Renal Obstruction & Ureteral Strictures

Find your care

Call 310-794-7700 to learn more about kidney stone treatment at UCLA Health.

Ureteropelvic Junction Obstruction & Ureteral Strictures

What is Ureteropelvic Junction Obstruction?

Ureteropelvic junction (UPJ) obstruction is when there is a blockage where the kidney attaches to the ureter (the tube that carries urine to the bladder). The blockage slows or stops the flow of urine out of the kidney, which can cause pain, infection, and kidney failure. The physicians in UCLA Urology’s Division of Endourology are experts in prompt diagnosis and treatment of UPJ obstruction.

What is a Ureteral Stricture?

The ureter is the tube that carries urine from the kidney to the bladder. A narrowing or stricture of the ureter can stop the flow of urine and cause pain, infection, and kidney failure. Our experts specialize in advanced endoscopic and minimally invasive techniques to reestablish drainage from the kidney and preserve kidney function.


UPJ obstruction is typically present from birth. Ureteral strictures are more likely to occur after undergoing a surgery in the urinary tract. Other causes include:

  • Abnormal blood vessel over the ureter
  • Scar tissue
  • Infection
  • Kidney stones


UPJ obstruction and ureteral strictures can sometimes occur without symptoms but when symptoms are present, they include:

  • Urinary tract infection with fever
  • Flank pain (pain in the upper abdomen or back, worse with fluid intake)
  • Kidney stones
  • Bloody urine
  • Nausea and vomiting


Comprehensive testing is required to properly diagnose someone with UPJ obstruction or a ureteral stricture:

  • Urine and blood tests
  • Renal ultrasound to evaluate for hydronephrosis
  • CT scan to study the patient’s anatomy
  • Nuclear scan for kidney function 
  • Endoscopic evaluation


Our experts utilize state-of-the-art surgical techniques to address UPJ obstruction or ureteral strictures:

Endoscopic (retrograde) technique – Without making any incisions, a small camera is placed into the urethra and bladder and into the affected ureter. This allows the surgeon to open the blockage from the inside.

Percutaneous (antegrade) technique – Using a small incision, a camera is introduced into the kidney directly through the skin between the ribs and the hip. The surgeon then uses various techniques to open up the blockage.

Robotic-assisted laparoscopic pyeloplasty – Through a few small incisions in the abdomen, the surgeon uses laparoscopic instruments to remove the blockage and reconnect the healthy part of the kidney to the healthy ureter. This technique offers the highest success rate.

A narrow silicone tube called a stent may be placed after these procedures to allow the area to heal properly while draining the kidney. The stent is removed a few weeks later in the office. 


Detecting and treating the problem promptly can help prevent loss of kidney function. Most people recover well from surgery and have no long-term problems. A small percentage of patients may still develop kidney stones or infections in the affected kidney.