[Dynamics of upper urinary tract during vesico-ureteral reflux]

Two types of experiments were performed in dogs to clarify physiological state during vesico-ureteral reflux (VUR). In the first experiment, VUR was established by performing operations to disturb the VUR protecting mechanism. In the second experiment, a tube was inserted into the uretero-vesical junction to prepare VUR model and using this model VUR was induced experimentally. In these experiments, recordings of ureteral myogram, intravesical pressure and intrapelvic pressure as well as macroscopic observations of the ureter were made and the following results were obtained. Functional failure of the ureteral orifice was the most important factor for the development of VUR. When the ureteral orifice showed functional failure, VUR appeared at a mean intravesical pressure of 20 cmH2O. During VUR developed, ureteral peristalsis occurred frequently, whereas no ureteral contraction was observed macroscopically. Antiperistalsis was not an immediate factor responsible for the induction of VUR. In the presence of VUR, intrapelvic pressure became lower than intravesical pressure. These findings seemed to have properly reflected the physiological states in patient with VUR.