Single-incision mini-slings were noninferior to midurethral slings, which have been the surgical treatment of choice in women with stress urinary incontinence, findings from the randomized SIMS trial showed.

“In a systematic review published in 2014, we found that the percentages of patients with patient-reported and objective success with mini-slings (excluding TVT-Secur devices, which were discontinued by the manufacturer for commercial reasons) were similar to those with midurethral slings during a median follow-up at 18 months; mini-slings were associated with less postoperative pain and a shorter recovery time,” Mohamed Abdel-Fattah, MD, clinical chair in gynecology at the University of Aberdeen in Scotland, and colleagues wrote in The New England Journal of Medicine. “However, trials included in this review were small and heterogeneous and had a high risk of bias.”

From February 2014 to July 2017, Abdel-Fattah and colleagues enrolled women from 21 U.K. hospitals in a pragmatic, noninferiority, randomized trial. The women, aged 18 years or older who had predominant symptoms of stress urinary incontinence, had either failed conservative treatment or declined to undergo such treatment. They were assigned in a 1:1 ratio to either a midurethral sling or mini-sling procedure.

In follow-ups through 36 months after randomization, women self-reported success and adverse events. Secondary outcomes were postoperative pain and recovery, objective success and the impact on symptoms, quality of life and sexual function.

A margin of 10 percentage points was required for mini-slings to be considered superior to midurethral slings.

Treatment success rates

At 15 months, 212 of 268 women (79.1%) with mini-slings who had data available reported success, as did 189 of 250 women (75.6%) with midurethral slings (adjusted risk difference = 4.6 percentage points; 95% CI, 2.7 to 11.8). Success at 36 months was reported by 177 of 246 women (72%) with mini-slings and 157 of 235 women (66.8%) with midurethral slings (adjusted risk difference = 5.7 percentage points; 95% CI, 1.3 to 12.8).

Objectively, 102 of 119 women (85.7%) with mini-slings and 83 of 110 women (75.5%) with midurethral slings had success at 15 months (adjusted risk difference = 5.2 percentage points; 95% CI, 5.9 to 16.2).

Also, 93 of 241 women (38.6%) with mini-slings and 72 of 217 women (33.2%) with midurethral slings reported no leaking at 15 months (adjusted risk difference, 6.4; 95% CI, 1.2 to 13.9).

Safety data

According to the researchers, women in the mini-sling group more often reported groin or thigh pain at 15 months than those in the midurethral sling group, although the proportion of each group reporting pain at 36 months was similar (14.1% and 14.9%, respectively; risk difference = 0.8 percentage points; 95% CI, 4.1 to 2.5).

Tape or mesh exposure occurred in 3.3% of women with mini-slings and 1.9% of women with midurethral slings, although the difference was not statistically significant (risk difference = 1.3 percentage points; 95% CI, 1.7 to 4.4). There was one person with persistent mesh exposure who had the exposed mesh removed.

Further surgery for stress urinary incontinence was performed in 2.5% of women with mini-slings and 1.1% of women with midurethral slings over the follow-up period.

Secondary outcomes

Mean 2-week postoperative pain scores showed women with mini-slings experienced less pain than those with midurethral slings (19.8 vs. 28.1; adjusted risk difference = 8.3; 95% CI, 12.8 to 3.8).

Differences in lower urinary tract symptoms, quality of life and sexual function between groups did not reach significance, although dyspareunia and coital incontinence were more common in the mini-sling group throughout follow-up.

Abdel-Fattah and colleagues were unable to conduct follow-up past 3 years, which limited the study. Other limitations included lack of blinding, inability to determine whether differences in adverse events were significant and limited data on objective success.

Despite these limitations, the researchers found that mini-slings were effective in their study population.

“In the SIMS trial, adjustable anchored mini-slings were noninferior to tension-free midurethral slings with respect to patient-reported success at 15 months, and the between-group difference remained similar at 36 months,” they concluded.