1. The cloacal malformation is a rare birth defect where the urinary, genital, and intestinal tracts converge into a single opening, known as the cloaca. 2. The authors reviewed imaging studies and records of 65 patients with cloacal malformation seen over 20 years to describe the spectrum of abnormalities. 3. Adequate preoperative planning requires precise radiological definition of the abnormal anatomy using imaging studies like cystoscopy, sonography, voiding cystourethrography, and MR imaging to discover coexisting anomalies and plan diversion of the fecal stream.

1. Diego Jaramillo, MD2 Robert
#{149} L Lebowitz, MD W.
#{149} Hardy Hendren, MD
The Cloacal Malformation: Radiologic Findings
and Imaging Recommendations’
The imaging studies and records of T HE cloacal malformation is a con- tion has improved significantly, and
65 patients with the cloacal malfor- stellation of congenital abnor- surgical repair with good functional
mation seen from 1969 to 1989 were malities in which the urinary, geni- outcome is now possible (7-9). Ade-
reviewed. The malformations were tab, and intestinal tracts converge quate surgical planning requires pne-
described according to cloacal con- into a common outflow structure, the cisc preoperative definition of the
figuration (urethral, vaginal), type cloaca (Latin for sewer). It is seen cx- abnormal anatomy by means of imag-
of uninary-cloacal communication clusively in phenotypic females (i) ing studies and cystoscopy. Preven-
(urethral, vesical), and level of rectal and occurs in one of every 40,000- tion of renal damage, which is the
communication (vaginal, cloacal, 50,000 newborns (2). The perineum most significant potential cause of
vesical, other). Lower urinary tract of the typical patient has a single morbidity in these patients (9), re-
abnormalities were frequent (reflux, opening that serves as the outlet for quines detection and treatment of uri-
ureteral ectopia, bladder diverticula, urine, genital secretions, and feces! nary tract obstruction and reflux,
bladder duplication, urachal rem- meconium, and the abdominal wall is plus early diversion of the fecal
nants, urethral duplication), as were normal (i) (Fig 1). stream by means of a colostomy. Ad-
genital abnormalities (uterine du- The term persistent cloaca has also ditionally, radiology has an impor-
plication, vaginal duplication, uter- been used to describe this anomaly tant role to play in discovering and
inc atresia, vaginal atresia), abnor- (3). In nonpiacental vertebrates such characterizing coexisting anomalies
malities of the bony pelvis (partial as fish, amphibians, reptiles, birds, in other organ systems.
sacral agenesis, pubic diastasis), and and monotremes, the cboaca is the or- Herein we describe our experience
renal abnormalities (agenesis, ob- gan for genitourinary and intestinal with 65 female infants and children
struction, horseshoe kidney). Con- storage and expulsion (4). A similar with the cloacal malformation seen at
trast material studies of the cloaca structure is present in the human em- our institution during the past 20
and the distal limb of the colostomy bryo at 4 weeks (5). However, unlike years. We will describe the spectrum
with fluoroscopy in various projec- the structure in animals and human of the malformation; the genitouri-
tions were essential for diagnosis. embryos, the cboaca seen in the mal- nary, intestinal, lower spinal cord,
Voiding cystourethrography was formation is a channel rather than a and pelvic wall abnormalities that oc-
important for detecting vesicoure- storage chamber. cur in close association with the mal-
teric reflux. Sonography was of lim- The cboacal malformation should formation; the extrapelvic abnormali-
ited value for evaluation of the mal- not be confused with exstrophy of ties that coexist; and the approach to
formation but was valuable for im- the cboaca, an entity having a similar imaging.
aging the kidneys. MR imaging name but differing greatly in em-
revealed that spinal cord abnormali- bryogenesis and clinical features. Ex-
MATERIALS AND METHODS
ties cannot be predicted based on strophy of the cloaca is seen in both
the appearance of the lumbosacral boys and girls, and there is a failure We reviewed the imaging, clinical, cys-
spine and are more common than of closure of the lower abdominal toscopic, and surgical findings in 65 fe-
previously thought. wall (6). male subjects (newborn to 21 years of age)
with the cloaca! malformation seen at our
In recent years, the prognosis of
hospital during the years 1969-1989. At
infants with the cboacal malfonma-
least one of us participated in the evalua-
tion of every patient, and one of us pen-
formed surgery in all but four of them.
We imaged 28 patients before repair of
I From the Departments of Radiology (D.J., the cloacal malformation. Their ages at
Index terms: Anus, abnormalities, 757.1433.
R.L.L.) and Surgery (W.H.H.), Children’s Hos- examination ranged from 1 day to 4 years
Anus, imperforate, 757.1433 Bladder,
#{149} abnor-
pita!, Harvard Medical School, 300 Longwood (except for one patient evaluated when
malities, 83.1469 Children,
#{149} genitouninary sys-
Ave. Boston, MA 021 15. Received April 6, 1990; she was 1 1 years old). Twenty-five of
tem, 80.1469 Genitourinary
#{149} system, abnor-
revision requested May 9; revision received these 28 patients had undergone divert-
malities, 80.1469 Infants,
#{149} genitourinary sys-
June 15; accepted June 22. Address reprint re- ing colostomy prior to imaging. All 28 pa-
tern, 80.1469 Magnetic
#{149} resonance (MR), in
quests to R.L.L.
infants and children Rectum,
#{149} abnormalities, tients had undergone one or more fluoro-
2 Current address: Department of Pediatric
757.1433 Urethra,
#{149} abnormalities, 851.1469. scopically monitored injection studies us-
Radiology, Massachusetts General Hospital,
Uterus, abnormalities, 854.1469 Vagina,
#{149} ab- Boston.
ing water-soluble contrast material for
normalities, 855.1469 C RSNA, 1990 evaluation of the malformation (26 injec-
See also the editorial by Wood (pp 326-327) tions into the perineal opening, 17 injec-
Radiology 1990; 177:441-448 in this issue. tions into the distal limb of the colosto-
441

2. Urethral Vaginal
a.
R
Figure 1. Perineum of a patient with do-
acal malformation. Featureless or blank pen-
neum has a single penineal opening, and the
anus is absent.
my, and 10 injections through catheters I
placed intraoperatively or into vesicos- b. C.
tomy on vaginostomy stomas) and at least Figure 2. (a) Cloacal configuration. Sagittal diagrams show the narrow urethral configura-
one study of the upper urinary tract (15 tion (left) and the wide vaginal configuration (right). Vagina can often be identified by the
sonographic, 15 excretory urographic, cervical impression. Sacrum is short, a frequent finding in the malformation. (b) Urethral
and eight scintigraphic studies). Nine pa- configuration. Contrast material was injected into a catheter in the cloaca with use of a nip-
tients in this group underwent magnetic ple for occlusion (straight arrow). Cloaca is long and narrow and communicates with the
resonance (MR) imaging for evaluation of urethra and the rectum (R). A small chamber lies between the cloaca and the rectum (solid
the lower spinal cord. curved arrow). Vaginal lumen is not opacified (open curved arrow) but is distended. Vagina
The other 37 patients were seen follow- indents the bladder (B) and rectum (R). (c) Vaginal configuration. A wide, short cloaca has
been opacified. Two vaginas (V) are present, one of which is partially hidden by the bladder.
ing some degree of repair of the cboacal
The communication with the rectum is not opacified.
malformation performed elsewhere.
Their imaging studies were reviewed,
and often new ones were performed.
The surgical treatment of these patients
has been reported elsewhere (7,8). (Fig 2b). The latter was a wide, usual- curred higher in the vagina. In two
ly straight cloaca that tended to be a cases the communication was with
continuation of the vagina (Fig 2c). the anterior wall (Fig 5a, 5b). In cases
RESULTS
The type of uninary-cloacal com- of cboacal communication, there was
We described the cboacal malfor- munication (Fig 3a) was urethral in direct communication between the
mation according to its radiobogic ap- 50 patients [77%]; in these patients rectum and the cloaca. In five cases,
peanance. The following categoriza- there was a well-formed urethra, usu- there was a tiny chamber acting as a
tion of the malformation, which is ally with a normal sphincter, joining passageway between the rectum and
based on radiologic findings, is an at- the bladder to the cboaca (Fig 3b). The the cloaca (Fig 2b). Three of these
tempt to serve as a guide to the radi- communication was vesical in 15 pa- five patients had a separate, blind-
ologist performing the imaging stud- tients (23%); the urethra was absent, ending vagina, distended with geni-
ies. The categorization is indepen- and there was direct communication tal secnetions (Fig 2b). In five other
dent of, but complementary to, the between the bladder and the cloaca patients, communication occurred
classification of the level of conflu- (Fig 3c). between the intestine and the blad-
ence of the cboacal malformation The level of rectal communication den when there was either no vagina
based on cystoscopic and operative (Fig 4a) was categorized as vaginal or when the vagina was malposi-
findings (7). (44 patients [68%]), cloacal (seven pa- tioned (Fig 6). These five also had pu-
The cloacal configuration (Fig 2a) tients [11%]), or other (ten patients bic diastasis.
was categorized as either urethral (34 [15%]). Vaginal communication usu- In four cases the rectum opened
patients [52%] or vaginal (31 patients ally occurred at the posterior wall of onto the perineum through an ante-
[48%)] . The former was a narrow, of- the lower vagina, or, in cases of vagi- riorly malpositioned anus (cboacal
ten long and curved cloaca with a nab duplication, at the lower end of variant, Fig. 4a). In one patient there
small penineal opening that tended the vaginal septum (Fig 4b, 4c). Less was a rectouterine communication.
to be a continuation of the urethra frequently, the communication oc- Four patients (6%) had had prior
442 Radiology
#{149} November 1990

3. pull-through operations elsewhere, dynamic examinations, and operative always had pubic diastasis (generally
and the level of the communication findings showed that the urinary wider than 4 cm) and severe genital
could not be determined. sphincter was located around the and rectal abnormalities (Fig 8). More
Abnormalities of the pelvic struc- urethra in 37 patients (57%) and than half of the patients had uretenal
tunes were common (Table 1). Three around the cboaca in 14 (22%). Four- reflux, usually bilateral (22 of 39
patients had an accessory urethra teen (22%) had no sphincter. cases). Uretenal ectopia was frequent
that exited just below a clitonislike Diverticula of the bladder were and ranged from lateral or inferior
structure (Fig 7a). This “phallic seen in 13 patients (20%). All six pa- location of the ureteral orifice in the
urethra” (2) was very small. There tients with peniuretenal diverticula bladder to insertion in the vagina
was a second, larger, more normal had reflux. Patients with either du- (five patients) or the cboaca (one pa-
urethra located posterior and inferior plication of the bladder or a common tient).
to it (Fig 7b). Imaging studies, uro- vesicovaginal or vesicocecal chamber Duplication of the uterus, usually
associated with vaginal duplication,
was seen in 36 patients (55%) (Figs 2c,
4c, 5b, 8, 9). Obstruction of the geni-
tab tract was present in 16 patients
(25%) and usually was at the level of
the vagina. Patients with obstruction
frequently had hydrometrocolpos at
birth (14 of 16 cases). Two patients
developed hematocolpos at puberty,
and one presented at age 16 with bi-
Figure 3. (a) Diagrammatic representation
of the types of urinary-cloacal communica-
Lirethro-cloacal Vesico-cloacal tion. The communication is called urethro-
cloacal when a well-formed urethra joins
the bladder to the cloaca (left). If the urethra
is absent or rudimentary, the communica-
tion is called vesicocloacal (right). (b) Ureth-
rocloaca! communication. Contrast material
V has been injected into a cloaca by means of
the nipple-occlusion technique. There is ret-
B rograde filling of the urethra (straight an-
row), which is opacified only to the level of
the urinary sphincter, indicating that the
sphincter is competent. The vagina (V) and
rectum (R) are also opacified. The rectoc!oa-
cal communication is very narrow (curved
arrow). The bladder (B) is faintly opacified.
(c) Vesicoc!oaca! communication. There is
,, opacification
uration
of a cloaca with vagina!
that communicates
config-
freely with both
the vagina (V) and the bladder (B). There is
, . , ,J.
no urethra. The rectum is not opacified.
‘..
Vaginal Cloacal
c#{231}
:
‘ .‘
#{149} jUro
. - ..
enitol Sinus
with nteriorty
Cloocol Variant)
Ptoced Anus
b. C.
Figure 4. (a) Diagrammatic representation of the level of rectal communication. The rectum usually joins the vagina low on its posterior
wall (upper left). The rectum can also join the cloaca (upper right). In the so-called cloacal variant (lower illustration), the rectum drains
through an anteriorly placed anus, very close to the opening of the urogenital sinus. (b, c) Low rectovaginal communication. The bladder
(which contains an air-filled urinary catheter balloon), vaginas (V), and rectum (R) are opacified by simultaneous injection into the suprapu-
bic bladder catheter and the distal limb of the colostomy. (b) Lateral projection. The communication (arrow) is between the rectum and the
lower portion of the superimposed vaginas. (c) Frontal projection. The communication (arrow) is into the incomplete septum that divides
the vagina into two chambers inferior!y.
Volume 177 Number
#{149} 2 Radiology #{149}443

4. lateral adnexal masses that were
found to be dilated fallopian tubes in
an otherwise atretic genital tract.
Eleven patients had abnormal sep-
aration of the pubic symphysis (Fig
8). Of eight patients with a diastasis
greater than 2 cm, six had no cvi-
dence of a functional urinary sphinc-
ten, and four had a common vesicova-
ginal chamber.
Some degree of sacnal agenesis was
seen in nearly half of the patients (26
of 65 [40%]). Spinal anomalies in-
cluded dysraphism, segmentation
anomalies, and spinal stcnosis.
The most frequent abnormality of
the spinal cord was tethering. A
high, stubby conus was seen in two
patients, each of whom had segmen-
tal sacral agcnesis. More than half of Figure 5. Anterior
rectovagina! communication. Curved arrows = cervical impression.
the cases of spinal cord anomalies (a) Oblique projection.
The rectum (R) passes over the vagina! septum to joint the lower por-
were detected since we began to use tion of the vagina (V) on its anterior wall (straight arrows). B = bladder. (b) Frontal projec-
MR imaging as a screening tool. Of tion. A midline septum separates two vaginas, and a cervical impression is seen at each apex
(curved arrows).
16 patients who underwent MR im-
aging, seven had some degree of spi-
nal cord abnormality. Of the six pa-
tients with tethered cord, three had
only minimal sacral abnormality, and
in one the sacrum was normal.
Multiple abnormalities of the cx-
trapelvic organs were seen (Table 2).
Seven of nine patients with only one
kidney had significant genital anom-
alies. However, only one of the seven
had ipsilatenal atnesia of a duplicated
genital tract. Only eight patients had
congenital anomalies of the upper
urinary tract that required surgery
(six with obstruction at the uretero-
pelvic junction and two with obstruc-
tion at the ureterovesical junction).
Congenital heart disease, although
Figure 6. (a) Frontal projection. This patient had a partially duplicated bladder (B) into
rare, was the cause of the only two which the rectum (R) drained. (b) Lateral projection. The vagina (V) has two cervices (an-
deaths. rows) and is infeniorly malpositioned. The cloaca has a urethral configuration. Confusing
anatomy in this patient necessitated four imaging examinations. The last was performed
with the patient under anesthesia during cystoscopy; contrast material was injected through
DISCUSSION catheters placed at that time.
A cow with a malformation result-
ing from confluence of the urinary,
genital, and alimentary tracts was de-
scnibed by Aristotle (10). In 1692, Sa-
viard performed an autopsy on an in-
fant who had died several days after
birth who had “no apparent marks of
either [sex] externally, . . . two kid-
neys fastened together . . . [which]
discharged . . . into a large hole, the
Cystis Communis, . . . whose aperture
was the only one external.” By using
a blow-pipe introduced into the “cys-
tis,” has was able to inflate the com-
municating structures and “found
two small wombs, . . . each [with] a
short vagina . . . which evacuated ...
Figure 7. (a) Diagrammatic representation of urethral duplication. A narrow accessory on
into that cystis, and this, to speak the
“phallic” urethra opens onto the perineum just beneath a large clitoris. The functional, more
truth, was only the extremity of the posterior on ventral urethra joins the cloaca. (b) A narrow, dorsal accessory urethra (arrow)
rectum a little dilated.” Saviard ends that exits beneath the clitoris is opacified, as is a wide ventral urethra that merges with the
his description with an insightful cloaca. The vagina is not opacified. B = bladder, R = rectum.
444 S Radiology November 1990

5. the rectum and the urogenital sinus.
Table 1
The cboacal membrane, which covers
Abnormalities of the Pelvic Structures
the perineum at this stage, cannot
No.of rupture if it is not joined by the uro-
Structure Patients rectal septum, so the normal penineal
openings do not develop. Further-
Lower urinary tract
Urethra more, abnormalities in cboacal septa-
Accessory or “phallic” urethra 3(5) tion and urogenital sinus formation
Absent or poorly developed 4(6)
Atresia or obstruction 5 (8) interfere with normal mesonephric
Bladder and paramcsonephnic duct develop-
Diverticula 13 (20)
ment. This may explain the very fre-
Duplication 6 (9)
Urachus 5(8) quent association of the cloacal mal-
Common vesicovagina! chamber 5 (8) formation with duplication or agene-
Hypoplasia 3 (5)
Lower ureter and ureterovesica! junction sis of genital structures and with the
Reflux 39 (60)* less frequent but still common anom-
Grade 1 0
alies of number and position of the
Grade 2 10
Grade 3 5 kidneys. As with imperforate anus,
Grade 4 7 primary obstruction of the rectum
Grade 5 5
Ectopia 18 (28)t with secondary formation of commu-
Genital tract nication between the rectum and ad-
Vagina
Duplication 30 (46)
jacent structures has also been postu-
Agenesis or atresia 16(25)1 bated and helps to explain some of
Hydrometrocolpos at birth 14(22) the unusual connections (13) (Fig 5).
Hematometrocolpos at puberty 2 (3)
Uterus The multiplicity of associated find-
Duplication 36 (55) ings, particularly in the lower spinal
Agenesis 10(15)
Adnexa (surgical data)
cord, lumbosacral spine, and bladder,
Absent or hypoplastic ovaries 4 (6) suggests that more complex and
Paraovanian and fallopian tube cysts 3 (5) probably multiple disturbances have
Cystic ovaries 2 (3)
Pelvic osseous structures occurred during the process of devel-
Sacral agenesis or hypoplasia 26(40) opment of the caudal pole of the em-
Pubic diastasis 11 (17)
Dysraphism 9(14)
bryo (15,16).
Lower spinal cord (data from 16 MR studies, seven abnormal) The few cases that are intermediate
Tethered cord 8(12)t between the cloacal malformation
Lipomyelomeningocele 3(5)11
High cord 2(3)1l and cboacal exstrophy are puzzling.
Retrorectal presacral space Abnormal separation of the pubic
Rectal diverticulum 1 (2)
Presacra! dermoid 1 (2)
symphysis, previously thought to be
Sacrococcygeal teratoma 1 (2) characteristic of exstrophy of the
Note-Percentages in parentheses. bladder or the cboaca, has been found
* Twenty-two bilateral cases. The grade of reflux was unavailable in 12 of the 39 patients. in association with other genitouri-
t Five extravesical cases. nary anomalies (17) and was present
I Includes four with rudimentary vaginal chambers. in 1 1 of the patients in this series.
§ Six cases found with MR imaging.
1 One case found with MR imaging. Two of these patients had a vesicoce-
cal communication, reminiscent of
the visceral configuration of cloacal
exstrophy. Failure of regression of
statement about the cboacal malfor- the cloacal membrane has been sug-
mation that is still valid: “It is very gested as one causative factor in both
probable . . . that if this child had the cloacal malformation and cboacal
lived to be adult, it would have been exstrophy; however, in cloacal cx-
incapable of generation from the strophy, the cloacal membrane be-
mixture of the seed with the stercoral comes interposed between the fusing
and urinary excrements. Besides, genital tubercles and interferes with
both these excrements would have the normal closure of the anterior
had an involuntary exit.” In the early pelvic wall (6,18). It is likely that this
19th century Meckel introduced the process operates to some degree in
term “cloaca congcnita” to describe the cases of the cloacal malformation
the malformation (10). with features of cloacal exstrophy.
The embryologic basis of the mal- A small group of patients had
formation is still a subject of contro- esophageal atresia (11%) and other
versy (5,1 1-14). What follows is a features of the VATER association
brief summary of the most widely ac- (vertebral, anal, tracheoesophageal,
cepted theories. The cboacal malfor- and radial and renal defects), but
mation is believed to result from fail- they had lower-limb anomalies and
ure of the urorectal septum to join not radial abnormalities.
Figure 8. Bladder duplication. Frontal pro-
the cloacal membrane during the 4th Until about 20 years ago the cboacal
jection shows two hemibladders (B), each
having its own refluxing ureter, and wide
to 6th weeks of embryonic develop- malformation was an embryologic
pubic diastasis. Two vaginas (V) are partially ment. This failure could result in a curiosity, rarely reported (3,16,19)
obscured by the left hemibladder. persistent communication between and having devastating effects and a
Volume 177 #{149}Number 2 Radiology 445
#{149}

6. Figure 9. Vaginal duplication. Two distended vaginas (1/) separated by an incomplete sep-
tum are we!! demonstrated by (a) the injection studs’ and (b) sonography. Sonogram is on-
ented to correspond to the vaginogram.
grim prognosis (20,21). In a series as
Table 2
recent as 1959 (3), the mortality was
Extrapelvic Abnormalities
greater than 50% because of urosep-
sis, renal failure, and cardiovascular
anomalies.
Today, however, repair of the mal- Upper urinary tract
formation and management of its Unilateral renal agenesis 9(14)’ b.
Ureteral obstruction 8 (12)t Figure 10. (a) Frontal radiograph shortly
complications have become possible.
Abnormalities of rena!
Death is very rare, and the morbidity after delivery shows a large pelvic mass oc-
position and rotation 6(9)
cupying most of the lower abdomen. There
related to the urinary and intestinal Horseshoe kidney 4(6)
Duplication of collecting is a linear calcification in the abdomen (an-
tract has been markedly reduced, system 4 (6) row) suggestive of meconium peritonitis.
mainly due to the recognition of the Gastrointestinal tract The sacrum is hypoplastic, and there is wide
Esophageal atresia 7(11)
importance of early colostomy to di- pubic diastasis. (b) Sagittal sonogram of the
Meckel diverticulum 6(9)
vent the fecal stream and decompres- Malrotation 5(8)
same infant shows a vagina with a fluid-
sion of the urinary tract. A divided- Intestinal atresia 3 (5)1 debris level. The compressed bladder (an-
Meconium peritonitis, row) is located anteriorly.
loop right-transverse colostomy to without bowel
avoid fecal contamination of the perforation 2(3)
urine is preferred for reasons out- Cardiovascular system
Ventricular septal defect 6(9)
lined previously (8). Intermittent Tetra!ogy of Fallot 2(3)
catheterization of the cloaca is often Musculoskeletal system
Vertebral anomalies 13 (20)
necessary in the neonatal period to Lower-limb anomalies 5(8)
drain urine from the distended vagi- Congenital hip dysplasia 4 (6)
Head and neck
na(s). Vaginostomy or vesicostomy
Craniofacial anomalies 6(9)
arc almost never needed. Correction Hydrocephalus 2(3)
of severe reflux is often performed
Note-Percentages in parentheses.
prior to definitive repair of the mal-
- Seven with significant genital anomalies.
formation. The definitive repair is , Six ureteropelvic junction. six ureterovesi-
complex and involves the separation cal unction.
I Two duodenal.
of the rectum, vagina(s), and urinary
tract, bringing each to the perineum
in a more normal fashion. The poste-
nor sagittal approach is preferred the immediate postnatal period in or- .,,.i,.,
(8,9). Functional repair of the cloacal den to prevent fecal contamination of
malformation can result in a conti- the urinary tract (8,9). Since the state Figure 11. Same patient as in Figure 4b
nent bladder and rectum, and in a va- of the urinary tract is the main factor and 4c. The bladder (B), vagina (V), and
gina of near anatomic configuration. deciding the prognosis of patients uterine horns (arrows) are opacified.
The outcome of repair of the genital with the cboacal malformation (9), de-
tract is difficult to assess at this time tection of reflux and obstruction
because most survivors arc only now should be done early. Imaging stud- studies to detect and characterize as-
reaching the reproductive age (8,9). ies to define the cloacal anatomy be- sociated anomalies.
The first step in the management fore planning the definitive repair Every newborn girl with imperfo-
of the malformation is the perfor- can then be performed electively. rate anus and a single penineal open-
mance of a diverting colostomy in Further imaging should include ing should be considered to have the
446 . Radiology November 1990

7. cloacal malformation until proved nipple (Poznanski technique) (24) throgram. Vesicoureteric reflux can-
otherwise. Just as there is wide varia- (Figs 2b, 3b) or with the balloon of a not be detected and characterized
tion in the internal anatomy, there is Foley catheter. without a cystogram. Catheterization
a spectrum of severity in the appear- Accessory penineal openings of the bladder may be difficult, even
ance of the abnormal perineum. Fig- should be soht. A tiny opening at with a coud#{233}atheter.
c In a few cases
ure 1 shows the typical cboacal anato- the base or the tip of the clitoris is the catheter can be placed in the
my. However, in some cases the in- usually the opening of a second ure- bladder only at the time of cystos-
troitus may have a more normal thra, sometimes called a phallic ure- copy.
appearance, and in others there is a thra. As in urethral duplication in In patients who have already had a
rudimentary phalliclike structure males, this uppermost (dorsal) ure- colostomy, injection into the distal
with poorly formed labia. thra is usually rudimentary, whereas limb of the colostomy should be
Imaging evaluation should begin the lower (ventral) urethra is the done. We usually do this as the first
with plain radiognaphs. A pelvic more functional of the two (25). injection study because, if all of the
mass is almost always a distended va- Imaging during injection of con- pelvic structures are shown, a cboacal
gina and/on uterus, secondary to ob- trast material into the cloacal open- injection is not needed. Injection into
struction (Fig 10). The level of this ing should begin in the lateral pro- the distal limb of the colostomy regu-
obstruction determines whether the jection to display the various commu- larly demonstrates the level of the
vagina is only distended by genital nications optimally. Examination in rectal communication and distin-
secretions on whether it contains the frontal projection is important for guishes the rectum from the vagina.
urine and meconium as well. If the showing vaginal and bladder dupli- This differentiation can sometimes
mass contains gas, the gas is most cation (Figs 4c, 5b, 8, 9). For all injec- be difficult during the cboacal injec-
likely from the colon and is a sign of tion studies, water-soluble contrast tion, particularly when the vagina is
rectovaginal communication (22). material (17% meglumine diatrizoate) distended and the rectum is poorly
Linear calcifications in the abdomen is preferred over barium because of opacified (Fig 3b).
along the peritoneal surfaces indicate the possibility of reflux into the up- Sonographic evaluation of the pd-
calcified meconium from meconium per urinary tract on flow into the vic viscera can occasionally help
peritonitis (Fig 10). This can occur in peritoneal cavity, because repeated characterize the cloacal malforma-
patients with the cboacal malfonma- injections are more readily done, and tiort, particularly when the vagina is
tion when meconium spills into the because rarely (in one case in our se- dilated (Figs 9, 10). However, in this
peritoneal cavity via the fallopian ries) barium may fail to demonstrate series, sonography was useful for
tubes and not necessarily from intes- a narrow communication that less evaluation of the pelvic structures in
tinal perforation (23). Granular calci- viscous water-soluble contrast mate- only one-third of patients, primarily
fications in the abdomen correspond- rial shows. due to difficulty in obtaining a full
ing to the course of the colon suggest It is important to distinguish be- bladder to use as an acoustic window.
calcified intnaluminal meconium, tween the bladder and vagina, but We evaluate the upper urinary
which can occur when there is mix- this can be difficult (Figs 4b,10). In tract initially with ultrasound (US)
ing of urine and meconium in the lu- one case initially treated elsewhere, and later with a functional urogna-
men of the colon. This is more likely this confusion led to performing a phic or scintigraphic study. If the
in patients with the cboacal malfor- vaginostomy instead of the planned sonogram is normal, either scintigra-
mation when there is vaginal atresia vesicostomy. Reflux into a ureter or phy or excretory urognaphy is used.
on stenosis and rectovesical or nec- into a urachal remnant helps to iden- If the sonogram is abnormal, we use
tounethral communication. Severe tify a structure as the bladder. A cen- excretory urography because precise
diastasis of the pubic symphysis sug- vical impression, which is not always anatomic definition is so important
gests poor development of the une- present, and a septum help to identi- in this complex malformation.
thral sphincter, rectovesical commu- fy the vagina (Figs 5, 6b). The posi- Since the prevalence of anomalies
nication, or a common vesicovaginal tion of a structure is not always a clue of the lower spinal cord is very high
chamber. as to its identity (Fig 6b). (43% in the patients evaluated with
Injection studies with fluonoscopic Failure to opacify the bladder, if MR imaging) and since the plain ra-
monitoring are the most important the retrograde injection of contrast diographs correlate poorly with
part of the nadiobogic evaluation of material stops at the urethral sphinc- pathologic features of the cord, we
the cboacal malformation. Cross-sec- ten, indicates that the sphincter is now evaluate the lower spinal cord
tional imaging techniques are not competent (Fig 3b). Failure to opacify in every patient with the cboacal ma!-
usually helpful because the multiple the vagina may indicate either vagi- formation. This can be done with US
structures involved and the unpre- nab atresia or obstruction (Fig 2b). If during the neonatal period, or with
dictable and erratic courses of the the obstruction is untreated, and the MR imaging later (16).
communications between them do patient has a uterus, she may develop Postoperative MR imaging for
not lend themselves well to studies hematocolpos at puberty. During do- evaluation of the adequacy of the nec-
in orthogonal planes. The structures acal injection, the rectum often fails tal pull-through (26) can be done si-
are readily accessible for catheteriza- to opacify. This occurred in 15 of 28 multaneously with the examination
tion, and studies with contrast mate- patients studied by us prior to repair. of the cord, as was done in six of 16
nial also provide functional infonma- Opacification of the endometrial cay- patients. MR evaluation of the uterus
tion about reflux and continence. Se- ity is extremely rare (the uterus was and ovaries was not helpful. This
dation is usually not necessary. seen in only two of these 28 patients) may be related to two factors, that
If the single perineal opening is (Fig 11). most patients were examined in in-
small, catheterization can usually be Following injection into the cloaca, fancy and that these structures were
accomplished with an 8-F feeding an attempt to advance the catheter frequently hypoplastic and located in
tube. If the opening is patulous, it into the bladder should be made in abnormal positions. Evaluation of ab-
should be partially occluded with a order to perform a voiding cystoure- normalities in other organ systems is
Volume 177 Number
#{149} 2 Radiology 447
#{149}

8. guided by the physical examination. 5. Moore KL. The developing human. 4th 16. Carson JA, Barnes PD, Tune!! WP, Smith
ed. Philadelphia: Saunders, 1988; 236-245, El, Jolley SC. Impenforate anus: the neu-
In summary, the cboacal malfonma-
257-285. rologic implication of sacral abnormali-
tion represents a spectrum of abnor- 6. Hurwitz RS, Manzoni GAM, Ransley PG, ties. J Pediatr Surg 1984; 19:838-842.
malities of the lower urinary, genital, Stephens DF. Cloacal exstrophy: a report 17. Steidle CP, Kennedy HA, Mitchell ME,
and intestinal tracts. Knowledge of of 34 cases. J Urol 1987; 138:1060-1064. Rink RC. Symphyseal diastasis in the ab-
the main anatomic patterns before ra- 7. Hendren WH. Further experience in re- sence of the exstrophy-epispadias corn-
constructive surgery for cloacal anoma- plex. J Uro! 1988; 140:349-350.
diobogic investigation is important. lies. J Pediatr Sung 1982; 17:695-717. 18. Mildenberger H, K!uth D, Dziuba M.
Injection studies with fluoroscopic 8. Hendren WH. Repair of cloaca! anoma- Embryology of bladder exstrophy. J Pc-
monitoring in the awake child arc lies: current techniques. J Pediatr Sung diatr Surg 1988; 23:166-170.
the mainstay of radiobogic evalua- 1986; 21:1159-1 176. 19. Stone HB. Imperforate anus with recto-
9. Hendren WH. Urological aspects of do- vagina! cloaca. Ann Sung 1936; 104:651-
tion. They are a challenge to perform acal malformations. J Urol 1988; 140:1207- 658.
and interpret. Coexisting anomalies 1213. 20. Snyder WH Jr. Some unusual forms of
are frequent and often important, 10. Bodenhamer W. A practical treatise on impenforate anus in female infants. Am
and they should be sought. #{149} the aetiology, pathology and treatment of Sung 1966; 111:319-325.
the congenital malformation of the rec- 21. RaffenspengerJG, Ramenofsky ML. The
tum and anus. New York: Wood, 1860; management of a c!oaca. J Pediatr Surg
Acknowledgments: We thank Diane de Al-
225-277. 1973; 8:647-657.
derete for secretarial assistance, Donald Sucher
1 1. Van den Putte SCJ. Normal and abnormal 22. Reed MH, Griscom NT. Hydrometnoco!-
for the photography, and Jean Kanski Bitt! for
development of anorectum. J Pediatr Sung 05 in infancy. AJR 1973; 118:1-13.
the drawings.
1986; 21:434-440. 23. Bear JW, Gilsanz V. Calcified meconium
12. Escobar LE, Weaver DD, Bixler D, Hodes and persistent c!oaca. AJR 1981; 137:867-
References ME, Mitchell M. Urorectal septum ma!- 868.
1. Donahoe PK, Pena A. Abnormalities of formation sequence. Am J Dis Child 1987; 24. Poznanski AK. Practical approaches to
the female genital tract. In: Welch KJ, Ran- 141:1021-1024. pediatric radiology. Chicago: Year Book
dolph JG, Ravitch MM, O’Neill JA, Rowe 13. Gray SW, Skandalakis JE. Embryology for Medical. 1976; 186-191.
MI, eds. Pediatric surgery. 4th ed. Chicago: surgeons. Philadelphia: Saunders, 1972; 25. Effman EL, Lebowitz RL, Colodny AH.
Year Book Medical, 1986; 1352-1362. 209. Duplication of the urethra. Radiology
2. Karlin G, Brock W, Rich M, Pena A. Per- 14. Cheng GK, FisherJH, O’Hare KM. Retik 1976; 119:179-185.
sistent cloaca and phallic urethra. J Urol AB, Darling DB. Anomaly of the persis- 26. Sato Y, Pningle KC, Bergman RA, et a!.
1989; 142:1056-1059. tent cloaca in female infants. AJR 1974; Congenital anorectal anomalies: MR im-
3. Gough MH. Anorecta! agenesis with per- 120:413-423. aging. Radiology 1988; 168:157-162.
sistence of cloaca. Proc Royal Soc Med 15. Karrer FM, F!annery AM, Nelson MD,
1959; 52:886-889. McLone DG, Raffensperger JG. Anorectal
4. Wake M. Comparative anatomy. 3rd ed. malformations: evaluation of associated
Chicago: University of Chicago Press, spinal dysraphic syndromes. J Pediatr
1979; 575-576. Sung 1988; 23:45-48.
448 Radiology
#{149} November 1990