Cloacal Exstrophy

18.1Introduction

•Cloacal exstrophy is an extremely rare and major birth defect representing the severe end of the spectrum of the exstrophy-epispadias complex (Fig. 18.1).

•It is also called vessico-intestinal fissure.

•The exact incidence of cloacal exstrophy is not known but the estimated prevalence ranges from 1 in 50,000 to 250,000 live births.

•It is more common in males than females (a male-female ratio of 2:1).

•Cloacal exstrophy, is also called the OEIS Complex:

–O: Omphalocele

–E: Exstrophy of the cloaca

–I: Imperforate Anus

–S: Spinal Defects

•Clinically, patients with cloacal exstrophy present at birth and it is characterized by the followings spectrum of anomalies (Figs. 18.2, 18.3, 18.4, 18.5, and 18.6):

–Two exstrophied hemibladders

–These are separated by a foreshortened hindgut or cecum

–The hindgut is often blind-ending resulting in an imperforate anus.

–This extrophied ileo-cecal region presents between the two hemi bladders (the “elephant trunk” appearance).

–Omphalocele

–The associated omphalocele may be major or minor and sometimes no associated omphalocele.

–Malrotation

–The symphysis pubis is widely separated

–The pelvis is often asymmetrically shaped

–The genitalia (ambiguous genitalia):

•In males, the penis is divided into two halves usually located separately on either side of the bladder plates with the adjacent scrotal halves.

•In females, the clitoris is divided into two haves usually located separately on either side of the bladder plates with the adjacent part.

•Duplication of the vagina and uterus

•Vaginal agenesis

18.2Etiology and Pathogenesis

•The exact etiology of cloacal exstrophy is not known.

•Several theories have been proposed to explain the pathogenesis of cloacal exstrophy but none of them can fully explain the spectrum of anomalies seen in cloacal exstrophy.

•The most accepted theory is that cloacal exstrophy results from premature rupture of the cloacal membrane prior to caudal migration of the urorectal septum, and failure of fusion of the genital tubercles.

•Embryo logically:

–The urorectal septum divides the cloaca into an anterior urogenital sinus and a posterior anorectal canal.

–This occurs around the fourth week of intrauterine life and simultaneously, the cloacal membrane is invaded by lateral mesodermal folds.

–It is postulated that if this mesodermal invasion does not occur, the infraumbilical

cloacal membrane persists leading to poor lower abdominal wall development.

–The cloacal membrane eventually ruptures but if this happens prior to the descent of the urorectal septum which happens at 6–8 weeks of gestation, then cloacal exstrophy results.

–Cloacal exstrophy develops as a result of:

•Failure of the urorectal septum to develop and divides the urogenital sinus anteriorly from the rectum posteriorly.

Figs. 18.4 and

18.5 Clinical photographs showing cloacal exstrophy in two patients. Note the absence of omphalocele in the first one and associated anorectal agenesis in the second one

NO OMPHALOCELE

OPENED

URINARY

BLADDER

PROLAPSED

ILEOCECAL

REGION

OPENED

URINARY

BLADDER

HEMIBLADDER

HEMIBLADDER

ANORECTAL

AGENESIS

Fig. 18.6 A clinical photograph showing cloacal exstrophy. Note the associated anorectal agenesis

•Failure of the mesoderm forming the infraumbilical abdominal wall to proliferate and form the lower abdominal wall

•Failure of the genital tubercle to develop.

•Failure of these events to occur results in exstrophy of both bladder and intestine.

–Classically, cloacal exstrophy is made up of omphalocele, exstrophied ileocecal region of bowel, exstrophied hemi bladders

PROLAPSED

ILEOCECAL

REGION

ANORECTAL

AGENESIS

each with its ipsilateral ureter, and anorectal agenesis.

–The pubic bones are widely separated, and spinal dysraphism is common in these patients.

18.3Associated Anomalies

•Cloacal exstrophy is commonly associated with other anomalies including cardiovascular, and central nervous system anomalies.

•Omphalocele is present in 70–90 % of patients with cloacal exstrophy.

•Spinal and skeletal anomalies (46 %). These include (Figs. 18.7 and 18.8):

–Hemivertebra

–Myelomeningocele

–Clubfoot deformities

–Absence of feet

–Tibial/fibular deformities

–Hip dislocation

Fig. 18.7 Clinical photograph of a newborn with cloacal exstrophy. Note also the associated bilateral tallipes equinovarus

•Upper urinary tract anomalies (42 %).

–Pelvic kidney

–Horseshoe kidney

–Hypoplastic kidney

–Solitary kidney

•Malrotation (30 %)

–Urological malformations:

•Ureteropelvic junction obstruction

•Ectopic pelvic kidney

•Horseshoe kidney

•Hypoplastic kidney or renal agenesis

•Megaureter

•Ureteral ectopy and ureterocele

•Lower extremity anomalies (30 %)

•Double appendix (30 %)

•Absent appendix (21 %)

•Short bowel syndrome (19–46 %)

•Gastrointestinal duplications

•Small bowel atresia (5 %)

•Abdominal wall musculature deficiency (1 %)

Fig. 18.8 Abdominal x-ray showing widened pubic bone and abnormal asymmetrical pelvis

–Sacralization of L5

–Congenital scoliosis

–Sacral agenesis

–Interpedicular widening

18.4Clinical Features and Management

•Cloacal exstrophy is a very rare and complex anomaly of the urogenital tract and intestinal tract resulting in exstrophy of both bowel and bladder (Fig. 18.9).

•Commonly in cloacal exstrophy, the exstrophied bowel is the ileo-cecal region with little or no large bowel distally, but there are cases where there is colonic exstrophy with sufficient large bowel length. A small colon usually ends blindly in the pelvis, and the terminal ileum often prolapses out of the exposed cecum (Figs. 18.10 and 18.11).

•The presence of enough large bowel is advantageous from the reconstruction point of view.

•The extrophied ileo-cecal region and in the presence of short large bowel should be preserved for reconstruction of the anorectal malformation.

•Every effort should be made to preserve all large intestines because not only it can be used for bladder augmentation which is necessary in the majority of these patients to increase the bladder compliance, but also for reconstruction of the anorectal malformation and vaginal reconstruction in those who have vaginal

Figs. 18.10 and 18.11 A clinical photograph showing cloacal exstrophy. Note the omphalocele, the urinary bladder into two halves and the prolapsed ileo-cecal

region with the terminal ileum open with meconium passing from it. Note the large size of the associated omphalocele

agenesis or those undergoing gender reassignment (Figs. 18.12, 18.13, 18.14, and 18.15).

•Add to this the valuable absorptive function of the large bowel.

•Augmentation of the urinary bladder may be performed using the hindgut if enough length is available, ileum, or part of the stomach. In the absence of large intestine, both small bowel and stomach can be used for bladder augmentation but gastrocytoplasty was shown to be superior.

•Gender assignment is one of the difficult tasks in the management of newborns with cloacal exstrophy.

•Genetic females should not raise a problem as they will be raised as females.

•In genetic males with cloacal exstrophy, the phallic structures are usually small and completely bifid with insufficient phallic tissue to reconstruct an adequate penis.

•There is now general consensus that genetic males with insufficient phallus be gender reassigned as phenotypic females, and to minimize testosterone imprinting on the nervous system, this should be done in the immediate newborn period with early orchidectomy.

•Males with adequate bilateral or unilateral phallic structures should however, be raised as males.

•In the classic repair of cloacal exstrophy in males an epispadias is created initially after

DIVIDED

ILEUM

HEMIBLADDER

URETERIC

CATHETER

HEMIBLADDER

URETERIC

CATHETER

Fig. 18.14 A clinical intraoperative photograph of cloacal exstrophy being repaired. Note the two ureteric catheters inserted and the mobilized urinary bladder. Note also the divided ileum to form an ileostomy. Part of the bowel is left in the posterior wall of the urinary bladder for bladder augmentation

urinary bladder closure. This is repaired later and will require the use of long acting testosterone to increase the size and length of the penis.

•The management of newborns with cloacal exstrophy has progressed over the years, and now a very reasonable outcome is expected in most cases.

ILEOSTOMY

HEMIBLADDER

URETERIC

CATHETER

Fig. 18.15 Clinical intraoperative photograph showing a diverting ileostomy and ureteric catheters prior to closure of the urinary bladder

•This, however, requires a team approach including:

–Neonatologists

–Pediatric surgeons

–Pediatric urologist

–Neurosurgeons

–Pediatric orthopedic surgeons

–Geneticists

–Social workers

–Stomatherapist

•Although there are general guidelines in managing newborns with cloacal exstrophy, after thor-