc.