Novel rat model of stress urinary incontinence with a retroflexed bladder

Introduction and hypothesis: We created a rat model with a retroflexed bladder that mimicked the loss of the posterior urethrovesical angle and compared the results with sham-surgery rats for the establishment of rat models of stress urinary incontinence. Methods: The retroflexed bladder was created by stitching the bladder posteriorly to the psoas muscle. Sneeze-induced urethral pressure response and urethral baseline pressure were measured using a microtip-transducer catheter and leak point pressures induced by sneezing, the Crede maneuver, and the vertical tilt table method were measured via a supra-pubic cystostomy. Results: In rats with a retroflexed bladder, both urethral pressure response and sneeze-induced leak point pressure were significantly decreased. Conclusion: A retroflexed bladder may cause stress urinary incontinence by attenuating the sneeze-induced active urethral closure mechanism. Urethral pressure response restored by resumption of the posterior urethrovesical angle would explain why no sling tension is needed to treat the stress urinary incontinence.