CONGENITAL ANOMALIES OF THE BLADDER
Exstrophy of the bladder is a rare congenital anomaly with complete ventral defect of the urogenital sinus and the overlying skeletal system (Gambhir et al, 2008). Incidence of this anomaly is reported to be 3.3 per 100,000 births. The male-to-female ratio is about 1.6 (ICBDMS, 1987; Jayachandran et al, 2011; Feldkamp et al, 2011).
The lower central abdomen is occupied by the inner surface of the posterior wall of the bladder, whose mucosal edges are fused with the skin. Urine empties onto the abdominal wall from the ureteral orifices.
The rami of the pubic bones are widely separated. The pelvic ring thus lacks rigidity, the femurs are rotated externally, and the child “waddles like a duck.”
The rectus muscles are widely separated from each other caudally. A hernia, made up of the exstrophic bladder and surrounding skin, is present.
Epispadias is almost always associated. Undescended testicles may be seen, and the anus and vagina are located anteriorly. Urinary tract infection and hydronephrosis are common.
Prenatal diagnosis is difficult, with approximately 13–16% that can be identified prenatally on routine ultrasound (Jayachandran et al, 2011; Austin et al, 1998; Emanuel et al, 1995; Cervellione et al, 2015). Up to 6% of babies will present with other congenital abnormalities (Cervellione et al, 2015) such as exposed bladder mucosa seen at time of birth or separation of pubic bones seen on x-ray.
Historical treatment includes staged repair of this anomaly (Stec et al, 2012). The first stage consists in closing the abdominal wall, the bladder, and the posterior urethra. An orthopedic procedure of sacral osteotomy in order to close the abdominal wall may be necessary (Meldrum et al, 2003; Suson et al, 2013; Vining et al, 2011). Mollard et al (1994) recommend the following steps for satisfactory repair of bladder exstrophy (Mollard et al, 1993): (1) bladder closure with sacral osteotomy in order to close the pelvic ring at the pubic symphysis (Cervellione, 2011), plus lengthening of the penis; (2) antiureteral reflux procedure and bladder neck reconstruction; and (3) repair of the epispadiac penis. Treatment needs to be initiated prior to the fibrosis of the bladder mucosa in order to repair this anomaly completely (Oesterling and Jeffs, 1987). When the bladder is small, fibrotic, and inelastic, functional closure becomes inadvisable, and urinary diversion with cystectomy is the treatment of choice. The modern approach is to perform primary repair of this anomaly completely, although some may opt to delay treatment for 2–3 months after birth rather than begin it within 72 hours of birth, as had been done traditionally (Mitchell, 2005; Mourtzinos and Borer, 2004).