Exstrophy and Epispadias

Updated: Jul 26, 2016
  • Author: Elizabeth B Yerkes, MD; Chief Editor: Marc Cendron, MD  more...
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Overview

Background

The exstrophy-epispadias complex comprises a spectrum of congenital abnormalities that includes classic bladder exstrophy, epispadias, cloacal exstrophy, and several variants. Each of these anomalies is thought to result from the same embryologic defect.

Separation of the primitive cloaca into the urogenital sinus and hindgut occurs during the first trimester at approximately the same time as maturation of the anterior abdominal wall. Failure of mesenchyme to migrate between the ectodermal and endodermal layers of the lower abdominal wall leads to instability of the cloacal membrane.

Premature rupture of the membrane before its caudal translocation leads to this complex of infraumbilical anomalies. Rupture of the cloacal membrane after complete separation of the genitourinary and gastrointestinal (GI) tracts results in classic bladder exstrophy. However, rupture prior to descent of the urorectal septum allows externalization of the lower urinary tract and the distal GI tract (cloacal exstrophy).

Cloacal exstrophy must be distinguished from the condition of persistent cloaca or cloacal malformation. The latter terms refer to the most extreme form of anorectal malformation in female infants. This complex anomaly involves incomplete separation of the urinary tract, genital tract, and hindgut. No abdominal wall defect is present in persistent cloaca.

Epispadias is a variant that displays normal bladder formation but incomplete urethral tubularization from the bladder neck down. [1]

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Pathophysiology

The true cause of bladder exstrophy has not been elucidated. In classic bladder exstrophy, the lower urinary tract, genitalia, and musculoskeletal system are affected. Cloacal exstrophy is a much more severe abnormality, with significant involvement of the GI tract and the central nervous system (CNS). In epispadias, only the urethra and the external genitalia are involved.

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Etiology

No definitive risk factors or causative agents are known. On the basis of the known embryologic principles of cloacal development, any inciting event would have to occur early in pregnancy.

Offspring of patients with exstrophy-epispadias complex have a 1 in 70 risk (500 times that of the general population) of being affected. Nevertheless, familial occurrence is uncommon in large series. [2]  The heritability of cloacal exstrophy has not been established, because no offspring have been reported.

Exstrophy has been reported in twins. Concordance rates show strong evidence of genetic effects, [3] but less than 100% concordance among identical twins suggests some role for environmental effect on development of exstrophy-epispadias.

A higher incidence of bladder exstrophy is observed in infants of younger mothers and in those with relatively high parity.

Maternal tobacco exposure is associated with more severe defects (cloacal vs classic exstrophy).

Growing evidence suggests an increased incidence of cloacal exstrophy and bladder exstrophy-epispadias with in-vitro fertilization (IVF) pregnancies. [4]

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Epidemiology

In the United States, the prevalence of classic bladder exstrophy is 3.3 per 100,000 births; male epispadias occurs in 1 in 117,000 births, female epispadias in 1 in 484,000 births, and cloacal exstrophy in 1 in 200,000-400,000 births. [5] Internationally, the prevalence is the same as that in the United States.

Because this is a congenital abnormality, newborns are affected. For classic bladder exstrophy, the male-to-female ratio is 2.3:1 and as high as 6:1 in some series. These conditions seem to be more common in whites than in other races.

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Prognosis

Mortality with classic bladder exstrophy or epispadias is rare. Cloacal exstrophy was associated historically with significant mortality. Reconstruction was not attempted until the 1970s. Advances in the care of critically ill neonates and recognition of the importance of early parenteral nutritional support have allowed successful reconstruction and survival of children with cloacal exstrophy.

Survival rates after surgical treatment are excellent. With respect to bladder function or continence, reports vary according to the type of reconstruction performed. [6, 7, 8] Objective and subjective evidence indicates that many exstrophic bladders do not function normally after reconstruction and may deteriorate over time.

Continence rates of 75-90% have been reported after staged reconstruction in classic exstrophy, but more than one continence procedure may be required (eg, bladder neck reconstruction, bladder augmentation, bladder neck sling, artificial urinary sphincter). Many of these patients require clean intermittent catheterization (CIC) through the urethra or a continent stoma because they are unable to void spontaneously to completion. Less encouraging results also are reported.

Continence results after staged reconstruction are poor (<25%) in cloacal exstrophy because of abnormal bladder innervation in many patients. Experience with rectal reservoirs (ureterosigmoidostomy and variants) for exstrophy continence demonstrates rates higher than 95%, but they present long-term malignancy risks. [9] Continent reconstruction with intestinal bladder augmentation and CIC has a success rate greater than 90%.

With regard to sexuality, males are generally potent, but some report inadequate phallus or residual curvature. Females report normal sexual function. [10]

With respect to fertility and childbearing, retrograde ejaculation or iatrogenic obstruction of the ejaculatory ducts or vas deferens after surgical reconstruction may result in abnormal semen analysis. Antegrade ejaculation is preserved after single-stage repair but abnormal semen parameters are common. However, fertilization, with viable pregnancy, has been achieved by male patients with exstrophy. [11]

Females have had successful pregnancies. [12] Cesarean delivery is recommended to avoid injury to continence mechanism. Postpartum uterine prolapse is common because of aggravation of preexisting abnormal pelvic support.

With regard to psychosocial concerns, education, employment, and social relationships generally are not affected substantially in adults with a history of bladder exstrophy and epispadias. [13, 14] Age-appropriate adaptive behaviors may be delayed in children with chronic medical conditions. [15] One study revealed below-average daily living skills and socialization but above-average self-esteem. Children may need support in disclosing their condition to new peers.

Multiple anomalies associated with cloacal exstrophy can have a significant impact on daily life. Patients are affected by permanent colostomy, the need for CIC, and impaired ambulation.

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Patient Education

Exstrophy-epispadias syndrome is a complex anomaly that often requires several surgical procedures and requires lifelong medical follow-up care. Patients and families need to be counseled about the complexity of the anomaly, the need for multiple procedures, and long-term expectations for continence, sexual function, and fertility.

The risks, benefits, and alternatives of urinary tract reconstruction must be explained carefully to the family, and they must accept responsibility for daily care of the patient (eg, CIC after bladder augmentation) before surgery can proceed.

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