Urethral pressure reflectometry before and after tension-free vaginal tape

Urethral pressure reflectometry (UPR) is a new method for measuring pressure and cross-sectional area in the urethra. Our aim was to investigate if the UPR parameters at rest and during squeeze were unchanged after TVT.

The technique enables measurement along the entire length of the urethra simultaneously and avoids the common artefacts encountered with conventional catheters. Twenty-two stress urinary incontinent women were included. The UPR polyurethane bag was placed in the urethra and connected to a pump and an acoustic transmitter. The bag was inflated, distending it accordingly, and the CA within the bag, and thus the urethra, was measured with acoustic reflectometry. Opening and closing pressure and elastance, and hysteresis were measured. "Relaxing" and "squeezing" measurements were conducted in the supine and standing position before and after TVT.

Subjective and objective cure rates were 82% and 100%, respectively. Maximum urine flow rate decreased from 31 to 18 ml/sec (P = 0.0002). Supine and standing relaxing urethral opening and closing pressures were unchanged. Supine opening elastance increased 18% (P = 0.04), which indicates an increased resistance against the opening of the urethra. Supine squeezing opening pressure decreased 10%.

UPR measurements confirmed that urethral opening pressure at rest is unchanged after TVT. The TVT somewhat improves the closure function by providing increased resistance against the dilation of the urethra, which probably explains the decreased maximum urine flow rate.