(1)
Pediatric Surgery, AlSadik Hospital, Qatif, Saudi Arabia
13.1 Introduction
Bladder exstrophy (also known as Ectopia vesicae) is a congenital anomaly that exists as part of the exstrophy-epispadias complex.
It is characterized by protrusion of the open urinary bladder through a defect in the lower abdominal wall.
Bladder exstrophy-epispadias complex is a spectrum of rare congenital malformations involving the urinary, genital, and musculoskeletal systems in which the bladder remains open through a lower abdominal defect.
Bladder exstrophy-epispadias-cloacal exstrophy complex is the most severe and comprises a spectrum of anomalies involving the urinary tract, genital tract, musculoskeletal system and sometimes the intestinal tract.
The bladder exstrophy-epispadias complex comprises a spectrum of congenital abnormalities that includes (Figs. 13.1 and 13.2):
Fig. 13.1
A clinical photograph showing classic cloacal exstrophy. Note the open urinary bladder into two halves and the ileocecal region protruding in the middle of the bladder. Note the small omphalocele
Fig. 13.2
A clinical photograph showing classic bladder exstrophy. Note the open urinary bladder. Note also the associated complete epispadias
Classic bladder exstrophy
Epispadias
Cloacal exstrophy
Other rare variants
The spectrum often include abnormalities of the bony pelvis, pelvic floor, and genitalia
The underlying embryologic mechanism leading to this spectrum of anomalies is unknown but it is believed that all represent a spectrum of the same embryological defect. It is thought to result from failed reinforcement of the cloacal membrane by underlying mesoderm.
The incidence:
The birth prevalence of classic bladder exstrophy has been estimated to be between 1 in 10,000 and 1 in 50,000 livebirths. Others reported a prevalence of 3.3 per 100,000 births.
Males are affected two to three times more often than females.
Isolated epispadias occurs in approximately 1 in 112,000 live male births and 1 in 400,000 live female births.
The prevalence of Cloacal exstrophy is 1 in 200,000–400,000 births.
The risk of bladder exstrophy in children born to parents with bladder extrophy is approximately 500-fold greater than the general population.
The classic manifestation of bladder exstrophy is characterized by:
A defect in the abdominal wall occupied by both the exstrophied bladder as well as a portion of the urethra
A flattened puborectal sling
Separation of the pubic symphysis
Shortening of the pubic ramii
External rotation of the pelvis
Females also have:
A displaced and narrowed vaginal orifice
A bifid clitoris
Divergent labia
Patients diagnosed intra-uterine with bladder extrophy should be referred to specialized centers for further evaluation and management.
Modern therapy is aimed at surgical reconstruction of the bladder and genitalia.
Staged Repair of bladder Exstrophy:
The initial step is closure of the abdominal wall, often requiring a pelvic osteotomy.
This leaves the patient with penile epispadias and urinary incontinence.
At approximately 6 months of age the patient then undergoes repair of the epispadias after testosterone stimulation.
Finally, bladder neck repair usually is done around the age of 4–5 years, though this is dependent upon a bladder with adequate capacity and, most importantly, an indication that the child is interested in becoming continent.
Complete Primary Repair of bladder Exstrophy:
The bladder closure is combined with an epispadias repair.
Epispadias is a congenital malformation of males in which the urethra opens on the upper surface (dorsum) of the penis.
Epispadias is an uncommon congenital malformation of the penis and rarely occur as an isolated defect.
It is seen more commonly as part of the epispadias-exstrophy complex.
It is now possible to diagnose exstrophy-epispadias complex antenatally using ultrasound and recently fetal magnetic resonance imaging. This is important to council the parents and also to transfer these patients in-utero to specialized centers with a team experienced in their management. The antenatal ultrasonography findings suggestive of exstrophy-epispadias complex include the following:
Failure to visualize the bladder
Lower abdominal wall mass
Low-set umbilical cord
Abnormal genitalia
Increased pelvic diameter
Omphalocele
Limb abnormalities
Myelomeningocele
Elephant Trunk sign from prolapsed intestine
Early attempts at bladder exstrophy repair were unsuccessful and for many years the management for exstrophy consisted of excision of the exstrophic bladder and urinary diversion commonly by ureterosigmoidostomy.
Anatomical defects in classic bladder exstrophy:
The urinary bladder is open on the lower abdomen
The urinary bladder mucosa is fully exposed through a triangular fascial defect on the lower abdomen.
The abdominal wall appears long because of a low-set umbilicus on the upper edge of the urinary bladder plate.
The distance between the umbilicus and anus is foreshortened.
The rectus muscles diverge distally, attaching to the widely separated pubic bones.
Inguinal hernias are frequently associated with bladder extrophy.
>80 % of males, and >10 % of females with bladder extrophy have inguinal hernias.
This is due to wide inguinal rings and the lack of an oblique inguinal canal.
The phallus (Figs. 13.3, 13.4, and 13.5):
Figs. 13.3 and 13.4
Clinical photographs showing epispadias. In the first picture, the epispadias is limited to the glans while in the second one there is complete epispadias
Fig. 13.5
A clinical photograph showing epispadias as part of classic extrophy. Note the site of closure of bladder extrophy
It is short and broad.
It is characterized by an upward curvature (dorsal chordee).
The glans lies open and flat like a spade.
The dorsal component of the foreskin is absent.
The urethral plate is open and extends the length of the phallus.
The bladder plate and urethral plate are in continuity, with the verumontanum and ejaculatory ducts visible within the prostatic urethral plate.
The anus is anteriorly displaced with a normal sphincter mechanism.
Anatomical defects in epispadias:
The urethra opens on the upper surface (dorsum) of the penis. The extent of this is variable from only the glanular part to the whole urethra.
The pubic symphysis is generally widened but only mildly.
The rectus muscles are divergent distally
This can be an isolated anomaly or more commonly part of the extrophy-epispadias complex.
Anatomical defects in cloacal exstrophy (Fig. 13.6):
Fig. 13.6
A clinical photograph showing cloacal extrophy. Note the urinary bladder divided into two halves. Note the ileocecal junction in the middle between the two halves of the bladder. Note also the associated large omphalocele
The bladder is open and separated into two halves
The exposed interior of the cecum is within it.
Openings to the remainder of the hindgut and to one or two appendices are evident within the cecal plate.
The terminal ileum may prolapse as a “trunk” of bowel onto the cecal plate.
The phallus:
The penis is generally quite small and bifid
A hemiglans is located just caudal to each hemibladder.
Infrequently, the phallus may be intact in the midline.
In females, the clitoris is bifid and two vaginas are present.
The anus is absent.
Nearly all patients have an associated omphalocele.
Musculoskeletal defects
The pubic symphysis is widely separated.
The rectus muscles diverge distally but remain attached to the pubis.
External rotation of the innominate bones results in a waddling gait but does not appear to result in orthopedic problems later in life.
Neurologic defects
In cloacal exstrophy, as many as 95 % of patients have myelodysplasia.
This may include myelomeningocele, lipomeningocele, meningocele, or other forms of occult dysraphism.
These patients are at risk of neurologic deterioration, and they should be observed closely.
Anatomical defects in exstrophy variants:
The pubic symphysis is widely separated
The rectus muscles diverge distally.
The umbilicus is low in position or elongated.
A small superior bladder opening or a patch of isolated bladder mucosa may be present.
The intact bladder may be externally covered by only a thin membrane.
Isolated ectopic bowel segments have been reported.
Genitalia generally are intact, though epispadias can occur.
13.2 Embryology
The exact cause of these anomalies is not known but it is believed that all represent a spectrum of the same embryological defect.
Embryoogically, the primitive cloaca is divided by the urorectal septum into the anterior urogenital sinus and posteriorly the hindgut.
This occurs during the first trimester at approximately the same time as maturation of the anterior abdominal wall.
Mesodermal ingrowth between the ectodermal and endodermal layers of the bilaminar cloacal membrane results in formation of the lower abdominal musculature and pelvic bones.
After mesenchymal ingrowth occurs, downward growth of the rectal septum divides the cloaca into a bladder anteriorly and a rectum posteriorly.
The genital tubercles migrate medially and fuse in the midline cephalad to the dorsal membrane before it perforates.
Failure of mesenchyme to migrate between the ectodermal and endodermal layers of the lower abdominal wall leads to deficient lower abdominal wall and instability of the cloacal membrane.
The cloacal membrane is subject to premature rupture depending on the extent of the infraumbilical defect.
Premature rupture of the cloacal membrane before its caudal translocation leads to this spectrum of anomalies.
The timing and location of rupture of the cloacal membrane dictate the patient’s presentation along the exstrophy-epispadias spectrum.
The stage of development when the membrane rupture occurs determines whether bladder exstrophy, cloacal exstrophy, or epispadias results.
Epispadias occurs if the rupture produces a division or nonunion at the distal end of the urinary tract.
The timing of the rupture of this cloacal defect determines the severity of the disorder.
Classic bladder exstrophy (60 %)
Exstrophy variants (30 %)
Cloacal exstrophy (10 %)
Rupture of the cloacal membrane after complete separation of the genitourinary anteriorly and the gastrointestinal tract posteriorly results in classic bladder exstrophy.
Rupture of the cloacal membrane prior to descent of the urorectal septum and separation of the genitourinary and the gastrointestinal tract leads to cloacal exstrophy.
Cloacal exstrophy must be distinguished from persistent cloaca or cloacal malformation.
This is the most extreme form of anorectal malformation in female infants in which there is incomplete separation of the urinary tract, genital tract and hindgut.
The exact embryological defect is not known and several theories have been proposed to explain this.
Marshall and Muecke theory is based on an abnormal lower overdevelopment of the cloacal membrane, which prevents the medial migration of the mesenchymal tissue which impairs the proper development of the abdominal wall.
Ambrose and O’Brian postulated that an abnormal development of the genital hillocks with fusion in the midline below rather than above the cloacal membrane result in the exstrophy defect.
Another hypothesis describes an abnormal caudal insertion of the body stalk with failure of the interposition of the mesenchymal tissue in the midline. As a consequence of this failure, translocation of the cloaca into the depths of the abdominal cavity does not occur. A cloacal membrane that remains in a superficial infraumbilical position represents an unstable embryonic state with a strong tendency to disintegrate.
13.3 Epispadias
13.3.1 Introduction
Epispadias, bladder extrophy and cloacal extrophy are major embryological defects that are known to be associated with long term morbidity. With the recent advances in surgical techniques including bladder closure, pelvic osteotomies, and traction and immobilization the majority of these patients can achieve full continence, adequate sexual function, and improvement in quality of life.
In males, the external urethral opening (external meatus) is normally located at the tip of the penis.
In females, the external urethral opening is normally located between the clitoris and the vagina.
Epispadias is the least severe form of Bladder Exstrophy-Epispadias Complex and it is characterized by a dorsally open urethral meatus with mild pubic diastasis and a closed anterior abdominal wall and bladder.
Epispadias is a very rare congenital malformation of the male or female urethra, in which the urethra opens dorsally.
In females with epispadias, there is a fissure in the upper wall of the urethra and out of the body through an opening above the clitoris or it can present as a double clitoris.
In males with epispadias, the urethra opens on the superior surface of the penis. The extent of this opening is variable. It can involve only the glans or extend to involve the whole shaft of penis.
This differentiates it from hypospadias which is a congenital defect, in which the urethra opens on the ventral surface of the penis.
Epispadias is very rare, with an estimated incidence of approximately 1 in 100,000 live male births.
It is extremely rare in females.
Complete epispadias is a rare congenital malformation.
It occurs in 1 in every 117,000 male births
It occurs in only 1 of every 484,000 female births
Epispadias rarely occur as an isolated defect.
It is commonly seen as part of the exstrophy-epispadias complex.
Diastasis of the pubic bone and external displacement of the hips is seen in severe cases of epispadias.
In males, epispadias is characterized by (Figs. 13.7, 13.8, 13.9, and 13.10):
Figs. 13.7, 13.8, and 13.9
Clinical photographs showing epispadias. The first is a glanular type of epispadias while the lower two show complete epispadias involving the whole urethra. Note the urethral opening on the dorsum of the penis
Fig. 13.10
A clinical photograph showing epispadias. Note the short phallus which is also broad. Note also the upward chordee of the penis and the urethral opening on the dorsum of the penis
The urethra opens on the dorsum of the penis. This can affect only the glans or extend to affect the whole urethra.
The normal urethra is replaced by a broad mucosal strip lying on the dorsum of the corpora cavernosa.
A short phallus.
A penis that is typically broad.
Dorsal chordee (marked upward curvature of the penis).
Patients with isolated epispadias have a low incidence of associated abnormalities but those with the more severe form of exstrophy-epispadias complex are at a slightly increased risk for associated malformations
These include:
Hydroureters
Hydronephrosis
Vesicoureteral reflux.
These patients are also at increased risk for retrograde ejaculation when they reach adolescence because of failure of bladder neck to close completely.
13.3.2 Etiology
The penis is formed by the corpus spongiosum surrounding the urethra and by two corpora cavernosa.
These are composed of erectile tissue surrounded by the tunica albuginea (Buck fascia) and the dartos fascia more superficially.
Normally, the male urethra runs through the penile shaft, ventrally to the corpora cavernosa, and meets with the meatus at the tip of the glans.
The exact etiology of eispadias is not known.
Epispadias and exstrophy of the bladder are considered varying degrees of the same disorder.
Epispadias results from defective migration of the paired primordia of the genital tubercle.
These fuse on the midline to form the genital tubercle at the fifth week of embryologic development.
13.3.3 Classification
The extent of epispadias is variable.
It can present as a small dimple on the tip of the glans penis just above the normal urethral opening (Figs. 13.11 and 13.12).
Figs. 13.11 and 13.12
Clinical photographs showing glandular epispadias. Note the urethral opening on the dorsum of the penis. It appear as a dimple on the dorsum of the glans
If the urethra and bladder are involved, the epispadias is severe and this is part of the spectrum of malformations called the exstrophy-epispadias complex (Fig. 13.13).
Fig. 13.13
A clinical photograph showing complete epispadias as part of the extrophy-epispadias complex. Note the dorsal chordee
Commonly, the classification of epispadias is based on the location of the urethral meatus as follows:
Glandular epispadias (Figs. 13.11, 13.12, and 13.14):
Fig. 13.14
A clinical photograph showing glandular epispadias. Note the urethra opening on the dorsum of the penis and limited to the glans of the penis
The extent of epispadias is limited to the glans of the penis.
This is the rarest type.
Penile epispadias (Figs. 13.15 and 13.16):
Figs. 13.15 and 13.16
Clinical photographs showing penile epispadias. Note the dorsal chordee and the urethral opening on the dorsum of the penis and extending along the shaft of the penis
The epispadias opening extends along the whole shaft of the penis.
Penopubic epispadias (complete):
The epispadias opening extends to the pubic bone.
Patients with glanular and about one-third of those penile epispadias usually have good prognosis with normal urinary capacity and no urine incontinence.
In most cases of penopubic epispadias, and approximately two-thirds of those with penile epispadias have urine incontinence.
These patients and those with exstrophy-epispadias complex will require reconstructive bladder neck surgery to achieve urine continence.
Currently, about 80 % of patients with male epispadias patients are continent postoperatively.
The remaining patients who are still incontinent may require later bladder neck reconstruction.
It is also estimated that about 87–100 % of isolated female epispadias are continent postoperatively.
13.3.4 Treatment
The goals of treatment of epispadias are:
To lengthen and straighten the penis by correcting dorsal bend and chordee.
To create a functionally and cosmetically acceptable penis with an external urethral meatus at the tip of the penis.
To establish urinary continence and preserve fertility in those with the more severe forms.
Patients with epispadias are born with a very small or severely underdeveloped penis. These patients are usually treated with long acting testosterone preoperatively to enlarge the size of the penis (Figs. 13.19, 13.20, and 13.21).
Figs. 13.19, 13.20, and 13.21
Clinical photographs showing epispadias before testosterone, after testosterone and at the time of surgery. Note the increase in the size of the penis following testosterone injections
They are given one or a maximum of three doses at 3–4 weeks intervals (2 mg/kg/dose). Others use topical testosterone.
The surgical treatment of epispadias differs according to the complexity of the malformation.
A staged approach has often been used for the management of the exstrophy-epispadias complex.
Currently, epispadias are treated with single stage procedures.
There are three surgical techniques used to correct epispadias:
The Cantwell-Ransley procedure.
The Young procedure.
The complete disassembly procedure.
In this technique the two corpora cavernosa and a single corpus spongiosum are totally separated and the three components are reassembled and the urethra constructed in such a way that the urethra is in its normal position.
A large number of children with the exstrophy-epispadias complex will subsequently require bladder neck repair to achieve continence.
13.3.5 Surgical Repair of Male Epispadias (Figs. 13.22, 13.23, 13.24, 13.25, 13.26, 13.27, 13.28, 13.29, 13.30, 13.31, 13.32, 13.33, 13.34, 13.35, and 13.36)
Figs. 13.22 and 13.23
Clinical photographs showing epispadias being repaired. This was part of the exstrophy-epispadias complex that was treated in two stages. Note the broad penis. The length of the penis increased as a result of testosterone injections
Figs. 13.24, 13.25, 13.26, and 13.27
Clinical operative photographs showing repair of glandular epispadias. Note the good size and normal shape of the penis
Figs. 13.28, 13.29, and 13.30
Clinical operative photographs showing repair of epispadias after closure of bladder extrohy. Note the scar of closure of the bladder extrophy and the normal size and shape of the penis
Figs. 13.31, 13.32, and 13.33
Clinical operative photographs showing repair of epispadias. Note the normal size and shape of the penis. Note also the good size and position of the urethral meatus
Figs. 13.34, 13.35, and 13.36
Clinical photographs showing a redo repair of epispadias after initial failure of the distal part of the repair
Intramuscular or topical testosterone is given preoperatively to increase the size of the penis.
The surgical repair of epispadias include:
Correction of dorsal chordee:
This is achieved by mobilizing the urethral plate from the underlying corpora from the level of glans down to the prostatic urethra.
The corporal bodies are anastomosed at the dorsal medial aspect over the tubularized urethra.
Persistent chordee is corrected by cavernostomy.
Glanular and urethral reconstruction:
The urethral meatus is correctly positioned using a reversed meatal advancement and glanuloplasty technique.
Closure of penile skin
The modern modified Cantwell-Ransley repair is the most commonly used technique to repair epispadias.
Mitchell and Bagli have described a further modification of Cantwell-Ransley repair “complete penile disassembly technique”.
The urethral plate and each corporeal body along with its hemiglans are dissected completely free from each other.
The urethra is then tubularized and placed into an anatomic, ventral position.
This method of epispadias repair is often performed at the time of primary bladder closure, the combination of which is called “complete primary repair of bladder exstrophy”.
This technique may be complicated by ischemia as a result damage to the blood supply during dissection.
The lateral dissection during this procedure can result in neurovascular bundle injury and consequent erectile dysfunction.
The tubularized urethra is usually shorter than the actual corpora, resulting in hypospadias which necessitate further urethroplasty.
Postoperatively, the patients undergo yearly gravity cystograms to measure bladder capacity. Bladder augmentation may be necessary for those with small bladder capacity.
Procedures to improve continence are usually done at 5–9 years of age.
The Young-Dees-Leadbetter bladder neck reconstruction.
Bladder neck transection, bladder augmentation, and continent urinary diversion can be done simultaneously in those with small bladder capacity.
13.3.6 Female Epispadias
Female epispadias is extremely rare.
The reported incidence is approximately 1 of 500,000–600,000 live girls.
Epispadias in females is commonly associated with separated pubic bones.
Female epispadias is characterized by:
A bifid clitoris.
Diastases of the corpora cavernosa.
Flattening of the mons.
Separation of the labia.
The diagnosis of epispadias in females is always delayed as the defect may not be obvious.
The bladder neck is almost always involved in these patients leading to urinary incontinence.
Repair of female epispadias is much simpler than male epispadias.
The two parts of the clitoris are sutured together and the urethra is positioned in its normal place.
The prognosis of these patients is good and fertility is not affected.
13.3.7 Surgical Repair of Female Epispadias
Repair of isolated female epispadias is generally done along with Young-Dees-Leadbetter bladder neck reconstruction, monsplasty, and clitoroplasty.Related posts:
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