IMPACT OF CHANGES IN POSTURE AND BLADDER FILLING ON THE MECHANICAL-PROPERTIES OF THE URETHRA IN HEALTHY AND STRESS-INCONTINENT FEMALES

A pressure/cross‐sectional area probe was used to examine the impact of changes in posture and bladder filling on the mechanical properties of the urethra in 29 healthy females and in 28 patients with genuine stress incontinence (GSI). Measurements were performed at the bladder neck, in the high‐pressure zone, and distally in the urethra. When changing posture from supine to standing position the urethral pressure at the bladder neck and midurethrally increased statistically significantly (P>0.01) in both groups. The urethral pressure increase was most pronounced in the midurethra which indicates that active muscle contraction is involved. Maximum urethral closure pressure was unchanged in the control group while it decreased statistically significantly (P>0.01) in the GSI group. Urethral elastance increased midurethrally in healthy women while it decreased in GSI women in the upright posture. Although these changes were not statistically significant, elastance was statistically significantly higher midurethrally in the erect position in the control group. These findings indicate impaired striated muscle function in or around the urethra in GSI women. Filling the bladder to 50% of the functional capacity did not change any urethral parameter in the two groups of women. The wide divergency in previously reported results is discussed. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company