An uncommon birth defect in which the bladder and urethra are turned inside out and are open to the outside of the body through a space in the lower abdominal wall. The bones of the pelvis are also separated. To reduce the risk of kidney infection and damage to the bladder lining, surgery to repair the defect is usually performed within 48 hours of birth. During surgery, the bladder is separated from the wall of the abdomen and closed. The urethra may be reconstructed at this time or closed in a second surgery. The pelvic bones may be repaired at the same time or in a later surgery. Follow-up operations are often needed, depending on the severity of the defect and associated problems.