UPJO – Ureteropelvis Junction Obstruction

UPJO is the most common disorder in the upper urinary system. It is usually diagnosed after evidence of ureteropelvic expansion is noticed in an ultrasound examination during the mother’s pregnancy. One of the functions of the kidneys is to clean the blood of various toxins and secrete them, together with the urine, into the bladder. After leaving the kidney tissue, the urine runs into the renal pelvis, moves into the ureter via a channel known as the ureteropelvic junction, and continues down into the bladder. Obstruction or lack of passage in the ureteropelvic junction leads to expansion of the renal pelvis and eventually to kidney function disorder.

There are a number of levels of UPJO, from light obstruction – that requires monitoring but no treatment – through medium and severe that obligate surgical repair aimed at saving the obstructed kidney and preventing complications such as urinary tract infections, high blood pressure, etc.

Symptoms and Diagnoses

Most of our patients are diagnosed with UPJO after evidence of fetal renal pelvic expansion during the mother’s pregnancy. In these cases, we advise strict monitoring during the pregnancy with the aim of negating or identifying changes in the extent of expansion, checking the amount of amniotic fluid and of course following the size of the pelvis throughout pregnancy. In most cases there is no need to induce birth, but in some extreme cases we do encourage a premature birth. 

Doctors in the Pediatric Urology Department are involved in the Multi-Disciplinary Pre-Natal Diagnosis Clinic which operates at Shaare Zedek, in which all complex cases are treated by a cadre of specialists from various disciplines, including Midwifery, Genetics, Pediatric Nephrology and Urology.

In rarer cases, children can be diagnosed with UPJO at a later age, after pains in the waist, infections in the urinary tract and sometimes purely by chance.


Children already diagnosed with UPJO in their mother’s womb usually undergo an ultrasound examination as part of the discharge process after birth, in coordination with the Pediatric Urologist. Another test is conducted after a month or two to assess whether there is still renal pelvic expansion and if so, what its dynamics are. The ultrasound can only support evidence of UPJO but cannot confirm or negate whether there is an obstruction or danger of kidney malfunction. 

Therefore, if the doctor decides that he or she needs to check that, the child will undergo a special kidney mapping test (MAG-3). This is done at Shaare Zedek’s Nuclear Medicine Institute. During the test – a light simulation test not requiring anesthesia and with minimal exposure to radiation – a miniscule amount of radioactive material is injected into the child’s vein. It is then possible to assess the functioning of each kidney separately and to see how the injected substance is released from the kidney, consequently allowing the doctor to confirm or negate obstruction. It is generally accepted that the normal functioning of a healthy kidney is around 50%.


Not every child with signs of UPJO needs surgical intervention. On the contrary. Less than 50% of children diagnosed with UPJO need surgical treatment. The Pediatric Urology Department at Shaare Zedek was one of the first in the world to start adopting this conservative approach in these cases. As of today, more than 1,000 children are under the department’s supervision and only 40% of them needed surgical repair.

A child with UPJO will need surgical repair in the following cases:

If there is deterioration in kidney function during the monitoring stages or if they have low kidney function after birth.

If, in the MAG-3 kidney mapping test, doctors identify a significant obstruction or note clinical symptoms such as urinary tract infections or waist pains.

The Pediatric Urology Department has much experience in treating children with UPJO, as is evident from participation in many international conventions and articles on the subject in some of the leading Pediatric Urology journals:

https://www.ncbi.nlm.nih.gov/pubmed/19692031 [article from 2009]

https://www.ncbi.nlm.nih.gov/pubmed/16504374 [article from 2006]

https://www.ncbi.nlm.nih.gov/pubmed/12081774 [article from 2002]

https://www.ncbi.nlm.nih.gov/pubmed/10458427 [article from 1999]

Links to-PubMed


Surgical Methods for Correcting UPJO

If it is decided that surgical repair is the solution, there are two main approaches: open surgery and micro-invasive surgery (Laparoscopy).


Open surgery is a standard operation we have been performing in the department for years. In recent years we have made some changes in order to obtain better cosmetic results and to enable earlier discharge from hospital. We always want to let the child go back to his or her home and natural surroundings as quickly as possible.

The surgery involves a 4cm incision in the waist. After removing the affected renal pelvic area, we perform anastomosis (linkage) between the remaining part of the renal pelvis and the ureter above the nephrostome. This is a tube of which part enters the bladder area and part stays outside the patient’s body to aid kidney drainage in the first 48 hours after surgery. After that, the nephrostome is sealed and kept under dressing on the child’s waist.

The child is then discharged and returns to the clinic after about 4-6 weeks to have the tube removed. This is a simple procedure lasting a few seconds with no need for sedation. It is worth noting that even while the child is carrying the sealed tube, he or she can return to normal activity in nursery, kindergarten or school. Parents only need to change the dressing regularly. 

With children over 4, or children on whom we need to perform micro-invasive surgery for technical reasons, we conduct a laparoscopy using small incisions. The laparoscopy maintains the surgical principles of open surgery, just using smaller incisions in the body. After the operation, the patient is discharged with an internal stent. In such a case, the child must have the stent removed, a procedure done in the Urology Institute under anesthetic or heavy sedation about 6 weeks after the initial surgery. 


If, after initial evaluation, the doctors decide on conservative treatment (ie only to monitor, not to operate), the newborn child will undergo periodical ultrasound tests every 3-6 months. In rarer cases they may also undergo the mapping test to ensure that kidney function remains intact.

If doctors decide to perform surgery, the first ultrasound will be done about three months after the operation. Six months after is the mapping test (MAG-3), which will show whether kidney function has indeed improved and the obstruction has not relapsed. Based on the results of these tests and as necessary, the doctors will decide when to perform future tests.