anorectal malformations

1. Anorectal Malformations
By Dr Aditya Kalyan
I Year Post Graduate
General Surgery

2. Objectives
• Definition
• History
• Incidence
• Embryology
• Anatomy
• Classification
• Associated Anamolies
• Clinical Presentation
• Management
• Prognosis

3. Definition
• Anorectal malformations comprise a wide
spectrum of diseases, which can affect boys and
girls, and involve the distal anus and rectum as
well as the urinary and genital tracts.
• Defects range from the very minor and easily
treated with an excellent functional prognosis, to
those that are complex, difficult to manage, are
often associated with other anomalies, and have
a poor functional prognosis

4. History
• Imperforate anus has been a well-known condition
since antiquity.
• For many centuries, physicians, as well as individuals
who practiced medicine, created an orifice in the
perineum of children with imperforate anus.
• Amussat, in 1835 was the first individual who sutured
the rectal wall to the skin edges, which could be
considered the first anoplasty.
• During the first 60 years of the 20th century, surgeons
performed a perineal operation without a colostomy
for the so-called low malformations.

5. • High imperforate anus usually treated with a
colostomy followed by an abdomino-perineal
pullthrough some time later in life but causes
incontinence.
• The surgical approach changed dramatically in
1980 with the introduction of the posterior
sagittal approach.
• It has become the predominant surgical method
for anorectal anomalies.

6. Incidence
• Anorectal malformations are congenital
anomalies that occur in approximately 1 in
4500 live births.
• Mostly it is of imperforate anus in majority of
the cases or imperfect fusion of post allantoic
gut with the proctodaeum

7. Embryology
• Primitive gut contains stomodaeum,fore
gut,midgut,hind gut,cloaca and allantoic diverticulum
• The part of hind gut caudal to attachment of allantoic
divericulum is called cloaca soon it shows subdivision
into broad ventral part & narrow dorsal part seperated
from each other by Urorectal septum formed between
allantois and cloaca

8. • Ventral subdivision forms primitive urogenital sinus
which in turn forms urogenital system
• Dorsal part forms primitive rectum which in turn forms
rectum and parts of anal canal
• The urorectal septum grows towards cloacal membrane
& eventually fuses with it. Cloacal membrane is now
divided into ventral urogenital membrane and dorsal
anal membrane related to rectum
• Mesoderm around anal membrane becomes heaped up
with the result that the anal membrane comes to lie at
the bottom of a pit called anal pit or proctodaeum. The
anal pit contributes to formation of anal canal

9. Anatomy

10. Rectum
• Rectum is 12 cm in length consists of
lower,middle and upper thirds.blood supply is
through inferior ,middle and superior rectal
arteries
• Lymphatics follows blood supply principle route is
upwards along superior rectal vessels to the para
aortic nodes
• Upper 3rd is mobile middle 3rd is widest and lower
3rd lies within the muscular floor of pelvis

11. Anal Canal
• Anal Canal : Contain internal and external sphincters.
• Internal sphincter composed of longitudinal and non
striated involuntary muscles supplied by autonomic
nerves
• External sphincter composed of striated voluntary
muscles supplied by pudendal nerve.
• Superior part of external sphincter fuses with levator
ani muscle to form puborectalis muscle essential for
maintaining of anorectal angle necessary for
continence
• Blood supply is via superior, middle and inferior
haemorrhoidal vessels

13. • Mainly Composed of Imperforate Anus
Embryology of the imperforate anus
Between 4-6 weeks, the cloaca becomes the common depository for the developing
urinary, genital and rectal systems.
The cloaca is quite promptly divided into an anterior urogenital sinus and a
posterior intestinal canal by the urorectal septum.
Two lateral folds of cloacal tissue join the urorectal septum to complete the
separation of the urinary and rectal tracts.

14. • Includes agenesis and atresia of the rectum and anus
• Etiology: unknown
• Incidence: 1 in 5000
• SEX: effects male and female almost eqally slight male
preponderance
Imperforate Anus

15. Anorectal malformations
• these represent a wide spectrum of defects.
• The terms “low,” “intermediate,” and “high”
used as arbitary
New born female with imperforate anus New born male with imperforate anus

16. Anorectal Malformations
Classification
Low abnormalities
Termination of bowel below the
pelvic floor
Easy to Dx
Simple to treat
Outlook is good
1)Covered anus
2)Ectopic anus
3)Stenosed anus
4)Membranous stenosis
High abnormalities
Termination of bowel above the
pelvic floor
Often have a fistula into the urinary
tract with deficient pelvic floor
Difficult to treat
1)Anorectal agenesis
2)Rectal atresia
3)cloaca

17. Classification
Males
1. Cutaneous (perineal fistula)
2. Rectourethral fistula
A. Bulbar
B. Prostatic
3. Recto–bladder neck fistula
4. Imperforate anus without
fistula
5. Rectal atresia
6. Complex malformations
Females
1. Cutaneous (perineal fistula)
2. Vestibular fistula
3. Imperforate anus without
fistula
4. Cloaca
5. Rectal atresia
A. Short common channel
B. Long common channel
6. Complex malformations

18. ASSOCIATED Anamolies
1. Sacrum and Spine
Sacral deformities appear to be the most frequently associated defect.
2. Genitourinary Defects
The frequency of associated genitourinary defects varies from 20% to 54%.
3. Anal atresia may occur as a part of the VACTERL group of anomalies
V Vertebral body segmentation defect
A Anal atresia
C Cardiovascular (PDA, VSD)
TE Tracheo esophagial fistula
R unilateral Renal agenesis
L Limb anomaly (radial ray hypoplasia)
So, very careful examination of the baby must be made to exclude these
anomalies

19. So The Anamolies Include
• In about 60% cases anorectal malformations
associated with some other malformation
most common is urinary tract defect.others
are
• CARDIOVASCULAR ANOMALIES
• GASTROINTESTINAL ANOMALIES
• SPINAL, SACRAL, AND VERTEBRAL
• GYNECOLOGIC ANOMALIES

20. Associated Syndromes
• Syndromic ARM VACTERL (Vertebral
anomalies, anal atresia,
• cardiac malformations, tracheoesophageal
• fistula, renal anomalies, and limb anomalies)
• MURCS (Mullerian duct aplasia, renal aplasia,
• and cervicothoracic somite dysplasia)
• OEIS (Omphalocele, exstrophy, imperforate
• anus, and spinal defects)
• Axial mesodermal dysplasia
• Klippel-Feil syndrome
• Sirenomelia-caudal regression
• Trisomy 21
• Trisomy 13
• Trisomy 18
• Pallister-Killian syndrome
• Cat-eye syndrome
• Parental unidisomy 16
• Deletion 22q11 syndrome (del22q11.2)
• Currarino syndrome
Pallister-Hall syndrome
Townes-Brock syndrome
Ulnar-mammary syndrome
Okihiro syndrome
Rieger syndrome
Thanatophoric dwarfism
Hirschsprung disease
Feingold syndrome
Kabuki syndrome
Optitz BBB/G syndrome
Johanson-Blizzard syndrome
Spondylocostal dysostosis
Short rib – polydactyly syndrome
Baller-Gerold syndrome
Ciliopathies
Fraser syndrome
Lowe syndrome
Heterotaxia
FG syndrome
X-linked mental retardation
MIDAS syndrome
Christian syndrome

21. Low Abnormalities
Female Male

22. Covered Anus
Anal canal covered by a bar of skin with a track
running forwards to the perineal raphae. This
track is called “Bucket Handle” midline Raphe
fistula.

23. Ectopic Anus
Anus situated anteriorly
in ♂, it opens in perineum
in ♀, it opens in vulva (more commonly) vulval
ectopic anus or vagina (rare)

24. Stenosed Anus
i.e. microscopic anus
There is a minute opening that can be seen if
examined carefuly

25. Membranous Stenosis
• Rare
• Anus is normally sited
covered with a thin membrane that bulges
with retained meconium

26. High Abnormalities
In Male
1.Rectoperineal Fistulas
• Rectoperineal fistula is what traditionally was known as a “low
defect.”
• The rectum is located within most of the sphincter mechanism.
Only the lowest part of the rectum is anteriorly mislocated .
• Sometimes,the fistula does not open into the perineum but rather
follows a subepithelial midline tract, opening somewhere along the
midline perineal raphe, scrotum, or even at the base of the penis.
• This diagnosis is established by perineal inspection.
• The terms covered anus, anal membrane, anteriorly mislocated
anus, and bucket-handle malformations all are refer to perineal
fistulas

27. Rectoperineal Fistulas

28. 2.Rectourethral Fistulas
Imperforate anus with a rectourethral fistula is the most frequent defect in male
patients.
The fistula may be located at
1. The lower (bulbar) part of the urethra
Lower urethral fistulas are usually associated with good-quality muscles, a well-developed sacrum, a
prominent midline groove, and a prominent anal dimple.
1. The higher (prostatic) part of the urethra
Higher urethral fistulas are more frequently associated with poor-quality muscles, an abnormally
developed sacrum, a flat perineum.

29. 3.Recto-Bladder Neck Fistulas
• In this defect, the rectum opens into the bladder
neck.
• The patient usually has a poor prognosis for bowel
control because the levator muscles, the striated
muscle complex, and the external sphincter
frequently are poorly developed.
• The sacrum is often deformed and short.
• The perineum is often flat, which is evidence of
poor muscle development.
• About 10% of males with anorectal atresia fall into
this category.

30. 4.Imperforate Anus without Fistula
• Interestingly, most patients with this unusual defect
have a well-developed sacrum and good muscles, and
have a good prognosis in terms of bowel function.
• The rectum usually terminates approximately 2 cm
from the perineal skin

31. 5.Rectal Atresia
• In this extremely unusual defect in male patients (~1% of the entire group
of malformations),
• 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 is represented by a small anal canal that is in the normal location
and is 1 to 2 cm deep.
• These two structures may be separated by a thin membrane or by dense
fibrous tissue.
• The repair involves a primary anastomosis between the upper pouch and
anal canal and is ideally approached posterior sagittally.
• Patients with this defect have all the necessary elements to be continent
and have an excellent functional prognosis. Because they have a well-
developed anal canal, they have normal sensation in the anorectum and
have almost normal voluntary sphincters

32. In female
1.Rectoperineal Fistulas
• From the therapeutic and prognostic viewpoint, this common
defect is equivalent to the perineal fistula described in the male
patient.
• The rectum is well positioned within the sphincter mechanism,
except for its lower portion, which is anteriorly located.
• The rectum and vagina are well separated

33. 2.Rectovestibular Fistulas
• Rectovestibular fistula is the most common defect in girls and
has an excellent functional prognosis.
• The diagnosis is based on clinical examination.
A meticulous inspection of the neonatal 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

34. 3.Imperforate Anus without Fistula
• This defect in female patients carries the same
therapeutic and prognostic implications as
described for male patients.

35. 4.Rectal atresia
• Rare
• Anal canal is normal but ends blindly at the
level of pelvic floor & the rectum also ends
blindly above the pelvic floor without a fistula
opening.

36. 5.Persistent Cloaca
• This group of defects represents the extreme in the spectrum of complexity of
female malformations.
• A cloaca is defined as a defect in which the rectum, vagina, and urinary tract meet
and fuse, creating a single common channel.
• The diagnosis of persistent cloaca is a clinical one.
• This defect should be suspected in a female born with imperforate anus and small-
looking genitalia.
• Careful separation of the labia discloses a single perineal orifice.
1. Long common channel more than 3 cm
The length of the common channel varies from 1 to 7 cm.
This distance has technical and prognostic implications.
2.Short common channel less than 3 cm

37. Complex Malformations
• Unusual and bizarre anatomic arrangements can be seen.
• Each case represents a unique challenge to the surgeon, with different
prognoses and therapeutic implications.
• No general guidelines can be drawn for the management of these
patients. Each case must be individualized.

38. Approach
• History >>> the systems involved
• Examination
• Investigations
• Management

39. History
• Failure to pass meconium within the 1st 24 hours of
life.
• Patients with anterior ectopic anus may present in
childhood or in adulthood. These patients have
lifelong histories of constipation and painful
defecation and usually have required laxatives or
enemas for management.

40. Differential Diagnosis of Conditions That May Be Associated with
Failure to Pass Meconium in the Newborn
• Hirschsprung's disease
• Meconium plug syndrome
• Meconium ileus
• Anorectal malformation
• Small left colon syndrome
• Hypoganglionosis
• Neuronal intestinal dysplasia type A
• Neuronal intestinal dysplasia type B
• Megacystis-microcolon-intestinal hypoperistalsis syndrome

41. Examination
Inspection alone is sufficient for management plan in 90% of patients.
Low
•Bucket handle defect
•Gas/meconium from perineum
•Perineal fistula if skin bridge
between vestibule and fistula.
•Anterior ectopic anus
i.e. normal sized anus
surrounded by normal muscle.
•Urine free of meconium
High
•Flat bottom
•Short sacrum
•Little muscle contraction
•Meconium per urethra
•Rectovestibular fistula if within mucosal
margin of the vestibule.
•Sphincter located close to the scrotum
or bifid scrotum often associated
with a Prostatic Fistula.
•Cloacae are often missed if urethral
opening is not identified in female
with a “recto-vaginal” fistula.
•Furthermore, cloacae often have small
openings and may be a cause of
referral for ambiguous genitalia.

42. Investigation
Very Important to:
1. Exclude other anomalies!!
2.Determine whether abnormality is high or low!!

43. 1.To exclude Other Anamolies
InvestigationAssociated abnormality
Spinal ultrasound, Spinal x-ray"V" Vertebral Abnormality (butterfly
vertebrae, hemi-vertebrae)
Cardiac ECHO"C" Cardiac, Heart Abnormality
Cardiac ECHO (VSD, ASD, PDA)
Renal ultrasound, Voiding cysto-
urethra-gram (VCUG)
"R" Renal, Kidney abnormality (solitary
kidney, horse shoe kidney)
Physical examination"TE" tracheoesophogeal abnormality
(TEF)
Physical examination, x-rays"L" Limb deformity

44. 2.Determine whether abnormality is high or
low!!
1.Lateral Table Xray
Lateral Xray Of the abdomen with a radio opaque marker on perineum

45. Murugassu’s technique: Through visible anal dimple,
meconium is aspirated by passing a needle into the
rectal pouch in sitting propped up position.
Watersoluble iodine dye is injected. Lateral X-ray is
taken to study the level through Stephen line and
Kelly’s point.
Or Invertogram:( Wangenstein’s Invertogram )
usually done after 6-12 hrs so as to allow air to reach rectal
pouch
with a metal button or a coin strapped to the site of the anus or a metal
bougie inserted into the blind anal canal
Infant is held upside down for 3-4 minutes

46. • Then radiograph in the inverted lateral position ( both
the greater trochanters should be on the same line)
• The gas in the rectum will rise to the top indicates the
distance between the site of the metal indicator and
the blind end of the rectum >>> if the distance > 2.5
cm, the abnormality is high!!
• if the rectum ends above the PC line (pubococcygeal
line = from the symphysis pubis to the last vertebra),
the abnormality is Low & vise versa or according to
ischeal line (between ant.-sup. Iliac spines).
When to be done?
Although it is a useful method, sometimes presense of a
plug of meconium in the rectum causing an apparent
gap far in excess of that actually present. So, it may be
necessary to wait until the baby is 24 hrs old before
rectal gas appears

47. PC line
(Stephen’s
Line)
Metal button
gas in the rectum

48. 2)Urine culture:
Presence of meconium
Presence of proteus or pseudomonas usually signifies that a fistula is present
3)USG:
To evaluate the lesion type, to see for urinary tract anamolies and usg spine to
see whether cord is tethered
4)MRI:
If we suspected complex malformation
5)Micturating cystourethrogram:
By injecting a dye in the urethra

51. Clinical management

52. 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?
And
• second, should the infant undergo a primary
procedure and no protective colostomy or a
protective colostomy and a definitive repair at a
later date?

53. Treatment of Low abnormalities:
1)Covered anus:
The track should be opened by scissors
Followed by routine dilatation of the anus
2)Ectopic anus:
Plastic “cut-back” operation
3)Stenosed anus:
Regular dilatation
4) Low anamolies with a perineal fistula can be treated by
anoplasty

54. Treatment of High abnormalities:
Very difficult problem & each case must be considered on its
merits
The possibilities are:
• Two-stage operation:
1st stage laparotomy
Division of rectourethral fistula
Transverse colostomy
2nd stage rectal “pull-through” operation
• One-stage operation:
laparotomy
Division of fistula
“pull-through” operation
• Division of fistula & rectal “pull-down” operation through the
perinum ( now rarely used)

55. Cont. Treatment of High abnormalities:
• The new technique is post-sagittal
anorectoplasty (PSARP)
• colostomy (only) in case of cloaca

56. Pull-through operation
• Lower bowel is mobilized
• New passage is created through the pelvic floor by
passing a pair of curved forceps & through it, keeping
close to the urethra, to the site of the future anus.
• This is dilated by Hegar’s dilator so that the bowel
can be pulled down and its mucosa stitched to the
skin of the newly formed anus.
• Daily dilatation will be required for at least 3 mo.
after the operation and it may be necessary for
years.

57. PSARP
Published by Dr. Albeto Pena It is assumed that the innervation to the
sphincter mechanism is paired and meets in the midline. The PSARP
dissection is along the midline providing excellent exposure with minimal
trauma to nerves and musculature.
It involves:
• Stimulation of muscles to demonstrate the midline and sphincter
• Posterior sagittal incision - length depends on severity of abnormality and
required extent of dissection
• Rectum identified. Abdominal approach may be required in addition in 10%
of males and 40% of cloacae
• Rectum dissected
• Separation from genitourinary tract
• Repositioning the neo anus within the sphincteric mechanism

58. Position for PSARP
• Prone Jack Knife Position

59. Incision in PSARP

60. Posterior sagittal repair of a rectovestibular fistula .

61. Outcome
• The outcome for 1192 patients who underwent this
procedure was recently reviewed by Peña and
• Hong. Seventy-five percent of patients were found to
have voluntary bowel movements, and nearly 40%
were considered
• totally continent. As a rule, the incidence of
incontinence is increased in patients with high
lesions, whereas those with low
• lesions are more likely to be constipated.

62. Laparoscopic Approach
• Management of the patient with high imperforate anus can be greatly
facilitated by the use of a laparoscopically assisted approach.
• In which the patient is operated on in the supine position and the rectum
is mobilized down to the fistulous connection to the bladder neck.
• This fistulous connection is then divided, and the rectum is completely
mobilized to below the peritoneal reflection. The operation then proceeds
at the perineum, and the location of the
• muscle complex is determined using a nerve stimulator. A Veress needle is
then advanced through the skin at the indicated site, with the laparoscope
providing guidance to the exact intrapelvic orientation.
• Dilators are then placed over the Veress needle, the rectum is pulled
through this peritoneal opening, and an anoplasty is performed.

63. Functional Problems
• Constipation is most frequent and
• Continence maitaining problems less
frequently may be associated

64. Prognosis
In high % of cases, imperforate anus is
associated with other congenital abnormalities
especially of the urinary organs & nearly 50% of
deaths in cases of imperforate anus are due to
other malformations

65. In Summary
• The most important investigation is the Cross
table xray or invertogram
• It is very important to rule out other
anomalies
• The best & the newest operation is PSARP for
High Anamolies

66. References
• Bailey and Love 26th Edition
• SRB’s manual of surgery 3rd edition
• Schwartz’s text book of surgery 9th Edition
• Inderbhir singh embryology
• internet