Overview of Vesicoureteral Reflux
Vesicoureteral reflux (VUR) is a condition where urine flows backwards from the bladder up into the kidneys, usually when urine is being eliminated from the body. This can happen if the tube that connects the kidney and bladder is too short. This condition was linked to repeat urinary tract infections, kidney scarring and permanent kidney damage, especially in children, around 1960.
VUR is quite common, affecting around 1% of all new born babies, and as much as 15% of babies diagnosed with prenatal hydronephrosis (a condition where a baby’s kidneys become enlarged).
VUR is more common in White people than Black people, and twice as common in women than in men. If hydronephrosis is detected, cases of VUR are more frequent in boys. Also, around 16% of new born babies diagnosed with hydronephrosis have VUR, and when tested, around 30% to 40% of children with a feverish urinary tract infection have some level of VUR.
There seems to be a genetic link to VUR, as children born to mothers with the condition are more likely to have it. Also, twins have a high likelihood of having VUR. If siblings are considered, around 30% will have VUR, but it is not recommended to screen siblings who don’t show any symptoms and have normal kidney scans. VUR can also be seen in people with other congenital conditions like posterior urethral valves, overactive bladder, spina bifida, urinary outlet obstruction, and others.
Sometimes VUR doesn’t show any symptoms, but could lead to nephropathy (kidney disease), which can be severe. Around 5% of all pediatric kidney transplants are due to kidney failure caused by reflux nephropathy. Fortunately, if VUR is diagnosed and treated early, it can prevent kidney damage and repeated urinary tract infections.
Bladder or bowel dysfunction involves issues in the lower urinary tract in children, like urinary urgency, postponement of urination, and other problems. These can also be accompanied by issues like chronic constipation. This dysfunction is more common in females.
VUR patients with bladder or bowel dysfunction have a higher risk of developing infections even after continuous medication is given, and the likelihood of spontaneous damping of the problem is lower (31% compared to 61%). However, treatment for the dysfunction, such as scheduled voiding, exercises, behavioural modifications and anticholinergic (nerve blocking) therapy, can reduce symptoms, improve bladder function and increase spontaneous damping.
To diagnose VUR, urinalysis including the evaluation for proteins and bacteria in urine, and a urine culture, is done. Also, creatinine level is determined to check the kidney function, particularly in severe cases. A baseline kidney scan using ultrasound is recommended initially and for follow-up, to check the kidney structure and detect any abnormalities.
A radionuclide renal scan and a voiding cystourethrogram (VCUG), which is a type of x-ray used to check the urinary tract, are recommended to evaluate the extent of VUR. Although, ultrasound is not very effective in detecting high-grade (severe) VUR, and infants and children need special care when undertaking a VCUG, to avoid emotional and physical stress.
When a child has their first feverish urinary tract infection, typically, an ultrasound is done first, then a VCUG is done if there are any abnormalities found in the ultrasound, a second urinary tract infection occurs, or any other high-risk factors are found. VCUG is the definitive test to identify VUR. To identify VUR effectively, at least two VCUG tests are usually necessary. Anesthesia can interfere with the test results, but sedation may be needed for some patients.
To ensure a good diagnosis and plan for the right treatment, imaging of the urinary tract is necessary, using the lowest possible radiation. The VCUG results, along with the age of the patient and how the condition presents itself, are used to determine the treatment plan.
Anatomy and Physiology of Vesicoureteral Reflux
The ureter is a tube-like structure that helps drain urine from your kidneys to your bladder. During our development before birth, a sprout-like structure, referred to as the ureteric bud, grows out from the furthest part of the Wolffian duct, a kidney-forming duct. This bud eventually reaches out and taps what’s known as the metanephric mesenchyme, contributing to kidney formation.
The ureter attaches to the kidney at the renal pelvis, and as it moves further down, it enters the bladder in a slanted manner, forming a tunnel known as the intramural or intravesical ureter. The point where the ureter and the bladder meet is called the ureterovesical junction (UVJ).
An essential function of the UVJ is to prevent urine from flowing back up the ureter (called VUR), more so as the bladder fills. If we cough, sneeze, or do anything that drives up bladder pressure, the intramural ureter will, in turn, increase its closing pressure to prevent VUR. This mechanism is supported by the contraction of a part of the bladder and the tubular muscles of the ureter.
The optimal ratio to prevent VUR is a 5:1 length to diameter ratio of the ureter tunnel. However, this ratio could change due to bladder wall reshaping and ureter narrowing.
VUR can happen for two main reasons. Primary VUR is usually due to a too short portion of the intravesical ureter that prevents the UVJ from blocking retrograde urinary reflux. Secondary VUR develops from increased pressure at the bladder during voiding. Various factors can contribute to secondary VUR, including anatomical or functional problems.
Primary VUR is the most common type and is directly due to the UVJ not functioning as it should. A short intramural ureter is the main cause of VUR, but other things like ureteral duplication, bladder outlet obstruction, abnormal bladder function, amongst others, could contribute.
VUR can occur at any time, but it usually happens when someone is urinating. VUR could resolve naturally over time as the child’s ureter lengthens, UVJ tissue remodeling, and bladder function matures.
Another condition associated with VUR known as intrarenal reflux is when urine backflows into the renal collecting ducts. This could pose significant risks like scarring the kidneys, stunted kidney growth, high blood pressure in children, and end-stage kidney disease. The occurrence of intrarenal reflux does not happen uniformly and depends on the individual’s functional anatomy.
Although VUR does not usually harm the kidneys, when associated with intrarenal reflux, bacteria present in the urine can infect the renal collecting ducts, potentially leading to kidney scarring and infection. Reflux doesn’t affect every calyx equally, and this depends on the functional anatomy of the individual and the pressure in the renal pelvis. Damage to the kidney from infections related to VUR can occur at any age and is not limited to just children.
Certain types of renal papillae (tube-like structures that drain urine into the larger kidney structure) are more prone to intrarenal reflux, while others are not. The renal papillae in the extreme upper and lower kidney areas are more susceptible to scarring due to VUR. Kidney scarring can also occur without an infection if urinary pressure is high.
Why do People Need Vesicoureteral Reflux
A VCUG, or Voiding Cystourethrogram, is a type of x-ray that helps doctors diagnose Vesicoureteral reflux (VUR). VUR is a condition where urine flows backward from the bladder into the kidneys. This test is often used in children who have recurring urinary tract infections or abnormal kidney ultrasounds. Doctors could also suspect VUR if a child has a swollen urinary tract (known as hydronephrosis), trouble urinating, bladder issues, pain when urinating, or blood in the urine.
The American Academy of Pediatrics recommends that children between 2 and 24 months old be checked for VUR if they have had two or more urinary tract infections with a fever, or if their kidney ultrasound is abnormal. In the UK, the National Institute for Health and Care Excellence recommends that babies under 6 months old with recurring or unusual urinary tract infections should be checked for VUR. But in children between 6 months and 3 years old, the doctor should also consider the child’s family history of urinary tract infections, whether the child has had a urinary tract infection caused by a bacterium other than E. coli, if the child’s urine flow is weak, or if the child has signs of a swollen urinary tract on an imaging test.
In general, long-term use of antibiotics and surgery are both good options for reducing the risk of urinary tract infections and kidney scarring caused by VUR. Normally, doctors initially recommend medicine, saving surgery for cases where medicine doesn’t work or isn’t needed, especially for mild cases of VUR. However, if VUR is still a problem despite using medicine, then surgery might be a good option.
Surgery might be considered in the following situations:
- if the kidneys aren’t growing as they should
- if the patient can’t tolerate or won’t take the antibiotics
- if the patient has multiple urinary tract infections or kidney infections despite using antibiotics
- if the patient’s parent or caregiver requests surgery
- if the patient still has severe VUR beyond 3 years old
- if the patient’s kidneys continue to be scarred or if the patient’s kidneys aren’t working properly.
When a Person Should Avoid Vesicoureteral Reflux
A VCUG (voiding cystourethrogram), a test that examines the urinary system, generally doesn’t have any absolute reasons why it shouldn’t be performed. However, there are some circumstances where it’s better to postpone or avoid it.
Pregnancy is one such situation, as the test uses radiation which could harm the fetus, so it’s not recommended. Another situation is when someone has an acute urinary tract infection (UTI), a severe form of bacterial infection in the urinary system. It’s best to hold off on the VCUG until the infection has been treated with suitable antibiotics.
There are also some particular situations where antireflux surgeries, procedures that stop urine from going up the wrong way in our urinary system, shouldn’t be performed. These include cases where the kidneys are nonfunctional or not working, people with Hutch diverticula (a small pouch in the bladder), people who are having problems with urination or have ongoing UTIs.
Lastly, any patient who, for any reason, cannot tolerate anesthesia (the medicine that makes you sleepy for surgery) would also be unable to have these procedures.
Equipment used for Vesicoureteral Reflux
A VCUG is a test that uses a special type of dye (water-soluble, iodinated contrast media) that can be seen on X-ray pictures. It needs a special X-ray machine called a fluoroscopy machine. This machine can take a series of images and turn them into a video. It can also take standalone images that can be analyzed later. These images are recorded and digitally stored on radiography computers. Then, they can be seen by doctors like radiologists and urologists while the VCUG is being performed.
The procedure known as laparoscopic extravesicular ureteral reimplantation for vesicoureteral reflux uses various tools. These include a synthetic absorbable suture on a tapered needle, working ports of 3 mm size, curved insulated rotating scissors, a laparoscope, tapered curved jaw dissectors, a special tube called a Hasson trocar, a reducer seal, Babcock forceps, a working port of 25 mm size, a circular Allis grasper, a ratcheted Diamond-flex retractor, and a ratcheted laparoscopic needle driver.
An open extravesical ureteroneocystostomy procedure makes use of tools such as scalpels, hemostats (used to control bleeding), scissors, needle holders, tissue forceps (for handling tissues), retraction tools (for moving tissues aside), surgical drapes and towels, sterile gloves and gowns, a Foley catheter (a tube to help with urine drainage), suture material (for stitching), and a ureteral stent (a tube inserted into the ureter to help urine drain).
In a robotic ureteroneocystostomy procedure, a specialized surgical robot with 4 arms is used. This robot includes a console for the surgeon to sit and perform the surgery. The robot arms hold the surgical instruments, which are controlled by the surgeon from the console. One of the robot’s arms holds a robotic camera to provide a high-definition view of the surgical area. The other 3 arms hold laparoscopic instruments, which are used to carry out the surgery. Other tools used in this procedure include special tubes called trocars, Foley catheters, double J stents, suture material, and surgical clips.
Who is needed to perform Vesicoureteral Reflux?
The VCUG, a certain type of imaging test, is done in a special section of the hospital (radiology suite) by a doctor who specializes in using medical imaging to diagnose and treat diseases (radiologist). This doctor gets help from a radiology technologist and a nurse. The test helps the doctor see how the organs are doing inside your body.
When it comes to fixing Vesicoureteral Reflux (VUR), a condition where urine flows back from your bladder into your kidneys, here are the medical professionals usually involved:
First, we have a pediatric urologist. This is a surgeon who specializes in diseases of the urinary tract in children. They’re the ones in charge and doing the actual surgery.
Next up is an anesthesiologist, or a nurse anesthetist. They’re responsible for giving you medicine that makes you sleep, so you don’t feel any pain during the operation. They also keep an eye on your vital signs (like your heart rate and blood pressure) while you’re asleep.
A surgical technologist or assistant is there to help the surgeon by giving them the tools they need, helping to move things out of the way in the operating area and generally providing technical help with the surgery.
A circulating nurse deals with equipment and materials in the operating room and gives assistance to the surgical technologist.
Last, but certainly not least, is the scrub nurse. They’re right there next to the surgeon, helping them directly during the surgery.
Preparing for Vesicoureteral Reflux
When performing a VCUG (Voiding cystourethrogram) – a medical test to check how well your bladder and urethra are working – the participation of both adults and children who are toilet-trained is important. The purpose of this test is to take high-quality images while making sure the person is as comfortable as possible, especially for children who might find this procedure unsettling. During this procedure, any advice and assurance from the radiologists or their assistants can significantly reduce any fear or anxiety. Sometimes, distractions or reassuring words can be helpful to calming children. Still, in some cases, a light sedative like midazolam might be used if the child is very nervous.
Now, if a person has specific heart conditions like artificial heart valves or holes in the heart, they would need some antibiotics before the procedure as a precaution. It’s essential to rule out any other causes of VUR (Vesicoureteral reflux – a condition where urine flows backward from the bladder towards the kidneys) before the test. The test is more effective when performed on a bladder that’s equivalent in size to a one-year-old’s. There’s no need for a cystoscopy (a procedure using a thin tube with a camera to look inside your urethra and bladder) before the VCUG.
During the procedure, several factors need to be checked, such as the size and function of the bladder, the person’s size and shape (body habitus), the condition of the kidney on the side not being tested, the person’s age, level of anxiety, any other health conditions (comorbidities), any history of kidney stones, how well the kidneys are working (relative renal function), severity of urinary tract infections (UTIs), and whether the person has a single or double kidneys.
It’s important to note that around half of the patients with abnormalities in the anus or rectum also have issues with their spinal cords. For these patients, problems with emptying the bladder and urine reflux might indicate a neurogenic bladder- a condition where a person has trouble controlling their bladder because of brain or nerve conditions. Hence, it’s usually suggested that these patients go through a complete evaluation, including a spinal MRI scan.
The setup for a VCUG might require the patient to take different positions depending on their gender to get the best possible images. Frontal images are taken for women, while men are slightly tilted to avoid overlap of pelvic bones onto the urethra. Lateral imaging is done when a urogenital sinus abnormality is suspected. The doctors will be looking for things like the structure and function of the urethra, abnormal passage (fistula), and the presence and degree of urine reflux. A process called cyclical voiding, i.e., filling up and emptying the bladder multiple times with a contrast fluid (a special dye that helps to see the organs better in the images), can improve the chances of detecting VUR. This process is generally done in children under the age of one. However, if VUR is detected during the first filling, this process doesn’t need to be repeated.
An important thing to remember is that patients might be allowed to use the washroom if they can’t empty their bladder during the test provided it’s close to the test room. After they’ve emptied their bladder, an image of the ‘renal fossa’ (the hollow space where the kidney lies) is taken immediately as reflux often happens during or right after voiding. Before the test, the doctor will review your medical history, prior test results and any imaging findings you may have.
As for the actual imaging procedure, a skilled nurse or radiology assistant will carefully insert a catheter into your urine passage, using a gel to reduce any discomfort. The size of the catheter will generally depend on the age of the patient, with the smallest size always being preferred.
Once the catheter is in place, a bottle filled with contrast fluid will be connected to it and placed 3 feet above the patient. The fluid will then flow into the bladder while being monitored through a technique called intermittent pulsed fluoroscopy. The goal here is to limit the radiation exposure as much as possible. The bladder is filled until either the patient, be it child or adult, feels the need to urinate.
Whether patients are seated or lying down when taking images, the results play a crucial role in any future urinary system treatments. Understanding the procedure can help patients manage anxiety levels and participate more effectively in their own healthcare.
How is Vesicoureteral Reflux performed
Vesicoureteral reflux (VUR) is a condition where urine flows backward from your bladder to your kidneys. A treatment for this condition, which started in 1984, involves using a thin tube with a light (endoscope) and a special compound to bulk up the area around the tubes that carry urine from the kidney to the bladder (ureters). This treatment can help control VUR in people with mild to moderate symptoms, and has even worked for some with more severe cases.
The good thing about this endoscopic treatment is its benefits: the outcome is usually good, there’s a less invasive process, it’s safe, it can be done as an outpatient procedure, and it can be repeated if needed. However, getting the injection technique and amount of bulking agent right is crucial. If there’s too little of the bulking agent, the urine reflux might not improve, and if there’s too much, there can be blockages which cause other complications. Younger patients, those with more severe VUR, and those who have had unsuccessful prior procedures may face reduced success rates with the endoscopy.
There are two main types of bulking agent currently used for this procedure: dextranomer-hyaluronic acid gel and polyacrylate-polyalcohol copolymer. Both have been used for a long time for milder cases of VUR and have similar outcomes. The doctor’s preference and their previous experience will influence which bulking agent they use. Over time, some types of bulking agents have been discontinued due to issues such as immune reactions, migration of the agents, potential cancer risks, and negative side effects.
Both agents have their advantages and disadvantages: Dextranomer-hyaluronic acid gel is less likely to cause blockages over time but it may result in high rates of VUR recurring. Polyacrylate-polyalcohol copolymer delivers a stable, long-lasting effect, but due to its property to cause significant scarring, it might result in a blockage in the long term. Therefore, long-term follow-ups are necessary for patients treated with this.
The three different approaches to apply these agents are the STING technique, the Hydrodistension Implantation Technique (HIT), and the dual HIT method. The STING technique creates a small mound near the ureteral opening that helps control urine flow. Variations of this method can also be used. The HIT method uses high fluid pressure for a better view of the area and the injection forms a mound similar to a volcano. It has a better antireflux effect as it modifies the whole length of the intramural ureter. Lastly, the Dual HIT method is a combination of two techniques that can further improve the management of VUR by altering the length in two sections.
Possible Complications of Vesicoureteral Reflux
A Voiding Cystourethrogram (VCUG) is a type of test that can be done to check for problems in your urinary tract. However, like most medical procedures, it’s not without its potential issues. Allergic reactions to the contrast media (the substance used to make certain structures or fluids in your body visible on an X-ray) can occur, but this is very rare. If you’ve had a previous allergic reaction to this type of contrast, doctors will give you medicine to prevent another reaction, and may consider other tests instead.
There is also exposure to radiation during a VCUG, but modern techniques can help to reduce this. The amount of radiation you’ll be exposed to is very small, about 0.2 to 1.1 milliSieverts (mSv). To put this into context, a chest X-ray gives you a dose of about 0.1 mSv. Still, doctors will always follow certain guidelines to limit your exposure to radiation as much as possible. There can also be problems related to inserting the catheter (the thin tube used in the test), such as discomfort, small amounts of blood in the urine, or urinary tract infections.
If you’re given antibiotics on an ongoing basis to prevent infections before the procedure, it may cause several side effects such as yellow skin and eyes in newborns, increased resistance to antibiotics, digestive disorders, a decrease in blood cells production, and different allergy responses which may result in life-threatening allergic reactions.
During the procedure of Vesicoureteric Reflux, it’s rare, but complication might happen and cause problems like blockages in the ureter (the tube that takes urine from your kidney to your bladder), discomfort when passing urine, blood in the urine, or needing to pee often. These issues usually resolve on their own. If the Vesicoureteric Reflux does not get better after the procedure, it might be because there’s not enough filler material, or the material has moved from where it’s supposed to be. In such cases, they might need to do the procedure again or consider alternative procedures.
There’s also a chance of infection or a recurrence of the reflux after surgery, although this is generally low. If the surgery involves a special kind of tube implant, there can be blockages or bleeding afterwards. This could be due to factors such as the new ‘opening’ for the ureter being placed in the wrong position, the ureter bending, twisting, scarring, not having enough blood supply, or being tunneled too tightly. Sometimes severe blockages might need to be managed with a special drain, and further tests can be done. If the blockage doesn’t get better on its own, they might need to redo the surgery.
After surgery for Vesicoureteric Reflux, other complications might include the reflux persisting, the formation of a pouch (diverticulum), discomfort when passing urine, blood in the urine, or not being able to fully correct the reflux. Bulking agents (used in one type of procedure) moving to an unintended location and causing a ureter blockage that leads to kidney swelling (hydronephrosis) have also been reported. For surgeries which involve restructuring the tubes from the kidneys to the bladder on both sides, there may be up to a 4% temporary risk of urinary retention – when you can’t fully empty your bladder. This might mean that a longer period of catheterization (having a thin tube inserted to drain urine from the bladder) or a temporary suprapubic tube (a tube inserted into the bladder through a small cut in the abdomen) may be needed.
What Else Should I Know About Vesicoureteral Reflux?
Vesicoureteral reflux or VUR is a condition where urine flows back from the bladder into the kidneys. If VUR is left untreated, it can lead to a kidney injury and eventually result in hypertension, chronic kidney disease or even end-stage kidney failure. This is particularly common in infants who have a urinary tract infection (UTI) as 30-40% of those children have underlying VUR. The good news is that for many children, VUR can get better on its own as they grow and their bodies develop. This self-correction generally happens due to the natural elongation of the tube that connects the bladder and kidney – known as the ureter – and the strengthening of the body’s natural mechanisms to prevent urine reflux.
One of the complications of VUR is renal scarring, usually occurring from infection and pressure caused by urine reflux. This scarring typically happens more frequently in patients who have severe VUR. The scar formation process begins when infected urine flows back into the kidneys, causing inflammation that results in fibrosis (tissue thickening and scarring). An ultrasound is often the best initial diagnostic method to detect abnormalities in the kidney’s outer layer, known as the cortex.
Several methods are used to diagnose VUR such as nuclear renal scanning, voiding cystourethrogram (VCUG), direct radionuclide cystography, and contrast-enhanced ultrasonography. The most preferred approaches are VCUG and nuclear renal scanning, although the latter involves radiation exposure and needs special equipment.
The severity of VUR often determines the course of treatment. VUR that often resolves itself before a child turns 5, particularly in younger males and those who have less severe reflux (Grades I – III). If patients suffer from recurrent UTI, despite antibiotic treatment, surgery may be considered as an option. However, in most cases, continuous antibiotic therapy is usually prescribed to prevent UTIs and lower the risk of kidney damage.
For patients with repeated UTIs, evidence of progressive kidney damage, or those who do not respond well to other treatments, surgery may be the best option. Several surgical techniques are available, each with its own risks and benefits. Traditional surgeries are considered the gold standard for managing VUR, but minimally invasive surgeries are becoming more common and generally have positive results.