Urethral mobility and urinary incontinence

Objective Urethral mobility is considered an important factor in female urinary incontinence. We therefore undertook a study to correlate segmental urethral mobility, as described by the urethral motion profile (UMP), with symptoms and urodynamic findings. Our null hypothesis was that there would be no statistically significant relationship between female urinary incontinence and segmental urethral mobility. Methods We performed a retrospective study in 198 women who had undergone multichannel urodynamic testing and four-dimensional translabial ultrasound for symptoms of lower urinary tract dysfunction or prolapse. Segmental urethral mobility was described by vectors of movement from rest to maximum Valsalva, relative to the posteroinferior pubosymphyseal margin. We described the mobility of six equidistant points located along the length of the urethra from the bladder neck to the external urethral meatus. The results were tested against symptoms and urodynamic findings. Results Stress urinary incontinence (SUI) and urodynamic stress incontinence (USI), but not urge incontinence, detrusor overactivity or voiding dysfunction, were strongly associated with mobility of the mid-urethra. Conclusion Impairment of mid-urethral fixation, rather than bladder neck fixation, seems important in the pathophysiology of SUI and USI.