Ureteropelvic Junction Obstruction

The urine formed in the kidney first comes to the kidney pool (renal pelvis) where it is collected through the small canals, and from here it is transmitted to the ureter (urinary canal) and then to the bladder, respectively. The point where the renal pelvis and ureter meet is called the “ureteropelvic junction”.

Stenosis due to congenital developmental disorders at this transition point between the kidney pool (pelvis) and ureter (urinary canal) is called Ureteropelvic Junction Stenosis (UP Stenosis or Kidney Outlet Stenosis). Due to this kind of stenosis, urine transmission is impaired, and enlargement (hydronephrosis) occurs in the kidney pool and in channels due to accumulated urine in the kidney. If this stenosis causes serious problems in urine transmission, it may cause a decrease in kidney functions over time, or even a complete loss of kidney functions.

What is the prevalence?

UP stenosis is the most common cause of this enlargement in babies with an enlarged kidney (hydronephrosis) in the mother’s womb. Approximately 1 in 1500 births. It is usually on the left side and is twice as common in men.

What is the reason?

It is often a congenital disorder. It is formed due to disorders in the development process of the ureter bud and the kidney, called metanephric blastema, and the structures that make up the urinary canals. In addition, abnormally developed renal vessels cross the UP junction or the UP junction with a higher outlet than normal may be the cause of congenital UP stenosis.

Other than congenital disorders, previous infections (especially tuberculosis), trauma and surgeries may be the causes of UP stenosis that develop later.

How is it diagnosed?

The diagnosis is usually made by ultrasound during routine pregnancy screenings, ie in the womb. Some cases are detected years later, even in adulthood, by radiological examinations performed for pain, urinary infection or any other reason. In cases diagnosed with UP stenosis radiologically, renal scintigraphy (DTPA or diuretic renogram with MAG-3) is performed to determine the severity of the stenosis and decide whether surgery is required. Early diagnosis and treatment of severe strictures is very important in terms of protecting kidney functions.

Who is due for treatment?

  • If kidney function is impaired (<40%) or decreases more than 10% during follow-up,
  • Poor drainage despite the medication given in the diuretic renogram,
  • If it causes persistent pain and infections

How is the treatment?

The treatment of UP Stenosis is surgical. In the surgery called pyeloplasty, the narrow UP junction is removed and the kidney pelvis is stitched back into the ureter and combined. This procedure can be performed open, laparoscopic or robotic. Laparoscopic and robotic surgery provides advantages over open surgery in terms of cosmetics and healing process.

Endopyelotomy surgery, which is performed endoscopically in people who have undergone pyeloplasty before but failed, is another surgical technique used in the treatment of this disease.

NOTE: The content of the page is for informational purposes only, consult your doctor for diagnosis and treatment.