What Is Bladder Exstrophy?

The bladder exstrophy-epispadias complex consists of rare congenital defects involving the genitourinary and gastrointestinal systems, abdominal wall muscles, pelvic structures, and sometimes the spine and anus. The combined incidence of exstrophy-epispadias complex is approximately 2.15 per 100,000 live births with twice (and up to six times) as many males being affected. Reduction in the expression of p63, a member of the p53 tumor suppressor family, may be a risk factor for development of exstrophy-epispadias complex. During the first weeks of fetal life, exstrophy-epispadias complex results from a derangement in mesodermal layer fusion. The defect in the abdominal wall is widely believed to be the result of overdevelopment of the cloacal membrane which prevents medial migration of the mesenchymal tissue towards midline. The rupture of the cloacal membrane results in herniation of the lower abdominal components to the surface of the abdominal wall.

The severity of the exstrophy-epispadias depends on whether the rupture occurs before or after the separation of the genitourinary and gastrointestinal tracts. The exstrophy-epispadias complex covers a range of severity from epispadias (least severe) to classic bladder exstrophy to cloacal exstrophy (most severe). Classic bladder exstrophy has an incidence of 1 per 10,000 to 50,000 live births and is characterized by an open bladder, exposed dorsal urethra, diastasis of the pubic symphysis, anteriorly displaced anus, inguinal hernia, and genitalia defects. Classic male and female exstrophy is demonstrated by Figure 44.1.

Figure 44.1 Classic features of bladder exstrophy by gender.

Illustration by Sandra Perez

Only 25% of exstrophy-epispadias complex cases are diagnosed prenatally with fetal ultrasound between 15 and 32 weeks of pregnancy, and the remainder are diagnosed during the postnatal examination. Prenatal diagnosis warrants referral to a specialized center with expertise in managing this complex anomaly. Likewise, any infants diagnosed at birth should be sent expeditiously to these centers for experienced evaluation and treatment. Nelson et al. described improved clinical outcomes, lower hospitalization costs, and lower morbidity and mortality rates when patients were treated at specialized hospitals.

What Other Anomalies May Be Associated with Bladder Exstrophy?

While epispadias occurs in isolation, cloacal exstrophy usually occurs with other anomalies. These include malformations of the gastrointestinal, musculoskeletal, and central nervous systems, known as the OEIS complex (omphalocele, exstrophy, imperforate anus, spinal abnormalities). Additionally, patients with classic exstrophy may have skeletal and limb deformities such as clubfoot, congenital hip dislocations, and tibial malformations. Horseshoe kidney and other renal anomalies are more common in children with classic bladder exstrophy (CBE). CBE are rarely associated with omphalocele, imperforate anus, and rectal stenosis. Approximately 7% of CBE patients may have spinal abnormalities such as spina bifida, scoliosis, and hemi-vertebrae.

What Are the Current Treatment Options for Classic Bladder Exstrophy?

Historically, bladder exstrophy patients underwent a cystectomy with high morbidity in the first year of life due to complications from renal failure. Advanced surgical techniques have greatly improved survival rates to nearly 100%. The primary reconstructive goal is closure of the bony pelvis, bladder, and abdominal wall defects, followed by epispadias repair; however, long-term goals include preserving renal function, obtaining urinary continence, achieving sexual function, and cosmesis.

The immediate management of bladder exstrophy consists of covering the extruding viscera with sterile silicon gauzes and occlusive dressing to prevent dehydration of the exstrophic plaque and keeping the areas clean with saline washes to reduce risk of infection. There are two main surgical approaches to bladder exstrophy repair: complete primary repair of exstrophy (CPRE) versus modern staged repair of exstrophy (MSRE). As the name implies, the staged repair involves several stages of repair. The first stage is closure of the abdomen and bladder during the newborn period. The second stage is closure of the urethral epispadias. The third stage is a continence procedure and delayed until between ages five to nine, so that the patient achieves an adequate bladder capacity. The complete primary repair combines the first two stages of MSRE. Proponents of CPRE suggest that combining the first two stages stimulates bladder growth and reduces cost by decreasing the number of operations.