Pseudoexstrophy: This is a type of exstrophy (see classic bladder exstrophy). The pelvic bones have the same defect as seen with exstrophy, but the bladder and the urinary tract are normal.
Superior vesical fissure: The pelvic bones are abnormal as seen in classic bladder exstrophy, but only the uppermost end of the bladder is opened near the belly button.
Duplicate exstrophy: The pelvic bones may be abnormal as in classic bladder exstrophy, but a separate piece of the bladder is opened and flattened on the wall of the abdomen. The remainder of the bladder is normal and within the abdomen. The normal bladder is most often in the pelvis posterior to the exstrophied bladder but can be side to side.
Covered exstrophy:The pelvic bones have the abnormality as seen in classic bladder exstrophy. A piece of bowel is opened on the wall of the abdomen. The urethra (channel that goes from the bladder to the outside through the penis) is also opened (see epispadias).
John P. Gearhart, Robert D. Jeffs: Exstrophy of the Bladder, Epispadias and other Bladder Anomalies in Campbell's Urology, Sixth Edition. Eds. Walsh PC, Retik AB, Stamey TA, Darracott Vaughan E, Jr., WB Saunders Co. Vol. 2 1772-1821.
John P. Gearhart: The bladder exstrophy-epispadias complex. In: Pediatric Urology. Es Gearhart JP, Rink RR, and Mouriquand P. Saunders, Philadelphia. Chapter 32, p 511-546.