Comparing risk of repeat surgery for stress urinary incontinence after mid-urethral slings and polyacrylamide hydrogel.

INTRODUCTION: Over the last two decades synthetic mid-urethral slings (MUS) have become established as the main surgical method for correcting stress urinary incontinence (SUI). However, transurethral injections with polyacrylamide hydrogel are gaining popularity. We used surgical codes from a national registry to explore potential differences in risk of later surgery for SUI comparing retropubic slings, obturator slings, and polyacrylamide hydrogel injections. MATERIAL AND METHODS: This cohort study used surgical codes from The Norwegian Patient Registry. All women recorded as having had surgery for SUI coded as retropubic sling, obturator sling, or polyacrylamide hydrogel injection from 2008 until end-of-study censoring in 2017, were included. Main outcome was time to any recorded new SUI procedure later in the study period. Unadjusted comparison between groups was done using Kaplan-Meier. A Cox regression analysis was then performed to adjust for hospital unit size and patient age at surgery. RESULTS: The unadjusted analyses showed significant differences between the chosen index method and the risk of later SUI surgery favoring retropubic slings (p < 0.01). The proportions of patients without any recorded new SUI procedure at 1 and 5 years were 99.3% and 97.7% for retropubic MUS, 98.7% and 96.1% for obturator MUS, and 82.7% and 72.4% for polyacrylamide hydrogel injections. The majority of women having a repeat procedure for SUI after a polyacrylamide hydrogel injection underwent repeat treatment within 1 year (63%). After adjusting for age at time of surgery and hospital size, obturator slings (hazard ratio 1.8, 95% CI 1.4-2.4) and polyacrylamide hydrogel (hazard ratio 23.1, 95% CI 17.6-30.3) remained associated with a higher risk of later incontinence surgery. CONCLUSIONS: Both retropubic and obturator slings have low long-term risks of repeat incontinence surgery compared with polyacrylamide hydrogel injections. Retropubic slings were found to have superior longevity of the surgical result.