Twenty six trials involving 2284 women were included. The quality of evidence was moderate for most trials and there was generally short follow-up ranging from 6-24 months.
One medium sized trial compared traditional suburethral sling operations with oxybutynin in the treatment of mixed urinary incontinence patients. Surgery appeared to be more effective than drugs in treating patient-reported incontinence (n = 75, Risk Ratio (RR) 0.18, 95% Confidence Interval (CI) 0.08 to 0.43).
One trial found that traditional slings were more effective than transurethral injectable treatment (RR for clinician-assessed incontinence within a year 0.21; 95% CI 0.09 to 0.21), and also cheaper on average cost.
Seven trials compared slings with open abdominal retropubic colposuspension. Patient-reported incontinence was lower with the slings after one year (RR 0.75; 95% CI 0.62 to 0.90), but not when assessed by clinicians. Colposuspension, however, was associated with fewer peri-operative complications, shorter duration of use of indwelling catheter and less long term voiding dysfunction. One study showed there was a 20% lower risk of bladder perforation with the sling procedure but a 50% increase in urinary tract infection with the sling procedure compared with colposuspension. Fewer women developed prolapse after slings (compared with after colposuspension) in two small trials but this did not reach statistical significance.
Twelve trials addressed the comparison between traditional sling operations and minimally invasive sling operations.These seemed to be equally effective in the short term (RR for incontinence within first year 0.97; 95% CI 0.78 to 1.20) but minimally invasive slings had a shorter operating time, fewer peri-operative complications (other than bladder perforation) and some evidence of less post-operative voiding dysfunction and detrusor symptoms.
Six trials compared one type of traditional sling with another. Materials included porcine dermis, lyophilised dura mater, fascia lata, vaginal wall, autologous dermis and rectus fascia. Patient-reported improvement rates within the first year favoured the traditional autologous material rectus fascia over other biological materials (RR 0.45; 95% CI 0.21 to 0.98). There were more complications with the use of non-absorbable Goretex in one trial.
Data for comparison of bladder neck needle suspension with suburethral slings were inconclusive because they came from a single trial with a small specialised population.
No trials compared traditional suburethral slings with anterior repair, laparoscopic retropubic colposuspension or artificial sphincters. Most trials did not distinguish between women having surgery for primary or recurrent incontinence when reporting patient characteristics.
For most of the comparisons, clinically important differences could not be ruled out.
