Urgency of voiding and abdominal pressure transmission in women with mixed urinary incontinence.

Abstract

To ascertain whether abdominal pressure transmission (a.p.t.) to the urethra would be affected by urgency of voiding in women with mixed urinary incontinence. We urodynamically assessed 80 consecutive women. Group 1 (n = 40), with stress incontinence, had stable bladders and no urgency. Group 2 (n = 40), with mixed (stress + urge) incontinence and overactive bladders, were split into Groups 2A (n = 20) and 2B (n = 20) according to the delay time of urgent void at cystometry (CMG) equating at least 2 min (taken as an index of moderate urgency) or, respectively, less than 2 min (taken as an index of severe urgency). Nonparametric statistics checked for significant differences in a.p.t. and in pelvic floor (peri-urethral) muscle strength level. We defined a.p.t. at stress (cough) urethral pressure profilometry (UPP) by the pressure transmission ratio (PTR). Pelvic floor muscle strength was defined at "holding" UPP by the maximum urethral pressure developed during attempts "to hold urine" (hMUP). PTR was reduced in all women, but PTR (and hMUP) proved relatively higher in Group 2, though nonsignificantly different values of PTR (and hMUP) were seen in Groups 2B and 1. Transmission of abdominal pressure to the urethra was reduced in all of the incontinent women. The mixed incontinence group, however, had a relatively less reduced (active component of) a.p.t., most likely dependent on a greater pelvic floor (peri-urethral) muscle strength level secondary to frequent contractions in response to urgency. Yet, of the same mixed incontinence patients, those with the most severe urgency degrees had relatively low pelvic floor (peri-urethral) muscle strength levels (eventually resulting from muscle fatigue? or primarily due to peri-urethral tissue atrophy?), which prevented (the active component of) a.p.t. from increasing.