Major congenital disorder resulting in abnormal
development of the cloacal membrane with failure of fusion of the entire
lower abdominal wall, including lower urinary tract, external genitalia, and
Incidence varies from 1:20,000 to 1:30,000 live births,
with a prevalence of 3.3:100,000 live births and a male-to-female ratio of
2:1 to 3:1. The recurrence risk for sibs is approximately 1%, with a one
in 70 recurrence risk for offspring of affected subjects.
Bladder exstrophy most likely is a
multifactorially inherited anomaly. Only 20 cases of familial bladder
exstrophy have been reported. One report of a pair of monozygotic
twins—one with bladder exstrophy, the other with no congenital
abnormalities—has been described. The authors of this report concluded
that the condition was not purely genetically determined.
Abnormal development of cloacal membrane during
the fifth and sixth weeks of embryonic life impedes normal mesodermal
movement and prevents midline fusion of the musculoskeletal elements of the
infraumbilical anterior abdominal wall.
Prenatal diagnosis using ultrasonography is the method
of choice. A reliable diagnosis can be obtained before 20 weeks of gestation
based on the absence of a bladder, normal kidneys, a semisolid mass
protruding from the lower abdominal wall, and a low insertion of the
umbilical cord into the abdomen. Clinical appearance and familial history
Prenatal diagnosis usually is made between 12 and
20 weeks of gestation. Failure of fusion of the cloacal membrane results in a
complete lower anterior abdominal wall defect. This malformation is
characterized by exstrophy of the bladder with a small bladder plate, lower
urinary tract defect (urethra and bladder neck), abnormal external
genitalia, open symphysis pubis, and nonfused lower abdominal wall. The
kidneys are usually normal in appearance. The defect may involve the lower
gastrointestinal tract and the spinal canal. Other anomalies can be
associated. Most affected males develop severe sexual dysfunction because of
a short penis and erection abnormalities.
Neonates require a full preoperative
assessment to determine the extent of the bladder exstrophy and the presence
of any other associated congenital abnormalities. Laboratory investigations
should include a complete blood count, blood glucose, urea, and
electrolytes, including calcium and phosphate. Renal and liver function
tests, a clotting screen, and cross-matching of blood should be obtained.
The cardiovascular status and state of fluid hydration should be assessed
because the condition is associated with marked fluid losses prior to
correction. Older children likely will have undergone several operations and
will benefit from sedative premedication. Latex allergy may be a problem in
children who have undergone several urologic or plastic reconstructive
procedures. Use of a latex-free anesthesia and surgery equipment is recommended.
Standard preparation for all neonates
undergoing major surgery, including arterial and central venous line. Repair of bladder exstrophy involves prolonged
surgery with major blood loss and significant fluid requirements. Epidural
analgesic techniques (caudal or lumbar approach) may be appropriate if the
defect does not involve ...