What is Bladder Exstrophy?
Bladder exstrophy is a serious birth defect that impacts various parts of the body, including the lower part of the body wall, urinary tract, genitals, pelvis, spine, and anus. This condition has been known since 2000 BC.
Despite over a century of surgical treatments, bladder exstrophy remains a complex issue for pediatric surgeons. This condition is not very common, appearing in roughly 3.3 out of every 100,000 live births, and it’s typically more common in boys. Many hypotheses have been proposed regarding what causes bladder exstrophy, but a definitive cause is yet to be determined. Doctors diagnose this condition based on physical examination and don’t generally need additional tests.
Surgical treatment for bladder exstrophy has two common approaches – the modern staged repair of exstrophy (MSRE) and the complete primary repair of exstrophy (CPRE). Surgeons around the world use these methods. The goal of surgery is to make sure the bladder can function and store urine properly, prevent damage to the upper parts of the urinary tract, and ensure the appearance of the genitals is acceptable. They also aim to enhance bladder control and sexual function.
What Causes Bladder Exstrophy?
While there are various theories that make an attempt to explain the cause of a medical condition known as bladder exstrophy, we still don’t know the exact reason behind it. The most widely accepted theory is by Marshall and Muecke, who suggest that an abnormally large membrane in the cavity that serves as a common passage for urinary and genital structures (known as the cloacal membrane) can cause a wedge effect. This means it blocks the movement of soft tissue (known as mesenchymal tissue) towards the center. This leads to the lower part of the stomach not forming properly. If the cloacal membrane bursts, all the contents could spill out, leading to a condition called the bladder-exstrophy-epispadias complex.
Some also suggest that the ‘wedge effect’ can happen if the structure that eventually forms the sexual organs (the primordia of the genital tubercle) begins too far upward on the body. Some experimental models suggest that the cloacal membrane rupturing too early can significantly contribute to the condition.
There are several other theories as well, including the downward movement of the genital tubercle, abnormal fluid storage leading to the rupture of the embryonic bladder, and others, that are proposed as potential reasons for the occurrence of bladder exstrophy. There’s a recent hypothesis by Varma and colleagues, who suggest that the separation of the pubic bones plays a central role in bladder exstrophy, and that it happens before the exstrophy development.
Risk Factors and Frequency for Bladder Exstrophy
Bladder exstrophy, a rare birth defect, has a prevalence of about 2 in every 100,000 births worldwide. In the United States, it affects roughly 3.3 out of every 100,000 babies born. This condition is twice as common in boys than in girls, with some studies reporting a male to female ratio of 6:1.
It’s less common among non-white races, people with very high or low socio-economic status, and those living in the western regions. Certain environmental factors also influence the risk of more severe forms of this condition. For example, mothers who smoke or are exposed to radiation during the first three months of pregnancy are more likely to have a baby with severe bladder exstrophy. However, taking folate around the time of conception can lower the risk.
Signs and Symptoms of Bladder Exstrophy
Bladder exstrophy is a condition that is typically diagnosed by pediatricians right after a baby is born. The condition is visible as a reddish, soft mass in the area above the pubic bone, which is the opening of the bladder. This area is continuously leaking urine. The amount of the bladder that is exposed can vary, and the ureter openings are often visible. However, no attempts should be made to blindly probe these openings.
For newborn boys, they may have a stubby, short penis that points upwards and the testicles might not have descended at birth. It is also common for these boys to have hernias on both sides of their groin. Newborn girls usually have a split clitoris and a slightly forward vaginal opening. It’s also not unusual for these girls to have duplicates of the uterus and vagina.
Both boys and girls with this condition have an abnormally positioned anus due to issues with the pelvic floor. Some children might have a dilated anal opening with a protruding mucous membrane. Even though the treatment for bladder exstrophy starts from birth, it is not uncommon for some children to show symptoms later on, especially in developing countries. These symptoms may include skin inflammation around the bladder area, a bladder opening that looks like polyps and has cell changes, lack of control over bowel movements, and a distinctive gait.
There can also be social issues because the child’s clothes are often wet due to the urine leakage.
Testing for Bladder Exstrophy
The diagnosis of bladder exstrophy (a birth defect where the bladder is turned inside out and protrudes through the abdominal wall) is usually based on clinical observations, meaning it can be identified by simply observing the physical signs and symptoms. It doesn’t typically require additional special testing. That being said, routine blood tests and blood chemistry assessments are done as common preparatory procedures before surgery.
Your doctor might also order an X-ray of your abdomen and pelvis to determine the extent of pubic bone separation, which is an important detail during this condition. Despite the continuous leakage of urine that is common in bladder exstrophy, damage to the upper urinary tract (which includes the kidneys and ureters) is rare before the closure of the bladder plate. Still, an ultrasound of the kidney, ureter, and bladder (referred to as KUB) is usually conducted to rule out any related abnormalities in the upper urinary tract.
Additional imaging exams and scans that track the movement and concentration of radioactive substances within the body (known as nuclear scintigraphy scans) are typically reserved for follow-up visits post-surgery. For females, it’s important to double-check for abnormalities of the Mullerian structures (organs that develop into the uterus, fallopian tubes and much of the vagina) through either an abdominal ultrasound or a perineal ultrasound (an ultrasound of the area between the anus and the vulva or scrotum).
Some surgeons may also conduct a ‘bladder swab,’ a test to check for bacteria in the bladder, before surgery. However, currently, there isn’t strong evidence to support the benefits of this procedure.
Treatment Options for Bladder Exstrophy
If you have an exposed bladder (a condition known as bladder exstrophy), which requires surgery, there are certain steps that doctors will take to prepare for and conduct the procedure.
Before the surgery, doctors use a film or wrap to cover the bladder. This is done to protect the bladder from injury or bleeding caused by a diaper, and to prevent the growth of polyps, which can make it difficult to close the bladder. A clear plastic wrap is typically used for this purpose.
The surgical treatment involves more than just closing the bladder. It also includes addressing related issues such as fixing the ureter (tube that caries urine from kidneys to the bladder), reconstructing the bladder neck (part of the bladder connecting to the urethra), repairing epispadias (a rare birth defect where the opening of the urethra is on the top or side of the penis, instead of the tip), and addressing any abnormalities in the bone structure of the pelvis and the pelvic floor. The main goal of these treatments is to allow the bladder to function properly, store urine, and grow along with the child, while also taking care of the genital area to establish normal sexual function.
Talking about the procedures, two are mostly performed: the Modern Staged Repair of Exstrophy (MSRE) and the Complete Primary Repair of Exstrophy (CPRE). Both of these have their own steps and approaches.
In MSRE, surgery is divided into stages or separate steps, which are usually performed at appropriate times. The thinking behind this approach is to provide some resistance each time which helps the bladder to grow. The first step involves ‘turning in’ or folding the bladder inward, typically during the first few days after birth. This step might also prevent the need for ‘osteotomy’, a procedure to cut and reshape bones, protects the skin from urine, and keeps the bladder safe. The second step is reconstructing the genitalia, performed when the baby is around 6 to 9 months old. This helps in early bladder cycling and gives some resistance to bladder growth. The third step is reconstructing the bladder neck, generally done when the child is between 4 to 5 years old when they are old enough to be involved in toilet training. At this time, the bladder should have enough capacity for the next step.
CPRE, on the other hand, involves doing all the steps in one go. The idea is to start bladder cycling early to ensure optimal bladder development and also to avoid subsequent surgeries. This procedure involves complete disassembly and reassembly of the penis and placing the bladder and the urethra deep into the pelvis.
Osteotomy may be performed to put less tension on the bladder and the abdominal wall after they are closed in. This is not always done and depends on various factors including the surgeon’s preference and the child’s age. There are different types of osteotomies, including the anterior osteotomy of the pubic ramus, anterior innominate osteotomy, and posterior iliac osteotomy each with its pros and cons.
It is important to note that in some cases, post-surgery, the bladder may not grow properly. In such situations, doctors might use a part of the intestine or stomach for bladder augmentation – to increase the size and improve the function of the bladder.
The treatment of bladder exstrophy is highly specialized and involves a series of procedures to repair the bladder and related issues to ensure optimal development and functioning of the bladder and the urinary system.
What else can Bladder Exstrophy be?
Classic bladder exstrophy should be distinguished from other abnormalities that occur in a range of conditions known as the bladder-exstrophy-epispadias-complex. This complex can include the milder form called epispadias, which only affects the genitals, with the bladder uninvolved, and the severe form called cloacal exstrophy, or OEIS complex. The latter condition is associated with a range of abnormalities including omphalocele, bladder exstrophy, an imperforate anus, and spinal issues. Notably, identifying bladder exstrophy and differentiating it from these conditions relies on a clinical examination without the need for additional tests.
Another group of rare abnormalities needs to be differentiated from bladder exstrophy. These are known as ‘exstrophy variants’ or ‘split symphysis variants.’ These differ from bladder exstrophy as they lack bladder abnormalities, but there is a gap in the pubic bone and the aligned rectus muscles are directed away from the midline. The exstrophy variants include the following:
- Pseudoexstrophy: The bladder covering is just skin and the misaligned rectus muscles and separated pubic bones are evident. When the bladder gets full, it bulges out like a hernia.
- Superior Vesical Fissure: The bladder is normal, but there is an opening in the skin connecting to the bladder which makes the bladder protrude. This should be distinguished from a patent urachus, which doesn’t have misaligned rectus muscles and separated pubic bones.
- Duplicate exstrophy: This involves a normal bladder with a normal phallus. Alongside this, there is an additional exstrophic mucosa just above the pubic area. This exstrophic bladder plate is dry and doesn’t connect to any ureters.
- Covered exstrophy: This differs from pseudoexstrophy by having an isolated ectopic bowel segment on the lower abdomen. It also includes abnormalities of the external genitalia.
What to expect with Bladder Exstrophy
The concept of “Continence” relates to the normal functioning of urination, which includes the ability to control urination at regular intervals during the day and night. However, there’s no universally agreed-upon definition for it. According to the Johns Hopkins group, continence is defined as being dry (not wetting oneself) for at least 3 hours during the day, being dry during the night, being able to urinate without using a catheter, and having no need for surgical enlargement.
According to this definition, 70% of their patients demonstrated continence. In another study by the Indiana group, more than 80% of their patients achieved continence. However, around 70% of their patients needed surgical enlargement. Similar rates were seen in another study conducted by the Seattle group.
One common effect seen after repairing a bladder condition called exstrophy is “upper tract damage”, which is a swelling or enlargement of the kidney. It was observed in 53% of the patients after a reconstructive procedure, with 30% experiencing this issue in both their kidneys. Men have been seen to have worse kidney outcomes as compared to women. Another concern is an increased risk of urinary tract infections and scarring in the kidney, which occurred in approximately 11.5% and 5.7% of patients.
In terms of sexual function, most patients maintained a normal long-term sexual function. Whilst fertility is normal in women after these procedures, it is significantly lower in men. It is noted that those who have had diversions of their urinary system tend to have better sexual function and fertility compared to those who have had their urinary system reconstructed.
Possible Complications When Diagnosed with Bladder Exstrophy
The most usual problems after bladder exstrophy surgery are wound separation and bladder coming apart. If these get worse, the bladder could slip out of place. To prevent this, surgeons use a method that adequately moves flaps and incorporates a specific kind of bone surgery while turning the bladder in. This reduces the strain on the stomach wall and bladder plate.
Below are some additional complications that may occur:
- Painful urination or dysuria: This often happens after bladder surgeries due to bladder muscle cramps.
- Wound infection.
- Blockage in the urinary passage: Over time, this has become less common as specific surgical methods have decreased. If it does occur, the first solution is to widen the urinary passage.
- Fistula between the skin and the urinary passage, narrowing of the urinary passage, loss of parts of the penis, and a persistent condition affecting penis shape: These usually happen after specific penis surgeries.
- Persistent inability to control urination, infection in the urinary system, and stones in the bladder: These issues happen after reconstructing the bladder neck.
- Bone surgery complications.
- Risk of cancer: There’s 1-2% chance of developing bladder cancer, with a common type being adenocarcinoma. This risk exists even in untreated bladders.
Recovery from Bladder Exstrophy
Proper after-surgery care for a child with bladder exstrophy is very important. This care first involves managing pain with medication. The immediate pain the child might feel after the surgery is usually managed with pain relief medication given through the spine (epidural analgesia). But, the child may need strong pain relief medication given into their vein (intravenous analgesia) for a longer time because they might be in pain from being kept still and having their body positioned in a certain way. Feeding can be resumed as soon as the child is fully awake.
It’s also crucial to ensure the child’s lower body parts are kept still, regardless of whether a surgical procedure to cut and reshape bones (osteotomy) is performed or not. Most pediatric surgeons prefer to keep the lower body still. If osteotomy is performed, keeping the treated part still and secure externally for around 4 weeks is generally suggested.
Additionally, starting medication that helps to relax the muscle in the wall of the bladder (the detrusor) and prevent muscle spasms might be beneficial. Also, it’s important to take good care of any tubes left inside the body to drain fluids (indwelling drains and catheter), to ensure the best possible recovery.
Upon going home, regular follow-up visits are needed. Tests should be done to make sure the upper parts of the urinary tract (ureters and kidneys) are in good condition, including an ultrasound KUB (kidneys, ureters, and bladder), MCUG (a test where x-rays are taken while the patient is passing urine) and renal scintigraphy (a test that shows how well the kidneys are working). In addition, a urodynamic study (a test to see how well the bladder works) should be done to check the lower part of the urinary tract.
Preventing Bladder Exstrophy
The quality of life for patients with bladder exstrophy, a condition where the bladder is formed on the outside of the body, is largely determined by how well they can control their urine. Patients who can grow a sufficiently large bladder as they get older can usually hold their urine for 2 to 3 hours during the day and stay dry throughout the night. However, for some children, poor bladder growth might make this difficult.
Not being able to control urination can lead to emotional and social challenges for these children, even causing some to leave school or fall behind in their education. The issue also impacts the family, often causing parents to take time off work. This has been widely noted in scientific studies.
It’s important to put a routine in place to help the child remember to urinate. Instruction about the advantages of clean intermittent catheterization (CIC) is also beneficial. CIC is a method that helps drain urine from the bladder periodically using a tube. Teaching the child how to do this themselves, emphasizing proper cleanliness, and ensuring they take their medication regularly, are all important steps. Parents need to be reminded of these things regularly to help improve the situation.
