Imperforate Anus Supervisor :

Prof.,Dr., Yasser Saad El-Din

Embryology

Formation of cloaca at 3rd week:• The hindgut forms the posterior portion of the cloaca( the

future anorectal canal)• the allantois forms the anterior portion ( the future urogenital

sinus. )

Development of urogenital sinus and rectum at 7th week:• Cloaca division into rectum and urogenital tract is initiated

by the caudal movement of ( the urorectal septum)

• proliferation of ectoderm closes the caudalmost region of the anal canal. During the ninth week, this region recanalizes.

rectoanal atresias and fistulas :are due to ectopic positioning of the anal opening.

imperforate anus:there is no anal opening. This defect occurs because of a lack of recanalization of the lower portion of the anal canal

Causes, incidence, and risk factors

• The rectum may end in a blind pouch that does not connect with the colon.

• The rectum may have openings to the urethra, bladder, and base of the penis or scrotum in boys, or vagina in girls.

• There may be narrowing (stenosis) of the anus or no anus.

It occurs in about 1 out of 5,000 infants.

Symptoms

• Anal opening very near the vagina opening in girls

• Baby does not pass first stool within 24 - 48 hours after birth

• Missing or moved opening to the anus

• Stool passes out of the vagina, base of penis, scrotum, or urethra

• Swollen belly area

Signs and tests

• A doctor can diagnose this condition during a physical exam. Imaging tests may be recommended.

Associated anomalies

• V - Vertebral anomalies• A - Anal atresia• C - Cardiovascular anomalies• T - Tracheoesophageal fistula• E - Esophageal atresia• R - Renal (Kidney) and/or radial anomalies• L - Limb defects

Diagnosis

• It is usually detected quickly as it is a very obvious defect.

• It is important to determine the presence of any associated defects during the newborn period in order to treat them early and avoid further sequelae.

• Sonography can be used to determine the type of imperforate anus.

• The decision to open a colostomy is usually taken within the first 24 hours of birth.

Investigations

1-Invertogram

2- Perineal U/S or MRI

3- X-ray

4- Colostogram

5-Abdominal U/S

Evaluation for other anomalies

Invertogram

- X-ray with head down hips flexed at 90 degrees and legs flexed at 90 degrees

 Baby held for several minutes to allow air to pass into the rectal

pouch. To find out the level of the rectal atresia by viewing how far the gas

has reached in relation to area where sphincter should be (Put a coin) High lesions are above the levator if the distance between level of the

air and coin more than 2cm. Intermediate lesions are characterized by the rectal pouch ending

within the levator, Low lesions, the rectal pouch has completely traversed the levator

musculature, the distance between level of the air and coin less than 2cm .

• If required, the level of the rectal pouch can be delineated more definitively by ultrasonography or magnetic resonance imaging.

• Perineal ultrasonography may be useful in determining the distance

between the rectal pouch and the anal skin.

Perineal U/S or MRI

X-ray

Abdominal radiograph performed at day one of life, shows multiple air filled distended bowel loops suggestive of bowel obstruction.

Colostogram Should be done under pressure to illustrate any fistula

Distal colostogram showing the colon ending in a long, narrow rectourethral fistula

Abdominal U/S

During the first 24 hrs. of life, All these patients need abdominal ultrasound evaluation To identify an obstructive uropathy especially in patients with;

Rectovesical fistula Rectoprostatic urethral fistula

Evaluation for other anomalies

1-Chest x-ray 2-Lumbosacral x-ray3-Abdominal pelvic ultrasonography4-Kidney Ureter Bladder KUB x-ray5-IVU6-Echocardiography and ECG7-Passage of nasogastric tube

Ivu showingRectovesical fistula

EXAMINE THE PERINEUM FOR THE MECONIUM

Diagnostic approach to male anorectal anomaly

Meconium discharge

through an orifice on perineum

Low anomaly

No meconium Examine urine for meconium

or mucus

Meconium/mucus present

Fistula present

High Anomaly

No meconium Inversion radiology

Careful examination of vulva and perinum

Diagnostic Approach to female anorectal Anomalies

Meconium present

Common to

urethera, vagina, rectum

High Anomaly

Separate urethra ,co

mmon rectum&

vagina

High Anomaly

One each urethera ,v

agina,Rectum.

Ectopic Anus

No meconium

Inversion Radiology or needle aspiration of

meconium and injection of contrast media

High or Low

Classifications of anorectal malformation

Wingspread classification (1984)

High Intermediate

Rectovaginal fistula

RectoVestibular fistula Persistant cloaca

Rectourethral fistula

Rectal atresia

Bulbar Prostatic

Bucket handle fistula

rectovesical

Vestibular fistula

Perineal fistula or an anterior ectopic anus

Males females

Perineal(cutaneous)fistula Perineal(cutaneous)fistula

Rectourethral fistula

Bulbar

Prostatic

Vestibular fistula

Rectovesical fistula Persistant cloaca

Imperforate anus without fistula Imperforate anus without fistula

Rectal atresia Rectal atresia

Pena classification (Therapeutic classification) 1995

Krickenbeck classification (2005):

Major clinical group Rare /regional variants

Perineal (cutaneous) fistulaRectourethral fistulaProstaticBulbarRectovesical fistulaVestibular fistulaCloacaNo fistulaAnal stenosis

Pouch colonRectal atresia/stenosisRectovaginal fistulaH fistulaOthers

Treatment of imperforate Anus

• Preoperative Therapy• NICU admission

• IV fluids …NPO & NG tube to exclude TOF.• Antibiotics

• Treatment of associated anomalies.

Vertebral anomalies Cardiovascular a

nomalies

Tracheoesophageal fistula

Renal

• Surgical treatment :

High and intermediate anomaly Low anomaly

-Initial pelvic colostomy.-Pull through operation.-Closure of colostomy.-Continence work up.

- Cut back in case of membrane.- Perineal anoplasty.- Regular post operative anal dilatation

Initial Pelvic Colostomy:

•Descending Colostomy- what’s colostomy ?- Advantages over other types - Errors of colostomy

Algorism of Management

Algorism of Management

• Posterior sagittal anorectoplasty(PSARP) = THE BEST• Anterior sagittal anorectoplasty(ASARP) • Followed by post operative dilatation.

Pull through operation

Algorism of Management

Postoperative Management • Rectouetheral fistula• Nutrition??• Dilatation ??

Postoperative functional disorders• Constipation is the most common problem.• Intestinal Obstruction.• Bowel incontinence.• Urinary tract infection.• Fecal impaction.• Colostomy related problems.( Like inflammation & colostomy Prolapse)• Recurrence of fistula & anal stenosis.

Thank You