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192 Urologic Anomalies in Anorectal Malformations
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ipsilateral ectopic ureter. e ectopic kidney can
be a component of more complex syndromes,
such as the Mayer–Rokitansky–Küster–Hauser
syndrome, Fanconi’s anemia or conjoined twins.
Horseshoe kidney
Horseshoe kidneys are encountered in 1:400 and
1:180 0 autopsies w it h male predominance. In 95%
of cases, the lower poles of the two kidneys are
joined by an isthmus of renal tissue, which may
consist of normal parenchyma or dysplastic or
brous tissue. In about 40% of cases, the isthmus
lies at the level of L4 where it is trapped beneath
the origin of the inferior mesenteric artery during renal ascent. (Figu re 14.10). A small proportion of horseshoe kidneys are fused at their upper
poles. e commonest complication horseshoe
kidney is ureteropelvic obstruction, which may
be due to the deviated course of the proximal
ureter as it arches anteriorly over the isthmus or
extrinsic compression by aberrant vasculature
(or a combination of both) (Figure 14 .11a and b).
Horseshoe kidney is commonly found in association with other abnormalities or syndromes
Figure 14.10 Intravenous urogram – pelvic
horseshoe kidney.
Figure 14.11 (a) Intravenous urogram demon-
strating dilatation due to obstruction in the
left side of a horseshoe kidney. (b) DMSA scan
in the same patient demonstrating reduced
isotope uptake in the central part of the left
kidney (dilated collecting system) and functioning tissue outlining the isthmus connecting the
right and left kidneys.
Abnormal migration and fusion of the kidney / Renal Ectopia 193
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(notably Turner’s syndrome) and abnormalities
of the central nervous system, the gastrointestinal tract and the skeletal and cardiovascular
systems.
Crossed renal ectopia
A crossed renal ectopic kidney crossed the midline during migration. ere are four varieties of
crossed renal ectopia:
●
With fusion to the contralateral kidney (85%
of cases)
●
Without fusion (<10%)
●
Solitary
●
Bilateral
ere is a slight male predominance, and crossing from le to right occurs more frequently than
from right to le. e point of fusion is usually
between the upper pole of the crossed kidney and
the lower pole of the normally positioned kidney
(unilateral fused type) (Fig ure 14.12). Associated
anomalies are commonly found with renal ectopia. In addition, renal ectopia may also be a component of more complex syndromes.
Presentation and investigation
of abnormalities of ascent
and fusion
Figure 14.12 Intravenous urogram – crossed
fused renal ectopia. Two collecting systems are
visualized on the right. No kidney is present on
the left side.
Abnormalities of ascent and fusion are most
commonly incidental ndings, typically on prenatal or postnatal ultrasound examinations.
Conversely, non-dilated pelvic ectopic kidneys
may be dicult to visualize on ultrasound, and
absence of the kidney in the renal fossa may be
misinterpreted as renal agenesis. In such cases,
the presence of ectopic functioning renal tissue
is best demonstrated by renography with 99m Tc
dimercaptosuccinic acid (DMSA). Crossed fused
renal ectopia may sometimes present clinically as
an incidentally discovered mass during the course
of abdominal examination. e occurrence of
pain or symptoms associated with urinary infection generally denotes additional pathology, such
as vesicoureteral reux or ureteropelvic junction
obstruction. Investigation of an uncomplicated
ectopic or horseshoe kidney can reasonably be
limited to ultrasound and a renogram. Additional
investigations are indicated if there is hydronephrosis or a history of documented infection
raising concerns about possible vesicoureteral
reux. It is important to stress that the majority
of patients are untroubled by their abnormally
placed kidney, and surgical intervention should
be conned to correcting coexisting pathology,
obstruction or reux. When surgery is warranted
it should be borne in mind that the anatomy may
be abnormal and that the blood supply can have
an aberrant course.
194 Urologic Anomalies in Anorectal Malformations
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KEY POINTS
●
Children with anorectal malformations
have a high incidence of urinary tract
abnormalities and functional urinary
problems.
●
Early recognition and eective management of urological problems is
essential to minimize the risks of renal
failure and urinary tract infection.
●
Higher rectourinary stula in males
and longer common channels in
females represent more severe anorectal malformations. More severe defects
are more likely to be accompanied by
associated anomalies including spinal
defects and renal anomalies.
●
Psychosocial and sexual concerns
are common as these patients reach
adulthood.
●
Anomalies of ascent and fusion,
including pelvic kidney, horseshoe
kidney, and crossed ectopia, are mainly
asymptomatic incidental ndings.
Surgical intervention is only required
when there is complicating pathology,
such as obstruction or reux.
FURTHER READING
Bischoff A, Bealer J, Wilcox DT, Peña A. Error
traps and culture of safety in anorectal malformations. Semin Pediatr Surg.
2019;28(3):131–134.
Boemers TM, Beek FJ, Bax NM. Guidelines for
the urological screening and initial management of lower urinary tract dysfunction in
children with anorectal malformations – the
ARGUS protocol. BJU Int. 1999;83:662–671.
Caldwell BT, Wilcox DT. Long-term urologi-
cal outcomes in cloacal anomalies. Semin
Pediatr Surg. 2016;25(2):108–111.
Kyrklund K, Taskinen S, Rintala RJ, Pakarinen
MP. Sexual function, fertility, and quality of life after modern treatment
of anorectal malformations. J Urol.
2016;196(6):1741–1746.
Peña A. Anorectal malformations. Semin Pediatr
Surg. 1995;4:35–47.
Thomas DFM. The embryology of persistent
cloaca and urogenital sinus malformations.
Asian J Androl. 2020;22(2):124–128.
Bladder Exstrophy and Epispadias
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PETER CUCKOW and KEVIN CAO
Topics covered
15
Embryology and anatomy
Bladder exstrophy: Management and outcomes
Cloacal exstrophy: Management and outcomes
INTRODUCTION
is chapter covers one of the most challenging
conditions in paediatric urology. As well as requiring complex reconstructive surgery to correct their
severe bladder and genital abnormalities, children
born with bladder exstrophy encounter continuing
problems throughout childhood and adolescence
and face possible long-term risks of renal failure and
infertility. e relative rarity of bladder exstrophy
and related conditions previously made it dicult
for paediatric urologists to acquire adequate experience in treating them because even major regional
centres received only one or two new referrals a year.
To overcome this problem, the United Kingdom
adopted a policy whereby the management of bladder exstrophy is conned to two supraregional
centres. is has enabled paediatric urologists in
these two centres to acquire and maintain a high
level of experience and specialist expertise. It has
also helped to facilitate the development and assessment of innovative approaches to the management
of exstrophy aimed at improving the outcome for
Primary epispadias: Management and outcomes
Other bladder conditions; diverticula and
urachal remnants
children born with this condition. Although the
treatment of bladder exstrophy is provided in a
greater number of centres in the Unites States there
is nevertheless a considerable degree of collaboration and sharing of expertise between some of the
major children’s hospitals. In addition to bladder
exstrophy, this chapter also considers some of the
other congenital disorders of the bladder.
EMBRYOLOGY AND ANATOMY
ree distinct anomalies constitute the
exstrophy–epispadias complex (EEC): classic
bladder exstrophy, epispadias and cloacal exstrophy. ey are thought to constitute a spectrum of
abnormalities arising from failure of development
of the lower abdominal wall during early gestation.
Bladder Exstrophy
Similarities between the three anomalies comprising the exstrophy–epispadias complex point
195
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to a similar embryological origin in the early
stages of gestation. However, the precise mechanism remains unclear. e cloacal ‘rupture’
hypothesis proposes that a failure of integration
of the mesodermal, endodermal and ectodermal
components of the cloacal plate causes it to rupture – leading to exposure of the bladder plate
and urethra. is is supported by animal models in which surgical disruption of the membrane
replicates the exstrophy morphology. e alternative ‘wedge-eect’ hypothesis postulates that
overgrowth of the cloacal membrane acts as a
mechanical wedge, which has the eect of separating the mesodermal components of the umbilical body wall. is explanation also has some
empirical support. Neither of these hypothetical
models adequately explains the existence of ‘late
rupture’ and ‘covered’ variants of EEC anomalies.
Bladder exstrophy is characterised by an open
bladder plate and urethra occupying a triangular infra-umbilical space above an open pelvic
ring with the rectus abdominis muscles lying
on either side. In the male, the penile roots are
attached to the lower border of the inferior pubic
rami and the two corpora traverse the intervening gap in the bony pelvis (the pubic diastasis)
to join each other to form a foreshortened penile
sha. e exposed bladder mucosa lies in continuity with the exposed urethral plate with the
openings of the ejaculatory ducts being located
at a level equivalent to the verumontanum. e
exposed urethral plate extends over the dorsal
surface of the corpora and glans (Fig ure 15.1).
e testes are usually descended. Failure of
Figure 15.2 Newborn female infant with bladder
exstrophy.
development of the lower anterior abdominal
wall and pelvic ring results in the anus being
located in a relatively anterior position. In
females, the bladder component is identical to
males and the clitoral corpora are separated with
a short urethral plate between the open bladder
and vagina (Figure 15.2).
Cloacal Exstrophy
Cloacal exstrophy is a more severe embryological variant, which is accompanied by defective
subdivision of the cloaca. Both the bladder and
bowel components of the anomaly are exteriorised, with a central area of bowel lying in the midline between two separated halves of the bladder.
ere is extensive prolapse of the proximal colon
and ileum and one or two appendices. A second
inferior opening corresponds to a rudimentary
loop of distal hindgut. e anus is imperforate.
Figure 15.1 Newborn male infant with bladder
exstrophy.
Table 15.1 Worldwide incidence and sex
distribution of the exstrophy–epispadias complex
Incidence per
live births
Bladder
exstrophy
Primary
epispadias
Cloacal
exstrophy
a
Because of the rarity of cloacal exstrophy and limita-
tions in methodology there is considerable variation
in the published gures for incidence and sex ratio.
1:50 000 2:1
1:120 000 5:1
1:300 000 0.6:1
Male to
female ratio
a
Figure 15.3 Newborn male infant with cloacal
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exstrophy.
e sacrum is foreshortened and there is a high
incidence of spinal dysraphism. e pubic diastasis (gap between the anterior pubic rami) may
be so wide that the penile corpora are completely
separated. In addition, the testes are oen undescended and absent from the scrotum or hemiscrotum. Cloacal exstrophy is oen accompanied
by an exomphalos located above it (Figure 15.3).
Primary Epispadias
e embryological origins are poorly understood. Primary penile epispadias is accompanied
by a variable degree of bony pelvic diastasis –
although this is usually less severe than in bladder
Embryology and anatomy / Primary Epispadias 197
exstrophy. In less severe forms of the anomaly
the pelvic ring may be complete, with an apparently normal abdominal wall. e anus is sited
normally and the scrotum also appears normal.
A variable length of the urethra lies exposed
on the dorsal aspect of the penis. According
to the degree of severity of the epispadias, the
urethra may open distally on the glans (glanular epispadias), on the sha (penile epispadias)
or proximally at the junction with the anterior
abdominal wall (pubic or penopubic epispadias)
(Figure 15.4). Underlying deciencies of the bladder neck, proximal urethra and striated sphincter
complex give rise to varying degrees of urinary
incontinence – which is more severe in proximal
and penopubic cases. In severe forms of epispadias, the posterior urethra merges with the bladder neck, and the verumontanum is either located
at this level or within the bladder itself. e ureteric orices oen lie close together and can be
normal or narrow in calibre, contrasting with the
wide reuxing orices seen in exstrophy.
In female primary epispadias, an abnormally
wide section of urethra lies open and exposed
on its dorsal surface and the clitoris is divided
(bid). e urethra is short and wide, with a decient bladder neck, leading to severe stress-type
incontinence in all patients (Figure 15.5).
Figure 15.4 Male primary epispadias: (a) glanular; (b) penile; and (c) penopubic.
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Figure 15.5 Female primary epispadias.
ANTENATAL DIAGNOSIS
Approximately, 50% of cases of bladder exstrophy are now detected antenatally and in a further
20% of cases the diagnosis can be made retrospectively upon further review of the antenatal scans.
Diagnostic features include; lack of urine in the
fetal bladder, low-set umbilical cord, short, wide
penis and bulging bladder plate. Maternal levels
of serum alpha feto protein (AFP) are elevated as
a result of exposure of bladder mucosa to amniotic
uid. e antenatal detection rate of cloacal exstrophy is even higher because of the coexisting anomalies. However, these sometimes lead to confusion
with abdominal wall defects such as gastroschisis.
Antenatal diagnosis provides an opportunity
for parents to consider termination of pregnancy,
but counselling should take into account the
improving outcomes of intervention, particularly
in classic bladder exstrophy.
CLASSIC BLADDER EXSTROPHY
Presentation and Clinical Features
Classic bladder exstrophy presents at birth with
a visible bladder plate below a low-set umbilical
cord. e mucosa may be inamed and polypoid,
due to exposure in-utero or following delivery.
e penile sha is usually short and thick, with a
good sized glans. e scrotum is present in boys
with the distinctive upwards direction of the
rugae and the testes are normally palpable.
Most aected infants are born at term and are
usually otherwise well at birth. e incidence of
other congenital anomalies is low, with the exception of inguinal herniae which are present in 80%
of males and 15% of females.
Neonatal Management
and Primary Closure
Following delivery most newborns can be put to the
breast normally. Vitamin K should be given (particularly if surgery is planned within the rst few
days) and the exposed bladder plate protected with
plastic lm inside the nappy. Antibiotics or intravenous access are not routinely required at this stage.
Urgent transfer to the specialist centre is rarely
indicated and it is preferable for the baby to remain
with the mother in the rst few days to establish
breastfeeding and promote bonding. is enables
feeding to be established to help ensure better
post-operative nutrition. e benets of a slight
delay outweigh any theoretical concerns regarding decreasing exibility of the pelvis because, in
Classic bladder exstrophy / Neonatal Management and Primary Closure 199
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practice, the abdomen and bladder can usually be
closed eectively without the need for osteotomies
in the rst two to three weeks of life. A baseline
renal ultrasound scan is performed to evaluate the
upper urinary tract prior to surgery. In premature
infants, a longer period of stabilisation is preferable and it is not unreasonable to delay closure for
several weeks if medically indicated.
Surgical technique (Figure 15.6)
e surgery is performed under intravenous
antibiotic cover and whenever possible an epidural catheter is inserted at the outset to ensure
optimal postoperative analgesia. Following
catheterisation of the ureters the bladder plate is
mobilised and dissected free of the skin and rectus muscles. Any large mucosal polyps are excised
and the resulting mucosal defects repaired. At
this stage any hernial sacs which are present can
be identied and ligated. Mobilisation of the
bladder plate is performed by extraperitoneal
dissection, which is then continued inferiorly on
both sides of the proximal urethral plate down
to the level of the verumontanum. In girls, this
dissection is continued to just above the vaginal
opening. Following deeper dissection around the
bladder neck, the bladder and proximal urethra
can be mobilised suciently to permit midline
closure with interrupted 4/0 absorbable sutures.
e pelvic oor muscles are divided anterolaterally to enable the urethral/bladder neck complex to be repositioned to lie behind the closed
abdominal wall. e ureteric catheters are
brought out through the bladder to emerge lateral
to the midline muscle and skin closure. e bladder is drained via a silicone stent emerging from
the urethral opening. Unless the diastasis is wide,
Figure 15.6 (a) Primary closure of a newborn male exstrophy. (b) Separation of the bladder plate.
(c) Closure of bladder with ureteric catheters. (d) Appearance after abdominal wall closure with
plaster cast (no longer used routinely).
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pressure applied to the iliac crests will bring the
so tissues of the abdominal wall together in front
of the bladder neck. However, this may not be sufcient to bring the pubic rami completely together
in the midline. e pubic rami are approximated
as far as possible by use of interrupted horizontal
mattress sutures of heavy-gauge polydioxanone
(PDS) and the rectus muscles are approximated
with interrupted absorbable sutures. During the
rst few weeks of life it is nearly always possible to
achieve successful primary closure without any
requirement for pelvic xation.
Feeding is recommenced postoperatively
and oral prophylactic antifungal and antibiotic agents are continued. When all the catheters have been removed an ultrasound scan is
performed prior to discharge from hospital to
assess bladder emptying and the appearances of
the upper tracts.
Complications (including wound breakdown
and partial or complete bladder dehiscence) occur
in around 10% of cases. Factors predisposing to
wound infection and dehiscence include pooling of urine at the new urinary meatus, the use
of stents emerging through the midline closure,
and retention of the umbilical stump (a focus
of potential infection). e risk of dehiscence
is also increased by tissue ischaemia if the closure has been performed under tension. Partial
dehiscence which does not involve exposure of
the bladder can be allowed to heal by secondary
intention. However, a more extensive dehiscence
with exposure of the bladder plate or prolapse of
the bladder will require re-closure, for which pelvic osteotomies are usually indicated.
In classic bladder exstrophy the ureters usually enter the bladder without the oblique transmural tunnel that would normally confer an
anti reux mechanism. For this reason, some
degree of vesicoureteric reux is almost invariably present following primary bladder closure.
Any degree of outow obstruction consequent
upon tight urethral closure can pose a risk of
upper tract dilatation and renal damage – particularly if infection supervenes. Close ultrasound surveillance is therefore essential to
detect possible upper tract dilatation and if this
does develop a period of intermittent catheterisation may be required.
Role of pelvic osteotomy
e pelvis in newborn exstrophy patients is sufciently exible to allow closure of the bladder
without osteotomy in 95% of cases. But where the
pubic diastasis is wide or when closure is delayed,
pelvic osteotomy is usually required to increase
pelvic mobility and facilitate a tension-free closure of the midline. e standard technique consists of division of the bony pelvis between the
anterior superior iliac spine and the greater sciatic notch on both sides. e drawbacks include,
prolonged operating time, increased blood loss
and longer postoperative immobility. Osteotomy
is best reserved for revision cases and the correction of cloacal exstrophy. Postoperative xation
of the bony pelvis in small infants can be eectively achieved by the use of frog-leg plasters and
mermaid dressings but a period of external xation is mandatory in older children because of the
greater density of their pelvic bones.
Secondary Procedures for Continence
and Genital Reconstruction
In girls, primary closure can occasionally be sucient to impart continence and create a satisfactory
cosmetic appearance without the need for further
surgery. In the overwhelming majority of exstrophy patients, however, additional procedures will
be required to achieve continence and to reconstruct functionally and cosmetically acceptable
genitalia. Until further continence procedures are
performed, the low bladder outlet resistance leads
to dribbling incontinence. Although urinary tract
infections are uncommon, some paediatric urologists prescribe prophylactic antibiotics.
Continence Surgery
ere are three accepted surgical strategies for
the management of bladder exstrophy.
Staged reconstruction
Popularised by Jes and Gearhart, this is a wellestablished standard approach (now termed the
‘modern staged repair of bladder exstrophy’) in
which conventional bladder closure is performed
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in the neonatal period followed by correction of
the epispadiac component at around 2 years of age
and bladder neck reconstruction around the age
of ve. If continence is not achieved because of
inadequate bladder capacity, further bladder neck
reconstructions may be undertaken – possibly
in conjunction with augmentation enterocystoplasty and a Mitrofano procedure.
Complete primary repair
is strategy was devised by Mitchell with the
aim of creating continence by combining full
anatomical reconstruction with the initial bladder closure. In addition to mobilisation of the
exposed bladder and urethral plate the penile
corpora are also extensively mobilised to facilitate complete penile reconstruction during the
same operation. is approach has been reported
to give good results whilst requiring fewer surgical procedures. However, the complete primary
repair is a technically challenging operation in a
newborn infant and it is of particular importance
to safeguard the blood supply to the penis.
Kelly operation
is is the procedure of choice at Great Ormond
Street Hospital for Children. Aer successful
neonatal bladder closure, examination under
anaesthetic to assess the bladder and bladder outlet is undertaken around 3 months later.
e Kelly operation is then performed from
around the age of 6 months onwards. e bladder
is reopened in the midline and both ureters are
reimplanted using the Cohen technique. e so
tissues, including the urethra, penile corpora and
pelvic oor, are then fully mobilised before reconstructing the bladder outlet, urethra, sphincter
and penis. Detachment of the penile corpora
from the lower border of the inferior pubic rami
is combined with release of the pudendal pedicles,
which lie beneath the pelvic oor muscles and run
from the greater sciatic notch to the base of the
penis in Alcock’s canal. Once the base of the penis
is freely mobile the two corporeal bodies can be
brought together in the midline, thus eliminating the eect of the pubic diastasis and greatly
increasing penile protrusion and apparent length
(Figure 15.7a). e urethral plate is dissected o
the corpora and the glans and tubularised over an
8 Fr stent. e bladder neck is delineated at a level
between the verumontanum and the ureteric orices and mucosal triangles are then removed on
either side. e bladder neck and bladder are then
closed in sequence. e tubularised urethral plate
is relocated between the penile corpora, to come
to lie in hypospadiac position where the muscles at
the base of the corpora are then wrapped around
it with loose sutures in a position corresponding
to the site of the physiological sphincter in normal males just below the veromontanum. e
corporeal bodies are joined in the midline with
external rotation to eliminate the dorsal chordee
and to secure the position of the urethra below
them with the new urinary meatus being sited
on the ventral surface of the reconstructed penis.
Abdominal wall closure can be combined with an
umbilicoplasty if required. e Kelly procedure
can be completed with either a glans plasty procedure to advance the urinary meatus on to the
glans or, alternatively by two-stage distal urethral
reconstruction (analogous to hypospadias repair),
using posterior auricular skin gras at some stage
in the following 12 months.
In the senior author’s experience, t he Kelly operation provides a superior penile cosmetic outcome
to the conventional staged repair (Figure 15.7b).
e Kelly procedure can also be performed in
girls in whom the two components of the bid clitoris are mobilised, with their pudendal pedicles
being preserved and the labia minora remaining attached. Reconstruction of the bladder neck
and urethra is undertaken in a similar fashion to
males. e mobilised clitoral corpora are brought
together in the midline to reconstruct the clitoris.
Genital reconstruction can be successfully completed in a single stage in girls.
Continence Outcomes
Considerable controversy has surrounded the
published continence rates following surgical
reconstruction of bladder exstrophy. Published
results vary considerably and continence rates as
high as 70% have been claimed by some groups.
Although the dierences in reported continence
rates can be partly explained by diering selection
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