[Analysis of continence mechanisms by stress urethral pressure profiles]

The urethral pressure profiles (UPP) at rest and under stress, using double lumens microtip transducer catheter, in 17 females without urinary incontinence (normal group) were compared with those in 39 females with stress urinary incontinence (SUI group). And UPP were compared pre- and postoperatively in 21 females of SUI group who had surgical cure of SUI by bladder neck suspension (operative group). Pressure transmission ratios (PTR) were calculated in each quartile dividing functional urethral length (FUL) into four equal lengths. Maximum urethral closure pressure (MUCP) and Functional urethral length (FUL) in normal group were significantly higher than those in SUI group. In normal group, although bladder neck opening under stress (bladder neck incompetence) existed in 41% of them, the PTR in the distal three-quarters of the FUL were significantly larger than those in SUI group and urinary continence was remained in all of them. On the contrary, in SUI group, there was an almost linear decrease in the value of the PTR along the FUL. Therefore, it was suggested that SUI patients might lose distal urethral compensatory mechanisms. The results, obtained from the resting UPP, show that there is no significant change in MUCP or FUL following bladder neck suspension. In contrast, the stress UPP shows that successful operation generated a magnification of the PTR in the proximal three-quarters of the FUL. Only 1 case of post operative group showed bladder neck incompetence. Therefore suspending the bladder neck in a high position might produce the ability to occlude proximal three-quarters of the FUL.