Bladder exstrophy is a congenital birth defect that is the malformation of the bladder and urethra, in which the bladder is turned "inside out". The bladder does not form into its normal round shape but instead is flattened and exposed outside the body. The lower portion of the bladder, a funnel-shaped bladder neck, made up of muscles that open and close the bladder, fails to form correctly. The urethra and genitalia are not formed completely (epispadius) and the anus and vagina appear anteriorly displaced. Additionally, the pelvic bones are widely separated (diastasis).
Exstrophy includes a spectrum of urologic malformations that range from mild to severe. Epispadias, the milder form, is a condition where the urethra (the tube that carries urine out of the body from the bladder) opens on the top surface of the penis instead of on the tip. In classic bladder exstrophy, the bladder and related structures are open and located outside the body. The pubic bones, which are normally joined to form the front of the pelvis, are separated. Cloacal exstrophy, the most complex and severe form of bladder exstrophy, also involves the bowel.
Bladder exstrophy is congenital (children are born with it) and rare, occurring in only three of every 100,000 live births. Although the causes of exstrophy are not known, there is some evidence that genetic factors may play a role. The risk of recurrence of exstrophy in a given family is one out of 275 births. There is a one in 70 chance that a parent with exstrophy will have a child with the same disorder.
Bladder exstrophy occurs in 1 in every 40,000 births, affecting two to three times more boys than girls. If you have a baby with bladder exstrophy the chance of having another baby with bladder exstrophy is increased to about 1 in 100. If you have any concerns about this, we can arrange for you to see a genetic counsellor.
No one is completely sure exactly what causes bladder exstrophy, although there are many theories. Some researchers believe that it is caused by overdevelopment of the cloacal membrane. If this membrane does not melt away at the proper time in development, the top part of the bladder and the skin layers surrounding it never form correctly. As a result, neither the bladder nor the skin on top of it closes. We do know for certain that heredity is not involved in the development of bladder exstrophy. Thus there is no reason to feel as though you are responsible. Nothing you did during pregnancy caused this to occur; nor could you have done anything to prevent it.
Bladder exstrophy will affect your child in several ways. First, the pelvic bones, which usually meet and join at the front of the body, remain separated. This may cause your child to start out walking with a wide, waddling gait. Such a gait poses no long-term problems, and your child will be able to run, jump, and participate in sports of all kinds. In fact, many of our patients have been good athletes.
Bladder exstrophy also affects the appearance of the genital area. In the female child, the urethra and vagina are shorter that usual, although the uterus, fallopian tubes, and ovaries are normal. The pubic area, clitoris, and labia are widely separated at birth but can be repositioned more normally along with a closure of the abdominal wall by surgery. In the male child, the penis appears shorter than usual, because the base of the penis is spread apart internally by attachment to the still separated pubic bones. The testicles may appear undescended at first, but with time the scrotum develops and the testicle almost always descend to a normal position.
The most troublesome problem your child will face is controlling the flow of urine. Surgery of some sort will probably be required to deal with the problem, and you will decide with you doctors which method of repair is best. More than one operation is usually required over the years.
Bladder exstrophy and its associated disorders are treated surgically, in a series of operations. When your child comes to Great Ormond Street Children’s Hospital, they will be prepared for surgery. This will involve investigations including an ultrasound scan (to check the kidneys), an abdominal x-ray (to assess the position of the pelvic bones and the spine), and blood tests (to assess kidney function).
The aim of the first operation, soon after birth, is to close the bladder and the abdominal wall defect. Further operations are required at a later stage to achieve adequate bladder control and improve the appearance and function of the external genitalia (sexual organs). A priority at all times is to keep your child’s kidneys working well.
Each child has a different plan of management which will be explained to you by their urologist (a doctor specialising in these problems). The surgeon will explain to you in detail about your child’s operations. Below is a brief description of procedures which may be required at some stage of their childhood.
The first operation to close the bladder and abdominal wall defect is usually done within a few days after your child is born. This may coincide with the correction of the widened pelvic bone, while the bones are soft enough to be repositioned. Following this operation your baby will have to have their legs in plaster casts or mermaid bandages where both legs are bandaged together with a crepe bandage for between one and four weeks. This is to stop them moving too much, and allow the bones to heal.
Your child may also require further surgery to reposition the pelvic bones at a later stage, which will involve an external fixator. This is where metal pins are inserted into the pelvic bones to stabilise and hold them in position while healing takes place.
In boys with epispadias, surgery will also be required to repair this. This may be done during the first operation to correct the exstrophy or may be delayed until your child is between six and twelve months old. The operation (which may be done in two stages) involves reconstructing the penis and so forming a new urethra, and the opening of the urethra will be moved from the top surface to the end of the penis.
As well as these first one or two operations, your child may well need more surgery to help them gain bladder control. Sometimes, the ring of muscle around the base/neck of the bladder (sphincter) does not work properly and urine dribbles out continuously. This sphincter can be tightened using a variety of different methods. Some surgeons wrap muscle around the neck of the bladder, an operation which is most common in boys. This can be combined with further surgery and as well as helping with bladder control it may make the penis more prominent. Alternatively, a substance called macroplastique can be injected into the bladder neck region.
As your child gets older, they may find that their bladder is too small to cope as they take in larger amounts of fluid. In this case, a bladder enlargement (augmentation or cystoplasty) may be necessary. This is usually done by using a piece of the intestine, and often coincides with a reconstruction of the bladder neck, and the formation of a "continent catheterisable channel" from the bladder onto the abdominal wall - sometimes called a mitrofanoff.
There will be scars from the operations, but these will fade with time, and some will become covered with pubic hair at puberty.