Bladder exstrophy

The exstrophy-epispadias complex comprises a spectrum of congenital abnormalities that includes classic bladder exstrophy, epispadias, cloacal exstrophy, and several variants. These conditions are thought to share a common embryologic basis. Separation of the primitive cloaca into the urogenital sinus and hindgut occurs in the first trimester, alongside maturation of the anterior abdominal wall. Failure of mesenchyme to migrate between ectodermal and endodermal layers of the lower abdominal wall leads to instability of the cloacal membrane. Premature rupture before caudal translocation produces this group of infraumbilical anomalies. Rupture after complete separation of the genitourinary and gastrointestinal tracts results in classic bladder exstrophy.

The bladder is open on the lower abdomen, with mucosa fully exposed through a triangular fascial defect. The abdominal wall appears long because of a low-set umbilicus at the upper edge of the bladder plate. The umbilicus-to-anus distance is shortened. The rectus muscles diverge distally and attach to widely separated pubic bones. Indirect inguinal hernias are frequent (more than 80% of males, more than 10% of females) due to wide inguinal rings and a shallow oblique inguinal canal.

The phallus is short and broad with upward curvature (dorsal chordee). The glans lies open and flat, and the dorsal foreskin is absent. The urethral plate runs the length of the phallus without a roof. The bladder plate and urethral plate are continuous; the verumontanum and ejaculatory ducts may be seen within the prostatic urethral plate. The anus is anteriorly displaced; the sphincter mechanism is typically normal.

The pubic symphysis is generally widened. The rectus muscles are divergent distally. When epispadias is the main or isolated finding, planning differs from classic exstrophy and is tailored to meatal position and local anatomy.

Nearly all patients have an associated omphalocele. The bladder is open and split into two halves flanking the exposed cecum. Openings to the remainder of the hindgut and to one or two appendices lie within the cecal plate. Terminal ileum may prolapse as a “trunk” onto the cecal plate. The penis is often small and bifid, with a hemiglans caudal to each hemibladder; rarely the phallus remains midline and intact. In females the clitoris is bifid and two vaginas may be present. The anus is absent.

The pubic symphysis is widely separated and rectus muscles diverge distally. The umbilicus may be low or elongated. A small superior bladder opening or patch of isolated bladder mucosa may be present; the bladder may be covered only by a thin membrane. Isolated ectopic bowel segments have been described. Patent urachus can mimic a superior vesical fissure variant, but urachal anomalies lack the typical musculoskeletal findings of exstrophy and open at the umbilicus, whereas superior vesical fissure is infraumbilical. External genitalia are often intact, though epispadias can occur.

The pubic symphysis is widely separated. Divergent rectus muscles remain attached to the pubis. External rotation of the innominate bones may produce a waddling gait in ambulatory patients; long-term orthopedic sequelae are uncommon in many series.

In cloacal exstrophy, a high proportion of patients have myelodysplasia, including myelomeningocele, lipomeningocele, meningocele, or occult dysraphism. These children warrant close observation for neurologic deterioration; early neurosurgical consultation is appropriate when imaging shows spinal cord or canal abnormalities.

Reconstruction of the exstrophy-epispadias complex remains among the most demanding areas in pediatric urology. Many surgical modifications have improved outcomes, but the optimal pathway for every patient remains individualized. Long-term prospective comparison of staged versus complete primary approaches continues to refine functional and cosmetic results.

Goals include urinary continence with preservation of renal function, reconstruction of functional and cosmetically acceptable genitalia, and often creation of a satisfactory neo-umbilicus.

1. Staged functional closure (classic bladder exstrophy)

A sequence of operations typically includes:

• Initial bladder closure is ideally completed within the first 72 hours of life. If closure is delayed, pelvic osteotomies are often required to allow closure of the abdominal wall and to seat the bladder within a supportive pelvic ring.
• Epispadias repair with urethroplasty around 12-18 months of age increases outlet resistance and can improve bladder capacity over time.
• Bladder neck reconstruction (often around 4 years, e.g. modified Young-Dees-Leadbetter) aims at continence and management of vesicoureteral reflux; numerous modifications exist.

2. Complete primary repair (classic bladder exstrophy)

A newer strategy performs primary bladder closure, urethroplasty, and genital reconstruction in one stage in the newborn period. In males this may involve complete penile disassembly; in females, mobilization of the urogenital complex. Hypospadias is a frequent outcome in males and may need later revision. The goal includes early bladder cycling; some patients achieve continence without separate bladder neck surgery.