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Ureteral Anomalies

by Ronald Rabinowitz, MD, Jimena Cubillos, MD

Ureteral anomalies frequently occur with renal anomalies but may occur independently. Complications include

  • Obstruction, vesicoureteral reflux (see Vesicoureteral Reflux), infection, and calculus formation (due to urinary stasis)

  • Urinary incontinence (due to abnormal termination of the ureter in the urethra, perineum, or vagina)

Diagnosis 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 UTIs. Testing typically involves ultrasonography of the kidneys, ureters, and bladder before and after voiding, and then fluoroscopic voiding cystourethrography.

Treatments are surgical.

Duplication anomalies

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 may occur. Surgery may be necessary if there is obstruction, vesicoureteral reflux, or urinary incontinence. Incomplete duplication is rarely of clinical significance.

Ectopic 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, 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.

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.

Ureterocele

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. Treatment options include endoscopic transurethral incision and open repair.

When a ureterocele involves the upper pole of duplex ureters, treatment depends on function in that renal segment, because of the significant incidence of renal dysplasia. Removal of the affected renal segment and ureter may be preferable to obstruction repair if no segmental renal function is found or if significant renal dysplasia is suspected.

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.

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