Anorectal Anorectal MalformationsMalformations

ARMARM

• With a reported incidence of With a reported incidence of 1 in 1 in

50005000 live births, anorectal live births, anorectal

malformations are a major problem malformations are a major problem

in the newborn period. Most of them in the newborn period. Most of them

present as emergencies. present as emergencies.

EmbryologyEmbryology Development of the anorectum is complete Development of the anorectum is complete

by the 9th week of intrauterine life and by the 9th week of intrauterine life and consists of:consists of:– a)a) cloaca formationcloaca formation

– b) division of the cloaca into urogenital b) division of the cloaca into urogenital sinus anteriorly and rectum posteriorly by sinus 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 can Any deviation in this normal development can lead to anorectal malformationslead to anorectal malformations

EmbryologyEmbryology

ClassificationClassification WingspreadWingspread classification - based on the classification - based on the

anatomical relation of the blind rectal anatomical relation of the blind rectal pouch to the Levator ani muscle.pouch 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

high anomalyhigh anomaly.. below the level of levator ani muscle it below the level of levator ani muscle it

is ais a low anomaly. low anomaly. partially within the muscle, the partially within the muscle, the

anomaly is ananomaly is an intermediateintermediate anomalyanomaly

The blind ending rectal pouch in high & The blind ending rectal pouch in high & intermediate anomalies commonly has intermediate anomalies commonly has a communication with the urogenital a communication with the urogenital system (fistula)system (fistula)

• In males – recto urinary fistulaIn males – recto urinary fistula

e.g: rectobulbar e.g: rectobulbar

rectovesicalrectovesical

retoprostaticretoprostatic

• In females – rectovestibular/ In females – rectovestibular/ rectovaginal fistularectovaginal fistula

Associated anomaliesAssociated anomalies

• VV – – vertebral : Predominantly vertebral : Predominantly lumbosacrallumbosacral

• 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

Clinical featuresClinical features

• In general, boys with anorectal In general, boys with anorectal

malformations present with intestinal malformations present with intestinal

obstruction (abd distension, failure to pass obstruction (abd distension, failure to pass

meconium, vomiting)in the newborn period.meconium, vomiting)in the newborn period.

• Girls present with h/o passing Girls present with h/o passing

meconium/stools from an abnormal site. meconium/stools from an abnormal site.

(within the fourchette) (within the fourchette)

ExaminatioExamination n

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

How to clinically assess level of How 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 opening Stenotic opening

• Bulged membrane seen at normal location of Bulged membrane seen at normal location of anusanus

• Well formed perineum & buttocksWell formed perineum & buttocks

Covered anus Anal stenosis

Low ARM - Male

Anocutaneous fistula Bucket handle

Low ARM - Male

Low ARM - Female

Vestibular anusAnterior ectopic anus

Aim of investigationsAim of investigationsTo assess the level of ARM-To assess the level of ARM-

• If the anomaly can be classified clinically If the anomaly can be classified clinically there is no need to do Invertogramthere is no need to do Invertogram

• InvertogramInvertogram in new born in 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)

Invertogram Invertogram

• PRINCIPLEPRINCIPLE: : aims to aims to correlate the correlate the blind rectal blind rectal pouch with the pouch with the bony bony landmarks of landmarks of the baby's the baby's pelvis.pelvis.

Prone cross table lateral X Prone cross table lateral X rayray

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.

• the blind pouch (represented by the the blind pouch (represented by the gas shadow) ends gas shadow) ends above the PC line above the PC line in ain a high anomaly high anomaly

• the blind pouch ends in the blind pouch ends in between the between the PC line & I lines PC line & I lines in anin an intermediate intermediate anomaly anomaly

• the gas shadow ends the gas shadow ends below the I below the I line line in ain a low anomaly low anomaly

MANAGEMENTMANAGEMENT

• Single stage for low ARMSSingle stage for low ARMS

• Staged for intermediate & high ARMSStaged for intermediate & high ARMS

Surgery for low ARMSurgery for low ARM

• Imperforate anus: AnoplastyImperforate anus: Anoplasty

• cruciate incision is made at the proposed site cruciate incision is made at the proposed site of anal opening and four skin flaps are raised. of anal opening and four skin flaps are raised.

• The blind pouch is identified, opened by a The blind pouch is identified, opened by a cruciate incision and the mucosal and skin cruciate incision and the mucosal and skin flaps are sutured after interdigitating them.flaps are sutured after interdigitating them.

• Anocutaneous fistulaAnocutaneous fistula: : Cutback Cutback anoplastyanoplasty

• Anterior Ectopic Anus: Anterior Ectopic Anus: repositioning repositioning of the anus at the normal site by of the anus at the normal site by Anterior Sagittal Anterior Sagittal AnoRectalPlasty(ASARP)AnoRectalPlasty(ASARP)

• Intermediate & High anomalies:Intermediate & High anomalies:

• Staged surgical procedure Staged surgical procedure a) preliminary colostomya) preliminary colostomy

b) A pullthrough operationb) A pullthrough operation

c) closure of colostomyc) closure of colostomy

Principles of Pullthrough Principles of Pullthrough procedures:procedures:

• a) Any fistulous communication to the a) Any fistulous communication to the urinary or genital tract should be urinary or genital tract should be divided.divided.

• b) The blind rectal pouch, after b) The blind rectal pouch, after adequate mobilisation, should be adequate mobilisation, should be brought down to the proposed anal site brought down to the proposed anal site within the sphincter complex.within the sphincter complex.

PSARP – PSARP – Posterior Sagittal Posterior Sagittal AnorectoplastyAnorectoplasty

PrognosisPrognosis

• Associated congenital anomalies, Associated congenital anomalies, specially sacral agenesis specially sacral agenesis – A neonate with anorectal malformation, without A neonate with anorectal malformation, without

major associated anomalies, has a good major associated anomalies, has a good prognosis.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 The results for high lesions are not so good in

terms of absolute continence.terms of absolute continence.