Complete duplication results when two entirely separate ureters drain separate parts of the kidney.
Partial duplication occurs when the two ureters join before reaching the bladder.
See more about duplication. When the ureteric bud does not meet the nephrogenic blastema, normal nephrogenesis does not occur. If the bud originates from the mesonephric duct either caudal to or cranial to the normal position, dysplasia may occur. This may explain why some kidneys with reflux or ectopic ureters have diminished function and capacity. As the metanephros is induced to develop functioning glomeruli and tubules the ureter opens to become a conduit.