[Effect of stress incontinence operations on urodynamic parameters. 1. Is surgical success measurable?]

Urodynamic parameters are changed by stress incontinence surgery. Our study, comparing pre- and postoperative measurements in 141 women with urinary stress incontinence, shows an increase of the transmission ratio in the proximal urethra and a decrease of depression factors in the proximal and mid urethra after surgery. The functional urethral length remains unchanged while the maximum urethral pressure decreases. Except for the maximum pressure decrease, these changes were only found after successful surgery and not in failures. Thus, effectiveness of operations can be quantificated by urodynamic measurements. The unfavourable prognostic influence of a preoperative hypotonic urethra on the results of surgery was confirmed by this study.