The dynamic urethral sphincter function in healthy females assessed by rapid dilatations in the resting state: evaluation of reproducibility.

Recording the pressure response to rapid dilatations enables one to assess urethral sphincter function. The rapid dilatations of the urethra experimentally simulate the ingression of urine. A method that enables standardized dilatations of 2-mm long urethral segments was urine (USED).A method that enables standardized dilatations of 2-mm long urethral segments was used, and the subsequent pressure response was measured. The reproducibility of the urethral pressure response to rapid and standardized dilatations was evaluated by repeating the measurements after 1 week in 10 healthy females. The pressure response showed an acceptable reproducibility. The urethral pressure increase as a response to dilatation is considered to rely on stretching of intra- and periurethral fibers. Calculations of strain (change in length divided by the original length) of circularly arranged fibers when the urethra is dilated indicate that the tension (and pressure) bearing layers must be located outside a circular zone with a radius of 4 mm perpendicular to the longitudinal axis of the urethra.