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Ureteral Anomalies


Ronald Rabinowitz

, MD, University of Rochester Medical Center;

Jimena Cubillos

, MD, University of Rochester School of Medicine and Dentistry

Reviewed/Revised Aug 2022 | Modified Sep 2022

Diagnosis of ureteral anomalies may be suggested by abnormalities on routine prenatal ultrasonography (eg, hydronephrosis) and occasionally by physical examination (eg, finding an external ectopic ureteral orifice or a palpable mass). Ureteral anomalies should be suspected in children with an episode of pyelonephritis or recurrent urinary tract infections Urinary Tract Infection (UTI) in Children Urinary tract infection (UTI) is defined by ≥ 5 × 104 colonies/mL in a catheterized urine specimen or, in older children, by repeated voided specimens with ≥ 105 colonies/mL... read more and in girls with persistent urinary incontinence. Testing typically involves ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then fluoroscopic voiding cystourethrography. Magnetic resonance urography may be used to identify an ectopic ureter associated with a nonfunctioning renal segment.

Ureteral anomaly treatments are surgical.

Ectopic ureteral orifices

Openings of single or duplicated ureters may be malpositioned on the lateral bladder wall, distally along the trigone, in the bladder neck, in the female urethra distal to the sphincter (leading to continuous incontinence despite a normal voiding pattern), in the genital system (prostate and seminal vesicle in the male, uterus or vagina in the female), or externally. Lateral ectopic orifices frequently lead to vesicoureteral reflux Vesicoureteral Reflux (VUR) Vesicoureteral reflux is retrograde passage of urine from the bladder back into the ureter and sometimes also into the renal collecting system, depending on severity. Reflux predisposes to urinary... read more , whereas distal ectopic orifices more often cause obstruction and incontinence. Surgery is needed for obstruction and incontinence and sometimes for vesicoureteral reflux.

Retrocaval ureter

Anomalous development of the vena cava (pre-ureteric vena cava) allows the infrarenal vena cava to form anterior to the ureter (usually the right); a retrocaval ureter on the left occurs only with persistence of the left cardinal vein system or with complete situs inversus.

Retrocaval ureter can cause ureteral obstruction. For significant ureteral obstruction, the ureter is surgically divided with uretero-ureteral anastomosis anterior to the vena cava or iliac vessel.

Ureter duplication anomalies

Incomplete (partial) or complete duplication of one or both ureters may occur with duplication of the ipsilateral renal pelvis.

In complete duplication, the ureter from the upper pole of the kidney opens at a more caudal location than the orifice of the lower pole ureter. As a result, the lower pole tends to reflux and the upper pole tends to obstruct when pathology is present. Ectopia or stenosis of one or both orifices, vesicoureteral reflux into the lower ureter or both ureters, and ureterocele Ureterocele Ureteral anomalies frequently occur with renal anomalies but may occur independently. Complications include Obstruction, vesicoureteral reflux, urinary tract infections, and urinary calculus... read more may occur. Surgery may be necessary if there is obstruction, vesicoureteral reflux, or urinary incontinence.

Incomplete duplication is rarely of clinical significance.

Ureteral stenosis

Narrowing may occur at any location in the ureter, most frequently at the ureteropelvic junction and less commonly at the ureterovesical junction (primary megaureter). Consequences include infection, hematuria, and obstruction. Stenoses often diminish as the child grows.

In primary megaureter, ureteral tapering and reimplantation may be needed when dilation increases or infection or obstruction occurs. In ureteropelvic junction obstruction, pyeloplasty (excision of the obstructed segment and reanastomosis) may be done by open, laparoscopic, or robotic techniques.


Prolapse of the lower end of the ureter into the bladder with pinpoint obstruction may cause progressive ureterectasis, hydronephrosis, infection, occasional calculus formation, and impaired renal function. Ureterocele treatment options include endoscopic transurethral incision and open repair.

When a ureterocele involves the upper of two duplex ureters, treatment depends on function in that renal segment, which is frequently dysplastic. Removal of the affected renal segment and ureter may be preferable to obstruction repair if that segment is nonfunctional or if significant renal dysplasia is suspected. Alternatively, ipsilateral ureteroureterostomy may be done to bypass the obstruction.

In rare instances, the ureterocele may prolapse beyond the bladder neck, causing a bladder outlet obstruction. In girls, this may manifest as an interlabial mass.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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