What is Uretero Pelvic Stenosis in Children?

The most important task of the kidney is to filter the blood and remove harmful substances and excess minerals from the body with urine, and the waste solution formed is called urine. After urine is formed in the kidney, it is excreted from the body through the urinary ducts.

The urinary ducts consist of the following structures: small and then large collecting ducts, pelvis renalis, ureters and bladder, urethra. The point where the pelvis and ureter meet (Figure-1, black circle) is called UPJ -Uretero-Pelvic Junction in Turkish, uretero-pelvic junction.

There is a urine drainage problem as a result of a stenosis in the transportation of urine at the transition point between the pelvis and the ureter (Figure-1, black circle). This is called uretero-pelvic junction stenosis (UPD stenosis). Due to this obstruction in the transmission of urine, urine accumulates in the pelvis and enlargement of the pelvis (hydronephrosis) occurs. If this stenosis is not treated in time, it can lead to a decrease in kidney function over time or to complete loss of kidney function.

Figure-1: Kidney pool (renal pelvis) and other internal structure with ureter. The transition point between the pelvis and ureter is the site of UPJ stenosis (black circle)

Hydronephrosis is the most common urinary system anomaly found in ultrasonography performed during pregnancy with 1-5%. Most of these are temporary conditions due to slow development of the urinary system. Most of them resolve spontaneously in the womb or up to 1 year of age after birth, so they have no clinical significance.

Despite the fact that this is the case, unfortunately, unnecessary and invasive examinations are performed in most of these patients by physicians who have no knowledge of the subject or who are too cautious.

The risk of ureteropelvic stricture in these patients increases as the degree of hydronephrosis increases or in cases where it is diagnosed very early in the womb. For example, while this rate is 10% in mild hydronephrosis, this rate increases to 60-65% in severe hydronephrosis.

What is the Frequency and Causes of Uretero-Pelvic Stenosis?

UPD occurs in approximately 1 in every 1500 live-born babies. The most common cause is congenital underdevelopment of muscle cells at the junction. Nearly 80% of ureteropelvic stricture is due to the condition we call intrinsic. Here, there is an inactive part with impaired functional contraction and relaxation. This area is narrow and fibrotic and therefore prevents flow. However, the reason for this failure to develop is not known exactly. As for the other causes; junctional polyps, VUR, external compression (such as mass and aberrant vascular compression).

How is UPD Diagnosed? What are the Methods Used in Definitive Diagnosis?

The main basis for diagnosis is history and physical examination. Prenatal period (period in the womb) must be questioned in the history. If there is enlargement in the pelvis in the womb, the time of diagnosis, that is, the month of pregnancy, unilateral or bilateral, the degree of enlargement and whether there is a change in the thickness of the fleshy part we call the parenchyma of the kidney, whether there is a change in the urinary canals (ureters) and bladder should be questioned.

After birth, a swelling, i.e. a mass, may be palpable in physical examination in infants, and the most common cause of intra-abdominal mass palpable in infants is hydronephrosis, and one of the most common causes of hydronephrosis is UPD. There may also be a history of urinary tract infection. Older children may have abdominal pain, especially flank pain, blood in the urine and sometimes hypertension.

In light of all this, the disease should be considered especially by the physician. The basic tests to be performed for diagnosis are urine and blood tests, urinary system ultrasonography and scintigraphy. Sometimes, depending on the patient's condition, additional tests such as MRI, IVP, VCUG may be required, but these are not routine tests that should be performed in every patient.

Ultrasonography (USG); If pelvic enlargement is detected, postnatal USG should not be performed as soon as the baby is born (because it may give false results), but on the 3-4th day or even at the end of the 1st week. If the enlargement is especially bilateral and severe and urgent intervention is required, then early USG can be performed.

In USG, just like in the womb, attention should be paid to the following; unilateral or bilateral enlargement, the degree of enlargement and whether there is any change in the fleshy part of the kidney called parenchyma (especially thinning), and whether there is any change in the urinary canals such as the ureter and bladder.

Ultrasonography alone is not diagnostic for UPJ stenosis, although it is often used in follow-up. Ultrasonography only shows the enlargement of the pool in the kidney, i.e. hydronephrosis, and the structure and thickness of the renal parenchyma.

Figure-2: Enlarged pelvis seen in the kidney with UPJ stenosis by renal ultrasonography, medically defined as hydronephrosis (fluid-filled cavities are seen as black on ultrasonography).

Scintigraphy; there are several methods in kidney scintigraphy, but as in UPD, if we suspect a stenosis that prevents flow in the urinary system, it is sufficient to perform scintigraphy (renogram with diuretic) with MAG3 or DTPA. With a renogram with diuretics, the function and drainage of the intravenously administered radiopharmaceutical is measured and evaluated separately in both kidneys as it is filtered through the kidney. The curve with UPJ stenosis does not empty and has an ascending curve. This rising curve should be seen in the definitive diagnosis of UPJ stenosis (Figure 3).

Figure 3: Renogram curves of normal kidneys in dynamic renal scintigraphy with diuretic on the left, and dynamic renal scintigraphy with diuretic on the right shows normal function in the left kidney and obstructive pattern in the renogram curve secondary to UPD in the right kidney.

Is MRI (Magnetic Resonance) Examination Necessary in Patients with UPD?

MRI urography obtained with MRI (magnetic resonance imaging), which has been used in recent years and has the advantage of not being exposed to radiation, can evaluate both renal systems and UPJ stenosis and the presence of cross veins at the same time. While UPJ stenosis is revealed with MR urography, the presence of cross veins can also be evaluated with MRI. However, since general anesthesia is required for this examination in infants and young children, it can be performed in selected patients.

In Which Situations Should a Voiding Cystogram be Performed in Patients with Ureteropelvic Stenosis?

It should be emphasized that routine voiding cystograms should not be performed in patients with UPD. However, it should be performed to rule out vesicoureteral reflux in the following cases.

• Frequent urinary tract infections
• Voiding problems
• Abnormal findings in the bladder on ultrasonography
• Abnormal findings in the ureter, i.e. enlargement
• Small kidney
• Serious changes in the renal parenchyma

How is Uretero-Pelvic Stenosis in Children Treated?

There are two main approaches to treatment.

• Follow-up
• Surgery

When determining the treatment option, parameters such as the patient's clinic, especially correctly diagnosed urinary tract infection and flank pain, the age and sex of the patient, the degree of urinary tract enlargement detected on ultrasonography, whether it is bilateral or unilateral, the condition of the renal parenchyma and the compliance of the family and the patient with the treatment to be given, renal function on scintigraphy and the discharge status of the system play an important role.

If the enlargement is not severe (especially on USG; if the diameter of the pelvis is less than 20 mm, the renal parenchyma is good and the scintigraphy is good, these patients are followed up and there is no need to give drug treatment. However, if there is deterioration in the tests and the above-mentioned clinic occurs, surgery comes to the agenda. If not, this group of patients are followed up as they may improve as the baby grows.

When is surgery performed for uretero-pelvic stenosis in children?

The criteria for surgery are the patient's clinic, especially side pain and urinary tract infection attacks, severe increase in pelvic diameter (>30 mm) on ultrasonography, deterioration in renal parenchyma, deterioration of renal function on scintigraphy or deterioration in follow-up, and inability of the pelvis to drain the radioactive substance.

How can you tell if uretero-pelvic stricture surgery is successful?

First of all, if the patient's clinical condition improves, the enlargement regresses or stops, and the kidney drains easily on scintigraphy. If clinical and USG follow-ups are normal, scintigraphic examination may not be necessary.

What are the Surgery Options for Uretero-Pelvic Stenosis?

The surgery can be performed open, laparoscopically and robotically, each method has advantages and disadvantages. The method to be chosen should be decided by talking to the physician who will perform the surgery.

However, patient comfort of the laparoscopic method is very important and should be the preferred method of surgery.

What are the Advantages of Laparoscopic (Closed) Surgery over Open Surgery?

• Less pain
• Less bleeding
• Less infection
• Less scarring or even no scarring
• Shorter hospitalization
• Faster and easier recovery
• Faster return to daily activities

How is Laparoscopic (Closed) UPD Surgery Performed?

In order to create a large area in the abdomen through these tiny holes opened in the abdomen; the abdomen is inflated by giving carbon dioxide (CO2) gas into the abdomen. New tubes are inserted by making 3 0.3-1 cm wide incisions in the abdomen, one of which is in the belly button, in appropriate places on the skin. “Long surgical instruments” are inserted through these newly inserted tubes and the planned surgery is performed.

However, it should not be forgotten that Laparoscopy can cause more serious complications when performed by ineffective people.

What is done before uretero-pelvic stenosis surgery?

First of all, a good history should be taken and a general physical examination should be performed. Then, the family (mother and father) should be well informed about the process, i.e. before, during and after surgery. If the child is older, the child is also included. A number of tests are performed, these tests are not general and are determined according to the patient. The patient is also seen by the anesthesiologist and the family and child are informed about the anesthesia process. The patient is fasted for 4 hours before surgery.

 

What is the Recovery Process After Uretero-Pelvic Stenosis Surgery?

Generally, in all 3 methods, the patient is fed 2 hours after the operation in accordance with the doctor and / or nurse directives. The patient is hospitalized for about 2 days and discharged.

When the patient is discharged, a dressing is applied, then there is no need for dressing, the stitches dissolve spontaneously and do not need to be removed. The patient continues his/her normal active life after the operation in line with the doctor's recommendations. Then the follow-up treatment described above is applied. A JJ stent is placed between the pelvis and bladder during surgery and this is removed cystoscopically after about 1 month.

What are the Risks of Uretero-Pelvic Stenosis Surgery?

Since the patient will receive general anesthesia during the operation, there may be anesthesia risks, which the patient's relatives are informed about by the anesthesiologist before the operation.

In addition, there may be some surgical complications (wound infection, bleeding, urinary tract infection, temporary or permanent obstructions in the urinary tract and urine leakage, recurrence of the stenosis, intestinal, spleen, cardiac injury, etc.).

*** The information provided here, the content of the website is organized for the purpose of informing the visitor, especially families. No information should be considered as advice by visitors and should not lead to any decision or action. The family should definitely have their patient examined by a pediatric surgeon, consult with him/her and make a decision by consulting his/her knowledge.