ANORECTAL MALFORMATIONS

1. ANORECTAL
MALFORMATIONS
Mukesh Sah, MD
United Kingdom

2. Alberto Pena
• Father of Anorectal
Malformations

3. ANORECTAL MALFORMATION
• Wide spectrum of congenital anomalies
that include imperforate anus and
persistent cloaca
• Incidence 1 in 5000 live births, M:F 1:1
• Embryologic basis > failure of descent of
the urorectal septum.
• In patients with imperforate anus, the
rectum fails to descend through the
external sphincter complex.
• Instead, the rectal pouch ends blindly in
the pelvis, above or below the levator
ani muscle.

4. Abbreviated history
For centuries, an anal orifice was blindly created by making an
incision in the perineum of children with imperforate anus.
Many of these children did well, probably because these were
defects with an anus located very close to the skin of the
perineum (low defects).
In contrast, most children with higher defects did not survive.
Amussat, c.1835 performed 1st surgical anoplasty by suturing the
wall of the rectum to the skin edges without a colostomy >
became standard for low IA
Posterior sagittal approach to ARMs c.1982. > provided better
approach for the surgeon to identify anomalies and taylor surgery

5. CLASSIFICATION

6. CLASSIFICATION - MALES
• Rectourethral
fistula – most
common
• Rectoperineal
fistula
• Rectovesicular or
recto–bladder neck
fistula.

7. CLASSIFICATION – FEMALES
• Rectovestibular
defect –most
common
• Cutaneous
perineal fistula.
• Cloaca

8. CLASSIFICATION –CLOACA
• Wide spectrum of
malformations
• Rectum
• Vagina
• Urinary tract
• Meet and fuse into a
single common channel.
• On PE  a single perineal
orifice is observed, located
at the place where the
urethra normally opens.
• Typically, the external
genitalia are hypoplastic.

9. ASSOCIATED MALFORMATIONS
• 60% of ARM patients have associated
malformation.
• Urinary tract defect, most common, in 50%
• Skeletal defects are also seen, and the sacrum
is most commonly involved.
• Spinal cord anomalies, especially tethered
cord, are common, particularly in children
with high lesions.
• GI tract anomalies occur, most commonly
esophageal atresia.
• Cardiac anomalies may be noted, and
occasionally patients present with a
constellation of defects as part of the
VACTERL association

10. MANAGEMENT
• Patients are usually stable
• Despite the obstruction, the abdomen
initially is not distended
• Insert orogastric tube (OGT)
• Monitor appearance of meconium in or
around the perineum, or in the urine
• Principles of management
• Diagnose type of defect (high vs. low)
• Associated anomalies.

11. MANAGEMENT

12. MANAGEMENT

13. MANAGEMENT
• Investigate VACTERL, etc
• V = babygram
• A = anorectal
• C = 2d echo
• TE = insert OGT
• R = Abdominal ultrasonography
• L = PE and x-rays
• Invertogram with anal marker at the
18th-24th hour of life

14. CLASSIC MODIFIED

15. MANAGEMENT – SURGERY
• Low type  perineal
operation is required without a
colostomy.
• High type  requires a
colostomy in the newborn
period,
• Followed by a pull-through
procedure at least 4 weeks
after
• If there is any doubt about the
type of lesion, it is safer to
perform a colostomy rather
than jeopardize the infant's
long-term chances for
continence by an injudicious
perineal operation.

16. PSARP (Posterosagittal
anorectoplasty)
• As described by Peña
• Prone jackknife position
• Levator ani and external
sphincter complex is
divided in the midline
posteriorly
• Communication between
the GI tract and the
urinary tract is divided
• Rectum is brought down
after sufficient length is
achieved
• Muscles are carefully
sutured

17. 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.