What is ureterovesical junction (UVJ) obstruction?
The ureterovesical junction is located where the ureter (the tube that drains urine from the kidney) meets the bladder. Ureterovesical junction (UVJ) obstruction refers to a blockage to this area. The obstruction impedes the flow of urine down to the bladder, causing the urine to back up into and dilate the ureters and kidney (megaureter and hydronephrosis).
Unilateral UVJ obstruction is the second most common prenatally detected obstructive disease, often picked up on maternal ultrasounds during pregnancy. Each year, we treat nearly 100 children who have a UVJ obstruction.
Signs and symptoms
Due to the increased use of prenatal imaging, UVJ obstruction may be identified before any symptoms are present. If any dilation is identified in the kidneys or ureters, the baby will be monitored throughout the pregnancy and after birth. Once the baby is born, further imaging studies may confirm the obstruction. Older children typically have back or flank pain and kidney stones. The pain may be associated with nausea and vomiting. Other symptoms might include bloody urine, a urinary tract infection (often with a fever), or might even be a vague abdominal pain.
Causes
UVJ obstruction usually occurs during fetal development. Most of the time, the blockage is caused when the connection between the ureter and the bladder narrows. UVJ obstruction can also be due to scar tissue, infection, a benign polyp or kidney stones.
Evaluation and diagnosis
Your child may undergo a variety of tests to help confirm his diagnosis and evaluate the extent of his condition.
Renal bladder ultrasound (RBUS): This procedure uses sound waves to outline the kidneys and bladder. It will enable us to see the degree of hydronephrosis (dilation of the kidney).
MAG III renal scan: This study helps us determine how each kidney is functioning and the degree of blockage. An intravenous line (IV) is used to inject a special solution called an isotope into your child's veins. The isotope makes it possible to see the kidneys clearly. Pictures of the kidneys will be taken with a large machine that rotates around your child. Your child will need an IV and a catheter for this study.
MRI/MRU: MRI is a radiation-free diagnostic procedure that uses a combination of a large magnet, radiofrequencies and a computer to produce detailed images of the body. Magnetic resonance urography (MRU) creates detailed pictures of the kidneys, ureters and bladder. Your child will need an IV and a catheter for this study. Your child may need sedation if she is young and might have difficulty tolerating the length of the study, which is typically 40 minutes.
Treatment
Each year, approximately 50 ureteral reimplantations are done at CHOP. Our overall goal in treating a UVJ obstruction is to preserve renal function. In situations where the kidney function is compromised, surgery is needed. In some children, an ultrasound may show a significant amount of dilation (megaureter and hydronephrosis) but the kidney functions and drains well. In this situation, we will closely follow your child with repeated imaging studies.
Cutaneous distal ureterostomy
In a newborn with massive ureteral dilation or poor renal function, a cutaneous distal ureterostomy may be recommended. The ureter is surgically brought to the surface of the skin to allow it to drain urine freely into the diaper. This allows the affected kidney and ureter to decompress. Around 18 months of age, the ureter is then reimplanted into the bladder.
In select cases, the obstruction can be managed completely endoscopically (without any skin incisions). Your child's surgery will be done under general anesthesia. While your child is asleep, the surgeon will use a laser to open up the obstruction. He will then use a small balloon to expand the narrow area and leave a temporary small tube, called a stent, to allow the urine to drain.
Ureteral reimplantation
The surgical procedure to correct UVJ obstruction is called a ureteral reimplantation. This surgical procedure involves removing the section of the ureter that is abnormal, reducing it and reconnecting the ureter.
In young babies, the reimplantation is done through a small incision. Minimally invasive surgery (MIS) is an option for children older than 6 months. The reimplantation can be done either laparoscopically or through a robotic assisted laparoscopic approach. The minimally invasive approach is accomplished through three small incisions, the size of a grain of rice. The advantages are smaller, less visible incisions and a quicker recovery period. The minimally invasive technique is not appropriate for all children. Your healthcare provider will work with you and your family to determine what kind of intervention is best.
Reviewed by: Division of Urology
Date: May 2011
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