Suburethral sling operations for urinary incontinence in women

Suburethral slings are surgical operations used to treat women with urinary incontinence. They were originally designed for recurrent stress incontinence, but have also been used recently for primary cases.

To determine the effects of suburethral slings on stress or mixed urinary incontinence in comparison with other management options.

We searched the Cochrane Incontinence Group's trials register, The UK National Research Register (Issue 1, 2001) and the reference lists of relevant articles. We hand searched the proceedings of the Brazilian Congress of Urology from 1991 to 1999, inclusive. Date of most recent search: March 2001.

Randomised or quasi-randomised trials that included suburethral slings for the treatment of urinary incontinence.

Both reviewers independently extracted data from included trials onto a standard form and assessed trial methodological quality. The data abstracted were relevant to predetermined outcome measures. Where appropriate, a summary statistic was calculated: a relative risk for dichotomous data and a weighted mean difference for continuous data.

Seven trials were identified including 682 women - 457 treated with suburethral slings and 225 with other procedures. Four compared suburethral slings with open abdominal retropubic suspensions (Burch/Marshall-Marchetti-Krantz) and one compared suburethral slings with needle suspension (Stamey). In the two last trials, different types of suburethral sling were compared with each other. Six types of slings were included (Teflon, polytetrafluoroethylene, prolene used for tension free vaginal tape (TVT), porcine dermis, lyophilized dura mater and rectus fascia). There were no comparisons of suburethral sling with anterior repair, laparoscopic retropubic suspension, peri-urethral injections, artificial sphincters or conservative management. In respect of short-term cure, overall rates are similar (RR 0.93; 95% CI 0.68 to 1.27) in comparison to open abdominal retropubic suspension. This mainly reflects the results of one larger trial on TVT. However, for long term results, data are too few to give a reliable estimate. Data were too few to address whether other types of suburethral slings were as effective as open abdominal retropubic suspension or needle suspension. There were no detectable differences in terms of voiding dysfunction, urge incontinence or detrusor instability between suburethral slings and abdominal or needle suspensions, but the data were few and the confidence intervals wide. About one in 11 had a complication during TVT, most commonly bladder perforation, but none had serious consequences. In the small trial which compared autologous (rectus fascia) with synthetic (Goretex) slings, 11/32 vs 2/16 women were not cured after a year (RR 0.36, 95% CI 0.09 to 1.45) which is not statistically significant but fewer women with autologous slings had complications (0/32 vs 5/16; RR 21.35, 95% CI 1.25 to 363.78). Two women in the Goretex group had late sling erosion of the urethra requiring removal of the Goretex, although their incontinence remained cured.

Preliminary results from a larger trial provide reassuring evidence about the performance of the less invasive TVT sling procedure. Cure rates after TVT were similar to those following open abdominal retropubic suspension, but with confidence intervals of around 10% absolute difference. About one in 11 women had a complication during TVT, most commonly bladder perforation, but none had serious consequences. Long term results are awaited. The data were too few to address whether other types of suburethral slings were as effective as open abdominal retropubic suspension or needle suspension. There was limited evidence from one small trial that slings made of Goretex had more complications than slings made of rectus fascia. The broader effects of suburethral slings could not be established since trials did not include appropriate outcome measures such as general health status, health economics, pad testing, third party analysis and time to return to normal activity level. Evidence that suburethral slings may be better or worse than other surgical or conservative management is lacking because no trials addressed these comparisons.