The mechanism of urinary continence in women with severe uterovaginal prolapse: results of barrier studies.

Eleven continent women with severe degrees of uterovaginal prolapse underwent a complete urodynamic evaluation that included passive and dynamic urethral pressure profilometry with and without careful barrier reduction of their prolapse. The aim of barrier placement was to reduce, but not overcorrect, the prolapse and to restrict stress-induced mobility of the viscera posterior and superior to the urethra. Each of the women had very high pressure transmission ratios in each quarter of the urethra (means of 257, 187, 170, and 166% from internal to external quarters) that were significantly reduced with barrier placement (means of 78, 84, 85, and 101%). Eight of 11 subjects had pressure transmission ratios less than 90% in the proximal three-quarters of the urethra with the barrier in place, a finding in nearly all subjects with genuine stress urinary incontinence. Maximum urethral closure pressure on passive urethral pressure profilometry also decreased significantly from a mean of 75 to 45 cm H2O with the barrier in place. We conclude that the stress continence mechanism in women with severe prolapse results from posterior-superior visceral descent with stress, causing mechanical obstruction of the less mobile urethra. The evaluation methods described may be useful in predicting which of these patients may require concurrent urethropexy at the time of prolapse reduction surgery to prevent postoperative stress urinary incontinence.