Ureteropelvic junction obstruction is one of the most common causes of hydronephrosis – literally “water in the kidney”. As the name implies, there is an obstruction, or blockage, where the ureter meets the pelvis of the kidney. This blockage can affect the function of the kidney, can cause intermittent episodes of abdominal pain, or both. Ureteropelvic junction obstruction is most commonly diagnosed in one of two ways. First, ultrasounds performed during pregnancy may reveal a dilated kidney, which on investigation after a baby is born might be due to ureteropelvic junction obstruction. It turns out that the majority of these can be observed, with approximately 10 to 25% requiring surgery to protect the function of the kidney. The second common presentation is intermittent episodes of abdominal pain, often associated with vomiting. During an episode of pain, the kidney will be dilated on ultrasound or CT scan. When the child is comfortable, the kidney will often appear less dilated or may even appear completely normal. Ureteropelvic junction obstruction may be caused by narrowing of the ureter where it meets the kidney, or it may be caused by kinking of the ureter over blood vessels to the lower pole of the kidney. The latter is more common in intermittent obstructions.
Generally speaking, ureteropelvic junction obstruction is repaired surgically when it affects the function of the kidney, or when it causes symptoms such as abdominal pain and vomiting. Standard repair consists of removing the obstructed segment and suturing the ureter to the kidney with a wide-opening to prevent future obstruction. Traditionally, this has been done through an incision on the front of the abdomen, an incision on the side, or flank, or an incision in the back. The expected success rate for these operations is greater than 95%. Risks include recurrent obstruction, urinary leakage, bleeding and infection. Complications are relatively infrequent.
There are alternatives to the traditional open operation for ureteropelvic junction obstruction. The first is called endopyelotomy, which consists of an incision through the narrowed segment from within the urinary tract followed by several weeks of catheterization to allow the ureter to heal with a wider caliber. This incision can be made through a telescope that is either inserted through the urethra, the bladder and up the ureter, or through a percutaneous (meaning through the skin) puncture into the kidney itself. Endopyelotomy carries a lower success rate than traditional repair of UPJ obstruction (pyeloplasty), and in children has been used mostly as a secondary procedure after failed pyeloplasty. Risks of the procedure include recurrent obstruction, bleeding, and infection.
Perhaps the best mix of a minimally invasive approach and traditional approach is laparoscopic pyeloplasty. This is an operation in which the traditional operation is performed, but using a laparoscope. Generally, three 5 millimeter incisions are made through which a telescope and surgical instruments are inserted. The operation is then performed as previously described. Sewing a small structure like the ureter is technically difficult, and so laparoscopic pyeloplasty is only performed at a handful of children's hospitals. The success rate thus far has been excellent, and we expect outcomes from laparoscopic pyeloplasty to be the same as those for open pyeloplasty. Generally, children go home the day after laparoscopic pyeloplasty and recovery is expected to be rapid. If you wonder whether your child is a candidate for a laparoscopic approach to ureteropelvic junction obstruction, please feel free to contact us. Children’s Hospital of Pittsburgh has the largest experience in pediatric laparoscopic pyeloplasty in the tri-state area.
