PROVIDENCE, R.I. – Use of a prophylactic mid-urethral sling during the course of transvaginal prolapse repair significantly reduced the risk of urinary incontinence symptoms at 3 and 12 months post surgery, according to Dr. John T. Wei.
“The basis for this trial is a common dilemma we face: When a woman with significant vaginal prolapse but no stress-related urinary incontinence undergoes transvaginal prolapse repair, should a sling be placed in all women or should treatment be delayed until she develops symptomatic urinary incontinence? Level 1 evidence does not exist to address that question, and that is why the Pelvic Floor Disorders Network [PFDN] commissioned the OPUS [Outcomes Following Vaginal Prolapse Repair and Midurethral Sling] trial,” said Dr. Wei, professor of urology at the University of Michigan, Ann Arbor. Dr. Wei's presentation earned the “Best Overall Paper” award at the meeting.
The PFDN was created by the National Institute of Child Health and Human Development's contraception and reproductive health branch. It consists of eight clinical sites and one data-coordinating center. This is the first protocol conducted by the PFDN.
In the OPUS trial, 337 women with symptomatic greater than or equal to stage 2 anterior prolapse who did not report symptoms of stress urinary incontinence (SUI) were randomized to undergo either insertion of retropubic tension-free vaginal tape (TVT) (n=165) or sham incisions (n=172) during prolapse surgery. The primary end point was urinary incontinence (UI) failure, defined as having at least one of the following: a positive cough stress test, bothersome UI symptoms, or treatment for UI (pharmacologic or surgical).
Three months after surgery, the rate of UI failure in those who received a prophylactic sling was less than half of that seen in the sham-operated group (23.6% vs. 49.4%, P less than .0001). Similar results were noted at 12 months (27.3% vs. 43.0%, P = .0024), even after allowing for additional UI postoperative treatment. Significant differences favoring the sling also were found for quality of life measures. However, no significant differences between groups were found for measures of other pelvic floor conditions such as prolapse, pain, or decreased sexual function or general health (as measured by the short form SF-36 questionnaire).
Although there were no significant differences between groups in serious and unexpected adverse events, those in the TVT group had higher rates of bladder perforations (6.7% vs. 0%), urinary tract infections (31% vs. 17.2%), major bleeding/vascular complications (3% vs. 0%) or incomplete bladder emptying at 6 weeks (3.7% vs. 0%).
In a companion presentation by Dr. Wei, the question was raised as to whether a preoperative prolapse reduction stress test (PRST) was of value for predicting which women would benefit most from prophylactic sling insertion. To answer this question, the group did a post hoc analysis, comparing outcomes according to whether the PRST was positive or negative.
The preoperative PRST was performed by retrograde fill (300 mL), removing the catheter and performing Valsalva and cough testing in lithotomy position without prolapse reduction, in lithotomy with prolapse reduced with Procto Swabs, and standing with prolapse reduced. A positive stress test was defined as urine leakage in either position, with or without reduction. The PRST results were masked to the surgeons, so the results had no influence on treatment assignment. Almost all women enrolled in the trial (98%) had undergone PRST.
Dr. Wei found that, at 3 months, insertion of the sling had a beneficial effect, whether or not the PRST was positive or negative, but the magnitude of effect of the sling was greater if the patient had a positive PRST. Treatment failure at 3 months in the positive PRST group was 29.6% in the sling group vs. 71.9% in the sham group; in the negative PRST group the rates were 20.6% in the sling group vs. 38.1% in the sham group (interaction P = .06). Similar trends were seen at 12 months but the differences were not significant.
“Women with a positive PRST who do not receive a TVT are at highest risk of having at UI at 3 months after vaginal prolapse surgery,” he said.
Another group included in the study was a “patient preference cohort” (PPC) which included a group of women who were eligible for inclusion in the randomized controlled trial but elected not to participate because of randomization. According to Dr. Wei, the goal was to measure the level of nonparticipation bias to improve the validity of the generalizability of the trial. “Both in magnitude and statistics, those in the PPC looked remarkably like those in the clinical trial.”