Congenital Anomalies: Urachal Anomalies, Exstrophy-Epispadias Complex, Imperforate Anus, Cloaca, and Prune Belly Syndrome

Congenital Anomalies: Urachal Anomalies, Exstrophy-Epispadias Complex, Imperforate Anus, Cloaca, and Prune Belly Syndrome

Joseph Borer


A. Background

The urachus is a fibrous band of tissue that extends from the dome of the bladder to the umbilicus as the remnant of the allantoic duct. Ordinarily, this tract obliterates by the end of the first trimester, but rarely it remains partially or completely patent.

B. Presentation

Complete failure of urachal obliteration may result in a persistent patent communication from the bladder to the umbilicus with either constant or intermittent leakage of urine or mucus. Although this may occur as a result of bladder outlet obstruction such as posterior urethral valves, more often there is no associated anomaly. The usual presentation is in the neonate with constant or intermittent moisture/drainage from the umbilicus that may worsen during crying or straining. If the urachal lumen is only partially obliterated, it may present later in childhood with enlargement due to accumulation of desquamated products or infection. Signs and symptoms may include pain, fever, mass, umbilical drainage, and in some cases signs of urinary tract infection (UTI) such as urinary frequency, urgency, and dysuria. Included in the differential diagnosis of such a presentation are infected urachal cyst, urachal sinus, or urachal diverticulum, vitelline cyst, umbilical hernia, and ovarian cyst. Often there is an associated UTI if the urachal remnant is in communication with the bladder.

C. Workup

If one suspects a urachal anomaly by history and/or physical examination, an ultrasound of the abdomen with particular attention to the abdominal wall may be diagnostic. Other forms of urachal anomalies may require placement of a probe into the urachal tract or instillation of contrast for a fluoroscopic fistulogram. Occasionally, a voiding cystourethrogram (VCUG) will delineate the communication. However, the VCUG is typically more useful for evaluating potential associated lower urinary tract anomalies.

D. Treatment

Complete extraperitoneal excision of the urachal malformation is indicated in most cases. Occasionally, infected cysts may benefit from percutaneous drainage and antibiotic therapy in the acute setting. However, definitive management requires resection because of the high likelihood of recurrence. Although adenocarcinoma of the urachus is rare, it has been reported to arise in patients with a history of infected cysts. For this

reason, it is recommended to resect a “cuff” of surrounding bladder tissue during excision of any urachal abnormality.

FIG. 16-1 Urachal anomalies. A: Patent urachus. B: Urachal cyst. C: Urachal sinus. D: Urachal diverticulum.


A. Background

The exstrophy-epispadias complex is a spectrum of anomalies with many similarities, but varying degrees of severity (Fig. 16-2). Within this spectrum, severity and complexity increases from epispadias to bladder

exstrophy to cloacal exstrophy. Bladder exstrophy is seen in approximately 1 in every 30,000 to 40,000 births, and is more common in boys. Within the exstrophy-epispadias spectrum, bladder exstrophy occurs in 60% of patients, epispadias (all forms) in 30%, and cloacal exstrophy and other variants in 10%.

FIG. 16-2 A: Exstrophy-epispadias complex. B: Epispadias, penopubic (boy). C: Bladder exstrophy (girl). D: Cloacal exstrophy (boy).

FIG. 16-2 (cont.)

B. Embryogenesis

The most popular theory suggests overdevelopment of a normal structure known as the cloacal membrane which is present during early fetal development, but abnormally persists beyond the 4th week of gestation, preventing the lateral mesoderm from migrating medially. Once the membrane disappears by the 9th week, the internal surface of the bladder is exposed on the lower abdominal wall with the umbilicus in abnormally low position adjacent to the cephalad apex of the bladder. There is also failure of urethral tubularization. In the most severe form, cloacal exstrophy, an abnormally large cloacal membrane perforates prior to division of the cloaca itself by the urorectal septum. This results in exstrophied bladder halves that are separated by an interposed exstrophied ileocecal bowel segment.

C. Anatomy

For individuals with bladder exstrophy, the inner surface of the urinary bladder is open and exposed on the lower abdominal wall. The bladder is not covered as normal by abdominal wall muscle, fascia, and skin, but rather the bladder is essentially inside out with the inner surface exposed. The disorder usually involves several organ systems including the urinary tract, reproductive tract, digestive system, muscles and the skin of the lower abdominal wall, and the muscles and bones of the pelvis. In addition, the inner lining of the urethra is also exposed on the dorsal surface of the penis in boys or between the separated right and left halves of the clitoris in girls. The failure of the urethra to close normally and its exposure on the surface is called epispadias. Epispadias is a consistent component of bladder exstrophy, but may also present in isolation (open, exposed urethra with closed bladder). In the absence of normal closure of the bladder and urethra, the bladder lacks the ability to store urine, and urine constantly trickles onto the exposed inner surface of the bladder and surrounding skin.

Bladder exstrophy and cloacal exstrophy may be diagnosed prenatally by an experienced ultrasonographer, or at birth as the exposed bladder and urethra (and bowel as well in cloacal exstrophy) are obvious malformations. The bladder plate may vary in size from a small vestigial structure to 6 cm to 7 cm in diameter. Pubic bone separation from the anterior midline (pubic diastasis) is present in all cases. The upper urinary tracts are generally normal except in cloacal exstrophy patients of whom up to two-thirds may have abnormalities such as renal ectopia, dysplasia, or agenesis. Exposure of the bladder results in bacterial colonization, and may result in squamous metaplasia along the edge of the bladder bordering skin. Once the bladder has been closed, vesicoureteral reflux (VUR) occurs in the vast majority of patients due to the abnormal insertion of the ureters and lack of muscular backing and thus lack of the normal anti-reflux flap-valve mechanism. Inguinal hernias are common, especially in boys. The testes are descended normally in most cases. Infrequently, rectal prolapse may be present due to weakness in the perineal floor and the anterior aspect of the levator muscle complex.

D. Initial Management and Evaluation

1. Soon after initial plastic clamp occlusion of the umbilical cord at delivery, the clamp should be exchanged for soft cloth “umbilical tape” or silk ligature to limit trauma to the exposed mucosal surface of the
bladder. The bladder and urethra may be covered with a transparent adhesive dressing (“Saran wrap”) that adheres to the intact skin immediately surrounding the exposed bladder, but glides over and protects the exposed mucosa. This allows free egress of urine from the ureteral orifices on the bladder surface and subsequent passage caudally along the genitalia and into a diaper. Touching the bladder mucosa and potential abrasion should be avoided.

2. Initial evaluation includes a complete blood count, serum electrolytes, blood urea nitrogen, and plasma creatinine. In general, patients with epispadias or bladder exstrophy have normal kidneys and normal renal function, whereas abnormalities in renal number, position, and function are common in cloacal exstrophy. Imaging studies include renal ultrasound to screen for any congenital anomaly of the kidney or urinary tract. Abdominal plain film is helpful for measuring the degree of pubic diastasis.

E. Initial Surgical Management

There are several different approaches to initial repair for the boy or girl with bladder exstrophy. Variation in management may exist per institution and/or surgeon for either timing and/or technique of initial and definitive repair of bladder exstrophy. With regard to timing, the initial reconstructive surgery may be performed within the first 2 to 3 days of life (immediate) or at approximately 6 to 8 weeks of age (delayed). Delaying the initial closure may be the preference of some pediatric urologists based on practice or based on the specific anatomy of the individual patient. Examples of this would be delaying initial surgery if the bladder or genitalia was too small for safe repair and/or if the baby was born prematurely. Regarding variation in technical approach to initial repair, of bladder exstrophy there are several options: (1) modern staged repair of exstrophy (MSRE), (2) complete primary repair of exstrophy (CPRE), (3) soft tissue reconstruction, and (4) urinary diversion.

1. Modern staged repair of exstrophy

Stage 1: Initial closure: During this first stage, the bladder, proximal urethra (in the boy), and abdominal wall are closed, the umbilicus is reconstructed, and an incision in the pelvic bones (osteotomy) is sometimes performed to aid in the repair. Whether or not the infant needs an osteotomy is dependent on how soon after birth the closure is performed, the degree of pubic diastasis, and flexibility of the pubic bones. Most include osteotomies with closure for a baby older than 72 hours of age.

After surgery, the baby will be placed with the lower abdomen, pelvis, and legs in traction/splint in order to stabilize the pelvis and repair as an aid to healing. Patients may stay in the hospital for 1 to 4 weeks and will be carefully observed during this time. Antibiotics are given during and after the surgery to decrease the risk of infection. The bladder is drained continuously with a suprapubic cystostomy tube and removed approximately 4 weeks following surgery provided VCUG and voiding efficiency are satisfactory.

Stage 2: Epispadias repair: Epispadias is a congenital defect wherein the urethra fails to close. Epispadias is always associated with bladder exstrophy. In boys, the distal exposed urethra, purposely not repaired at the first stage, is now closed at the second stage of the MSRE. In girls, the urethra is usually closed along its entire length at the first stage of MSRE, extending all the way from the bladder to the surface of the introitus between the labia to end in normal position. The surgical procedure used to correct epispadias in boys aims to complete the reconstruction of the urethra with urethral meatus on the glans and
restore the appearance of the external genitalia to normal. This repair is performed at approximately 6 months of age.

Stage 3: Bladder neck reconstruction: Bladder neck reconstruction (BNR) represents the third and final stage of the modern staged approach. Bilateral ureteral reimplantation is almost always performed with BNR. Performance of this stage of the MSRE depends on sufficient growth of the bladder as judged by bladder capacity. BNR is usually performed between the ages of 4 and 8 years.

2. Complete primary repair of bladder exstrophy: With advances in surgical technique, the initial surgery for children with bladder exstrophy may combine the first two stages of the MSRE, that is, closure of the bladder and epispadias repair at the same setting, and is called complete primary repair of bladder exstrophy (CPRE). This technique combines the goals of the first two stages of the staged reconstruction into a single operation in order to create an environment that allows more normal bladder function (cycling) to begin earlier, optimizing bladder growth and development. In some boys and more often in girls, successful CPRE may eliminate the need for BNR later in life.

The operation consists of closure and internalization of the bladder, closure of the urethra (epispadias repair), repair of external genitalia, and repair/approximation of the lower abdominal wall muscles and skin. Some newborns may require osteotomy in order to help bring the pelvic bones closer together. This approach has resulted in adequate urinary continence in some patients, therefore making it unnecessary to perform formal BNR to treat incontinence. Regardless of the outcome of continence, almost all boys and girls with bladder exstrophy will require surgery for treatment of vesicoureteral reflux, which is present in nearly all babies with bladder exstrophy. All of these babies require traction in order to stabilize the repair and optimize healing following initial repair.

Complete primary repair may be delayed and performed at approximately 6 to 8 weeks of life with the addition of a bilateral pelvic bone osteotomy. It is felt by some that delaying CPRE beyond the first 2 to 3 days of life has several advantages for the child and the family unit. It presents an opportunity for normal bonding between the baby and parents before the initial reconstructive surgery and lengthy recovery period that follows. This time between birth and initial repair will allow for growth, development, and additional maturation of some organs and systems prior to the complex surgery, and will make the anesthesia and the surgery safer.

3. Soft tissue reconstruction: The soft tissue reconstruction/mobilization technique involves two stages. Initial bladder closure similar to that in the first stage of the MSRE is performed in the newborn with or without osteotomy. The second stage involves bilateral ureteral reimplantation, bladder neck reconstruction/tubularization, epispadias repair, and freeing of the neurovascular bundle proximal to the pudendal pedicle. Dissection under the periosteum provides a delicate but safe plane to the experienced surgeon for freeing of the neurovascular bundle and is felt to gain length on the phallus.

4. Urinary diversion: This strategy for management, applied in some institutions, involves creating a purposeful and functional connection between the urinary and intestinal tracts. Although there are several variations on this theme, basically the urine is diverted (directed away) from the urinary bladder and into the bowel (large intestine/colon) for temporary storage and then intermittent emptying per rectum with the stool. Passage at regular intervals is under the control
of the child. The bladder and urethra are closed, but are “dry” and are neither exposed to the urine nor necessary as a conduit for the urine.

F. Epispadias

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Sep 29, 2018 | Posted by in UROLOGY | Comments Off on Congenital Anomalies: Urachal Anomalies, Exstrophy-Epispadias Complex, Imperforate Anus, Cloaca, and Prune Belly Syndrome

Full access? Get Clinical Tree

Get Clinical Tree app for offline access