The area where the kidneys and ureters meet is called the ureteropelvic junction (UPJ). When this area forms abnormally during fetal development, it can cause a blockage—a congenital condition known as ureteropelvic junction obstruction (UPJ) obstruction. It occurs only once out of every 1,500 births.
In a healthy body, the kidneys filter the impurities in our blood and flush waste into urine. Urine flows into renal calyces, which are collecting areas for urine located in the kidneys. From there, urine drains into the renal pelvis and then the ureter. When this area is obstructed, urine cannot flow normally. This obstruction can cause serious damage to the affected kidney.
UPJ obstructions typically occur on one side of the body—usually the left side. Most blockages are minor and resolve on their own over time; only 15 – 20% of babies affected by this condition undergo surgical repair.
Children are typically diagnosed with UPJ obstruction after a prenatal ultrasound shows swelling in one of the kidneys—a secondary condition called hydronephrosis that happens in 1- 5 percent of all pregnancies. Once these babies are born, pediatric urologists at Riley at IU Health follow them closely with serial ultrasounds to see if the swelling subsides. Depending on their progress, we may also run other tests to fully assess their anatomy. Among them are:
Once these tests are done, we can begin planning treatment for any obstructions.
The degree of swelling noticed during fetal development is a good predictor of which babies will need surgical treatment after they are born. Surgery is only necessary if swelling does not decrease or if further tests show the kidneys are not functioning as they should. The age at which we encourage surgery varies based on each child’s progress. Some children may have surgery during the first few months of life; others may not need it until they are 2 or 3 years old.
An open or robotic surgery repairs the tube that drains the kidney (the ureter) by removing the part that does not allow proper drainage. Surgeons use healthy tissue from the body to create a normal funnel. This surgery has a 98 percent success rate. We continue to follow these children after surgery with routine ultrasound, but most never have another problem with the urinary tract system afterwards.
Another form of obstruction—symptomatic ureteropelvic junction obstruction––can occur in older kids and even adults. This version of UPJ is usually caused by a congenital condition that was too mild to be detected during fetal or newborn development; it can also stem from a blood vessel that crosses the ureteropelvic junction, causing occasional blockage. It is diagnosed after a child complains of side pain, nausea and vomiting and diagnostic imaging shows hydronephrosis. These children always need surgery and have similar success rates to those of younger children and babies after they are treated.
Some babies are born with a blockage in the area between the kidneys and the ureters. Physicians call this abnormality ureteropelvic junction obstruction (UPJ).
This patient education resource is published by the American Urological Association to offer information about urological conditions such as UPJ obstruction.
The U.S. National Library of Medicine shares public health information on thousands of conditions, including UPJ obstruction.
Pediatric urologists at Riley at IU Health have a grant from the National Institutes of Health to compare robotic surgery with open techniques for repairing ureteropelvic junction obstruction. They are studying any differences between recovery times, length of hospital stays and issues related to pain management.