Long-term efficacy of a vaginal sling procedure in a rat model of stress urinary incontinence

Purpose: We examined the long-term efficacy of a newly created vaginal sling procedure for the restoration of leak point pressure (LPP) in a rat model of stress urinary incontinence (SUI). Material and Methods: A total of 20 female Sprague-Dawley rats were randomly assigned to 1 of 4 groups, namely normal control, SUI plus vaginal sling, SUl plus sham sling and SUI only. SUI was created in the latter 3 groups by bilateral pudendal nerve transection (PNT). In the sling procedure a 2 X 0.3 cm strip of polypropylene mesh was placed at the mid urethral level. Animals in the SUI plus sham sling group underwent vaginal dissection only. After 5 weeks LPP was measured 4 or 5 times in each rat and the mean was determined. The Kruskal-Wallis and Wilcoxon rank sum tests were used to evaluate whether levels of measurements differed across and between groups. Results: Mean LPP +/- SD in control rats was 48.8 +/- 10.2 cm H2O, PNT decreased LPP to 23.5 +/- 7.4 cm H2O. Sling placement improved LPP at 5 weeks to 35.5 +/- 2.3 cm H2O, whereas LPP in the sham sling group was 29.1 +/- 4.9 cm H2O. LPP recovery in the sling group was significantly above levels for PNT (p = 0.037). LPP in the sling group did not differ statistically from that in the control group (p = 0.11). Conclusions: The newly created vaginal sling model restores the LPP in the rat model of SUI in the long term (5 weeks). This model could be used to address research questions related to the sling procedure.