Anorectal malformations

1. AnorectalAnorectal
MalformationsMalformations

2. ARMARM
• With a reported incidence ofWith a reported incidence of 1 in 50001 in 5000 livelive
births, anorectal malformations are abirths, anorectal malformations are a
major problem in the newborn period.major problem in the newborn period.
Most of them present as emergencies.Most of them present as emergencies.

3. EmbryologyEmbryology
Development of the anorectum is complete byDevelopment of the anorectum is complete by
the 9th week of intrauterine life and consiststhe 9th week of intrauterine life and consists
of:of:
– a)a) cloaca formationcloaca formation
– b) division of the cloaca into urogenitalb) division of the cloaca into urogenital
sinus anteriorly and rectum posteriorly bysinus anteriorly and rectum posteriorly by
the urorectal foldthe urorectal fold
– c) development of the anal canalc) development of the anal canal
Any deviation in this normal development canAny deviation in this normal development can
lead to anorectal malformationslead to anorectal malformations

4. EmbryologyEmbryology

11. ClassificationClassification
WingspreadWingspread classification - based on theclassification - based on the
anatomical relation of the blind rectal pouchanatomical relation of the blind rectal pouch
to the Levator ani muscle.to the Levator ani muscle.
When the blind pouch isWhen the blind pouch is
 above the levator ani muscle, it is aabove the levator ani muscle, it is a highhigh
anomalyanomaly..
 below the level of levator ani muscle it is abelow the level of levator ani muscle it is a
low anomaly.low anomaly.
 partially within the muscle, the anomaly is anpartially within the muscle, the anomaly is an
intermediateintermediate anomalyanomaly

12. The blind ending rectal pouch in high &The blind ending rectal pouch in high &
intermediate anomalies commonly has aintermediate anomalies commonly has a
communication with the urogenital systemcommunication with the urogenital system
(fistula)(fistula)
• In males – recto urinary fistulaIn males – recto urinary fistula
e.g: rectobulbare.g: rectobulbar
rectovesicalrectovesical
retoprostaticretoprostatic
• In females – rectovestibular/ rectovaginalIn females – rectovestibular/ rectovaginal
fistulafistula

16. Associated anomaliesAssociated anomalies
• VV –– vertebral : Predominantly lumbosacralvertebral : Predominantly lumbosacral
• AA –– anorectalanorectal
• CC -- cardiac : TOF, VSDcardiac : TOF, VSD
• TT -- tracheotracheo
• EE -- esophagealesophageal
• RR –– renal: VUR, UDT, Hypospadiasrenal: VUR, UDT, Hypospadias
• LL –– limb: Radial ray anomalieslimb: Radial ray anomalies

17. Clinical featuresClinical features
• In general, boys with anorectal malformationsIn general, boys with anorectal malformations
present with intestinal obstruction (abdpresent with intestinal obstruction (abd
distension, failure to pass meconium, vomiting)indistension, failure to pass meconium, vomiting)in
the newborn period.the newborn period.
• Girls present with h/o passing meconium/stoolsGirls present with h/o passing meconium/stools
from an abnormal site. (within the fourchette)from an abnormal site. (within the fourchette)

18. ExaminationExamination
PerineumPerineum
• No openingNo opening
• Abnormal openingAbnormal opening
• Anal dimple +/-Anal dimple +/-
• Bulge at the site of anusBulge at the site of anus
ButtocksButtocks –– flat /well developedflat /well developed
Sacral spineSacral spine –– sacral agenesis etcsacral agenesis etc
Associated anomaliesAssociated anomalies

19. How to clinically assess level ofHow to clinically assess level of
deformity?deformity?
• HighHigh--
• Flat perineum & buttocksFlat perineum & buttocks
• No pigmentation or dimple at site of anusNo pigmentation or dimple at site of anus
• Meconium per urethra in malesMeconium per urethra in males
• LowLow--
• Stenotic openingStenotic opening
• Bulged membrane seen at normal location of anusBulged membrane seen at normal location of anus
• Well formed perineum & buttocksWell formed perineum & buttocks

22. Covered anus Anal stenosis
Low ARM - Male

23. Anocutaneous fistula Bucket handle
Low ARM - Male

24. Low ARM -
Female
Vestibular anus
Anterior ectopic anus

25. Aim of investigationsAim of investigations
To assess the level of ARM-To assess the level of ARM-
• If the anomaly can be classified clinicallyIf the anomaly can be classified clinically
there is no need to do Invertogramthere is no need to do Invertogram
• InvertogramInvertogram in new bornin new born
To look for associated anomalies-To look for associated anomalies-
• USGUSG abdomen (kidneys)abdomen (kidneys)
• EchoEcho (cardiac status)(cardiac status)
• X ray spineX ray spine (sacral spine abnormalities)(sacral spine abnormalities)

26. InvertogramInvertogram
• PRINCIPLEPRINCIPLE::
aims toaims to
correlate thecorrelate the
blind rectalblind rectal
pouch with thepouch with the
bony landmarksbony landmarks
of the baby'sof the baby's
pelvis.pelvis.

27. Prone cross table lateral X rayProne cross table lateral X ray

28. 3 bony landmarks :
P pointP point -- mid point pubic symphysis.
C pointC point -- tip of 5th sacral vertebra
(unossified coccyx)
I pointI point-- tthis is the lower most point (tip)
on the comma shaped ischium
Based on these points, two lines can be drawn-
P-C lineP-C line -- This joins the P point to the C point and
represents the upper level of the levator ani muscle.
I lineI line -- This is a line drawn parallel to the P-C line through
the I point, and represents the lower level of the levator ani
muscle.

29. • the blind pouch (represented by the gasthe blind pouch (represented by the gas
shadow) endsshadow) ends above the PC lineabove the PC line in ain a
high anomalyhigh anomaly
• the blind pouch ends inthe blind pouch ends in between the PCbetween the PC
line & I linesline & I lines in anin an intermediateintermediate
anomalyanomaly
• the gas shadow endsthe gas shadow ends below the I linebelow the I line inin
aa low anomalylow anomaly

36. MANAGEMENTMANAGEMENT
• Single stage for low ARMSSingle stage for low ARMS
• Staged for intermediate & high ARMSStaged for intermediate & high ARMS

37. Surgery for low ARMSurgery for low ARM
• Imperforate anus: AnoplastyImperforate anus: Anoplasty
• cruciate incision is made at the proposed site ofcruciate incision is made at the proposed site of
anal opening and four skin flaps are raised.anal opening and four skin flaps are raised.
• The blind pouch is identified, opened by aThe blind pouch is identified, opened by a
cruciate incision and the mucosal and skin flapscruciate incision and the mucosal and skin flaps
are sutured after interdigitating them.are sutured after interdigitating them.

39. • Anocutaneous fistulaAnocutaneous fistula:: CutbackCutback
anoplastyanoplasty
• Anterior Ectopic Anus:Anterior Ectopic Anus: repositioningrepositioning
of the anus at the normal site byof the anus at the normal site by
Anterior SagittalAnterior Sagittal
AnoRectalPlasty(ASARP)AnoRectalPlasty(ASARP)

40. • Intermediate & High anomalies:Intermediate & High anomalies:
• Staged surgical procedureStaged surgical procedure
a) preliminary colostomya) preliminary colostomy
b) A pullthrough operationb) A pullthrough operation
c) closure of colostomyc) closure of colostomy

41. Principles of PullthroughPrinciples of Pullthrough
procedures:procedures:
• a) Any fistulous communication to thea) Any fistulous communication to the
urinary or genital tract should beurinary or genital tract should be
divided.divided.
• b) The blind rectal pouch, afterb) The blind rectal pouch, after
adequate mobilisation, should beadequate mobilisation, should be
brought down to the proposed anal sitebrought down to the proposed anal site

42. PSARP –PSARP – Posterior SagittalPosterior Sagittal
AnorectoplastyAnorectoplasty

43. PrognosisPrognosis
• Associated congenital anomalies,Associated congenital anomalies,
specially sacral agenesisspecially sacral agenesis
– A neonate with anorectal malformation, without majorA neonate with anorectal malformation, without major
associated anomalies, has a good prognosis.associated anomalies, has a good prognosis.
• Type of anomalyType of anomaly
– It is good in about 95% of low anomalies.It is good in about 95% of low anomalies.
– The results for high lesions are not so good in termsThe results for high lesions are not so good in terms
of absolute continence.of absolute continence.