This document discusses anorectal malformations, which are anomalies of the anorectal system, urogenital system, sacral spine, and perineal musculature. It describes the embryological development of the hindgut and cloaca. Various classifications of anorectal malformations are presented, including the Wingspread, Pena, Krickenbeck, and anatomic classifications. Associated anomalies are discussed. The document outlines the approach to examining and investigating a newborn with an anorectal malformation, including history, physical exam, and imaging studies. It discusses early management decisions and various surgical procedures for treating anorectal malformations.

1. -- Dr. Anusha.M
Dept. of Paediatric Surgery

2.  Anorectal malformations comprise a wide spectrum of
anomalies of the anorectal system, urogenital system,
sacral spine and perineal musculature.
 The extent of anomalies in these four components decides
the type of anorectal malformation.

3. Embryology
*The hindgut gives rise to the distal
third of the transverse colon,
The descending colon,
the sigmoid, the rectum and the
upper part of the anal canal.
*The hindgut enters the posterior
portion of the cloaca, the future
anorectalcanal.The allantois enters
the anterior portion, the future
urogenital sinus.
• The urorectal septum is formed by
merging of the mesoderm covering
the allantois and the yolk sac.

4. • As caudal folding of the embryo
continues, the urorectal septum
moves closer to the cloacal
membrane.
• Breakdown of the cloacal
membrane creates an opening for
the hindgut and one for the
urogenital sinus.
The tip of the urorectal septum
forms the perineal body.

5.  Most frequent congenital anomalies encountered in
Paediatric Surgery.
 Anorectal malformations may be caused by
abnormalities in formation of the cloaca and or
urorectal septum.
 For example, if the cloaca is too small or urorectal
septum does not extend far enough caudally, the
opening of hindgut shifts to anteriorly leading to the
opening in urethra or vagina.

6. Classifications:
 Wingspread Classification.
 Pena’s Classification
 Krickenbeck Classification.
 Anatomic Classification.

7. Terms High, Intermediate and Low are relation of
the terminal end of bowel remaining above, within
and below the levator ani muscle respectively.

9. Krickenbeck Classification

10. Anatomic Classification

11. Associated anomalies

12. A sacral ratio is an objective
evaluation of the sacrum. The
sacral ratio can range from 0.0
to 1.0.
The normal sacral ratio in
children is 0.77. Children with
anorectal malformations suffer
from varying degrees of poor
sacral development.
Greater
than 0.7 is usually
associated with good
bowel control.

14. Rectoperineal fistulas
It is Low ARM.
Rectum is within most of the
sphincter mechanism.Lowest
part is anteriorly mislocated.
Anal Fistula opening is stenotic
or follows a subepithelial midline
tract opening along the midline
perineal raphe, scrotum or even
at the base of the penis.
In females, the defect is
equivalent to that of males.
Rectum and vagina are well
separated.

15. Rectourethral Fistulas
• Imperforate anus with a rectourethral
fistula is the most common defect in
males.
• The fistula may be located at the lower
(bulbar) or the higher (prostatic) part of
the urethra.
• Immediately above the fistula, the
rectum and urethra share a common
wall.
• The lower the fistula, the longer is the
common wall. This is an important
anatomic fact, which guides the
operation.

16. • Lower urethral fistulas are usually associated
with good-quality muscles, a well-developed
sacrum, a prominent midline groove, and a
prominent anal dimple.
• Higher urethral fistulas are more frequently
associated with poor-quality muscles, an
abnormally developed sacrum, a flat perineum, a
poor midline groove, and a barely visible anal
dimple.

17. Rectovestibular fistula
• Rectovestibular fistula is the most
common defect in females and has
an excellent functional prognosis.
• The diagnosis is based on clinical
examination.
• A meticulous inspection of the
newborn’s genitalia allows the
clinician to observe a normal
urethral meatus and a normal
vagina, with a third hole in the
vestibule, which is the
rectovestibular fistula.
• About 5% of these patients will
have two hemivaginas with a
vaginal septum.

18. • The sacrum is often deformed and
short. In fact, the entire pelvis
seems to be underdeveloped.
• The perineum is often flat, which is
evidence of poor muscle
development. About 10% of males
fall into this category
Recto Bladder neck
Fistulas
• In this defect, the rectum opens into
the bladder neck.
• The patient usually has poor
prognosis for bowel control because
the levator muscles, the striated
muscle complex and the external
sphincter are poorly developed.

19. Imperforate Anus without
Fistula
• The rectum usually terminates
approximately 2 cm from the
perineal skin.
• The rectum and urethra do not
communicate, these two structures
are separated only by a thin
common wall.
• About half of the patients with no
fistula also have Down syndrome,
and more than 90% of patients with
Down syndrome and imperforate
anus have this specific defect,
suggesting a chromosomal link.

20. Rectal Atresia
• The lumen of the rectum is totally
(atresia) or partially (stenosis)
interrupted.
• The upper pouch is represented by
a dilated rectum, whereas the lower
portion empties into a small anal
canal that is in the normal location
and is 1–2 cm long.
• These two rectal structures may be
separated by a thin membrane or by
dense fibrous tissue.
• The repair involves a primary
anastomosis between the upper
pouch and lower anal canal, and is
ideally approached posterosagittally
with splitting of the anal canal
longitudinally.

21. Persistent Cloaca
A cloaca is a defect in which the distal portions of the
rectum, vagina and urinary tract fuse and create a single
common perineal channel.
-Careful separation of
the labia discloses a
single perineal orifice.
-The length of the
common channel
varies from 1–7 cm,
and is very important
for operative and
prognostic
implications.

22. *A common channel of less
than 3 cm usually means
that the defect can be
repaired with a posterior
sagittal operation without
opening the abdomen.
*Common channels longer
than 3 cm are more
complex, mobilization of the
vagina is often difficult, and
some form of vaginal
replacement may be needed
during the
definitive repair.

23. Frequently, the vagina is abnormally
distended and full of secretions
(hydrocolpos)
The distended vagina compresses
the trigone and interferes with
drainage of the ureters, and is
frequently associated with
hydronephrosis. This condition may
be diagnosed prenatally.
The dilated vagina can also become
infected (pyocolpos) and may lead to
perforation and peritonitis.
Such a large vagina may represent a
technical advantage for the repair as
there is more vaginal tissue to
facilitate the reconstruction.

24. Another frequent finding in cloacal
malformations is the presence of
different degrees of vaginal and
uterine septation or duplication.
In these cases, the rectum usually
enters between the two hemivaginas.
Rarely, patients have cervical atresia.
During puberty, a variety of anatomic
anomalies may mean that
they are unable to drain menstrual
blood through the vagina, can
accumulate menstrual blood in the
peritoneal cavity, and sometimes
require emergency operations

25. Approach to a baby with ARM
 History
 Examination
 Investigations
 Management

26. History:
Failure to pass meconium within the 1st 24 hours of
life.
Abdominal Distension
Passage of meconium per urethra.
Examination of perineum
Presence or absence of anus.
Gas/meconium from perineum
Presence of vaginal and urethral opening.
Size of vaginal introitus.
Size of anal dimple.
Position of anus.
Midline groove
Anal membrane
Presence of presacral mass
No. of openings in vestibule

27. Wangenstein’s invertogram: Usually
done 6-12 hours after birth, so as to
allow air to reach the rectal pouch.
A metal coin (marker) is strapped at
the presumed site of anus and
X-ray is taken.
Length between the rectal pouch and
anal dimple marker is more than 2.5
cm in high anal fistula.
a. In low fistula, rectal pouch is distal
to the Stephen’s line (Pubococcygeal
line).
b. In intermediate, pouch is at the
level of ischial spine(Kelly’s point).
c. In high fistula, rectal pouch is
proximal to the Stephen’s
line.

29. Murugassu’s technique: Through visible anal
dimple, meconium is aspirated by passing a needle into
the rectal pouch in sitting propped up position.
Water soluble iodine dye is injected.
Lateral X-ray is taken to study the level through
Stephen line and Kelly’s point.
*Other investigations required would be to rule out
associated anomalies:
Echocardiography to see for cardiac defects
Ultrasonography abdomen to look for renal anomalies
and gonadal abnormalities.

32. Management

33. Early decision-making
• The early management of a newborn infant born
with an anorectal anomaly is crucial and two
important questions must be answered during the
first 24 to 48 hours of life.
• First -- are there associated anomalies that
threaten
the baby's life and should be dealt with right away?
•Second, should the infant undergo a primary
procedure and no protective colostomy or a
protective colostomy and a definitive repair at a
later date?

34. • During the first 24 hours, the neonate should receive intravenous fluids,
antibiotics, and nasogastric decompression and be evaluated for
associated defects that may represent a threat to life.
• If the neonate has signs of a rectoperineal fistula, an anoplasty can
be performed in the newborn period without a protective colostomy.
• After 24 hours, if there is no meconium on the perineum, we
recommend obtaining a cross-table lateral radiograph with the
patient in the prone position.
• If air in the rectum is seen distal to the coccyx and the patient is in
good condition with no significant associated defects, one may
consider performing a posterior sagittal operation without a
protective colostomy.
• If the rectal gas does not extend beyond the coccyx, or the patient
has meconium in the urine, an abnormal sacrum, or a flat bottom, we
recommend a colostomy.
• This allows for a future distal colostogram, which will delineate the
distal rectal anatomy.
• Posterior sagittal anorectoplasty can be planned two to three months
later, provided the neonate is gaining weight appropriately.

35. OPERATIVE PROCEDURES
• Colostomy
• Posterior sagittal anorectoplasty
• Reconstruction surgeries

36. COLOSTOMY
As a first stage procedure
• Descending colostomy is preferred.
• The colostomy is constructed through
a left lower quadrant oblique or
transverse incision.
• The proximal stoma is exteriorized
through the upper and lateral part of
the wound and the mucous fistula is
placed in the medial or lower part of the
wound.
• The colostomy should be made in the
mobile portion of the colon,
immediately distal to the descending
colon taking advantage of its
retroperitoneal attachments and the
mucous
fistula is made very small to avoid
prolapse.

37. Advantages of descending colostomy
• Mechanical preparation of the distal colon before the
definitive repair is easy due to small length of
remaining segment.
• Due to shorter distal segment in patient with recto-
urethral or recto-vesical fistula urine is not accumulated
in distal segment of colon.
--- Less chance of development of megarectosigmoid.
• The incidence of prolapse in the proximal limb
of descending colostomies is almost zero.

38. • Distal
colostography/Loopography:
Important investigation to
delineate the altered anatomy of
ARM and know the spectrum of
associated fistulae between blind
rectum on one side and the bladder,
urethra, vagina on the other side.
----Prerequisites:
Preparaton of distal colon and
removal of accumulated meconium
before injection of contrast.

39. Technique:
- Barium sulphate is used to visualize the
distal blind end.
-A marker is placed over the anal dimple or
expected position of the anus. Another
marker is placed at the point where urine or
faecal matter is seen to be discharging.
-After passing an indwelling catheter
through the stoma leading to the distal
colon, its balloon is inflated and it is pulled
back during injection of contrast to avoid
any spillage.

40. Distal blind end fills progressively and the
pressure is maintained till the contrast fills
the fistulous tract.
-Images are taken under fluoroscopy.
-Colostogram is obtained in the lateral
position with the femora overlapping as
perfectly as possible to determine the level of
blind end of the rectum and identify the type
of ARM.

41. LIMITED POSTERIOR SAGITTAL
ANORECTOPLASTY
--When a low anomaly (perineal fistula) is diagnosed, the fistulous
track to the perineum is always located anterior to the sphincter
mechanism.
A limited posterior sagittal anorectoplasty can be performed in the
newborn period
-The baby is placed prone.
- The distal end of the rectum is intimately attached to the posterior
urethra, and urethral injury must be avoided.
-Multiple 6-0 silk sutures are placed at the mucocutaneous junction
around the fistula orifice.
- An incision divides the posterior sphincter in half and is continued
circumferentially around the fistula.
-While traction is maintained on the bowel, a circumferential
dissection is performed to mobilize the bowel and reposition
it within the limits of the sphincter. Mucosa is sutured to
skin with fine, absorbable sutures under slight tension. The
perineal body is reconstructed.

42. Posterior sagittal
Anorectoplasty

43. A posterior sagittal incision is made. The
parasagittal fibers, muscle complex, and
levator muscle fibers are completely
divided in the midline.
Sometimes,the coccyx can be split in the
midline or dissected on each side with
cautery, particularly in those cases of a
rectoprostatic fistula when the surgeon
requires more exposure in the upper part
of the incision.
The higher the malformation, the deeper
the levator muscle.
With the entire sphincter mechanism
divided, the surgeon should
identify the rectum.

44. • The rectum is going to be
found just below the levators,
with little risk of inadvertent
injury to the urinary tract. In
this situation, the rectum
actually bulges through the
incision when the sphincter
mechanism is divided .
• Minimal mobilization of the
rectum is needed because only
a short gap exists between the
rectum and perineum.
The initial search for the
rectum should be near the
coccyx.

45. • Looking for the rectum lower than the coccyx risks injury to
the urethra.
• If the colostogram shows a rectobladderneck fistula , the
posterior sagittal approach is not appropriate as a means of
identifying the distal bowel.
• The rectum should be identified and separated from the
urinary bladder through an abdominal approach (via
laparoscopy or laparotomy).

46. *The anterior rectal wall above the fistula is part of a common
wall.
*A plane of separation must be created in the common wall. For
this, multiple 6-0 silk traction stitches are positioned in the rectal
mucosa immediately above the fistula orifice.
*The rectal mucosa is then separated from the urethra for 5–10
mm above the fistula using a submucosal dissection.
*A lateral plane of dissection on either side of the Rectum is
made to help delineate the rectal wall from the urethra
and prostate.
Once the rectum is fully separated from the deep structures of
the urinary tract, a circumferential perirectal dissection is
performed to gain enough rectal length to reach the perineum.

47. • Uniform traction is applied on the
multiple silk traction sutures that were
placed on the rectal edges and also on
the mucosa above the fistula.
• Uniform traction helps expose the rectal
wall and allows identification of fibrous
bands and vessels that hold the rectum
in the pelvis. These bands must be
carefully separated from the rectal wall
using cautery because they contain
vessels that tend to retract into the
pelvis once divided. The dissection
should be performed as close as
possible to the rectal wall without
injuring the wall.

48. The circumferential dissection of the rectum must continue until enough
length has been gained to allow for a tension-free rectoperineal
anastomosis.
The anterior rectal wall is frequently thinned to some degree as a
consequence of the mucosal separation between the rectum and urethra.
To reinforce this wall, both smooth muscle layers can be approximated
with interrupted 5-0 absorbable stitches.
The urethral fistula is closed with the same suture material.
The perineal body is reconstructed,
bringing together the anterior limits of the
sphincter.
The rectum must then be positioned in
front of the levator and within the limits of
the muscle complex.
Long lasting 5-0 absorbable stitches are
used to bring together the posterior edge of
the levator muscle.

49. The posterior limit of the muscle complex is
then reapproximated behind the rectum.
These sutures should incorporate part of
the rectal wall to anchor it and help
avoid rectal prolapse.
An anoplasty is performed with
16 interrupted long-lasting absorbable
stitches.
The ischiorectal fossa and the
subcutaneous tissue are then
reapproximated, and the wound is closed
with subcuticular 5-0 absorbable
monofilament suture.

50. IMPERFORATE ANUS WITHOUT FISTULA
The blind end of the rectum is usually located at
the level of the bulbar urethra and easily
reachable from the posterior sagittal approach.
The rectum must be carefully separated from the
urethra because these structures have a
common wall, even though no fistula is present.
The rest of the repair is performed as
described for the rectourethral fistula defect.

51. RECTAL ATRESIA AND STENOSIS:
The upper rectal pouch is opened and
the distal anal canal is split in the
posterior midline.
An end-to-end anastomosis is
performed.
If a presacral mass is identified, it is
removed with presacral dissection
at the same time.

52. PSARP for Rectovestibular Fistulas:
--A long common wall exists between the vagina and the rectum, and two
walls must be created out of one using meticulous,delicate technique.
The dissection continues cephalad until the rectal and vaginal walls are
fully separated and an areolar plane between the two is encountered.

53. If the rectum and the vagina are not completely
separated, a tense anal anastomosis predisposes
the patient to dehiscence, retraction, and stricture.
--The perineal body is repaired .
--The anterior edge of the muscle complex is
reapproximated .
--The sutures include the posterior edge of the
muscle complex and the posterior rectal wall to
avoid rectal prolapse.
--The anoplasty is performed

54. Cloacas with a Common Channel
Shorter than 3 cm
The incision extends from the middle portion of then sacrum down
to the single perineal orifice and rectum is approached as said in
previous manner.
The rectum is opened in the midline, and silk sutures are introduced
along the edges of the posterior rectal wall.
A mosquito clamp placed in the single perineal orifice facilitates
extension of the incision through the posterior wall of the common
channel. The entire common channel is exposed, the separation of
the rectum from the vagina is performed.
The total urogenital mobilization is done which
consists of bringing both vagina and urethra to the
Perineum as single unit.

55. • Multiple silk traction sutures are placed at the edge of the vagina
and the common channel in order to apply uniform traction on the
urogenital sinus.
• Another series of fine traction sutures is placed transversely
approximately 5 mm proximal to the clitoris.
• The urogenital sinus is transected between the last row of silk
stitches and the clitoris.
• The anterior aspect is dissected full thickness from the pubic
symphysis, taking advantage of the natural plane that exists
between it and the pubis.
• Lateral and posterior dissection of the urogenital sinus will provide
an additional 0.5–1.0 cm in length, allowing for complete urogenital
mobilization.
• On splitting the common channel upto urethra, urethral meatus and
vaginal introitus can be anastomosed to perineum at appropriate
locations.
• The common channel creates two lateral flaps that are sutured to
the skin, creating the new labia.
The vaginal edges are mobilized to reach the skin to create a natural-
looking introitus.

56. Cloacas with a Common Channel
Longer than 3 cm:
*The rectum is separated from the vagina and
urethra via a posterior sagittal incision or via
laparotomy when it is located very high.
*Leave the common channel in place, which can be
used as urethra for intermittent catheterization.
--In this situation the vagina should be separated
from the urinary tract by placing multiple 6-0 silk
sutures through the vaginal wall to try to create a
plane of dissection between the vagina and the
urinary tract. This is best done through the abdomen
when the vagina(s) are high.
*The urinary tract and vaginas must be separated
and the neourethra tubularized.

57. *The bladder must be opened in the midline and feeding
tubes placed into the ureters to protect them.
In these types of malformations there is an extensive
common wall between vagina and bladder.
*Both ureters run through that common wall, and therefore
during separation of the vagina from the urinary tract, the
ureters must sometimes be skeletonized and thus need to
be protected.
*Once the separation has been completed, if the vagina
does not reach, the surgeon has to make decisions about
the vaginal reconstruction on the basis of specific anatomic
findings.

58. Vaginal Switch Maneuver :
In patients with hydrocolpos and two hemivaginas,
Hemivaginas are large and the two hemiuteri are
separated, the distance between them being longer
than the vertical length of both hemivaginas.
In these cases it is ideal to perform a maneuver
called a “vaginal switch” .

59. --One of the hemiuteri and the ipsilateral fallopian tube
Is resected with particular care taken to preserve the
blood supply of the ovary.
--The blood supply of the hemivagina of that particular
side is sacrificed.
--The blood supply of the contralateral hemivagina is
preserved and provides for both hemivaginas.
--The vaginal septum is resected, and both hemivaginas
are tubularized into a single vagina by taking advantage
of the long lateral dimension of both hemivaginas. Then,
what used to be the dome of the hemivagina where the
hemiuterus was resected is turned down to the
perineum.

60. Vaginal Replacement :
In a patient with a small vagina or in the rare case of an
absent vagina, a vaginal replacement is required.
In such cases the choices are rectum, colon, or small
bowel.
Rectum: This form of vaginal
replacement is feasible only in
patients who have a good size
rectum that is large enough to be
able to divide it transversely or
longitudinally
into a portion with its own blood
supply that will form a new vagina
and another portion with enough
circumference to reconstruct an
adequately sized rectum

61. Colon: The colon is an ideal
substitute to replace the
vagina.
Sometimes the location of the
colostomy interferes with this
type of reconstruction.
The left colon or sigmoid
work well because their
arcades reach the perineum
nicely.
Sometimes taking
the colostomy down and
using its distal segment for
the vaginal graft is a helpful
maneuver.

62. Small Bowel:
When the colon is not available, the most
mobile portion of the small bowel is used for vaginal
reconstruction. The mesentery of the small bowel is
longest
in an area located approximately 15 cm proximal to
the ileocecal valve, which is the best portion of the small
bowel for vaginal replacement. A portion of the ileum is
isolated and pulled down while preserving its blood
supply

63. Post operative care
• In cases of rectourethral fistula in boys, the urethral
catheter is left in place for 7 days.
• If the urethral catheter is accidentally dislodged, the
patient can be observed for spontaneous voiding, which
usually occurs.
Attempts to reintroduce a urethral catheter can be
dangerous and must be avoided.
• Intravenous antibiotics are administered for 24 hours.
An antibiotic ointment is applied to the anoplasty for 5
days.

64. • The patient is discharged after 2 days in cases of a
posterior approach without a laparotomy or laparoscopy,
and after 3–5 days in cases of an abdominal approach
• The parents are instructed to keep the incision clean,
not to wipe, and to apply antibiotic ointment for 1 week.
• Two weeks after the operations, anal dilatations are
started. On the first occasion, a dilator that fits loosely
into the anus is used to instruct the parents, who must
carry out dilatation twice daily.

65. *Every week, the size of the dilator is increased until the
rectum reaches the desired size, which depends on the
patient’s age.
• Once the desired size is reached, the colostomy can be
closed.
• Frequency of dilatation should be reduced in
following schedule :
---- at least once a day for one month; every third day
for one month; twice a week for one month; once a
week for one month; and every 2 weeks for three
months.

67. COMPLICATIONS:
*Wound infection
*Anal strictures
*Constipation
*Transient femoral nerve pressure
*Neurogenic bladder
*Fecal incontinance