Efficacy of a vaginal sling procedure in a rat model of stress urinary incontinence

Purpose: We validated the efficacy of the vaginal sling procedure for the restoration of leak point pressure (LPP) in the rat model of stress urinary incontinence (SUI). Materials and Methods: SUI was created in 10 female Sprague-Dawley rats by bilateral pudendal nerve transection (PNT) under urethane anesthesia. Vaginal dissection was performed, followed by placement of a 2 X 0.3 cm strip of Prolene (Ethicon, Somerville, New Jersey) mesh at the mid urethral level. LPP was measured before and after PNT through a suprapubic tube using a Crede maneuver. It was also measured after vaginal dissection (sham sling) and after true sling placement. All procedures and measurements were done at the same experimental setting. In each animal LPP was measured 4 or 5 times and the mean was taken. Pairwise differences in LPP between the true and sham slings were calculated using the Wilcoxon signed rank test with p < 0.05 considered significantly different. Results: Mean LPP at baseline in all rats was 65.1 +/- 6.0 cm water. LPP decreased to 42.7 +/- 3.7 cm water after PNT. The sham sling further decreased LPP to 26.5 +/- 2.2 cm water, whereas the true sling restored LPP to 56 +/- 4.8 em water. LPP after true sling placement was not different from baseline (p = 0.16), whereas LPP after sham sling placement was significantly different from baseline (p = 0.002). Conclusions: This rat vaginal sling model represents a valid surgical method for LPP restoration in the rat model of SUI. This animal model could be used for future studies related to SUI and its treatment relevant to sling surgery.