ABSTRACT: Postoperative urinary incontinence develops in about 25% of previously continent women undergoing vaginal surgery for pelvic organ prolapse. At the time of prolapse repair, many surgeons insert a concomitant midurethral sling in all continent women to reduce the risk of stress incontinence. The benefits and risks of this prophylactic intervention are unclear.
This multicenter, randomized, single-blind study was designed to determine the prevalence of postoperative urinary incontinence at 3 and 12 months among women without a prior history of stress incontinence who underwent vaginal prolapse surgery. Participants planning to undergo prolapse repair had anterior prolapse (of stage 2 or higher on a Pelvic Organ Prolapse Quantification system examination). A total of 337 women were randomly assigned during surgery to receive either a midurethral sling (the sling group, n = 165) or sham incisions (the sham group, n = 172). There were 2 primary end points. The first was the occurrence of urinary incontinence or treatment for this condition at 3 months. The second was the occurrence of incontinence at 12 months, allowing for subsequent treatment for incontinence.
Of the women undergoing randomization, 97% (332/337) completed follow-up at 1 year. At 3 months after surgery, the rate of urinary incontinence or treatment was 23.6% in the sling group and 49.4% in the sham group; the adjusted odds ratio was 0.31, with a 95% confidence interval of 0.19 to 0.50 (P < 0.001). Twelve months after surgery, the rate of urinary incontinence (with allowance for subsequent treatment of incontinence) was lower in the sling group than in the sham group (27.3% vs 43.0%; adjusted odds ratio, 0.48; 95% confidence interval, 0.30–0.77 [P = 0.002]). At 12 months, the number needed to treat with a sling to prevent 1 case of urinary incontinence was 6.3. Compared with the sham group, rates of the following adverse events were all higher at 12 months in the sling group: bladder perforation (6.7% vs 0%), urinary tract infection (31.0% vs 18.3%), major bleeding complications (3.1% vs 0%), and incomplete bladder emptying 6 weeks after surgery (3.7% vs 0%) (all comparisons, P ≤ 0.05).
These findings show that use of a midurethral sling at the time of vaginal prolapse repair in previously continent women reduces the rate of urinary incontinence at 3 and 12 months after surgery but increases the likelihood of adverse events.