Paraureteral diverticula. Associated renal morphology and embryogenesis.

A study was made of paraureteric diverticula, the associated ureteric orifices, and the accompanying kidneys. It was shown that the kidney was more abnormal as the ureteric orifice position lay more laterally and into the diverticulum. The fascial arrangements of the terminal ureter and the related diverticulum were examined. When the ureter opened totally within the diverticulum, both structures showed a single investment of fascia, suggesting a common embryologic orgin of the two structures. When the ureter opened either separately into the bladder or on the verge of the diverticulum, the urter and the adjacent diverticulum each had separate fascial investment, suggesting a different etiology for the formation of this type of diverticulum. A total of 25 single-system specimens were employed for the above study. In the series there were an additional three duplex systems associated with paraureteric diverticula in shich the kidney morphology followed the above pattern but the fascial arrangements were different. Based on the observations of this investigation, it is suggested that the renal morphology is governed by the position of the ureteric orifice in the diverticulum and that the term vesical hiatal diverticula be used to denote those diverticula occurring in the vicinity of the ureteric orifice. It is further suggested that the diverticulum which engulfs the ureteric orifice be called paraureteral, and those with separate orifices in the bladder be termed periureteral to differentiate the embryologic from the pulsion etiologies.