Hydrodynamic assessment of efferent limb valve mechanisms in continent urinary diversion: comparative study on a cadaveric model.

ABSTRACT

Various valve mechanisms, customarily employed in continent urinary diversion, were constructed from fresh cadaveric porcine bowel for later urodynamic assessment. A total of six different types of valves were formed from ileum or colon in varying lengths and tested by volume pressure trials. The leak point or maximum pressure were recorded at constant perfusion rates of 30 ml/min of the constructed reservoir. Ileal or colonic nipple valves, as well as the embedded or pulled-through ileum, tapered to 12 F at a length of 3 cm, withstood maximum pressures ranging between 75 and 138 cm H2O before leakage or protrusion of the valve occurred. Plicated or tapered terminal ileum in caecal reservoir revealed water leakage at pressures as low as 25 to 40 cm H2O. A newly-developed valve mechanism consisting of a 12 F, plicated colonic-serosal tunnel with a minimum intra-reservoir length of 5 cm resisted maximum pressures of more than 70 cm H2O. Our cadaveric porcine bowel model proved to be reliable for acute volume/pressure trials and correlated with all clinical urodynamic results and animal trials. It is simple, inexpensive and allows scope for individual ideas before commencing with animal trials.