Bladder Exstrophy

Bladder exstrophy is a congenital midline defect in which the bladder lies open on the lower abdominal wall. The posterior bladder wall is exposed, with an epispadiac urethra, a widened pubic symphysis (diastasis of 4 to 6 cm or more) and low set umbilicus. Incidence of classic exstrophy is about 1 in 30,000 to 50,000 live births, with a male-to-female ratio of 2 to 3:1.

It lies at the severe end of the exstrophy epispadias complex. The complex runs from isolated epispadias, through classic bladder exstrophy (the commonest form), to cloacal exstrophy. Cloacal exstrophy has bladder halves separated by an exposed hindgut, with omphalocele, imperforate anus, spinal dysraphism and neurological or limb defects.

The defect results from failure of mesenchymal ingrowth between the ectoderm and cloacal endoderm. This leaves an unstable cloacal membrane that ruptures prematurely.

Recurrence risk for a sibling is about 1 in 275, and for offspring of an affected parent about 1 in 70. Risk factors include assisted reproduction, maternal smoking and advanced paternal age.

Associated features:

• Bilateral inguinal hernias (over 80 percent of boys).
• Anterior displaced anus with perineal shortening, and rectal prolapse.
• Outward rotation of the pelvis with waddling gait if untreated.
• Reflux in virtually all (the ureters enter the bladder perpendicular and are refluxing after closure).
• Short penis with dorsal chordee in boys.
• Bifid clitoris with anteriorly displaced vaginal opening in girls.

Long term risks are urinary incontinence, recurrent infection, bladder adenocarcinoma in an untreated or intestinal augmented bladder, renal scarring, and sexual dysfunction.

• Obvious at birth: exposed bladder mucosa that is red, oedematous and weeping urine from the ureteric orifices; pubic diastasis; epispadias; low umbilicus.
• Bladder plate may be small, fibrotic or polypoid (metaplasia). Mucosa is delicate and bleeds on contact.
• Prenatal clues: non-visualisation of the fetal bladder on repeated scans, low set umbilical cord insertion, widened pubic rami, a lower abdominal wall mass or a small penis with anteriorly displaced scrotum.
• Inguinal hernias, rectal prolapse and a wide gap between the anus and genitalia are common.
• Examination of the upper tract is often normal at birth, but hydronephrosis may develop later.

• Mainly clinical at birth.
• Prenatal ultrasound after 18 to 20 weeks: absent bladder filling on serial examinations, a lower abdominal protruding mass, small genitalia; confirmed with fetal MRI if needed.
• Postnatal renal and bladder ultrasound for hydronephrosis, and spine ultrasound to exclude occult dysraphism.
• Pelvic X-ray to measure pubic diastasis; consider MRI for pelvic floor and anatomy before reconstructive surgery.
• Serum electrolytes and creatinine when bowel or augmentation is planned.
• Assessment for cloacal exstrophy features: omphalocele, anorectal malformation, neural tube defect.
• Karyotype and genetic counselling if other anomalies are present.

Management is surgical, staged or complete primary repair, undertaken in a specialist centre.

• Delivery: normal vaginal delivery is possible, with immediate transfer to a specialised centre.
• At birth, clamp the cord with a plastic or silk ligature (not the usual clamp, which abrades the bladder plate). Cover the exposed bladder with cling film (changed with each dressing) or a non-adherent dressing, and irrigate with warm saline. Avoid dry gauze or adherent dressings.
• Place the baby supine, keep warm, start intravenous fluids, and begin prophylactic antibiotics (amoxicillin 15 mg/kg orally once daily, or cefalexin 10 mg/kg once daily) in the perioperative period.
• Primary closure at 24 to 72 hours of age (neonatal single stage reconstruction) or at 3 to 4 months in staged repair. Bladder, posterior urethra and abdominal wall are closed in layers, with the pubic bones brought together by pubic symphysis approximation.
• Osteotomy (bilateral iliac) is used when the pubic gap cannot be approximated, if the child is older than 72 hours, or after failed closure.
• Postoperative immobilisation (modified Buck traction, Bryant traction or spica) for 4 to 6 weeks. Use ureteric stents and suprapubic catheter drainage for 3 to 4 weeks, with prophylactic antibiotic therapy until the catheters are removed and reflux is evaluated.
• Epispadias repair (Cantwell-Ransley or modified approach with penile lengthening and chordee correction) at 6 to 12 months. It is often combined with testosterone priming (testosterone enanthate 2 mg/kg intramuscularly monthly for 2 doses before surgery) to enlarge the penis.
• Bladder neck reconstruction (Young-Dees-Leadbetter, or Kropp or Pippi Salle procedures) at 4 to 5 years, when the bladder capacity reaches 60 to 100 mL and the child is ready for toilet training and clean intermittent catheterisation. It is combined with ureteric reimplantation to treat reflux.
• Bladder augmentation (ileocystoplasty or other segments) with a continent catheterisable channel (Mitrofanoff appendicovesicostomy) for small bladder or poor compliance, with sodium bicarbonate, mucous irrigation and surveillance cystoscopy.
• Surveillance: renal ultrasound every 6 to 12 months, urine culture, serum creatinine and bicarbonate, vitamin B12 if ileum is used, urodynamics if incontinent. Perform bladder cystoscopy annually after adolescence in augmented bladders for tumour screening.
• Long term: continence is achieved in 70 to 80 percent after all steps.
• Counselling is needed on gender specific sexual function, fertility and pregnancy. Fertility is reduced in men because of retrograde ejaculation and obstructed ejaculatory ducts; assisted reproduction may be needed. In pregnancy there is a pelvic organ prolapse risk; caesarean section at term, often with a urologist present.
• Psychological support is advised.