Measurement of the transmission factor and stress factor at four points in the urethra in patients with stress incontinence.

The transmission factor and the stress factor (a new parameter introduced by us) were determined at points corresponding to 10%, 40%, 70%, and 90% of the functional length of the urethra in 25 women with stress-incontinence and were used to construct urethral closure pressure profiles. The measurements were made with the patients supine after infusion of 200 ml into the urinary bladder, and in the standing and supine positions following infusion of 300--400 ml. There was an almost linear decrease in the value of the transmission factor along the functional length of the urethra. In the distal third of the urethra we found significant differences in vesico-urethral pressure transmission between patients with differing degrees of stress incontinence. The significance of the transmission factor in the preoperative and postoperative evaluation of urethral closure pressure profiles is discussed.