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1. Anorectal Malformation
Presenter Dr. Temesgen N. (PSRIII)
Moderator Dr. Seye (pediatric surgery fellow)

2. Outlines
• Introduction
• Embryology
• Classification
• Associated Anomalies
• Specific defects
• Management
• Complication
• Summary
• References
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3. Introduction
History
• ARM has been a challenge to surgeons
• Soranus (2nd century) described dividing a thin anal
membrane and dilating the opening
• Up to 17th century same procedure with subsequent
dilation
• The first inguinal colostomy was performed in 1783,
• In 1835 Amussat performed the first proctoplasty
• Stephens described the puborectalis sling.
• PSARP described by Peter deVries and Alberto Peña
1982
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4. Epidemiology
• The average incidence is 1 in 5000 live births
• A slight male preponderance
• The most common defect in females is
rectovestibular fistula, whereas in males
rectourethral fistula
• Imperforate anus without fistula occurs in 5% ,
half of them also have Down syndrome.
• Patients with Down syndrome and ARM have IA
95% of the time
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5. Embryology
• Cloaca is first formed at
around 21 days of gestation
• The septum in the middle
grows downward until it joins
the cloacal membrane, 6th wk
• Cloacal membrane ruptures
at 7th wk creating urogenital
and anal openings
• Muscles that surround the
rectum are seen in 6&7 wks
• By 9th wk, all relevant
structures are in place
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6. Physiology of continence
Fecal continence depends on three main factors:
1. Voluntary muscle structures-
– Levator muscle, the striated muscle complex, and the
external sphincter
2. Sensory mechanism
– Liquid or soft fecal material may not be felt by the patient
with anorectal malformations as the rectum is not
distended
3. Bowel motility--the most important factor in continence
• These mechanisms are affected in ARM patients
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7. Associated Anomalies
• 50% to 60% of ARM patients have one or more
associated anomalies
• Higher abnormalities are associated with more
malformations
• Association with VACTERL syndrome
Cardiovascular ASD, PDA, VSD, TOF
Gastrointestinal TEF, duodenal obstruction, HSD
Urologic VUR, renal agenesis, UDT, hypospadia
Gynecologic Hydrocolpos, uterine and vaginal malformations
Spinal/ vertebral Tethered cord, hemisacrum ,hemivertebra, CURRARINO triad
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8. Classification
• The terms ‘low,’ ‘intermediate,’ and ‘high’ are
arbitrary and not useful in current therapeutic
or prognostic terminology
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9. Male defects
Recto-perineal
Recto-urethral
Recto-bladder neck
Imperforate anus without fistula
Rectal atresia/stenosis

10. Recto-perineal fistula
• The lowest and simplest defect
• The rectum is located within most of the
sphincter mechanism except anteriorly
• Covered anus, anal membrane, anteriorly
mislocated anus, and bucket-handle
malformations all refer to rectoperineal
fistulas
• The sphincter and the sacrum are usually
very good and associated defects are rare
• Diagnosis– perineal inspection, No further
investigations are required
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11. Recto-urethral fistula
• The most common defect in males
• Can be located at the lower (bulbar) or the
higher (prostatic) part of the urethra
• Immediately above the fistula, the rectum
and urethra share a common wall.
• The lower the fistula, the longer is the
common wall
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12. Recto-bladder neck Fistulas
• About 10% of males
• The opening is above the
sphincter mechanism
• Associated defects occur in 90%
• The entire pelvis seems to be
underdeveloped
• Has poor prognosis for bowel
control (15%)
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13. Imperforate Anus Without Fistula
• Rectum ends blind at ~ 2 cm above the perineal
skin(the level of the bulbar urethra)
• Rectum and urethra share a longer common wall
• 50% have Down syndrome
• Have good sphincters, good sacrums, and,
therefore, good clinical prognosis even if they
have Down syndrome.
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14. Rectal Atresia/Stenosis
• < 1% of ARM
• Rectal lumen is totally (atresia) or partially
(stenosis) interrupted.
• Because the anal opening and sphincter
mechanism is normal, the prognosis
is excellent
• Must be screened for a presacral mass
(currarino triad)
• Delayed diagnosis
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15. Female Defects
Recto-perineal
Recto-vestibular
Persistent cloaca
Imperforate anus without fistula
Rectal atresia/stenosis

16. Recto-vestibular Fistulas
• Most common defect with an excellent
functional prognosis
• In 5% of patients -- two hemivaginas with
a vaginal septum
• Rectum and vagina share a common wall
• Diagnosis is a clinical
• Associated with failed attempted repair
• “these patients have a single opportunity
to have a good repair.”
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17. Persistent Cloaca
• Rectum, vagina, and urinary tract meet and
fuse into a single common channel
• No anus and the external genitalia look small
• The diagnosis is a clinical
• The length of the common channel (1–10 cm)
– In 60% <3cm – less associated anomalies
– In 40% >3 cm--a very high frequency of
association with complex pelvic anomalies
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18. • 30% have duplicated Mullerian structures
• 50% have Hydrocolpos-- hydronephrosis, peritonitis
• The reason for hydrocolpos remains a mystery
• Complete urological evaluation at birth, ultrasound of
the kidneys and ultrasound of the pelvis is must
NB. Rectoperineal fistula, imperforate anus without fistula ,
and rectal atresia/stenosis are the same as in males
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19. Newborn evaluation and management
• Two important questions
 Does the baby have serious associated defect--
ultrasound( renal, spinal), echocardiogram, plain
radiograph of the lumbar spine and sacrum
 Primary anal repair Vs colostomy?
Our eyes only see what our mind suspects
• Thorough perineal inspection
• No decision about a colostomy or a primary
operation before 24 hours of life
• If still unclear– Cross table lateral x-ray (>24hrs)
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20. • During the first 24 hours
– NPO
– Intravenous fluids
– Antibiotics
– NGT decompression
– Evaluation for associated defects
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21. 3/6/2024 21

22. Colostomy
Indications
• Rectal gas above the coccyx
• Meconium in the urine,
• Significant associated defects
• Abnormal sacrum or a flat bottom
• Cloaca
• RVF ???
• Advantages – distal colostogram,
optimization, protection
for the final reconstruction
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23. • Divided descending colostomy
• The proximal part of the stoma is at the start of
sigmoid colon
• The stomas are at the edges of the wound
• Drain hydocolpos
• Irrigate distal rectum
• Transverse colostomy, distal sigmoid colostomy
???
• High-pressure distal colostography
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25. Definitive Repair
Basic principles
• All defects can be repaired
using PSARP
• Patients with RBNF and
cloaca may, in addition,
require laparatomy
• Bowel preparation
(perineal and vestibular
fistulas)
• Catheterization
• Positioning
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26. • Incision
– Length depends on the
specific defect
– Run from the lower
sacrum to the perineal
body
– Skin, Sc tissue, parasagittal
fibres, muscle complex
and levator muscle
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27. RPF for both sexes
Options
• Dilation
• Cut-back
• Limitted/minimalPSARP
Dilation
– Patient with multiple serious
associated defects and
abdominal distention.
– Premature who are poor surgical
candidates
Cut-back
• Same indications as for dilation
• Making an incision in the
posterior rim of the anal opening
and suturing the skin to the
mucosa
• Good temporizing preliminary
operation
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28. Limited/ Minimal PSARP
• Standard operation for RPF
• Prone position
• Multiple 6-0 silk stitches are placed in the fistula orifice
• 2 cm incision is created dividing the entire sphincter
mechanism located posterior to the fistula
• Circumferential dissection is performed to mobilize the
bowel and reposition it within the limits of the sphincter.
• Mucosa is sutured to skin
• The perineal body is reconstructed
• Feared complication (in males)– urethral injury (
prevented by catheterization)
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29. PSARP for anomalies in Males
RUF
• The dissection must
stay as close as possible to the
rectal wall without
injuring it
• Separation of the urethra from
the rectum is the most
delicate part of the operation
• Tapering should be done on
the posterior wall if needed
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30. RBNF
• total body preparation.
• The operation is started via
a posterior sagittal
approach
• A rubber tube is placed in
the presacral space
• The perineal body, levator
and muscle complex are
reconstructed around the
rubber tube that represent
the rectum
• laparotomy is performed
• fistula is divided and the
bladder end is sutured
• rectum anchored to the
rubber tube
• rubber tube pulled together
with the rectum
• The anoplasty is performed
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31. PSARP for anomalies in Females
RVF
• Excellent potential for bowel control
• A primary repair Vs colostomy depends on surgeons
experience
• Unfortunately, girls with these defects usually suffer from
more complications after a failed attempt to repair
• Separation of the rectum from the vagina--the most delicate
part o f the operation
•
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32. Persistent Cloaca
• Goals of repair
– Urinary control
– Bowel control
– Sexual function
• Before the operation
– Cloacagram 3D
– Endoscopy
• If the common channel is
– >5 cm- open the abdomen
– <3cm– posterior sagittal
– 3-5cm-- try to repair by
posterior sagittal approach
• If < 3cm- total urogenital
mobilization perineally
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36. POSTOPERATIVE CARE
• In PSARP feedings may begin when the child is awake.
• Antibiotics are given for 48 hours
• Catheter
• RUF repair -- 7 days
• Cloaca repair -- 2 to 3 weeks
• Anal dilation
– Once this desired size is reached, the colostomy can be
closed
– Start after 2wks
• Colostomy closure–
– diarrhae—constipation– normalize after about 3months
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37. Outcomes
• Good prognosis
– One to three bowel movements per day
– Clean between bowel movements
– Feeling or pushing during bowel movements
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38. Outcomes
COMPLICATIONS
• Wound infection, retraction and
dehiscence
• Rectal or vaginal strictures
• Rectal mucosal prolapse
• Urologic injuries (Urethral, ureteral,
vas deferens, and seminal vesicle
injuries, neurogenic bladder)
• Fecal incontinence
• Constipation- most common
sequela
– vicious cycle
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39. Summary
• ARM is one the common causes of neonatal
intestinal obstruction
• Looking for associated anomalies and deciding
what to do are the most important questions
• It has got variable functional outcomes
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40. References
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41. Thanks
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