Uretero-Pelvic Junction Obstruction (UPJ Obstruction)


The urinary tract includes 2 kidneys, 2 ureter tubes, a bladder and a urethra. Properly functioning kidneys produce urine by removing salt, water and waste.  Urine should flow in one direction down from the kidneys, through the ureter tubes, to the bladder and out the urethra.

Each kidney contains a large cavity which enables it to collect the urine. This is called the renal pelvis. Uretero-Pelvic Junction obstruction (UPJ obstruction) occurs when kidneys produce urine too fast to drain out of the renal pelvis into the ureter. Urine becomes blocked and is unable to flow to the bladder. This can cause kidney damage.

UPJ obstruction occurs in approximately one in 1,500 children.1 UPJ obstruction is the most common obstructive disease found prenatally in fetuses.

Patients can be seen by Texas Children's experts in Urology and Robotic Surgery.

Causes & Risk Factors

UPJ obstruction usually develops in the fetus while the kidneys are developing. Older children may also experience obstruction, due to:

  • Misplaced blood vessel
  • Surgery
  • Kidney stones
  • Scar tissue
  • Infection
  • Prior treatment for a blockage
  • Disorders that cause inflammation of the urinary tract

If untreated, UPJ obstruction can lead to permanent loss of kidney function (kidney failure). Even after surgery, your child may have an increased risk of developing kidney stones and infection. But despite the risks, long-term outcomes are generally good.

Symptoms & Types

Children with UPJ obstruction can have pain without an infection. Or the pain can be irregular - urine may drain normally one day and be completely blocked another. This can produce sporadic pain.

For other children, there are no symptoms at all. If symptoms do occur, they can include:

Diagnosis & Tests

Ultrasounds can often detect the presence of UPJ obstruction before the baby is born. This is a good way to screen for the problem. To confirm the diagnosis, physicians must perform tests after birth.

Tests for UPJ obstruction can include:

  • Ultrasound 
  • Voiding cystourethrogram - an x-ray of the bladder and urethra is taken while the bladder is emptying
  • Renal Scan with Lasix - radioactive material is injected into the blood and followed with a camera to observe kidney function and drainage

Treatment & Care

The testing listed above will help determine if the obstruction should be repaired (pyeloplasty) or the kidney should be removed (nephrectomy).2

Standard treatment for UPJ obstruction is pyeloplasty. Pyeloplasty is used to reconstruct the ureter and renal pelvis to allow for better drainage of urine.

Pyeloplasty can be performed via open surgery or robotic / laparoscopic pyeloplasty. Robotic / laparoscopic surgery uses smaller cuts, resulting in smaller scars, less bleeding and faster return to normal activity.  The use of robotic laparoscopic surgery allows the surgeon to see images that are 10 times greater than what the human eye can see. Robotic laparoscopic surgery in children also leads to shorter hospital stays and a reduced need for pain medication after surgery.  Recovery time following robotic surgery is faster and there are less scarring.3

Living & Managing

Your child may experience swelling of the ureter and poor drainage of his kidney immediately following surgery. This will clear up as the area heals. A UPJ obstruction almost never comes back once it has been repaired.

But there is no way to prevent further problems with the kidney. You'll want to monitor your child for kidney stones or infection. Stones or infection may occur in the affected kidney even after treatment.

More Information & Related Links





[1] Washington University School of Medicine in St. Louis. Urologic Surgery: "Ureteropelvic Junction (UPJ) Obstruction in Children." http://www.urology.wustl.edu/en/Patient-Care/Pediatric-Urology/UPJ-Obst…

[2] Weill Cornell Medical College, Department of Urology. "Laparoscopic Pyeloplasty." https://www.cornellurology.com/clinical-conditions/minimally-invasive-s…

[3] Texas Children's Hospital, Texas Children's Blog. "Helping Hands with the Assistance of a Robot Named DaVinci." http://www.texaschildrensblog.org/2013/10/helping-hands-with-the-assist…