Anorectal
Malformations
Dr Hasan Nugud
Consultant
Paediatric Surgeon
Anorectal Mlaformations
Examination of the Perineum
Anal opening
Absent
Present
Normal
Abnormal
Normal size
catheter can
be passed
Catheter cannot
be passed
beyond 2-3 cms
Normal
anus
Rectal
atresia
Anal opening
is very small
Anal stenosis
“microanus”
Anal opening
covered by
skin bridge
“Bucket handle”
anomaly
Perineal inspection
•Anal dimple = EAS (cutaneoanal reflex, EMG)
•Fistula visible?
•Midline groove between buttocks and
anal dimple (“flat buttocks”)
decreased prominence ~ height of the
fistula
•Boys:
–meconium or squamous epithelium in urine =
fistula
–white epithelial pearls = fistula
•Girls: number of orifices + probing
Anorectal Mlaformations
Examination of the perineum
Absent anal opening
Anal dimple +
Cough impulse +
Low anomaly
-normal skin
-no meconium
is seen
Covered anus
-Flat perineum
-no natal cleft
-no anal dimple
-no cough impulse
High anomaly
-covered by
-Fistulus opening in the
a membrane
meconium can perineum,
be seen through median raphae, or scrotum,
-meconium discharge
Covered anus
Anocutaneous fistula
Anorectal Mlaformations
Examination of the Perineum
Abnormal anal opening
Vestibule
Perineum
Ectopic anus
Direction of
the track
Direction
of the track
Posterior
Anocutaneous
Fistula
Upwards
Rectocutaneous
Fistula
Posterior
Anovestibular
Fistula
Upwards
Rectovestibular
Fistula
Anorectal Mlaformations
Examination of the Perineum
High Anomaly
Boys
Girls
Examination of genitalia
Urine
One opening
Meconium
stained
Rectourethral
Fistula
Normal
No
Fistula
Cloaca
Meconium is passed
per vagina
Rectovaginal Fistula
Two openings
No meconium
passed per vagina
Rectal atresia
Without fistula
Anorectal Mlaformations
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Meconium is passing
from the vestibule just
anterior to the poster
forshette and behind the
posterior vaginal wall.
Careful negotiation of
the fistula track and
meticulus dilataion
defltes the baby and
resolves distension
Anorectal Mlaformations
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The rectal opening
follows a subepithelial
fistula tract in the
midline raphe extending
on the scrotum (may
extend and involve the
foreskin midline raphe)
Black or white ribbon in
the midline raphe
presumes low anorectal
malformarion.
Anorectal Mlaformations
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Note the vaginal opening
(the hymen) forward to
the fistula which is wide
and functioning
Anorectal Mlaformations
-Flat buttocks
-No fistula can be notissed
in the perineum
- Impression high anomally
Anorectal Mlaformations
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Wangensteen and Rise
Invertogram
PC Pubococcygeal line
Ischial line (blue arrow)
Intermediate line
(white arrow)
Note the end rectal
shadow above the PC
line indicating high
anomally pattern
Anorectal Mlaformations
Wangensteen Rice Invertogram
Marker
Marker
Stomach
High
Imperforate
Anus with
Dudenal
atresia
N.G.T.
Prone cross-table lateral X-ray
PC line and I point = levator complex
•After 24 hours!
•Wait 3 minutes in this position
•Accurate centering on greater trochanter
•Cave meconium plugs, crying, levator muscle
contraction
PC line and I point = levator complex
Anorectal Mlaformations
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In normal individuals, the voluntary striated muscle
structures responsible for fecal control are
represented by a funnel-like muscle structure that
inserts in the pubic bone, the lowest part of the
sacrum and the middle portion of the pelvis.
From there, this diaphragm-like muscle structure
extends medially, surrounding the rectum all the
way down to the perianal skin.
The upper portion of this funnel-like structure is
known as the “levator muscle”, and the lower
portion as the “external sphincter”.
Anorectal Mlaformations
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Different slings and subdivisions of these
structures have been described, including the
“ischiococcygeus”, “ileococcygeus”,
“pubococcygeus”, “puborectalis”, “deep external
sphincter”, and “superficial external sphincter”.
Experience obtained through posterior sagital
exploration of normal individuals with pelvic
tumors, demonstrates continuum of striated
muscles that run around the rectum and parallel to
it down to the skin.
Anorectal Mlaformations
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The external sphincter is parasagital muscle fibers
that meet anterior and posterior to the anus.
The levator muscle fibers come from upper
insertion and run parallel to the rectum
(perpendicular to the parasagital fibers).
The upper portion of the funnel is the (levator
muscle), the lower portion is the (external
sphincter), while the intermediate portion, vertical,
fibers, is the (muscle complex).
Anorectal Mlaformations
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The internal sphincter in a normal individual is
represented by the thickening of the circular layer
of the smooth involuntary muscle of the bowel
located in the anorectal area.
The internal sphincter is present in patients with
anorectal malformations regardless of the height
of the defect. This involuntary sphincter seems to
be located in the most distal part of the rectum.
Very high defects are associated with abnormal
sacrums and poor muscle development.
Anorectal Mlaformations
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The genitourinary tract is the most serious and
frequent of associated defects in anorectal
malformations.
It is true that the higher the malformation
(cloaca or rectovesical fistula), the more
frequently is associated with severe urologic
problems,
Anorectal Mlaformations
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The sacrum is frequently abnormal,
Sacral vertebrae may be deformed or reduced in
number,
It is well known that the absence of more than
three sacral vertebrae is associated with severe
neurogenic deficit including neurogenic bladder
and lack of bowel control,
The upper spine frequently shows hemivertebrae.
Anorectal Mlaformations
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The normal descent of the rectum has been halted,
therefore the parasagital fibers get closer together
in the midline.
Below the lowest part of the rectum all the striated
muscle meet together forming a solid mass of
muscle. It’s length depends on the height of the
defect of anorectal malformation.
The lower the defect the shorter the mass of
muscles and the wider the funnel-like muscle
structure.
Anorectal Mlaformations
M
Male Newborn
with
Anorectal malformation
Perianal Inspection
And
Urinalysis
Clinical evidence
80-90 %
Questionable
20-10 %
Anorectal Mlaformations
Clinical evidence 80 – 90 %
Perianal fistula
“Bucket handle”
Midline raphe fistula
Anal stenosis
Anal membrane
Flat buttom
Meconium in urine
Air in bladder
Colostomy
Minimal PSARP
Newborn
No colostomy
PSARP
Anal stenosis
Bucket handle
Anal membrane
Covered anus
Anorectal Mlaformations
Questionable 20-10%
Wangensteen and Rice
Invertogram
> 1 cm bowel-skin distance
Colostomy
4-8 weeks rule out
Associated malf.
Verify normal
growth
< 1cm bowel-skin distance
PSARP
Minimal PSARP
Newborn
No colostomy
Anorectal Mlaformations
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Perineal inspection in female babies with anorectal
malformations is more valuable than in male
patients, e.g. single perineal orifice is a cloaca where
90% of them having an associated urological defect
which needs urgent urological intervention.
Such a patient may need urgent colostomy and
sometimes vesicostomy,
Imperforate anus without a fistula is very rare in
female patients.
Anorectal Mlaformations
Female Newborn with Anorectal Malformations
Perineal Inspection
Fistula (approximately 90%)
No fistula (approx. 10%)
Anorectal Mlaformations
Fistula (90%)
Cloaca
Emergency UT
evaluation
Colostomy and
if nessecary
Vesicostomy,
Vaginostomy,
or
other urinary
diversion
6 month
Cutaneous
Perineal
Vagainal or
Vestibular
Minimal PSARP
Newborn
No colostomy
Colostomy
PSARVUP
4-8 weeks, rule out
Associated malFormations,
Verify normal growth
PSARP
Vestibular fistula
Common wallbetweenrectum andvagina
Anorectal Mlaformations
No Fistula (10%)
Wangensteen Rice
invertogram
< 1 cm bowel-skin distance
Minimal PSARP
Newborn
No colostomy
> 1 cm bowel-skin distance
4-8 weeks, rule out assoc. malform.
Verify normal growth
Colostomy
PSARP
International classification for anorectal
malformations
(Krickenbeck)
Major clinicalgroups
–All:
•No fistula
•Anal stenosis
•Perineal (cutaneous) fistula
•Rectovesical fistula
–Female:
•Vestibularfistula
•Cloaca
–Male:
• Rectourethralfistula
•Bulbarfistula
•Prostatic fistula
Imaging
–Prone cross-table lateral film
–Cystourethrography
–Ultrasound abdomen
•Kidney, pelvis (genitourinary)
–Transperineal ultrasonography for location of distal rectal
pouch (> 15 vs. < 15mm) and fistula
–Echocardiography
–Spine
•X-ray spine
•X-ray pelvis-sacrum
•US spine for detection of spinal dysraphism
•MR spine
Sacral ratio
cave pelvic tilting
Normal sacral ratio: a/b ≥0.74 (anteroposterior)
If sacral ratio < 0.5: bad prognostic sign for ultimate continence
Anorectal Mlaformations
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Distal Colostogram prior to the final repair to
determine the precise type of the anatomical
defect as it has important prognosis and
therapeutic implications.
Using Foley catheter, through distal stoma with
balloon inflated, with the patient on the lateral
position, hydro-soluble contrast injected using
pressure to overcome the contraction of the
funnel-shaped muscle structure that surrounds
the lowest part of the rectum to see the real
fistula site.
Anorectal Mlaformations
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During distal colostogram, the lower the defect, the more
hydrostatic pressure the surgeon must apply to fill up the
distal part of the colon,
The study must be done preferably with video,
No MCUG is needed as the bladder will be filled through
the fistula,
In addition to the distal colostogram, it may be necessary
to inject die through the single orifice in the perineum in
order to fill the three structures that constitue the cloaca
(Bladder, Vagina, Rectum).
Voiding
cystourethrography
•Antegrade
urethrogram +
retrograde
whilst removing
the catheter
•In all patients
–Renal tract
anomalies?
–Fistula?
(but less reliable
than colostogram)
Anorectal Mlaformations
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Male defects as in all anorectal malformations are
part of a wide spectrum that goes from a very low
and simple malformation (perineal or cutaneous
fistula) to the extremely complex malformation
(with a rectobladder neck fistula). In between these
two extremes are, the recto-urethral bulbar fistula
and rectourethral prostatic fistula. However, most
anorectal defects in male fall within these four
categories and it must be remembered that the
surgeon is dealing with spectrum.
Anorectal Mlaformations
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Imperforate anus
Note passage of
meconium through the
urethra
Can be any of the wide
range of high or
intermediate type of
recto urethral fistula
Rectovesicalfistula
•= rectobladder
Rectovesical fistula
•= rectobladder neck fistula
•Flat perineum
•Sacrum and pelvis can appear dysmorphic
Anorectal Mlaformations
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Moving more towards the simpler side of the
spectrum (low), there is a better chance of having a
normal sacrum, good muscles, and a good looking
perineum,
While moving towards the complex side (high), the
chances significantly worsen.
Very poorly developed sacrum, and therefore poor
innervation, underdeveloped muscles, narrow
pelvis and decreased potential for continence.
Anorectal Mlaformations
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Only recto-bladder fistula will require an
abdominal approach in addition to posterior
sagital approach,
The rest can be repaired only through posterior
sagital incision,
Low anomalies are repaired by minimal
posterior sagital anoplasty.
Anorectal Mlaformations
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In low defects the rectum opens in the perineum
anterior to the center of the external sphincter,
with most of the rectum passing through the
funnel-like muscle mechanism, intimately
attached to the posterior urethra, with only the
most distal part of the rectum anteriorly deviated,
The perineal fistula usually causes obstruction
because it is very narrow
Anorectal Mlaformations
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Many times the rectum does not open directly into
the perineum, but rather follows a subepithelial
fistula tract in the midline raphae, opening
somewhere, at the base of the scrotum, at the
scrotum itself, at the base of the penis, or even at
the foreskin,
Therefore, a “black ribbon” type of structure
located in the midline raphae, should alert the
surgeon of the presence of one of these low defects.
Anorectal Mlaformations
Black ribbon
-Perineal cutaneous
Fistula
-Covered anus
-Incomplete
commonest male
fistula
“White epithelial pearl”
Anorectal Mlaformations
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Anal membrane is a thin epithelial layer covering
the anus, through which the meconium can be
seen. Simple excision of the membrane solves
the problem,
The so called “Bucket handle” malformation, is
a prominent midline skin tag, below which a fine
instrument can be passed as an evidence of a
low defect type and no other studies are required
to make the diagnosis.
Anorectal Mlaformations
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It is important to place a Foley catheter in the bladder
before prone positioning for operation with the pelvis
elevated
Protective colostomy is not necessary ,
The dissection is carried out very carefully, particularly in
the anterior aspect of the rectum to prevent urethral
damage,
The electrical stimulator proved to be very effective and
helpful in identifying all striated muscle structures and
preserving them intact with dissection in the midline.
Anorectal Mlaformations
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Imperforate anus without fistula (5%). In both males and
females the rectal end lay about 2 cm from the perineal
skin,
Most of these patients have good sacrum and good
muscles with good prognosis,
Despite the fact that there is no fistula, rectum and
urethra share a common wall and have intimate contact
requiring sub-mucosal dissection to separate the rectum
from the urinary tract,
Rectal atresia and stenosis are very unusual in males.
Anorectal Mlaformations
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Of female spectrum of defects, the simplest is
the perineal or cutaneous fstula with a very
obvious good plain of separation between the
rectum and the vagina.
The rectum passes through most of the muscle
mechanism and is only deviated anteriorly in it’s
most distal part.
The fistula opens in the middle of the perineal
body, and therefore is called perineal or
cutaneous fistula.
Anorectal Mlaformations
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Anorectal malformation
Note the position of the
anal opening
Can be mistaken for
recto-vaginal fistula (two
openings or
Recto-vestibular fistula
(three openings)
Also note the place of
the normal anus (arrow)
Anorectal Mlaformations
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Next in complexity is the vestibular fistula.
Quality wise, muscles and sacrum could be compared
to the recto-urethral bulbar fistula in males with good
prognosis.
The characteristic part of this defect is that, the
anterior rectal wall and the posterior vaginal wall fuse
together into a simple common wall without a
distinctive plain of separation. The fistula is located
within the vestibular mucosa immediately behind the
hymen.
Protective colostomy is safer with Limited PSARP.
Anorectal Mlaformations
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Few patients fall between the perineal fistula and
the vestibular fistula and they are called
fourchette fistula where the opening is located
between the mucosa of the vestibule and the
perineal skin.
The cutaneous fistula does not require a
colostomy, on the other hand patients with
vestibular fistula, require a protective colostomy
prior to the main repair (in both limited PSARP).
fourchette fistula
where the opening
is located between
the mucosa of the
vestibule and the
perineal skin.
Anorectal Mlaformations
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Low vaginal fistula can not be seen even by
separating the labia in a baby girl. Meconium
seems to be coming from deep inside the vagina,
Posterior rim of the hymen is not visible,
Common vagina and ractal wall immediately
above the fistula,
Low vaginal fistula indicates that the fistula
opens in the lower part of the vagina, but in fact
it is not a synonym for low defect.
Anorectal Mlaformations
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High vaginal fistula is equivalent to the recto
bladder neck fistula seen in males,
Muscle and sacrum quality are significantly poor,
A good distal colostogram will demonstrate the
fistula,
Abdominal approach is required with a full
posterior sagital anorectoplasty,
Many require tapering of the bowel.
Anorectal Mlaformations
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Rectal atresia (blind, usually separated by a very
thin membrane or fibrous tissue), or stenosis
(partially communicating), are located at the
natural limit of rectum and anal canal (immediately above the pectinate line), with normal
looking external anus, and anal canal not deeper
than 1-2 cm, discovered by a nurse while taking
temperature.
Anorectal Mlaformations
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Rectal atresia or stenosis are rare anorectal
malformations and usually seen in females,
They have good prognosis if they are treated
properly, because they have all necessary
elements responsible for bowel control,
Treatment consists of posterior sagital incision.
Both upper and lower bowel ends are opened
and reconnected with a wide anastamosis.
Anorectal Mlaformations
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The main characteristic of this defect is the
confluence of rectum, vaqgina and urinary tract
into a single channel or persistent cloaca,
The surgical management of a persistent cloaca
represents the most serious technical challenge
in pelvic paediatric surgery.
Anorectal Mlaformations
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The length of the common channel varies from 2
to 7 cm (typical cloaca with short channel, or high
cloaca with long channel),
Muscle complex and external sphincter are located
in a normal site, posterior to the single cloacal
opening in the perineum, which is usually located at
the site of normal urethral orifice,
The genitalia look smaller than in a normal baby,
(imperforate anus with small looking genitalia on a
baby girl should alert the physician to this defect).
Anorectal Mlaformations
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The degree of sacral abnormalities and muscle
deficiencies, usually varies along with the height
of the defect. High cloacas (3-7 cm long common
channel), are more frequently associated with an
abnormal sacrum and poor muscles.
Presents a serious challenge for the pullthrough
of the rectum, for the vaginal repair (not enough
tissue to mobilize and repair the vagina) with
prognosis not as good as in other types of cloaca.
Anorectal Mlaformations
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High incidence of associated urological
abnormalities, with the high type long common
channel cloaca, such as ;
hydronephrosis, megaureters, reflux,
renal dyspalsty, renal agenesis
and neurogenic bladder.
Anorectal Mlaformations
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Very low type of cloaca (length of common
channel 0.5 to 1.5 cm), called recto-low vaginal
fistula, associated with female hypospadias,
The ideal treatment is to separate the rectum
from the cloaca, locating it within the external
sphincter, and leaving the genitourinary portion
of the defect untouched, (only two perineum
openings)  continue
Anorectal Mlaformations
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The patient will be left with a high urethral
opening at the anterior wall of the vagina
(female hypospadias), with excellent functional
prognosis,
Their separation from the functional point of
view ( to achieve complete repair), is not
absolutely necessary.
Anorectal Mlaformations
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Hydrocolpos is frequently seen in cloacas. Very
large vagina, distended and filled with fluid,
promoting UT obstruction and subsequent
frequent UTI, which dramatically improves after
surgical drainage of the vagina,
Presence of hydrocolpos represents an advantage
in terms of vaginal reconstruction, because the
surgeon can use all the extra tissue of the enlarged
vagina in the vaginal pullthrough
Anorectal Mlaformations
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Sometimes urine passes from the short proximal
urethra directly into the distended vagina and
subsequently during the day the urine dripples
out constantly from the vagina simulating
incontinence (pseudourinary incontinence)
which is changed to normal voiding pattern after
total repair of this kind of defect in cases with
normal sacrum
Anorectal Mlaformations
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Another type of frequent cloacas is the one with
double vagina and double uterus or partially
bicornate uterus, with partial or complete
vaginal septum,
Unique oportunity exists to surgically fuse
together both vaginas creating one.
Anorectal Mlaformations
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In the newborn before colostomy, full urological
evaluation to rule out the frequently associated
urinary tract obstruction is mandatory, to treat it
if any with colostomy in the same session,
It is considered an error to establish a colostomy
in a patient with a cloaca without being aware of
associated urological defects,
The total repair of the cloaca is carried out
usually when the baby is 6 months old provided
the baby growing and developing normally.
Anorectal Mlaformations
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The operating surgeon must remember that the
rectum and vagina share a common wall, but
most importantly , the vagina and the urethra
also share a common wall,
No attempt is made to place a Foley catheter
into the bladder prior to the operation because
there is no control of the direction of the
catheter through a single common channel.
Anorectal Mlaformations
In those cloaca cases where the vagina does not
reach the perineum, the surgeon may use one of
the following maneuvers : Skin or labia flap to fill a 1 or 2 cm gap,
 Vaginal replacement with a vascularized piece of
intestine for long gap or total vaginal replacement,
 Vaginal dome flap in those cases with long
common channel associated with a very large but
high vagina (hydrocolpos).
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(Anterior) ectopic anus
•Abnormally located anus,
Scrotum
mainly in girls
–Girls: anal index < 0.34
–Boys: anal index < 0.46
•Surrounded by internal and external sphincter
•Problem
Constipation
•In most cases no surgery needed
Associated anomalies (1)
• More associated anomalies in high lesions
• Serious, potentially lethal defects
• Vertebral - spinal deformities
– hemivertebrae
– sacral deformities
– caudal regression syndrome
– tethered cord?
• skin lesion: lump, vascular nevus, sinus,
angioma on the midline of the back,
hypertrichosis, skin dimple, sacral lipoma
• neurological or neuro-orthopedic abnormalities of
lower extremities, scoliosis
Neural tube defect of terminal spinal cord:
• bladder and bowel dysfunction permanent - Vertebral abnormalities
- Flat buttocks
colostomy
- Lower limb neurological deficit
- Neurogenic bladder
- ARM
Male
Perineal repair
Cutback anoplasty
Perineal operation
(Browne, Potts 1954)
–Cutback anoplasty
(Browne)
Colostomy formation
Later high-pressure colostogram
Stoma
Mucus fistula
Anorectal Mlaformations
International groupingof surgical procedures
(Krickenbeck)
•Pull-through abdominoperineal (Rhoads, 1948)
•Sacroperineal approach (Stephens 1953)
•Perineal operation (Browne, Potts 1954)
–Cutback anoplasty (Browne)
–“Potts transfer anoplasty”
•Pull-through abdominosacroperineal
(Kiesewetter 1966 , Rehbein 1967)
•PSARP (Peña-deVries, 1982)
•Anterior sagittal approach (Mollard, 1989, Okada, 1992)
•Pull-through laparoscopic-assisted (Georgeson, 2000)
Anorectal Mlaformations
PSARP
Proper comfortable positioning
Anorectal Mlaformations
PSARP
Anorectal Mlaformations
Indicators of
prognosis for bowel
control in ARM
patients
Anorectal Mlaformations
Conclusions
•A good, simple classification is crucial for adequate comparison
of data
•Surgical and prognostic relevance
•“high and low”is too general
•Ectopic anus is not the same as ectopic anal canal
•Multidisciplinary collaboration
•Pediatrician, pediatric surgeon, radiologist, nursing team, psychologist,
physiotherapy, stoma nurse…
•Preoperative work-up
•Meticulous surgical technique
•Postoperative follow-up into adulthood
•GI, urinary, sexual, psychosocial
THANKS