Laboratory Studies
Before complex reconstruction of the urinary tract, it is important to obtain information about the patient's baseline renal function. In patients with cloacal exstrophy, losses from the terminal ileum short-gut physiology can result in significant electrolyte abnormalities.
Imaging Studies
Baseline examination of the kidneys with ultrasonography (US) is recommended for all patients with exstrophy because increased bladder pressure after bladder closure can lead to hydronephrosis and upper urinary tract deterioration. Congenital upper urinary tract anomalies are uncommon with classic exstrophy and epispadias but are present in approximately one third of patients with cloacal exstrophy (eg, ectopic pelvic kidney, renal agenesis, or hydronephrosis).
Spinal US or radiography may be helpful. Myelodysplasia should be excluded in newborns with cloacal exstrophy. This can be accomplished by means of US early in life. In cloacal exstrophy, magnetic resonance imaging (MRI) is recommended to help identify occult abnormalities that may predispose to symptomatic spinal cord tethering.
Bilateral vesicoureteral reflux (VUR) is present in nearly all patients with classic bladder exstrophy. Voiding cystourethrography (VCUG) is performed in early childhood to assess bladder capacity in preparation for reconstructive continence surgery. Evaluation of the bladder neck and proximal urethra is recommended in patients with epispadias in order to plan surgical management.
Histologic Findings
Histologic studies are not routinely performed. However, clinical investigations have revealed an increased ratio of extracellular matrix to muscle within the bladder wall. In particular, the amount of type III collagen is increased. This ratio seems to approach a more normal range (ie, relative increase in muscle) after successful bladder closure. Exstrophied bladders also have fewer myelinated nerve fibers than unaffected bladders do.
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Open bladder plate and urethra with bifid clitoris in female patient with classic bladder exstrophy. Note low-set umbilicus and anteriorly displaced anus. Courtesy of Richard Rink, MD.
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Male with classic bladder exstrophy. Note low-set umbilicus and short, broad, upturned phallus. Distance between phallus and scrotum is abnormal. Courtesy of Richard Rink, MD.
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External view in female patient with epispadias. Labia are separated anteriorly. Courtesy of Richard Rink, MD.
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Female patient with epispadias with labia retracted. The clitoris is bifid, and the urethra is open dorsally. Courtesy of Richard Rink, MD.
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Penopubic epispadias in male patient. Typical spadelike configuration of glans penis with incomplete foreskin, dorsal urethral plate, and open bladder neck. Courtesy of Richard Rink, MD.
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46,XY newborn with cloacal exstrophy. A very large omphalocele is present, and the hemibladders flank the exstrophic cecal plate. The phallus is small and bifid, with the hemiglans and hemiscrotum located just distal to the bladder. Courtesy of Martin Kaefer, MD.
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Lipomeningocele in the same newborn shown in Image 6, a 46,XY newborn with cloacal exstrophy. Courtesy of Martin Kaefer, MD.
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Superior vesical fissure variant of exstrophy. Genitalia are normal. Patent urachus is considered in the differential diagnosis, although the opening is well below the umbilicus. Rectus abdominis and pubic abnormalities are found in the exstrophic variant but not with patent urachus. Courtesy of Richard Rink, MD.
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Female with covered exstrophy. The umbilicus is very low, the pubic bones are widely separated, and the rectus muscles are divergent. The bladder is intact, but the patient has undergone bladder neck reconstruction to achieve urinary continence. The external genitalia are normal. Courtesy of Elizabeth Yerkes, MD.
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Typical appearance of pelvis in patient with exstrophy-epispadias complex with wide separation of pubic symphysis.
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Bilateral vesicoureteral reflux and small-capacity bladder after initial exstrophy closure. Contrast escapes readily through the incompetent bladder neck.
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Use of plastic wrap to protect the delicate bladder mucosa in a newborn with bladder exstrophy. Courtesy of Richard Rink, MD.
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Subtotal prolapse of bladder wall through patulous bladder neck after bladder closure in female with cloacal exstrophy. The bladder mucosa appears healthy, and urine is draining freely. Courtesy of Richard Rink, MD.
