The impact of tension-free vaginal tape on the urethral closure function: Mechanism of action

Aim To investigate if the tension-free vaginal tape (TVT) works by increasing the abdominal to urethral pressure impact ratio (APIR). Methods Twenty 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 (PAbd) by straining. Related values of PAbd and urethral opening pressure (Po) 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. Results The urethral opening pressure at rest (Po-rest) was unchanged after TVT, while APIR increased in all women (from 0.7 to 1.4, P