Overview of Vesicoureteral Reflux
Vesicoureteral reflux (VUR) is a condition where urine flows backward from the bladder to the upper part of the urinary tract. This backward flow occurs due to a short ureter, a tube connecting the bladder to the kidneys. It took until 1960 for doctors to realize why VUR matters: it’s linked with urinary tract infections (UTIs), kidney scarring, and lasting damage to the kidneys, mostly in children.
Among newborn babies, nearly 1 in 100 have VUR. However, if these newborns are diagnosed with prenatal hydronephrosis (a condition where a baby’s kidney swells because the flow of urine is obstructed), this number is a lot higher, reaching 15%. VUR is found more frequently in white patients compared to Black ones, as well as more often in women than men. This doesn’t apply, though, when prenatal hydronephrosis is involved – in which case, boys are more affected. Some studies even say that nearly 1 in 6 babies showing signs of hydronephrosis end up having VUR. Additionally, approximately 1 in 3 to 4 children with UTIs have some degree of VUR.
VUR is often found in babies known by doctors as “phenotypically male” (babies who are identified as male at birth based on physical characteristics) with enlarged ureters. In these cases, the chances of having VUR are especially high. And, if a baby has a UTI, the likelihood of finding VUR increases even more, rising above 66%.
There’s also a hereditary aspect of VUR. Up to two-thirds of children born to women with primary VUR (a type of VUR that the child is born with) will also have the condition. It’s also common in twins. If someone’s sibling has it, there’s around a 30% chance they will have it too. Nonetheless, it’s currently not advised to screen siblings who have no symptoms and normal kidney scans routinely. VUR may also come along with other conditions that are present at birth such as urinary tract issues, spina bifida (a birth defect where the spine and spinal cord don’t form properly), bladder issues, and more.
In some cases, patients with VUR may not exhibit any signs. It could show up in one or both the kidneys or come with kidney-related diseases, all varying from mild to severe conditions. Children with severe kidney disease due to VUR account for about 5% of all kidney transplants in children. However, an early diagnosis and treatment can prevent kidney damage and recurrent UTIs, saving the kidneys.
VUR may coincide with bladder or bowel dysfunction, basically abnormalities with the lower urinary tract. These abnormalities can lead to urinary urgency, incontinence, and other issues with urination. Females are more likely to have these conditions, which might also come along with constipation. Patients with VUR and bladder or bowel dysfunction have a higher chance of getting infections and often a lower rate of the condition healing by itself. These patients also have reduced success rates after VUR surgical treatment. However, treating bladder or bowel dysfunction effectively reduces symptoms, improves bladder function, and helps resolve the condition more naturally.
How is it diagnosed?
Diagnosis starts with a urinalysis (a test of their urine) that checks for protein and bacteria. Kidney function is assessed using a creatinine level test, especially in severe cases. In addition, an ultrasound is advised to check the kidney’s structure and any abnormalities. Unfortunately, ultrasound is not very accurate in detecting high-grade VUR.
Doctors use technetium-99m–labeled dimercaptosuccinic acid radionuclide imaging to evaluate the kidney function and the extent of kidney scarring. However, the best way to assess VUR is through a particular test called direct cystography with voiding cystourethrogram (VCUG). This test provides detailed pictures of your bladder and identifies abnormalities, making it easier to grade VUR. Even so, performing VCUG in infants and young kids requires specialized skill to lessen emotional and physical harm and reduce radiation exposure.
VCUG is usually recommended when abnormalities are found in the ultrasound, when a second UTI occurs, or if other high-risk factors such as bowel or bladder dysfunction are present. It’s important to note that ultrasound or radionuclide scanning can’t replace VCUG as the go-to way for diagnosing VUR. In fact, multiple VCUG scans are recommended as reflux often happens early or late in the voiding cycle.
Images are taken with the least amount of radiation possible to maintain quality imaging, as an accurate diagnosis is crucial for selecting the best treatment. The patient’s age and clinical presentation, together with VCUG findings, helps determine the grade of VUR, which guides the treatment plan. Following the 2016 protocol outlined by the American Academy of Pediatrics ensures minimal discomfort and risk to the patient while ensuring optimal VCUG imaging quality.
Anatomy and Physiology of Vesicoureteral Reflux
The ureter is a small, tube-like structure in your body. It’s job is to carry urine from your kidneys to your bladder. In other words, it’s like a pipe for waste removal. It starts from the renal pelvis, which is a funnel-like tube in your kidney, and ends in a area of your bladder known as the bladder neck. The point where the ureter connects with your bladder is called the ureterovesical junction.
Normally, urine flows from the kidney to the bladder and prevents backflow of urine, which is mainly due to the special structure of the ureterovesical junction. If you cough, sneeze, strain or do anything that increases the pressure inside your bladder, this can stop the backflow of urine. This is because the pressure causes the ureter where it connects to bladder to close up. However, if the tube-like ureter inside the bladder wall is not long enough compared to its diameter, urine could flow backwards. This backward flow of urine is also known as Vesicoureteral Reflux (VUR).
VUR can be of two types – primary and secondary. Primary VUR is when the problem is within the junction itself. This could be due to the ureter not being long enough inside the bladder. There could be other factors as well, like if the ureteric opening in the bladder isn’t in the right place, if there is increased pressure inside the bladder or if there are abnormalities in the muscle and nerve supply of the tube-like structure. The second type, Secondary VUR, occurs due to high pressure inside the bladder, which could be due to abnormal bladder function or anatomy.
VUR can resolve naturally over time in children due to growth and development. However, when VUR occurs along with a condition called intrarenal reflux, which is the backflow of urine into the kidney tubes, it can cause kidney damage. The bacteria from the urine rushing backwards can infect the kidney leading to inflammation and subsequently, scarring. The way your kidney structure is, can also affect whether urine refluxes into your kidneys or not. It’s important to note that VUR does not just affect children; adults can have it too. Continually high pressures in the bladder due to VUR can also damage the kidneys.
Why do People Need Vesicoureteral Reflux
A VCUG, which is a special type of x-ray that looks at how your child urinates, is the best way to diagnose a condition called VUR (or vesicoureteral reflux). This is when urine flows backward from the bladder into the kidneys. Some signs that a child might have this condition include getting urinary tract infections (or UTIs) often, their first feverish UTI coming with a strange kidney ultrasound, having a bigger urinary tract either before or after birth (also known as hydronephrosis), having a hard time peeing, having a blocked bladder, having a condition that affects the nerves of the bladder (neurogenic bladder), having painful urination (dysuria), or seeing blood in the pee (hematuria).
The American Academy of Pediatrics suggests that children between 2 and 24 months old should be checked for VUR if they have had two episodes of feverish UTI or if their kidney ultrasound looks strange. However, the UK’s National Institute for Health and Care Excellence has different recommendations based on age. For example, they advise that infants under 6 months old with repeat or unusual UTIs should be tested for VUR. Yet, in children between 6 months and 3 years old, some things need to be considered before they get tested. This includes having a family history of UTI, previous episodes of non-Escherichia coli UTI, poor urine flow, or signs of hydronephrosis on the images from their tests.
In general, continuous use of antibiotics and surgery seem to lower the risk of UTIs and kidney scarring in about the same way. Usually, using medication is the first step, and surgery is only chosen for cases where the medication does not work or seems unneeded, especially in mild VUR cases (grades I and II). However, if VUR continues despite using medication, surgery should be an option.
Surgery might also be the best choice if:
- The kidneys are not growing properly
- The child cannot or will not take the antibiotic regularly
- They keep getting UTIs, or their kidneys get inflamed despite taking the antibiotic (pyelonephritis)
- The parents ask for it
- The VUR is severe (grade IV or V), and continues even after the child is 3 years old
- The kidneys keep getting scarred, or they are failing
When a Person Should Avoid Vesicoureteral Reflux
There are no absolute reasons why a VCUG, a type of bladder X-ray, can’t be done. However, there are some circumstances where it may be better to wait or not do it at all. This includes when a person is pregnant or has an untreated urine infection. An X-ray during pregnancy could expose the baby to radiation, which isn’t safe. The urine infection should be treated with antibiotics before the X-ray is done.
There are some conditions where surgery that prevents backward flow of urine is not recommended. This includes when the kidneys are not working, if the patient has a condition called Hutch diverticula (in which small pouches form in the bladder), if they have trouble urinating, or if they have ongoing urine infections.
Another situationwhen this X-ray or surgery might not be done is if a patient can’t have anesthesia for any reason. Anesthesia is a medication that makes them sleep and not feel pain during procedures or surgery.
Equipment used for Vesicoureteral Reflux
A VCUG, which stands for Voiding Cystourethrography, is a test that uses a water-soluble dye that contains iodine and requires a special X-ray machine called a fluoroscopy machine. Devices attached to this machine can take still or moving images. These images are then processed and saved on computers specifically designed for X-ray pictures. Doctors who specialize in reading these X-ray images (radiologists) and doctors who treat urinary tract problems (urologists) can then view these images as they are being taken in real time.
For a Laparoscopic Extravesicular Ureteral Reimplantation, a surgery used to treat Vesicoureteral Reflux, a condition where urine flows back into the kidneys from the bladder, doctors will utilize a variety of tools. These tools include: a synthetic absorbable suture with a 26 mm tapered needle, various sized ‘working ports’, which are used as entry points during the surgery, curved scissors, a Laparoscope which is a slender instrument used for examining and potentially operating on the interior of a bodily canal or organ, dissectors which are used to separate or remove tissue, a Hasson trocar which helps in the creation of the working port, a reducer seal which helps in secure instrument exchange, a Babcock forceps, a working port and grasper which are used to hold and manipulate organs, a retractor that holds back the muscles, and a laparoscopic needle driver which is used to hold and guide the needle when suturing tissue.
For an Open Extravesical Ureteroneocystostomy, a surgery used to treat serious kidney and urinary problems, doctors will use scalpels, hemostats which are used to control bleeding, scissors, needle holders, tissue forceps, retractors, surgical drapes and towels, sterile gloves and gowns, a Foley catheter which is a tube that helps remove urine from your body, suture material (meaning thread-like material used for stitching), and a ureteral stent (a tube inserted in the ureter to prevent or treat obstruction of urine).
For a Robotic Ureteroneocystostomy, a type of surgery somewhat similar to the open procedure but performed using a surgical robot, various specific tools are required. The surgical robot includes a console for the surgeon to sit and a robotic cart housing the 4 arms. These arms are equipped with surgical instruments that the surgeon operates from the console. A robotic camera is attached to one of the robotic arms, providing the surgeon with a high-definition view of the surgical site. The remaining 3 arms are equipped with robotic laparoscopic instruments used to perform the actual surgery. Other tools used in this surgery include trocars, Foley catheters, double J stents (which are like ureteral stents but are shaped like the letter J at both ends), suture materials, and surgical clips.
Who is needed to perform Vesicoureteral Reflux?
The test called a VCUG is done in a special room called a radiology suite. A radiologist, who is a doctor specializing in using X-rays, leads the process with the help of a radiology technologist and a nurse. The VCUG is a test for a condition called VUR.
When fixing VUR, there are numerous healthcare professionals involved in the operation room:
* The main doctor is called a pediatric urologist, this is a doctor who specializes in children’s urinary problems. They lead the team and handle the operation.
* To ensure you don’t feel any pain during the procedure, an anesthesiologist or nurse anesthetist will give you anesthesia. They also monitor everything like your heart rate and breathing during the operation.
* The surgical technologist or surgical assistant helps the urologist during the surgery. They hand over surgical tools, help with moving parts of the body during the surgery (this is done using retractors) and they help with other technical things during the operation.
* The job of a circulating nurse is to handle equipment and supplies in the operating room. They also help the surgical technologist when needed.
* Lastly, a scrub nurse is there to help the main doctor, the pediatric urologist, during the surgery.
Preparing for Vesicoureteral Reflux
If you or your child need a VCUG (Voiding cystourethrogram) procedure, you will be an active participant in the process. It’s important to try and reduce any feelings of anxiety or discomfort, especially for children since this procedure can be a little overwhelming. Doctors or their assistants will guide you through the procedure to help lessen any fear or worries you might have. If a child is very anxious, they might be given a sedative to help them relax.
For patients that might be at risk of certain heart issues such as artificial heart valves or septal defects, a preventive dose of antibiotics might be given before the procedure. Before any treatment is started, any secondary causes of VUR (Vesicoureteral Reflux) should be ruled out.
Factors such as bladder size and function, body build, condition of the kidney, patient age, anxiety levels, other medical conditions, the presence or history of kidney stones, the severity of UTIs, and whether the patient has a single or double kidney, should all be evaluated.
About half of patients with defects in the rectum and anus have spinal cord abnormalities. The more severe these lesions are, the higher the grading of these rectal lesions. If there are signs of VUR and incomplete bladder emptying, it could mean that the patient’s neurogenic bladder isn’t functioning properly. In these cases, it would be a good idea to have a comprehensive evaluation that might include a spinal MRI scan.
The positioning for the imaging depends on whether the patient is male or female. For men, they would need slightly tilted positioning during the imaging of the urethra. For women, they need to have a front projection. If there is any suspicion of abnormalities, lateral imaging can be performed. The images should be reviewed for the anatomy and function of the urethra, and the presence and degree of VUR. Images should be taken right after voiding, as VUR often occurs during or immediately after voiding.
Repeating the voiding cycle 2 to 3 times before removing the catheter is common for children aged 1 or younger, because of their lower voiding volumes. It is also done for patients that are likely to have VUR. However, if VUR is detected during the initial filling, the cycle should not be repeated.
If the patient is unable to urinate during the procedure, they may be allowed to use the restroom if it is close to the examination room. A lying-down image of the kidney area should be taken immediately after urination. The time between the image and urination should be recorded. Images after urination should be taken to assess how much urine is left in the bladder. The kidney area should also be included in the post-urination image to assess reflux.
Prior to the procedure, the patient’s medical history and any initial studies and imaging findings should be reviewed. An initial image should be taken of the abdomen, including kidneys, ureters, and bladder. This is important to identify any bone abnormalities related to VUR, as conditions like spina bifida are often linked with neurogenic bladder and sometimes VUR.
During the procedure, an experienced nurse or radiology assistant will insert a catheter into the patient using sterile precautions. An anesthetic gel is often used to reduce any pain or discomfort. The catheter size is usually chosen based on the age of the patient, but the smallest possible catheter will be used. After the catheter is inserted, it will be secured to prevent it from moving around during the procedure. The bladder should be completely emptied before starting the study.
The catheter is then connected to a bottle filled with a contrast dye via tubing. The bottle is raised around 3 feet above the bed to allow the dye to flow into the bladder under gravity. Patients with recent bladder surgery may require the bottle to be placed lower to maintain lower pressure filling. The dye is allowed to flow into the bladder, which can be viewed under a fluoroscope.
For younger children and adults who are not toilet-trained, the bladder should be filled until urination occurs. For older children and adults who are toilet-trained, the bladder is filled until the natural need to urinate is felt. However, if the patient feels pain or discomfort, the bladder filling should be stopped.
How is Vesicoureteral Reflux performed
Endoscopic treatment of Vesicoureteral Reflux (VUR), a condition that allows urine to flow backward from the bladder into the ureters, has been in use since 1984. This treatment uses a minimally invasive procedure that involves injecting bulking agents near the ureter to manage the reflux, making it suitable for patients with low to high-grade VUR.
The endoscopic approach has many benefits, such as favorable results, minimal harm to the body, lower health risks, and the possibility of outpatient treatment. Moreover, the treatment can be repeated if necessary. However, the success of the treatment significantly depends on the injection technique and the volume of the bulking agent used. If the volume is too little, it may not reduce the reflux, but if it’s too much, it can lead to a blockage in the ureter and a kidney condition called hydronephrosis. Factors like a younger age, higher reflux grade, and previous unsuccessful endoscopic antireflux procedures can lower the chances of successful reflux resolution through this method.
The bulking agents that are specifically used in endoscopic antireflux surgery include dextranomer-hyaluronic acid gel and polyacrylate-polyalcohol copolymer. These bulking agents enhance the tissue’s thickness, aiding in managing lower-grade VUR effectively. Although the dextranomer-hyaluronic acid copolymer has a marginally higher success rate initially, it comes with the higher risk of ureteral obstruction. Moreover, there’s also a significant chance of late reflux recurrence. Therefore, a doctor often takes into account their experience and preference when choosing a bulking agent for treatment.
Dextranomer-hyaluronic acid copolymer and Polyacrylate polyalcohol copolymer are two types of bulking agents used. The dextranomer-hyaluronic acid copolymer, introduced in 2002, is a thick gel containing tiny spheres in a carrier base. This is a non-degradable and immunologically inert material (doesn’t react with the body). It has a low risk of causing ureteral obstruction over time and doesn’t seem to contribute to the formation of malignant (cancerous) cells. Despite these advantages, this copolymer has been found to have high long-term VUR recurrence rates.
The polyacrylate polyalcohol copolymer introduced in 2010, on the other hand, is a bulking agent that has a relatively large microsphere size and is non-degradable, ensuring more stability. However, it often leads to scarring and inflammation at the injection site, which can subsequently lead to ureteral obstruction. Therefore, long-term monitoring is recommended when using polyacrylate polyalcohol copolymer.
Three different treatments are performed using an endoscope and bulking agents, which include the suburethral transurethral injection (STING) technique, the hydrodistension implantation (HIT) method, and the combined proximal/distal intraluminal injections (double-HIT) procedure. These treatments have their own merits and demerits and can be chosen based on the patient’s condition and the doctor’s preference and experience.
Possible Complications of Vesicoureteral Reflux
A procedure known as Voiding Cystourethrogram (VCUG) can sometimes cause complications like allergic reactions to the contrast media (a substance used in this test) and exposure to radiation. If someone has had an allergic reaction to iodinated contrast (a type of contrast media that contains iodine) before, it’s recommended that they’re given preventive anti-allergy medication. This type of allergic reaction, however rare, usually happens when the iodinated contrast is absorbed by the body or injected, rather than just staying in the urinary tract.
The use of digital imaging and other techniques can help reduce the amount of radiation patients are exposed to. The average dose of radiation is about 0.2 milliSieverts (mSv). However, in one study, the radiation dose during a standing VCUG in women came to about 1.1 mSv. It’s crucial to follow the guidelines from the AAP Sections on Urology and Radiology Protocol to ensure the patient is exposed to the least possible amount of radiation. Other risks associated with this procedure include pain, blood in urine, scarring or narrowing of the urethra, and urinary tract infections (UTIs).
Continuous use of antibiotics can have its own complications like hyperbilirubinemia (high levels of bilirubin, a substance that’s produced when red blood cells break down) in newborn babies, increased antibiotic resistance, digestive system issues, a decrease in bone marrow function, and different allergic reactions including Stevens-Johnson syndrome (a rare, serious skin disorder).
There may also be complications associated with surgical procedures for vesicoureteral reflux (a condition where urine flows back from the bladder into the ureters), but these complications are quite rare. Some of the side effects reported include blockage of the ureters (tubes carrying urine from kidneys to the bladder), painful urination, blood in urine, and increase in the frequency of urination. Most of these problems will cease on their own. If the reflux doesn’t improve, it might be due to inadequate bulking material (substances used to bulk up the tissues to stop reflux) or migration of the injected agent. In such cases, repeat endoscopy (a procedure to look inside your body) or alternative procedures like robotic or open ones can be considered.
Although post-procedure UTIs, persistent reflux, and VUR recurrence have been reported after endoscopic VUR surgical corrective procedures, other procedures like robotic, laparoscopic, and open reimplant ones typically have low complication rates. Despite this, there can be complications like blockage or blood in the ureter after intravesical ureteral reimplantation (surgical correction for VUR). Other complications can include persistent reflux and development of diverticulum (a small pouch in your digestive tract).
In extremely rare cases, problems in establishing a pneumovesicum (air in the bladder) can lead to an early conversion to open laparotomy (a surgical procedure involving an incision into the belly). If a blockage in the ureter leads to acute hydronephrosis (a condition where the kidneys are enlarged due to excess urine), it may need to be drained post-procedure. If the blockage doesn’t resolve on its own, another surgical reimplantation might be needed. Another complication could be the development of reflux in the other kidney (up to 22% of patients) after a single-sided repair. This usually mild and resolves on its own without any surgical intervention.
Additional possible complications include persistent reflux and diverticulum formation, painful urination, blood in urine, failure to correct VUR, migration of bulking agents, and blockage of the ureter leading to hydronephrosis can happen after endoscopic bulking agent injections (injections used to increase tissue mass to stop reflux). Lastly, getting bilateral extravesical ureteral reimplantation (surgical correction for VUR in both kidneys) carries a temporary risk (up to 4%) of not being able to urinate. This may require a prolonged use of a catheter or the use of a temporary suprapubic tube (a tube inserted into the bladder through the belly).
What Else Should I Know About Vesicoureteral Reflux?
Vesicoureteral reflux (VUR) is a condition where urine flows backward from the bladder into the kidneys. If left untreated, it can injure the kidneys, leading to scarring, high blood pressure, or chronic kidney disease. In severe cases, it may lead to end-stage kidney failure. Often, 30% to 40% of infants diagnosed with a urinary tract infection (UTI) have underlying VUR. The good news, however, is that low-grade VUR usually gets better on its own as the child grows.
How does VUR result in renal scarring or kidney scarring? Well, it’s mostly due to infection and pressure. When infected urine flows back into the kidney, it causes an inflammatory response that often results in fibrosis, a thickening or scarring of tissue, and subsequent kidney scarring. This is most common in patients with severe VUR.
How is VUR detected? Usually, an ultrasound is the initial preference to detect kidney abnormalities. For a more accurate picture of kidney scarring, nuclear renal scanning is employed, although this method involves radiation exposure and special equipment. A test called VCUG is preferred for diagnosing VUR grade and figuring out anatomical details. There are also alternative methods for diagnosing VUR, however, they might not provide detailed anatomical information.
Now, how to manage VUR? In most cases, VUR tends to resolve spontaneously before age 5, and often doesn’t require surgery. Antibiotics are frequently used for treating VUR to prevent urinary tract infections and reduce the risk of kidney damage. Antibiotics like Nitrofurantoin, Cephalosporins, Trimethoprim or Sulfamethoxazole are often used for this. That said, some studies warn against too much use of antibiotics because their effectiveness in preventing kidney damage is limited and it can cause antibiotic resistance. Therefore, doctors often recommend scanning the kidneys before stopping antibiotics to check for any kidney abnormalities. If there are recurrent UTIs, kidney damage, or inadequate kidney growth, surgery may be considered.
There are several surgical options to treat VUR, each with its own set of risks and benefits. Traditional surgery is still widely used but minimally invasive procedures such as robot-assisted surgeries are becoming increasingly popular and have shown positive results.