Mechanism of urinary continence after colposuspension: barrier studies.

To test the postulate that colposuspension cures genuine stress incontinence by repositioning the proximal urethra against the posterosuperior surface of the symphysis pubis, 48 patients cured by colposuspension were studied to note the effects of a barrier placed in the vagina to interrupt the posterior route of force transmission. The barrier reduced peak transmission by 59% (P less than 0.0001). When the barrier was used to block compression by the high cystocoele, stress incontinence recurred transiently in 90% of patients. These results confirm Hilton's postulate (1981) that colposuspension constructs a novel, mechanical urinary sphincter rather than restoring normal sphincter function.