retrocavaler Verlauf des Ureters

Circumcaval ureter, also known as retrocaval ureter, is a term used to describe an abnormal course of a ureter that encircles the inferior vena cava. Both of these terms are somewhat misleading, as this configuration is considered a developmental anomaly of the inferior vena cava (IVC). There are two types:

  • low loop (type 1)
  • high loop (type 2)

Clinical presentation

Many patients with this anomaly are asymptomatic. Depending on the degree of compression patients may develop partial right ureteral obstruction or recurrent urinary tract infections due to urinary stasis.


This congenital abnormality occurs as a result of the right supracardinal system failing to develop normally. The right posterior cardinal vein persists, and therefore ends up passing in front of the ureter.

With one reported exception, the anomaly always occurs on the right side, as this is the side of the normal IVC.

Radiographic features

The proximal ureter courses posterior to the IVC, then emerges to the right of the aorta, coming to lie anterior to the right iliac vessels. Any chosen imaging modality will usually show a right hydroureteronephrosis above the segment embracing the IVC. Intravenous urogram classically depicts a fishhook-shaped or S-shaped deformity of the ureter in type 1 or the low loop variety.  In type 2, the retrocaval segment is at the same level as the renal pelvis; the sickle-shaped appearance of the involved ureter can be identified on IVU. Type 2 generally causes mild hydronephrosis and is less common than type 1.

Treatment and prognosis

If treatment is required, surgical relocation of the ureter anterior to the IVC can be performed.

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