1. Art and Diseño

Journal of Pediatric Surgery (2011) 46, 1593–1602
www.elsevier.com/locate/jpedsurg
The anomalous clinical anatomy of congenital pouch colon
in girls
Rajiv Chadha ⁎, Subhasis Roy Choudhury, Nitin Pant, Vishesh Jain, Archana Puri,
Himanshu Acharya, Noor Ullah Zargar, Anjani Kumar Kundal
The Department of Pediatric Surgery, Lady Hardinge Medical College and Kalawati Saran Children's Hospital,
New Delhi 110001, India
Received 26 September 2010; revised 11 December 2010; accepted 12 January 2011
Key words:
Anorectal malformation;
Cloaca;
Pouch colon, congenital;
Uterus didelphys;
Septate vagina;
Urinary incontinence
Abstract
Background/Purpose: The aim of this study was to evaluate the anomalous clinical anatomy of
congenital pouch colon (CPC) associated with anorectal agenesis in 22 consecutive girls managed over
a study period of 7 years.
Methods: The 22 patients were categorized into 2 groups. Group A consisted of 10 patients who presented
during the neonatal period (n = 9) or as a young infant (n = 1). In these patients, only preliminary
assessment results were available. Group B (12 patients) comprised 5 newborns who remained on followup and 7 patients who presented after the age of 1 year. These 12 patients were assessed and investigated
in more detail.
Results: In group A patients, apart from absence of the normal anal opening, the appearance of the
external genitalia and perineum was essentially normal. Retraction of the labial folds showed radiation of
folds inward from the margins of the vulval vestibule toward the center, at a point of confluence located at
a higher level. At laparotomy, the subtypes of CPC were type I (n = 4), type II (n = 5), and type III (n = 1).
In 8 patients, uterus didelphys was present. In all group B patients, the appearance of the external genitalia
was similar to that in group A patients. However, separate openings of the urethra, septate vagina, and
vestibular fistula (if present) were visible in 5 patients, whereas in 3 patients, a single perineal opening was
identified. A total of 9/12 patients (75%) had urinary incontinence. Examination under anesthesia and
endoscopy revealed a septate vagina in all 12 patients and an open, incompetent bladder neck with reduced
bladder capacity in the 9 patients with urinary incontinence. The terminal fistula of the colonic pouch
opened just distal to the bladder neck (n = 1), just posterior and cephalad to the urethral opening (n = 2),
low in the vestibule (n = 5), and undetermined (n = 4). The subtypes of CPC were type I CPC (n = 2), type
II CPC (n = 9), and type III CPC (n = 1). All 12 patients had uterus didelphys.
Conclusions: The characteristics in the anomalous clinical anatomy of CPC in girls, as described here,
appear to be almost invariable and, especially in regions where CPC is common, should alert the clinician
to the presence of this malformation.
© 2011 Elsevier Inc. All rights reserved.
⁎ Corresponding author. G-123 Vikaspuri, New Delhi 110018, India. Tel.: +91 011 28547640, +91 09312226036 (M).
E-mail address: [email protected] (R. Chadha).
0022-3468/$ – see front matter © 2011 Elsevier Inc. All rights reserved.
doi:10.1016/j.jpedsurg.2011.01.013
1594
Congenital pouch colon (CPC) is an unusual abnormality
in which a pouchlike dilatation of a shortened colon is associated with an anorectal malformation (ARM). This malformation has most frequently been reported from centers in
northern India [1-9] where it is fairly common, comprising
4.38% [1] to 18.7% [9] of all ARM. The condition is less
common in girls, the male to female ratio in large series
ranging from 2.25:1 [7] to 7:1 [8]. In boys with CPC, the
colonic pouch almost invariably ends in a colovesical fistula
[3,5-7]. However, in female patients, the anatomy of the
anomaly is more variable, perhaps because of the additional
role played by the Müllerian duct system in the development
of the internal genital organs, lower urinary tract, and the
external genitalia [10]. In addition, a large number of girls
with CPC may present for the first time during infancy or
childhood if evacuation through the terminal fistula of the
colonic pouch is effective [2,4-6,11-13].
This report describes a study of the anomalous clinical
anatomy of CPC in 22 girls who presented at our institution
with this malformation over a study period of 7 years. In 10
patients, assessment could be performed only during the
neonatal period or early infancy. In the remaining 12
patients, belonging to an older age group, a more detailed
evaluation and assessment was performed.
1. Material and methods
During the period from January 2003 to December 2009,
22 girls with CPC associated with an ARM were managed by
the Department of Pediatric Surgery, Lady Hardinge Medical
College and Kalawati Saran Children's Hospital, New Delhi.
A detailed record of the patients was maintained and forms
the basis for this study.
The 22 patients were categorized into 2 groups. The first
group (group A) consisted of 10 patients who presented during
the neonatal period (n = 9) or as a young infant (n = 1) and
underwent clinical assessment, investigations, and primary
surgery at this stage. Subsequently, these patients were lost to
follow-up, and therefore, only the results of preliminary
assessment and operative findings were available (Table 1).
The second group (group B) of 12 patients comprised 7
patients who presented after the age of 1 year and were
investigated in more detail, especially regarding the status of
the urinary tract, including examination of the external
genitalia and perineum under anesthesia (EUA) and endoscopic examination of the lower genitourinary tract (Table 2).
This group also included 5 patients who had presented initially in the neonatal period, undergone preliminary management, and remained on follow-up for further investigations
and treatment. Their age at assessment for this study is shown
in Table 2. Preliminary surgery in these 5 patients had consisted of excision of the colonic pouch after ligation of the
terminal fistula as low down as possible in 4 patients (cases 35 and 8) and ligation of the fistula, subtotal excision of the
pouch with tubularization of its remaining portion, and an end
R. Chadha et al.
Table 1
Newborns and infant girls with CPC (n = 10)
Age
Clinical examination
1. Typical CPC appearance
external genitalia
2. Gross abdominal
distension
3. Stigmata of
pseudoexstrophy
Radiologic findings
1. Invertogram/plain
x-ray abdomen (n = 8)
2. X-ray sacrum (n = 8)
Operative findings
1. Subtype of CPC
2. Distension of colonic
pouch
3. Appendiceal
abnormalities
4. Internal genitalia
NB-20d (n = 9), 4 mo (n = 1)
10 (100%)
3 (all NB) (30%)
1 (10%)
Large AFL (4); smaller AFL (1);
no AFL (n = 3)
Normal (6); partial sacral
agenesis (2)
Type I (4); type II (5); type III (1)
Moderate (3); severe (7)
Double appendix (4; type II, 3;
type III, 1); absent appendix
(4; type I, 3; type II, 1)
Double Ut., V (8); NE (2)
NB indicates newborn; AFL, air-fluid level; Ut., uterus; V, vagina;
NE, not examined.
colostomy in one girl (case 10). The protocol for radiologic
assessment consisted of x-rays of the sacrum, an abdominal
ultrasound (US), and a micturating cystourethrogram (MCU).
However, because of logistic reasons, MCU could be
attempted in only 6 patients. In 3 patients, an intravenous
urogram (IVU) had been performed elsewhere, before referral
to our center.
Based on operative findings, patients in both groups were
categorized into the 4 subtypes of CPC as described by
Narasimharao et al [3], namely:
Type I: normal colon is absent and the ileum opens directly
into the colonic pouch
Type II: the ileum opens into a short segment of cecum,
which then opens into the colonic pouch
Type III: presence of a significant length of normal colon
(7-8 cm in the newborn) between the ileum and the
colonic pouch, and
Type IV: presence of near normal colon with only the
terminal portion (rectum and a varying length of the
sigmoid colon) being converted into the colonic pouch.
2. Results
2.1. Group A
The important findings in patients belonging to group A
are shown in Table 1. All the patients had absence of the anal
opening at its normal site. One patient, with gross abdominal
Older girls with CPC (n = 12)
Patient
characteristics
Clinical examination
Radiology
EUA and endoscopy
Case no.
External
genitalia
Urinary
incontinence
US
KUB
MCU
Position of
urethral opening
Bladder neck
Location of fistula
Bladder
capacity
CPC
subtype
Double
Ut., V
SPO
—–
N
—–
High
N
Behind urethral meatus,
ant. to vagina (high VF)
Proximal urethra
Not seen
VF
Not seen
VF
VF
Not seen
VF
Not seen
Behind urethral meatus,
ant. to vagina (high VF)
VF
N
II
+
N
NE
↓↓
↓↓
↓↓
↓↓
↓
↓
↓
↓↓
I
II
II
II
II
II
I
III
II
II
+
+
+
+
+
+
+
+
+
+
↓↓
II
+
Age (y)
1
3
2
3
4
5
6
7
8
9
10
11
2
1.5
2
2.5
10
3
2
1.5
14
5
Ur. Sept. V
SPO
Typ. CPC app.
SPO
Ur. Sept. V, VF
Typ. CPC app.
Typ. CPC app.
Ur. Sept. V, VF
Ur. Sept. V
Typ. CPC app.
—–
—–
CUI
CUI
CUI
CUI
PUI
CUI
PUI
PUI
N
N
N
N
N
N
N
N
N
N
—–
—–
Uns.
—–
Uns.
BNI
BNI, Bl. cap. ↓↓
BNI, Bl. cap. ↓
N
—–
Low
High
High
High
High
High
High
High
Low
High
N
NE
BNI-severe
BNI-severe
BNI-severe
BNI-severe
BNI-partial
BNI-partial
BNI-partial
BNI-partial
12
1
Ur. Sept. V, VF
CUI
N
—–
Low
BNI-severe
Operative findings
Clinical anatomy of congenital pouch colon in girls
Table 2
SPO indicates single perineal opening; Ur. Sept. V, urethral opening with septate vagina; Typ. CPC app., typical CPC appearance; N, normal; BNI, bladder neck incompetent; VF, vestibular fistula;
KUB, kidneys and urinary bladder; ant., anterior; Uns., unsatisfactory; Bl. Cap., bladder capacity.
1595
distension, had edema of the perineum and vulva with
clinical evidence of systemic sepsis. Continuous dribbling of
urine was noted in 1 newborn. On clinical examination, all
10 patients had a very characteristic and typical appearance
of the external genitalia, as shown in Fig. 1. At first sight,
apart from absence of the anal opening at its normal site,
without retraction of the labia, the appearance of the external
Fig. 1 Appearance of the external genitalia in 2 newborns with
CPC. The vestibule is wide with folds from its margins radiating
inward and upward. B, the folds appear to meet at a higher level.
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R. Chadha et al.
2.2. Group B
Fig. 2 Photograph taken during surgery in a newborn with type II
CPC showing the dilated colonic pouch (arrow), uterus didelphys
with both uterii distended with gas and meconium (arrowheads),
and the normal proximal colon.
Table 2 summarizes the important findings in the 12 girls
belonging to group B. In all 12 patients, on initial examination in the outpatient clinic, the essentially normal appearance of the external genitalia was similar to that seen in group
A patients. However, in 5 patients, the openings of the
urethra, septate vagina, and vestibular fistula (if present)
could be identified on mild to moderate retraction of the
labial folds (Fig. 3), whereas in 3 patients, only a single, but
wide, perineal opening was visible (Fig. 4). Nine (75%) of
the 12 patients had urinary incontinence (UI), which was
partial in 3 girls and complete in 6 others. The girls with
partial urinary incontinence (PUI) were passing urine in a
stream at regular intervals but had diurnal and nocturnal
dribbling. Extensive perineal and perivulval excoriations
owing to UI were present in 5 of the 6 girls with complete
urinary incontinence (CUI) (Fig. 3-B), whereas a mild degree
genitalia and perineum was essentially normal without any
of the features characteristic of cloacal malformations.
Retraction of the labia majora showed radiation of folds
inward from the margins of the vulval vestibule toward the
center, at a point of confluence located cranially at a higher
level (Fig. 1). In one girl, the openings of the double vaginas
could be seen lowdown in the vestibule after moderate
retraction of the labial folds. In the other 9 patients, it was not
possible to separately identify the urethral or vaginal orifices
or the opening of the terminal fistula of the colonic pouch.
Perineal excoriations were seen in 1 girl. One girl had features of pseudoexstrophy with a low-set umbilicus, widely
separated pubic ramii, and scarring of the lower abdominal
wall. Abdominal x-ray/invertogram showed a large air-fluid
level characteristic of type I/II CPC [3,5-7] in 4 patients,
whereas this feature was absent in 3 patients, probably because of decompression of the pouch through the associated
fistula. In 1 girl with a type III anomaly, a relatively smaller
air-fluid level was seen. Laparotomy revealed that 8 patients
had uterus didelphys with one hemiuterus and vagina flanking the distal part of the colonic pouch on each side (Fig. 2).
In 3 of these 8 patients, all of whom had presented with gross
abdominal distension, the fallopian tubes, uterii, and vaginas
were grossly distended with gas and meconium (Fig. 2),
with, in addition, the urinary bladder being thick walled in 1
child. Although the colonic pouch narrowed distally toward
the pelvis, it was still quite wide at the level of the peritoneal
reflexion (Fig. 2), and the exact level of termination of
the colonic pouch could not be made out in any patient.
Appendiceal abnormalities were common (Table 1). In 2
patients, the general condition was poor, and during construction of a window colostomy in one girl and a proximal
loop ileostomy with decompression of the pouch in the other
girl, no attempt was made to study the anatomy of the
internal genitalia.
Fig. 3 Low defects. Light retraction of the labial folds showing
case 2 (A), the urethral and vaginal openings, and case 9 (B), the
urethral and vaginal openings, and the vestibular opening of the
fistula. Note excoriations owing to complete urinary incontinence.
Clinical anatomy of congenital pouch colon in girls
1597
Fig. 5 (Case 4) MCU showing a widely open, patulous bladder
neck and a bladder of very small capacity in a girl with CUI.
Fig. 4 (Case 1) Retraction of the labial folds in the outpatient
clinic (A), showing only a single but wide perineal opening, and
during EUA (B), showing a high defect with a septate vagina. A
transurethral catheter is draining the urinary bladder.
of perineal excoriation was seen in one girl with PUI. One 14year-old girl (case 10) had had a normal puberty and was
having normal menstrual periods. In all 12 patients,
biochemical renal function tests were normal. X-rays of the
sacrum were normal in 11 patients, whereas in one patient
(case 12), the films were not available for assessment. An
MCU, attempted in 6 patients, was unsuccessful in 2 patients
as the dye could not be retained because of an incompetent
bladder neck (Fig. 5). Intravenous urogram, performed in 3
patients, was normal in 1 girl (case 4), although filling of the
vaginas was noted after the child micturated. In another girl
(case 9), mild bilateral hydroureteronephrosis was present,
whereas in the third patient (case 10), the IVU was normal
apart from a unilateral bifid renal pelvis.
The EUA and endoscopic examination confirmed the
presence of a septate/double vagina in all 12 patients. The
position of the urethral opening and, thus, the meeting point
(confluence) of the urethral and vaginal openings in the
vestibule were classified as being “low” or near normal
(b1.5 cm from the base of the clitoris) or “high” (N1.5 cm
from the base of the clitoris) (Table 2) (Figs. 3,4,6,7). As
expected, cases where the confluence was high were those
where, in the outpatient department, the anatomy of the
external genitalia was not clear and only the typical CPC
appearance had been seen. Especially in cases where the
confluence was quite high, the vaginal openings seemed to
be tilted with the anterior ends meeting at the confluence
medially at a higher or more cranial level and the posterior
Fig. 6 (Case 11) The high vestibular opening of the fistula
(arrowhead) is just posterior to and at a slightly higher level than the
urethral opening (arrow). Note the wide urethral meatus. Asymmetrical appearance of the openings is owing to asymmetric
retraction of the labial folds.
1598
Fig. 7 (Case 8) External genitalia in a girl with type I CPC. Note
that the vaginal openings are quite widely apart, especially
posteriorly, and the posterior margin of the vestibule is very wide.
ends diverging laterally and inferiorly to end closer to the
wide posterior margin of the vestibule (Figs. 4 & 7). On
clinical examination and/or endoscopy, the urethral meatus
appeared to be wider than normal in all 12 patients (Fig. 6).
The urethra was short in length (b2-cm long) in the 11
patients in whom cystourethroscopy was performed. In 3
patients (cases 5, 8, and 9), the urethra was very short, b1 cm
in length, and all these patients had UI, CUI in cases 5 and 9,
and PUI in case 8. However, 2 patients (cases 1 and 3) with a
high confluence of openings and a short urethra had normal
urinary continence. Cystourethroscopy showed an open or
incompetent bladder neck with reduced bladder capacity in
all 9 patients with UI (Table 2). In 2 patients with CUI (cases
6 and 7), the bladder neck was very widely open. In 2 girls
with PUI, the bladder neck was seen to close partially after
withdrawing the examining cystoscope, in one case (case 8),
the bladder neck being deficient posteriorly.
On EUA and endoscopic examination, the terminal fistulous opening of the colonic pouch could not be identified in
4 patients, all of whom had undergone primary surgery in the
neonatal period. In one of these patients (case 3), endoscopy
could not be performed because of malfunctioning equipment. In one patient (case 2), the fistula opened into the
urethra just distal to the bladder neck. In the remaining 7
patients, the opening of the terminal fistula was just posterior
and a little proximal to the urethral opening, anterior to the
vaginal orifices in 2 patients (Fig. 6), a position that can be
described as high vestibular, whereas 5 patients had a low
vestibular fistula. The position of the vestibular fistulae was
also unusual in being very anteriorly placed in most cases,
quite close to the urethral openings and in relation to the
anterior margin of the vaginal openings (Fig. 3-B). In one of
the patients operated on earlier in the neonatal period (case
4), at presentation, the typical CPC appearance as seen in the
patients of group A was noted, and the child was thought to
be continent for urine. At 2 years, CUI was apparent, and
EUA and endoscopic examination revealed a short urethra
R. Chadha et al.
with a patulous bladder neck, a septate vagina, and a vestibular fistula. Interestingly, at surgery during the neonatal
period, a type II CPC had been found with what appeared to
be a colocloacal fistula, and the child had undergone division
ligation of the fistula. The vestibular fistula, therefore,
represented the distal remnant of the colonic pouch. In
another girl (case 5) too, CUI became apparent only when the
child was brought at the age of 2 1/2 years.
At laparotomy, all 12 patients (100%) had uterus
didelphys with one hemiuterus and vagina flanking the
termination of the colonic pouch on each side (Figs. 8 and 9).
Varying degrees of distension of the colonic pouch was
noted. The appendix was absent in the 2 patients with type I
CPC. Duplication of the appendix was present in 4 patients
with type II CPC; in 2 of these patients, both appendices
were short and stubby. A Meckel diverticulum was present
in 1 patient.
3. Discussion
The present study showed that although essentially the
anatomy of the malformation was similar in all the patients,
there was a spectrum of severity of defects. In newborns,
initial examination revealed a fairly wide vulval vestibule,
and retraction of the labia majora showed radiation of folds
inward from the margins of the vestibule toward the center,
at a point of confluence located at a higher level. In older
patients, more details were apparent on clinical examination/
EUA and on endoscopy, the terminal fistula of the colonic
pouch opening into the urethra or in the vestibule at a high or
a low level (Fig. 9 ). All patients had uterus didelphys with a
double vagina. Patients in whom the position of the urethral
opening, and thus the confluence of the urethral and vaginal
openings in the vestibule, was relatively high can well be
Fig. 8 (Case 7) Operative photograph showing uterus didelphys
with one hemiuterus and vagina flanking the colonic pouch on
either side.
Clinical anatomy of congenital pouch colon in girls
1599
Fig. 9 Diagrammatic representation of the anatomy in a girl with type II CPC showing the various positions of the terminal fistula of the
colonic pouch: urethral, low vestibular, and high vestibular.
termed as having a persistent cloaca. However, this may not
be entirely correct because, unlike cloacal malformations, in
CPC, the appearance of the clitoris, labial folds, vulval
vestibule, and the perineum is essentially normal. In addition, during EUA in older girls, probably because of the wide
vestibule, even with a high defect, light to moderate retraction of the labial folds can usually, clearly show the separate
vaginal openings and, often, the urethral meatus.
There are few detailed reports in the literature describing
the anomalous clinical anatomy of CPC in female patients.
As in boys, and similar to our findings, the CPC subtypes I
and II appear to be more common than the subtypes III and
IV [2-6,13]. In most cases, the colonic pouch has been
reported to terminate in a fistulous communication with
either the vagina or a persistent cloaca [1-6,8,9,11-19]. In
other reports, the colonic pouch has been described as
ending in a vestibular fistula [2,6,9,10,12,16,18,20], a colovesical fistula [2,6,7,9,10,13,14,21], or, as in one case, a
perineal fistula [22]. Mathur et al [9] reported that 16 of 27
girls with CPC had a colouterine fistula. There are several
reports of girls with CPC having a septate vagina and/or a
double uterus and vagina (uterus didelphys) [1,3,5,6,8,10,
13,14,16,20,21,23,24]. The presence of a bicornuate uterus
has also been reported [3,6,13,14,16,17].
There are some reports in the literature of girls with CPC
in whom the abnormal anatomy was very similar to that
described in the present study [1,10,14,20,23,24]. In an
earlier study reported from our center [10], 5 girls, not
included in the present study, had type I/II CPC with findings
virtually identical to those reported here. In 2 patients, the
colonic pouch ended in a colovestibular fistula and, in 3
others, in a colovesical fistula. However, detailed assessment
of the genitourinary tract, including endoscopic examination,
was not performed in any patient. One additional patient had
type I CPC, a colovesical fistula, and a persistent urogenital
sinus, the uterus and vagina being single. Trusler et al [14]
reported a newborn girl, admitted with electrolyte imbalance,
who had type II CPC with a colovaginal fistula, which was
ligated at laparotomy. Autopsy revealed a double uterus and
vagina with the vaginas entering a short “cloacal chamber,”
and, posteriorly, a short tubular structure opening in the
vestibule. Similar to the findings in one of our cases (case 4),
this structure probably represented the distal remnant of the
vestibular fistula, which had erroneously been ligated higher
up. Sarin et al [13] reported 8 girls with CPC and a persistent cloaca in 2 of whom the cloacal opening had a characteristic “clover-leaf” appearance, similar to the appearance
of the external genitalia in newborns as described by us. In
4 patients, the cloaca was short (approximately 5-mm long)
and led to closely approximated orifices of the hypospadic
urethra and vagina(s). Gharpure [24] reported a child with
type I CPC, double uterus and vagina, a colovestibular
fistula, and bladder hypoplasia with CUI. One of the 2 girls
reported by Demirogullari et al [23] had type I CPC and
what appeared to be a colovesical fistula, which was ligated
just above the peritoneal reflexion. Examination when
the girl was 14-years old revealed CUI, external genital
appearance similar to that reported here, and a 7-cm-long
1600
blind-ending tubular structure opening into the vestibule
between the vaginas. This structure probably represented the
distal remnant of the fistula ligated during the previous
surgery. Cystoscopy showed a small hypocompliant urinary
bladder. The second patient, a 2 1/2–year-old girl with type
II CPC, also had a septate vagina, recessed urinary meatus, a
vestibular fistula, and UI. Similar to our findings, in both
patients, the sacrum was normal.
Although the present study suggests that the abnormal
clinical anatomy in girls with CPC, as described by us, is
almost invariable, apart from the few exceptions detailed
above, other reports, including earlier ones from our center
[5,7], have not consistently described these findings. A
likely reason is that in newborns and small infants, the
anatomy of the external genitalia and perineum is not clear
on clinical examination, and endoscopic examination of the
genitourinary tract is usually not feasible. Even in older
girls, light retraction of the labial folds may only show the
folds from the margins of the vulval vestibule radiating
upward, the so-called clover-leaf deformity [13], which
would usually lead to the diagnosis of a persistent cloaca.
The vast majority of reports, including large series [2,37,9,10], have recorded only the findings at primary surgery,
usually in the newborn, and not the results of any detailed
examination, endoscopy, and/or investigations performed
later. As shown by our study as well as other reports [14,23],
determining the level of termination of the colonic pouch
and associated fistula based on the laparotomy findings
during the primary surgery may be fallacious because the
dilated pouch narrows down gradually toward the pelvis but
is fairly broad even at the level of the peritoneal reflection.
The gross appearance may erroneously suggest that the
colonic pouch is opening into a cloacal chamber, the urinary
bladder, or the vagina. The UI can also be missed in the
neonatal period and at laparotomy, unless specifically
looked for; the presence of a double uterus and vagina can
also easily be missed, especially in newborns with a grossly
distended colonic pouch.
It is interesting to speculate on the possible embryology
of this unusual malformation. According to traditional embryologic doctrine [25,26], the cloaca is partitioned between
the 4- (4-week) and the 16-mm (6-week) stage by downward
growth of the urorectal or cloacal septum (URS). The classic
theories of cloacal partitioning have been challenged by
studies, which indicate that ARM result from defective
development, to a varying degree, of the dorsal cloaca and/
or cloacal membrane and that there is no evidence that
descent of the URS plays any role in the process [27,28].
However, recent research by other workers suggests that
some form of descent of the URS and its fusion with the
cloacal membrane does occur and that this has an important
role to play in differentiation of the cloaca [29-31]. It is
likely that very early during cloacal differentiation, the primary event responsible for the occurrence of CPC is “defective organogenesis” of a varying degree of the distal most
segment of hindgut close to the descending URS [7,10].
R. Chadha et al.
This defective segment could “anchor” the entire cloaca
ventrally, preventing further descent of the URS [7,10].
During later development, the abnormal segment of colon
would dilate and distend to form the colonic pouch [5,7,10].
The early arrest of cloacal septation accounts for the high
and anterior level of the fistulous termination of the colonic
pouch in our patients. Even in patients with a vestibular
fistula, the fistulous opening was often located quite anteriorly between the anterior margins of the vaginal openings,
a position that can more correctly be termed intervaginal.
The early error in cloacal septation can also explain the
associated abnormalities of the genitourinary tract. During
normal development, between the 60- and 110-mm stages,
long after cloacal septation is complete, the fused paramesonephric ducts forming the vagina, distally in contact
with the Müllerian tubercle, descend toward the perineum
[32,33]. This descent, along the anterior surface of the URS,
is believed to be responsible for the formation of the dorsal
urethra and the closely related trigonal region of the bladder
[32-34]. It is because of these relationships that the vagina
generally does not extend beyond the termination of the
rectum, wherever that may be [33]. In girls with CPC, the
descending paramesonephric ducts, kept widely apart by
the relatively high communication between the terminal
hindgut and the UG sinus, would not be able to fuse leading
to uterus didelphys with one hemiuterus and vagina flanking
the terminal bowel on each side. Because the ducts do not
fuse and remain apart to a varying degree during their
descent to the vestibule, the development of the trigone,
bladder neck area, and the dorsal portion of the urethra
would be affected. This would account for the short urethra in all patients and the varying degree of defective
development of the bladder neck with resultant PUI or CUI
in 9/12 of our patients. This can also explain the oblique
orientation of the openings of the 2 vaginas with a wide
posterior margin of the vestibule in several of our patients,
including one patient in whom the 2 vaginal openings
were very widely apart. The CPC in female patients is
also unique because it probably represents the only ARM
where the vaginas may be located posterior to the terminal
fistula from the hindgut. Interestingly, a severe defect with
a high confluence of the urethral and vaginal openings was
seen in 3 of our patients, 2 of whom (cases 1 and 3) had
normal urinary continence. In 2 other patients, the urethral
and vaginal openings were closer to the margins of the
vestibule (cases 10 and 12), but UI was present. Thus, the
severity of the external anatomical findings and defect does
not seem to correlate with whether UI is present. The
integrity of the bladder neck, even in the presence of a short
urethra, appears to be the main factor responsible for urinary continence.
It is also important to realize that as reported earlier
[4,7,10] as well as shown by the present study, CPC is very
infrequently associated with major malformations in other
organ systems including the upper urinary tract. Despite
the high nature of ARM associated with CPC, sacral
Clinical anatomy of congenital pouch colon in girls
abnormalities are rare, and the voluntary musculature of the
pelvis and the perineum is well developed [4,7,10]. Thus, the
constellation of defects seen in girls with CPC is probably
secondary to occurrence of the CPC itself and not owing to a
generalized maldevelopment in the cloacal region (cloacal
dysgenesis). In this respect, the embryopathogenesis of CPC
very likely differs from that of the usual ARM, which are
believed to result from defective development of the dorsal
part of the cloaca [27,28] and in whom major abnormalities
of the caudal developmental area and other major organ
systems are common.
A noticeable fact is that, in reports from countries other
than India, especially those from northern Europe, the
anomalous anatomy of CPC appears to be more complex.
Dénes et al [35] reported a girl with type I CPC, Down's
syndrome, and hydronephrosis. Herman and Coplen [15]
reported a girl of Northern European descent who had a type
I CPC with persistent cloaca, partial sacral agenesis, widened
pubic symphysis, double uterus with absence of one fallopian tube, a duplex left kidney, and a megaureter. Wester
et al [16] reported 2 girls, one of whom had type II CPC with
cloaca, hemiuterii with short vaginal stumps, partially duplicated urinary bladder, and partial sacral agenesis. The other
girl with type II/III CPC had a vestibular fistula with vaginal
atresia and 2 isthmus remnants, partial sacral agenesis, and a
duplex system draining the left kidney. A similar high incidence of associated major malformations in girls with CPC
was reported in 2 studies from Saudi Arabia [18,36]. This
would indicate that, unlike in India where, in most cases,
CPC and its associated malformations appear to be the consequence of an isolated defect in the development of the
terminal bowel during early cloacal differentiation [7], outside India, CPC may occur only as a part of a major constellation of congenital defects.
Certain lacunae in the present study, mainly because of
problems with logistics and patient compliance, also deserve
mention. An IVU should be performed in all patients,
because in our study, IVU detected urinary tract abnormalities missed on US examination. In our study, assessment of
bladder neck competence, bladder capacity, and pattern of
micturition was fairly subjective because it was based on
clinical evaluation, MCU, and cystoscopy. Ideally, especially in older girls, a urodynamic assessment should be
performed for this purpose. Only one our patients had been
followed up till puberty. As shown by a recent study [37],
gynecologic anomalies are common in girls with ARM. A
longer period of follow-up, well beyond puberty, is, thus,
essential for all these patients.
In conclusion, the characteristic anatomy of the external
genitalia in girls with CPC, such as described here, appears to
be almost invariable. This typical appearance, especially in
regions such as north India where CPC is common, along
with the characteristic radiologic features should alert the
clinician to the presence of a CPC malformation. In newborn
girls with CPC, if plain x-ray films of the abdomen are not
conclusive, US and/or magnetic resonance imaging scan,
1601
such as described in a recent article [38], may help in making
a definitive preoperative diagnosis of CPC. In addition, girls
with CPC may present for the first time beyond infancy. It
is also apparent that in girls with CPC presenting in the
neonatal period or early infancy, it would be wise to perform
only a proximal diverting ileostomy during primary surgery.
Definitive surgery can then be performed when the child is
older, after detailed assessment has delineated the exact
anatomy of the defect.
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