Ureteropelvic junction (UPJ) obstruction is caused when the connection between the ureter and the renal pelvis of the kidney (ureteropelvic junction) is blocked—or narrower than normal—and urine builds up behind the obstruction. This can cause the affected kidney to swell (hydronephrosis). Untreated, the condition can cause severe damage to the kidney.
Ureteropelvic junction (UPJ) obstruction is treated surgically under general anesthesia. Prior to surgery, however, several tests are conducted to confirm how well the kidney is working—such as whether it is able to make urine and pass it from the renal pelvis (uppermost part of the ureter that links to the kidney) to the tube that transports urine from the kidney to the bladder (ureter).
Surgical Options for UPJ Obstruction
Most cases of UPJ obstruction are congenital (present from birth), meaning the majority of these patients are infants and young children. Before surgery, children are monitored closely. If their kidneys are developing poorly or are not draining urine well, open surgery may be required to fix the obstruction.
In children, surgery involves removing scar tissue from the blocked area. Known as pyleoplasty, the procedure calls for the reconstruction or alteration of the renal pelvis, in which healthy parts of the ureter are joined to the kidney. In older children, this can sometimes be done less invasively via laparoscopy, in which tubes are placed through small incisions in the abdomen to allow the urologist to perform the surgery without a large incision.
In adults, surgerical options include:
- Endoscopic surgery (endopyelotomy) - Small instruments are inserted through the urethra (the tube that carries urine from the bladder), and then the blockage is burned with a laser or electrical current, or cut with a small scalpel. A small tube called a stent is placed in the area to act as a scaffold and to allow healing of the ureter and urine drainage.
- Percutaneous surgery - This is similar to the endoscopic method, except that a small cut for the surgical instruments is made on the side of the body between the hip and the ribs.
- Laparoscopic pyeloplasty - As in children, in this approach the blockage is removed and the healthy ureter is reconnected to the kidney to allow urine to flow.
UPJ Obstruction Surgery Success Rates
Success rates vary depending upon the skill of the surgeon and the complexity of the obstruction. Laparoscopic pyeloplasty can have success rates as high as 95 percent. This is similar to the success rates of open surgery, but requires a shorter hospital stay and allows for a faster recovery.
For endopyelotomy, when the obstruction is removed using tools inserted through the urethra, success rates range from 80 to 90 percent. This procedure can also be done in older children, or repeated if the first attempt at surgery fails.
Post UPJ Obstruction Surgery Follow Up
After surgery, antibiotics are given to prevent infections. If a stent was inserted in the urethra, it will be removed after four to eight weeks.
A follow-up exam is performed one to three months after surgery. This includes an ultrasound of the kidney. In addition, after three to six months, another test is done to see how well the kidney is functioning. This may include an imaging test using a small amount of radioactive material or an intravenous pyelogram, a special type of X-ray that shows how effectively the kidneys filter a dye injected into the blood.
Additional imaging tests may be done up to a year or longer after surgery, ensuring the kidney continues to work properly.
Potential complications of open UPJ obstruction surgery include:
- Kidney infection
- Leakage of urine from the connection between the kidney and ureter
- Return of the obstruction, or narrowing of the ureter where it connects to the kidney
Complications of endopyelotomy include:
- Internal bleeding
- Appearance of another obstruction
UPJ obstruction. (2011). A.D.A.M. Medical Encyclopedia.
Nakada SY, Hsu TH. (2011). Management of Upper Urinary Tract Obstruction. Campbell-Walsh Urology, 10th. ed.