Comparison of leak point pressure methods in an animal model of stress urinary incontinence.

We compared three different methods of testing leak point pressure (LPP) in rats with or without the pudendal nerves and nerves to the iliococcygeus/pubococcygeus muscles transected: (1) sneeze induced with a whisker in the nostril (sneeze LPP), (2) manually increased abdominal pressure (Crede LPP), and (3) increased intravesical pressure using the vertical tilt table method (vertical tilt table LPP). In sham rats, passive intravesical pressure rises in Crede and vertical tilt table methods induced active urethral closure mechanisms that contributed to high LPPs (41.4 and 35.5 cm H2O, respectively), which were significantly reduced by nerve transection. During sneezing, leakage was observed in nerve-transected rats, but not in sham rats, indicating that sneezing can activate an additional urethral closure mechanism. Measuring LPP during sneezing or passive intravesical pressure rises in the vertical tilt table and Crede method seems to be useful for assessing the continence mechanisms under different stress conditions in rats.