The Mechanism of Vesicoureteral Reflux (mit Film)

Zusammenfassung

Although many experimental and clinical studies on the etiology of vesicoureteral reflux (VUR) have been carried out, its mechanism is still an open question to urologists. In examing the various proposed theories, the question is raised as to which one is most accurate [1, 2, 3, 4]. Among these, the passive valve theory, first advanced by Sampson [1], has received wide support. Sampson’s concept of the oblique passage of the ureter through the bladder wall does encompass some reasonable points. Using photomicrographs of the ureterovesical junction, Sampson showed the ureter becoming increasingly oblique as the bladder was distended. This was apparently due to the insertion of the distal tip of the ureter into the fixed trigone and occurred because the intramural ureter was carried upwards as the bladder wall stretched. Sampson also showed that the lumen of the intravesical ureter is round when the bladder is empty and flattened when the bladder is distended. He postulated that it is this compression of the intravesical ureter between a firm bladder wall and an increasing pressure in the bladder that prevents reflux.