Duplicated collecting system overview

Duplicated collecting system is the most common upper urinary tract anomaly, affecting nearly 15% of the population. ^{[1] [2] [3]}

Embryologically occurs when 2 separate ureteric buds arise from a single wolffian duct. The future lower pole ureter separates from Wolffian duct earlier and migrates superiorly and laterally as the urogenital sinus grows.

Weigert-Meyer rule for bladder insertion: the upper pole ureter inserts inferior and medial to lower ureter.

Alternatively, the 2 ureters may fuse to form a single ureter prior to inserting into the bladder, termed a bifid system.

The lower pole system is usually dominant, while the upper system may drain a single or few calices.

The upper pole ureter may demonstrate a ureterocele, which is associated with ureteral obstruction and recurrent UTIs in children. The upper pole ureter may also be ectopic or stenotic.

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