Anorectal anomaly(Imperforate Anus)

ANORECTAL ANOMALIES ANORECTAL ANOMALIES

(IMPERFORATE ANUS) (IMPERFORATE ANUS)

ANORECTAL ANOMALIES

Dr.B.SELVARAJ MS;Mch; FICS;

ASSOCIATE PROFESSOR IN PEDIATRIC SURGERY

MELAKA MANIPAL MEDICAL COLLEGE

MELAKA 75150 MALAYSIA

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ANORECTAL ANOMALIES

Appropriate workup to confirm the type of anomaly

Able to identify associated anomalies

Objectives

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Identify anomalies in male & female babies Identify anomalies in male & female babies

Proper postop care & followup Proper postop care & followup

Planning of surgical treatment for different types Planning of surgical treatment for different types

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ANORECTAL ANOMALIES-Embryology

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C •Cloaca formed at 21 days with

Allantois joining anteriorly & hindgut

joining posteriorly

•Urorectal septum divides cloaca into

anterior urogenital cavity & posterior

rectoanal cavity

•Urorectal septum touches cloacal

membrane & divides it into anterior

urogenital membrane & posterior anal

membrane

• Ultimately these membranes breakdown

producing anterior urogenital& posterior

anal openings

ANORECTAL ANOMALIES-Embryology

Rectoanal atresias & fistulas occur 1/5000 livebirths due to defective cloacal formation

Decrease in size of posterior portion of cloaca & shortening of cloacal membrane results in ectopic anal opening into urogenital sinus

Depending on the size of posterior portion of cloaca the rectourethral fistula may be high or low

Defect is due to ectopic positioning of anal opening & not in any defect in urorectal septum

Imperforate anus: The anal canal fails to recanalise, leaving a diaphragm between the upper & lower portions of the anal canal

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Classification of Anorectal Anomalies

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Classification of Anorectal Anomalies

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ANORECTAL ANOMALIES

Develop during first 2 months of life- but cause is unclear

Agents causing the anomaly have general noxious effects on the developing fetus- hence associated anomalies are common

Males are more affected with severe malformation

Incidence 1 in 5000 livebirths

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ANORECTAL ANOMALIES

Present as absence of anus in it’s normal position

In mild forms bowel outlet opens in perineum outside the well developed muscle sphincter complex

In severe forms bowel outlet opens in urogenital tract in males & genital tract in females

Neonatal recoginition of type of anomaly is essential for planning the surgical management

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MALE ANORECTAL ANOMALIES

Perineal Fistula

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C Associated with a median bar Opens also on either side of median bar(covered anus)

Opens along or tip of median bar/ stenotic opening

Opens in midline perineal

raphae, scrotum or base of

penis

MALE ANORECTAL ANOMALIES

Rectobulbar fistula

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Rectum opens into the bulbar

urethra Presence of anal pit in perineum

Long common wall of rectum and urethra

Voluntary sphincter muscle

complex is well developed

MALE ANORECTAL ANOMALIES

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C Rectum opens into prostatic urethra

Passing meconium through

urethra

Sacral deformity is more severe than in bulbar fistula

Flat perineum with hypoplastic

voluntary sphincter muscles

Rectoprostatic urethral fistula

MALE ANORECTAL ANOMALIES

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Rectum opens into urinary bladder

Relatively uncommon; no common wall

between rectum and bladder

Severe Sacral deformity

Flat perineum with hypoplastic voluntary

sphincter muscles

Recto vesical fistula

MALE ANORECTAL ANOMALIES

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Rectum ends blindly behind the urethra

Blind end usually extends to a well

formed anal pit

Typical presentation in a Down’s syndrome

Presence of well developed voluntary

sphincter muscle complex

Anorectal Anomaly with no fistula

MALE ANORECTAL ANOMALIES

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Normal looking anal opening ending just above dentate line

Proximal blind ending rectum is very

much dilated

Local vascular abnormality is the cause

Voluntary sphincter muscle complex is

well developed

Rectal Atresia(same in male & female)

FEMALE ANORECTAL ANOMALIES

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Moderately stenotic anus situated anteriorly right behind vestibule

Fistula opening more anterior than in

males

Perineal groove between fistula and

vestibule

Voluntary sphincter muscle complex is

well developed except anteriorly

Perineal Fistula(Anterior Ectopic Anus)

FEMALE ANORECTAL ANOMALIES

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Fistula in posterior fourchette of vestibule behind hymenal ring

Anterior rectum and posterior vagina join

& forms common wall for 2-4 cms

Vaginal anomalies are common

Voluntary sphincter muscle complex is

well developed

Rectovestibular Fistula

FEMALE ANORECTAL ANOMALIES

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Urinary tract, vagina and rectum join in a common channel

The orientation and anatomy of cloaca

are extremely variable

Vaginal & uterine duplications with

Neonatal Hydrocolpos occur in 50%

Urinary tract abnormalities like obstructive

uropathy is common

Cloacal Anomaly with < 3 cms common channel

FEMALE ANORECTAL ANOMALIES

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Babies with long channel tend to have poor sphincter

Agenesis of Mullerian structures is not

uncommon

Severe sacral anomalies

Cloacal Anomaly with > 3 cms common channel

FEMALE ANORECTAL ANOMALIES

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Uncommon in females

Most babies have Down’s syndrome

Short distance between blind ending rectum and well

formed anal pit

Anorectal Anomaly with no fistula

Well-developed sphincters

ANORECTAL ANOMALIES

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Associated Anomalies

ANORECTAL ANOMALIES- Preop workup

Clinical examination discloses the type of anomaly in majority of cases

Cross-table lateral plain xray in doubtful cases to be done after 18-24 hrs

Early perineal USG to confirm type of anomaly

Abdominal USG& Echo to R/O associated anomalies

CT & MRI to reveal integrity of sphincter muscles

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ANORECTAL ANOMALIES- Preop workup

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Cross-table lateral radiograph

ANORECTAL ANOMALIES- Preop workup

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Cross-table lateral radiograph

Low anomaly

Intermediate Anomaly

High anomaly

ANORECTAL ANOMALIES- Surgeries

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Newborn male with anorectal malformation

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Newborn Female with anorectal malformation

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Anoplasty for low anomaly in Male

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Anterior Ectopic Anus- Posterior

Transposition

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Proximal Sigmoid Colostomy

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Split Colostomy in proximal

sigmoid colon

Washout of distal blind ending bowel is easier

Risk for prolapse is less

Distal Colostogram

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Pressure distal colostogram

revealing the fistula

Dye fillsup both bladder and urethra

Posterior Saggital Anorectoplasty

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Baby in prone position

Midline Saggital incision

Posterior Saggital Anorectoplasty

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Opening Rectum

Identifying Fistula

Separating Fistula

Posterior Saggital Anorectoplasty

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Mobilising rectum

away from fistula

Closing Fistula

Mobilising rectum

for tappering

Posterior Saggital Anorectoplasty

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Closing muscle

complex

Closing Sphincter

Closing skin

Posterior Saggital

Anorectovaginourethroplasty

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Posterior midline

incision

Opening common

channel

Identifying vagina

rectum & urethra

Posterior Saggital

Anorectovaginourethroplasty

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Separating rectum

from vagina

Separating vagina

from urethra

Tubularising

common channel

Posterior Saggital

Anorectovaginourethroplasty

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Total Urogenital Mobilisation

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Cloacal anomaly

Separating rectum from

vagina & urethra

Separating urogenital

sinus

Total Urogenital Mobilisation

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Total urogenital

mobilisation

Mobilising rectum from

urogenital sinus

Skin closure

Total Urogenital Mobilisation

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Assessment of functional outcome

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Assessment of functional outcome

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