[Ultrasound imaging of the urethral sphincter]

The integrity and functional capacity of the urethral sphincter is one of the important prerequisites of urinary incontinence in women. Urodynamic investigations revealed repeatedly that the maximum closure pressure in the median portion of the urethra corresponds to the maximal thickness of the external urethral sphinctor (rhabdosphincter urethrae). This striated muscle is adapted to maintain a relatively steady tonus which assists the closure mechanism of the urethra [4]. In the submitted study the authors focused attention on the ultrasonic visualization of the internal urethral sphincter in order to assess the relationship between the size of this sphincter and the stress type of incontinence (genuine stress incontinence-GSI). The investigation comprised thirty women with confirmed GSI and a control group of thirty asymptomatic volunteers. During perineal ultrasonic examination of women in a supine position by means of an ACUSON 128 XP 10 apparatus using a convex probe with a frequency of 5 MHz the authors recorded statistically significant differences in the areas and maximal thickness of the urethral sphincter in women with stress incontinence and symptom-free women. From the results ensues that the size of this muscle is much smaller in women suffering from GSI.