Bladder Exstrophy (BE) is a complex and rare congenital birth defect involving the urinary system and the musculoskeletal structures of the pelvis. It is characterized by the bladder being open and exposed on the outside of the lower abdominal wall at birth. The bladder tissue is turned outward, preventing the bladder from storing urine. This serious malformation requires immediate and specialized surgical intervention for functional and anatomical correction.
Defining Bladder Exstrophy
Classic Bladder Exstrophy is the most common presentation within a group of related defects known as the exstrophy-epispadias complex. The primary anatomical feature is the exposed bladder plate, which is the inner lining of the bladder turned inside out and visible on the abdomen. Since the anterior abdominal wall did not fuse properly, the urinary bladder cannot function as a reservoir, and urine continuously drains onto the skin from the ureter openings.
This defect is invariably accompanied by a malformation of the pelvic bones and the urethra. The pubic bones, which normally join at the front, are widely separated, a condition called diastasis of the symphysis pubis. This separation causes the legs and hips to rotate externally and the abdominal muscles to diverge. All children with classic Bladder Exstrophy also have epispadias, where the urethra is malformed and does not form a complete tube. In boys, the urethral opening is on the top surface of the penis, which is often short and broad. In girls, the clitoris is split, and the urethral opening is higher and wider than normal.
The exstrophy-epispadias complex exists on a spectrum of severity. Classic Bladder Exstrophy makes up about 60% of cases. Epispadias alone, where only the urethra is malformed without the exposed bladder, represents the mildest form. At the most severe end is Cloacal Exstrophy, a multisystem defect where the bladder, large intestine, and other abdominal organs are exposed.
Embryological Causes and Risk Factors
The condition originates from an error in fetal development, specifically between the fourth and eighth weeks of gestation. During this period, the lower abdominal wall and the pelvis fail to fuse properly in the midline.
The prevailing theory points to a premature rupture of the cloacal membrane, a temporary structure that covers the developing lower urinary and intestinal tracts. If this membrane ruptures before the surrounding tissue, called mesoderm, has adequately reinforced the area, the structures beneath are prevented from migrating to the midline and closing. This results in the exposed bladder and the separation of the pelvic bones. The cause is considered multifactorial, meaning a combination of genetic predisposition and unknown environmental factors is likely involved.
Staged Surgical Management and Repair
The treatment for Bladder Exstrophy is a complex, multi-stage surgical reconstruction performed at specialized centers, often beginning within the first days of life. The primary goal is to close the bladder, reconstruct the external genitalia, and establish urinary continence while preserving kidney function. The traditional approach, known as Modern Staged Repair of Exstrophy (MSRE), typically involves three distinct surgical stages spread over several years.
The first stage, Primary Closure, is performed shortly after birth, ideally within 72 hours. This operation involves closing the bladder, relocating it back into the pelvic cavity, and closing the abdominal wall defect. For successful closure, especially in infants with wide pubic separation, a neonatal orthopedic procedure called pelvic osteotomy is often performed. This procedure temporarily reconnects the widely separated pelvic bones to reduce tension on the abdominal closure.
The second stage, Epispadias Repair, is typically performed around 6 to 12 months of age. This surgery focuses on reconstructing the urethra and the external genitalia. In males, this involves creating a tubular urethra and lengthening the phallus for a cosmetically and functionally acceptable result. Reconstructing the urethra early can also help increase the bladder’s capacity by providing outlet resistance.
The final and most challenging stage is Bladder Neck Reconstruction, usually performed when the child is between four and five years old. This timing is chosen because the child can actively participate in toilet training. This procedure aims to tighten the bladder neck muscles that control the flow of urine, which are naturally absent or severely underdeveloped in Bladder Exstrophy patients. Sometimes, a portion of the intestine is used to enlarge the bladder, a procedure called augmentation cystoplasty, to ensure it has enough capacity to hold urine.
Long-Term Functional Outcomes
With advancements in surgical techniques, the long-term prognosis for individuals born with Bladder Exstrophy is positive, and a good quality of life is achievable. The most important functional outcome is achieving urinary continence, which often requires multiple procedures beyond the initial three stages.
Continence rates vary, but studies show overall continence—defined as a dry interval of three or more hours—is achieved in approximately 76% of patients following all necessary procedures. A smaller percentage, around 25%, are able to void normally without needing a catheter. For many, achieving dryness requires clean intermittent catheterization, a technique where the bladder is emptied several times a day using a small tube. Maintaining kidney health is a primary goal of treatment, and most individuals successfully prevent upper urinary tract damage and maintain normal renal function.
In adulthood, sexual function and fertility are generally not impaired. Most patients report a normal capacity for sexual relationships, and successful pregnancies are common for women who have undergone successful reconstruction.