The Impact of Tension-Free Vaginal Tape on the Urethral Closure Function: Mechanism of Action

AimTo investigate if the tension-free vaginal tape (TVT) works by increasing the abdominal to urethral pressure impact ratio (APIR). MethodsTwenty one women with urodynamically proven stress urinary incontinence (SUI) were assessed by ICIQ-SF, pad-weighing test, incontinence diary and Urethral Pressure Reflectometry (UPR) before and after TVT. UPR was conducted during resting and increased intra-abdominal pressure (P-Abd) by straining. Related values of P-Abd and urethral opening pressure (P-o) were plotted into an abdomino-urethral pressuregram. Linear regression of the values was conducted, and the slope of the line was found. The slope expresses the ratio of pressure increase in the urethra compared to the pressure increase in the abdomen and was called APIR. ResultsThe urethral opening pressure at rest (Po-rest) was unchanged after TVT, while APIR increased in all women (from 0.7 to 1.4, P<0.0001). ConclusionsThe TVT seems to strengthen the urethral closure function by increasing the APIR while Po-rest is unchanged regardless of the type of pre-operative dysfunction. This confirms the theory of TVT's mechanism of action being mid-urethral support. Neurourol. Urodynam. 34:50-54, 2015. (c) 2013 Wiley Periodicals, Inc.