The present study deals with the pathogenesis of vesicoureteral reflux. It was found from the electro-ureterographic and urometric examinations that no active contraction was present in the intramural portion of the ureter and that the urine was passively transported through the portion by peristaltic contraction in the extravesical ureteral portion.
The occurrence of reflux in the ureter after its ureterovesical junction had been kept constantly patent by insertion of a polyethylene tube was observed by fluoroscopy with an image-intensifier. From this observation it was noticed that relux occurred in the ureter during its resting phase without participation of retrograde peristalsis.
Further, functional and histological examinations were carried out on the ureter after uretero-cystostomy. The results obtained suggested that the implanted portion of the ureter functioned essentially in the same way as in the natural ureterovesical junction.