Causes and Disease Development

At what stage of prenatal development does bladder exstrophy occur?
The condition of exstrophy occurs during the development of the embryo (the name given to the baby during this stage) very early in the pregnancy, about 4 to 5 weeks after conception. The cause and nature of the faulty development is not exactly certain. It is 4 to 5 weeks after conception that the various organs and different types of muscles and tissues of the body begin to form from layers of cells that separate, divide and fold. One theory suggests that something goes wrong during this early folding and separation, causing the cloacal membrane to fail to close, leaving the bladder outside of the abdominal wall. A second theory proposes that the layer of skin which forms over the bladder at this stage is thin and unable to hold in the bladder. It pulls apart, again leaving the bladder inside out.

What determines the extent of the exstrophy?
The extent of the exstrophy depends on how small or how large the opening is. One can think of exstrophy as a spectrum of conditions that ranges from the milder form, epispadias (only a urethral defect or opening), to the most severe form, cloacal exstrophy (defect of the urethra, bladder and bowel), with classic bladder exstrophy (defect of urethra and bladder) being in the middle.

What causes bladder exstrophy?
Medical science has no explanation for why an embryo may develop bladder exstrophy. It is not because of anything the mother or father did or did not do during the pregnancy. On the other hand, it is not simply an inherited condition.

What is the likelihood that a child will be born with bladder exstrophy?
Although bladder exstrophy occurs in only 1:30,000 births in the general population, it may be more likely to recur in a family. Based on some studies, there may be a 1:100 chance of it among siblings and a 1:70 chance of it among offspring of a person with bladder exstrophy. Exstrophy of the bladder also occurs 2-3 times more frequently in males than in females.  

Cloacal exstrophy: The incidence of cloacal exstrophy is 1:200,000 and is much less common in females. This disorder is much more complex than exstrophy and requires an extensive evaluation for associated abnormalities of the nervous system, upper urinary tract, and gastrointestinal tract. The treatment of storage abnormalities of the bladder usually involves bladder augmentation with intestinal segments. Clean intermittent catheterization also may be required to maintain urinary continence.

Female epispadias: Female epispadias may result in a variable presentation depending on the severity of the urethral defect. In complete epispadias, incontinence results secondary to (1) a foreshortened and widened urethra, (2) a partially absent external urethral sphincter, and (3) a poorly developed bladder neck. Treatment is directed at reconstruction of these deficient structures and at ureteral reimplantation proximal to the reconstructed bladder neck region. Persistent incontinence may be treated with collagen injection at the bladder neck.

Treatment

How are bladder exstrophy and its related conditions treated?
Exstrophy of the bladder requires surgical repair. The treatment plan devised for your child will depend on the type and the extent of the abnormality. Just as no two exstrophy children are exactly the same, no two treatment plans will be the same. The surgical care of the child with exstrophy has evolved significantly, and research continues with the goal of correcting the defect and achieving continence with one single procedure.

How long does treatment last?
At this time the current treatment involves a series of surgeries over a number of years. This plan is called staged reconstruction. The exact timing, nature, and outcome of these surgeries will depend on your child's particular situation. Your surgeon will discuss with you the plan for your child and how successful you can expect it to be.

What are the goals of treatment?
The goals of the staged reconstruction include (a) closure of the bladder and urethra, (b) closure of the abdominal wall, (c) preservation of kidney and sexual function, (d) satisfactory cosmetic appearance of the penis in the male and external genitalia in the female, and (e) a psychologically stable child and family.

How is treatment usually approached?
The following is an overview of the staged reconstruction and the way in which surgical treatment is usually approached:

• Primary closure of the bladder is usually performed within 24-48 hours of birth. During this surgery, the separated pelvic bones are brought together, the bladder is closed and remodeled to allow it to hold urine, the bladder is placed inside the pelvis, and the abdominal wall is closed over the repaired bladder.

• Genital repair is often accomplished at different times for the boy and girl with exstrophy. In females, the genitalia and urethral repair can often be accomplished at the time of the initial bladder closure. In males, reconstruction of the penis and urethra (epispadias repair) is usually accomplished between 1 and 2 years of age. This surgery is also important in that it usually causes some urethral resistance, which in turn results in pooling of urine in the bladder which can stimulate bladder growth and capacity.

• Bladder neck reconstruction is accomplished to allow the child to achieve control of urine. It is typically performed at approximately 5 years of age, to allow for continence before starting school. During this surgery, the ureters are repositioned to prevent reflux of urine back up to the kidneys and a bladder sphincter is created that can open and close. This procedure is usually accomplished only after the bladder has grown to a reasonable size.