What is Ureteropelvic Junction Obstruction?

Ureteropelvic junction (UPJ) obstruction is a blockage that affects urinary tract function. Usually a congenital condition, ureteropelvic junction obstruction may also develop in adults with conditions that adversely affect ureter function. Treatment for ureteropelvic junction obstruction is generally dependent on the severity of the blockage. The condition can subside without treatment, but blockages that threaten kidney function and health can necessitate surgical correction.

Considering most cases of ureteropelvic junction obstruction are congenital, detection occurs while the fetus is in utero. Ultrasounds usually display hydronephrosis, or kidney distention, where the ureter joins the kidney's base, called the ureteropelvic junction. Testing for UPJ obstruction outside the womb can include the administration of an intravenous pyelogram (IVP), which utilizes imaging technology and contrast dye to evaluate the condition and functionality of the urinary tract. A renal scan may also be conducted to assess the degree of ureter obstruction.

Anatomically speaking, the ureters are dual tubes that funnel urine from the kidneys to the bladder. Each paired with its respective kidney, anomalous uretal constriction can occur with an abnormal growth or inflammation. Congenital presentations of uretal reduction generally originate from a malformation, namely an unusual narrowing, of the uretal tube.

Early childhood presentations of ureteropelvic junction obstruction generally cause symptoms that mimic those associated with a urinary tract infection (UTI). It is not uncommon for a child to pass dark or blood-tinged urine, display abdominal distention, or to experience discomfort when urinating. Some children may also experience frequent urinary tract infections accompanied by abdominal cramping and discomfort.

It is entirely possible for mild obstructions to subside independently without treatment. If the obstruction is mild, regular monitoring may be utilized to determine if ureter function improves. When ureteropelvic junction obstruction worsens or threatens kidney or bladder function, surgery may be performed.

Pyeloplasty is the surgical removal of the uretal blockage and repositioning of the ureter tube to facilitate proper urinary tract function. Detaching the affected uretal tube from the kidney, the surgeon will excise the constricted tissue and reattach the remaining uretal tube back to the kidney. If the uretal tube has been damaged or weakened from prolonged distention, short-term stent placement may be performed to reinforce the compromised tissue. Once the ureter mends, the stent is removed.

A pyeloplastic procedure may be performed openly with a single incision or laparoscopically with several small incisions. Both surgical approaches require hospitalization and carry risk for complication, including infection. Though laparoscopy is most frequently used, the severity of one’s condition and overall health will generally dictate surgery type.