Anorectal malformation seminar

Anorectal
Malformation
Dr. Dixit Prajapati (Surgery Resident)
Dr. Jay Makadia (Surgery Resident)

Introduction
• Anorectal malformation (ARMs) are the more
frequent congenital anomalies encountered in
paediatric surgery.
• Incidence : 1 in 5000 live births
Male > female

• In female: Rectovestibular fistula is the most
common
• In male :Rectourethral fistula is the most
common
• Most female have low or intermediate
anorectal malformations while the reverse is
true for males.

• Female babies usually have a fistula from the
terminal end of the bowel opening externally
while in male this fistula is usually well
hidden.

Embryology
• The hindgut gives
rise to the distal
third of the
transverse colon, the
descending colon,
the sigmoid, the
rectum, and the
upper part of the
anal canal.

• The hindgut enters the
posterior portion of the
cloaca, the future anorectal
canal; the allantois enters
the anterior portion, the
future urogenital sinus.
• The urorectal septum is
formed by merging of the
mesoderm covering the
allantois and the yolk sac.

• As caudal folding of
the embryo
continues, the
urorectal septum
moves closer to the
cloacal membrane.

• breakdown of the
cloacal membrane
creates an opening for
the hindgut and one
for the urogenital
sinus. The tip of the
urorectal septum
forms the perineal
body.

• Anorectal malformations may be caused by
abnormalities in formation of the cloaca
and/or urorectal septum.
• For example, if the cloaca is too small or
urorectal septum does not extend far enough
caudally, the opening of hindgut shifts to
anteriorly leading to the opening in urethra or
vagina.

• Imperforate anus occurs when cloacal
membrane fails to breakdown.

Classifications
• Wingspread classification
• Pena’s classification
• Krickenbeck classification
• Anatomical classification

Wingspread classification (1984)

• The terms high, intermediate and low are in
relation to the terminal end of the bowel
remaining above (high), with in
(intermediate) or below the levator ani
muscle.

Pena’s classification
Continue..

Rectoperineal Fistulas
• Rectoperineal fistula is what traditionally was
known as a “low defect.”
• The rectum is located within most of the
sphincter mechanism. Only the lowest part of the
rectum is anteriorly mislocated .

• Sometimes,the fistula does not open into the
perineum but rather follows a subepithelial
midline tract, opening somewhere along the
midline perineal raphe, scrotum, or even at
the base of the penis.
• This diagnosis is established by perineal
inspection. No further investigations are
required.

• The terms covered anus, anal membrane,
anteriorly mislocated anus, and bucket-handle
malformations all are refer to perineal fistulas.

Rectourethral Fistulas
Imperforate anus with a rectourethral fistula is the
most frequent defect in male patients.
The fistula may be located at
1.The lower (bulbar) part of the urethra
Lower urethral fistulas are usually associated with good-quality muscles, a
well-developed sacrum, a prominent midline groove, and a prominent anal
dimple.
1.The higher (prostatic) part of the urethra
Higher urethral fistulas are more frequently associated with poor-quality
muscles, an abnormally developed sacrum, a flat perineum.

Recto-Bladder Neck Fistulas
• In this defect, the rectum opens into the
bladder neck.
• The patient usually has a poor prognosis for
bowel control because the levator muscles, the
striated muscle complex, and the external
sphincter frequently are poorly developed.
• The sacrum is often deformed and short

• The perineum is often flat, which is evidence of
poor muscle development.
• About 10% of males with anorectal atresia fall
into this category.

Imperforate Anus without Fistula
• Interestingly, most patients with this unusual
defect have a well-developed sacrum and good
muscles, and have a good prognosis in terms of
bowel function.
• The rectum usually terminates approximately 2
cm from the perineal skin.

Rectal Atresia
• In this extremely unusual defect in male
patients (~1% of the entire group of
malformations),the lumen of the rectum is
totally (atresia) or partially (stenosis)
interrupted.
• The upper pouch is represented by a dilated
rectum, whereas the lower portion is
represented by a small anal canal that is in the
normal location and is 1 to 2 cm deep.

These two structures may be
separated by a thin membrane or by
dense fibrous tissue.

• Patients with this defect have all the necessary
elements to be continent and have an
excellent functional prognosis.
• Because they have a well-developed anal
canal, they have normal sensation in the
anorectum and have almost normal voluntary
sphincters.

Rectoperineal Fistulas
• From the therapeutic and prognostic
viewpoint, this common defect is equivalent to
the perineal fistula described in the male
patient.
• The rectum is well positioned within the
sphincter mechanism, except for its lower
portion, which is anteriorly located.
• The rectum and vagina are well separated .

Rectovestibular Fistulas
• Rectovestibular fistula is the most common
defect in girls and has an excellent functional
prognosis.
• The diagnosis is based on clinical examination.
A meticulous inspection of the neonatal
genitalia allows the clinician to observe a
normal urethral meatus and a normal vagina,
with a third hole in the vestibule, which is the
rectovestibular fistula .

Imperforate Anus without Fistula
• This defect in female patients carries the same
therapeutic and prognostic implications as
described for male patients.

Persistent Cloaca
• This group of defects represents the extreme
in the spectrum of complexity of female
malformations.
• A cloaca is defined as a defect in which the
rectum, vagina, and urinary tract meet and
fuse, creating a single common channel.

• The diagnosis of persistent cloaca is a clinical
one.
• This defect should be suspected in a female born
with imperforate anus and small-looking
genitalia.
• Careful separation of the labia discloses a single
perineal orifice.

The length of the common channel varies from 1 to 7 cm.
This distance has technical and prognostic implications.
1. Short common channel less than 3 cm
2. Long common channel more than 3 cm

Examination
Pelvic floor
• Absence or presence of anal opening
• Position of anus – normal or anteposed
• Bulge in perineum on crying or straining
• Anal dimple
• Anal reflex
• Perineal groove
• Bucket handle deformity
• Meconium or mucus run ning up the
median scrotal raphe

Abdomen
• Large visible loop occupying more than half of
abdomen
• Palpable kidney/any other palpable lump –
solid or cystic
• Hydrocolpos(in girl) – palpable lump in lower
abdomen

Lumbo-sacral spine
• Occult or obvious spinal dysraphism
• Absent sacral vertebrae of variable levels

Associated anomalies
Continue…….

Management protocol of Congenital
Anorectal Malformation in Boys

Management protocol of Congenital
Anorectal Malformation in Girls

Approach to a case of ARM
 History of neonate
 Clinical examination
 Investigation

History
Abdominal distension and non-passage of
stool per anus.

General examination of neonate
(for VACTERL association)
 Examination of spine.
 Passage of nasogastric tube
 Central cyanosis
 Limb anomaly
 Examination of genitalia

Examination of perineum
 Presence or absence of
anus.
 Gas/meconium from
perineum
 Presence of vaginal and
urethral opening.
 Size of vaginal introitus.
 Size of anal dimple.
 Position of anus.

 Midline groove
 Anal membrane
 Presence of presacral mass
 No. of openings in vestibule

Imaging Studies
 Invertogram
 Crosstable lateral radiography
 USG abdomen+pelvis(to rule out genitourinary
anomalies)
 Ultrasonography
a)transperineal
b)infracoccygeal
 MCU,IVP
 CT Scan,MRI
 High-pressure distal colostography

Invertogram
Above PC line – High type ARM
Between PC line and I point – Intermediate type ARM
Below I point – Low type ARM

Crosstable lateral radiograph of a patient

Transverse infracoccygeal sonogram shows the distal rectal pouch (R), which
passes through the puborectalis muscle (arrows), indicating low-type imperforate
anus. U = urethra

CT scan
 Mainly required before surgery.
 Clearly shows the anatomy of sphincter muscles,
 Levator ani, muscle complex.
 Delineates the rectal pouch and fistula.
 Clearly shows the relationship between intestine
 Surrounding muscles.

MRI
 Provides better soft tissue imaging .
 Better than CT in soft tissue imaging and no
radiation hazard.
 Scan is expanded to include pelvis , kidneys and
spinal cord in case of associated anomalies.
 Post operatively it clearly shows whether the pulled
through intestine is within levator ani sling or not

High-pressure distal colostography
• Before the definitive repair, distal
colostography is performed.
• It is the most valuable and accurate diagnostic
study to define the anatomy of the anorectal
malformation.

• Water-soluble contrast medium is instilled
into the distal stoma, which fills the distal
intestine and enables demonstration of the
location of the blind rectum and the precise
site of a rectourinary fistula.
• The contrast medium must be injected with
considerable hydrostatic pressure under
fluoroscopic control.

• The use of a Foley catheter is recommended; it is
passed through the distal stoma, the balloon is
inflated (2–5 mL), and it is pulled back as far as
possible to occlude the stoma during the
injection of the contrast medium.
• This maneuver permits to overcome the muscle
tone of the striated muscle mechanism, fill the
rectum, and demonstrate the urinary fistula
when present

OPERATIVE PROCEDURES
• Colostomy
• Posterior sagittal anorectoplasty
• Pull through procedures
• Laparoscopic assisted procedures

COLOSTOMY
• Descending colostomy is preferred.
• The colostomy is constructed through a left
lower quadrant oblique or transverse incision.
• The proximal stoma is exteriorized through
the upper and lateral part of the wound and
the mucous fistula is placed in the medial or
lower part of the wound.

• The colostomy should be made in the mobile
portion of the colon, immediately distal to the
descending colon taking advantage of its
retroperitoneal attachments, and the mucous
fistula is made very small to avoid prolapse.
• During the opening of the colostomy, the distal
intestine must be irrigated to remove all the
meconium, preventing the formation of a
mega-sigmoid.

Advantages of descending colostomy
• Mechanical preparation of the distal colon
before the definitive repair is easy due small
length of remaining segment.
• Due to shorter distal segment in patient with
recto-urethral or recto-vasical fistula urine is
not accumulate in distal segment of
colon.(which leads to development of
metabolic acidosis)

• Less chance of development of
megarectosigmoid.
• The incidence of prolapse in the proximal limb
of descending colostomies is almost zero.

POSTERIOR SAGITTAL ANO-
RECTOPLASTY
• All anorectal malformations benefit from the
use of the posterior sagittal approach.
• The length of the incision depends on the
specific defect.
• The patient is placed in the prone position
with the pelvis elevated.

• An incision that starts in the lower portion of
the sacrum and extends anteriorly to the anal
sphincter.
• Recto vestibular and recto perineal fistula
requires smaller incision so, called limited
posterior sagittal ano rectoplasty and minimal
posterior sagittal ano rectoplasty respectively.

Repaires in boys
Rectoperineal fistula
• The repair of these defects consists of a small
anoplasty with minimal mobilization of the
rectum, sufficient for it to be transposed and
placed within the limits of the sphincter.
• It is done during the neonatal period without
a colostomy.

• These patients have an excellent prognosis.
• if they have significant associated spinal or
sacral problems an alternative approach, a
Pott’s transplant anoplasty, whereby the
majority of the perineal body is preserved, the
mobilized fistula is brought through a separate
incision which is confined to the size of the
future neoanal canal.

 Rectourethral fistula
• Most important thing in these cases are to put
per urethral catheter.
• To avoid the catheter to be entered in rectum,
the catheter must be intentionally directed
anteriorly by the use of a lacrimal probe
inserted in the distal tip of the catheter to find
its correct path.

 Rectobladderneck fistula
• As it is very high defect both approach (through
perineum and through abdomen) is needed.
• A plasty of the distal dilated portion of the
rectum is necessary in some cases to reach the
perineal skin.
• It is also called as abdomino perineal pull through
operation.

 Imperforate anus without fistula
• About 5 percent of patients have imperforate
anus without a fistula.
• In both boys and girls, the rectum lies about 2
cm from the perineal skin.

• The rectum must be carefully separated from
the urethra because the two structures have a
common wall. The rest of the repair must be
performed as described for the rectourethral
fistula type of defect

 Rectal atresia and stenosis
• These defects are repaired through a posterior
sagittal approach.
• The entire sphincteric mechanism is divided in
the midline. The narrowed area of the distal
rectum is opened posteriorly.

• The posterior rectum is mobilized to reach the
anal skin. No anterior dissection is needed.
The sphincter mechanism posterior to the
rectum is reconstructed.
• Any presacral mass deals simultaneously in
the same operation.

Repairs in girls
Rectoperineal fistula
• The treatment of rectoperineal fistula in girls
is the same as that discussed for boys, except
of course that the anterior rectal wall is
mobilized off the area behind the vagina.

Rectovestibular fistula
• Incision in this defect is usually shorter as compare to
recto urethral fistula in boys.
• Starting from posteriorly sphincter mechanism is
divided till reach rectal fascia which is helpful in
indenting the plane of dissection.
• Than we go laterally and than anteriorly using this
plane.

• Because the rectum and vagina have single wall it
is divided using needle cautery.
• The most common error in performing this
operation is incomplete separation of the vagina
and rectum.
• This may create a tense anastomosis between
the rectum and the skin, which may provoke
dehiscence and recurrence of the fistula

• The anterior limit of the external sphincter is
identified using electrical stimulation and the
anterior edge of the muscle complex are
reapproximated as previously described,
creating the perineal body.

Rectovaginal fistula
• Imperforate anus with a true rectovaginal
fistula is extremely rare.
• A true rectovaginal fistula requires a full
posterior sagittal incision.

• The operation is essentially the same as that
described for a rectovestibular fistula, except
that it is necessary to dissect much more of
the rectum to gain enough length to pull it
down to the perineum.

PSARP PROCEDURE
STAY SUTURES RECTAL POUCH

PSARP PROCEDURE
AFTER MOBILIZATION AFTER CLOSURE
FINAL PICTURE FOLLOW UP PICTURE

PSARP IN FEMALE
 Involves a midline incision from the fistula to the putative
site of the anus.
 Division of the muscles in the midline,separation of the
rectum from the vagina under vision
 Placement of the rectum within sphincteric complex and
reconstruction of the perineal body.
 Indications:
 All low and intermediate type of abnormality in females
 Revision surgery following cutback operations
94

ABDOMINOPERINEAL pull-through operation
 Lower bowel is mobilized
 New passage is created through the pelvic floor
keeping close to the urethra
 Fistulous tract is divided and ligated
 Bowel can be pulled down and its mucosa stitched to
the skin of the newly formed anus.
 Daily dilatation will be required for at least 3 months

Laparoscopically assisted anorectal
pull through (LAARP) for high ARM
 Advantages:
 LAARP allows the surgeon to treat a high lesion
like a low lesion.
 No need to divide the muscle complex from
below.
 Immediately after the procedure strong and
symmetric contraction of the sphincter around
the neoanus can be seen.

 It also avoids the,complication and multiple procedures
associated with colostomy.
 More rapid return of bowel function
 Improved cosmetic appearance
 Shorter postoperative recovery
 Decreased postoperative complications

Post operative care
• In cases of rectourethral fistula in boys, the
urethral catheter is left in place for 7 days.
• If the urethral catheter is accidentally
dislodged, the patient can be observed for
spontaneous voiding, which usually occurs.
Attempts to reintroduce a urethral catheter
can be dangerous and must be avoided.

• Intravenous antibiotics are administered for 24
hours. An antibiotic ointment is applied to the
anoplasty for 5 days.
• The patient is discharged after 2 days in cases of a
posterior approach without a laparotomy or
laparoscopy, and after 3–5 days in cases of an
abdominal approach.

• The parents are instructed to keep the incision
clean, not to wipe, and to apply antibiotic
ointment for 1 week.
• Two weeks after the operations, anal
dilatations are started. On the first occasion, a
dilator that fits loosely into the anus is used to
instruct the parents, who must carry out
dilatation twice daily.

• Every week, the size of the dilator is increased
until the rectum reaches the desired size,
which depends on the patient’s age.
• Once the desired size is reached, the
colostomy can be closed.

• Frequency of dilatation should be reduce in
following schedule :
• at least once a day for one month; every third
day for one month; twice a week for one
month; once a week for one month; and every
2 weeks for three months.

• Initially patient having diaper rash due to
multiple bowel movement which is converted
to 2 or 3 bowel movement per day in 6
months.
• Patient with 2 to 3 bowel movement in
day,with some feeling on having bowel
movement have good prognosis and responds
to toilet training.

COMPLICATION
Wound infection
Anal strictures
Constipation
Transient femoral nerve pressure
Neurogenic bladder
Fecal incontinance

 Wound infection
• Wound infections and mild dehiscences of the
posterior sagittal incision can occur. The
infection usually affects only the skin and
subcutaneous tissue, can be resutured, and
will heal with local care.

Anal strictures
• A direct correlation exists with intraoperative
devascularization of the distal rectum or
excessive tension on the anoplasty.
• Other cause of anal stricture is that protocol
of serial anal dilatation is not followed.

Constipation
• This is the most common functional disorder
observed in patients with anorectal
malformations, particularly prevalent in lower
malformations; rectoperineal, bulbar, and
vestibular fistulas

Transient femoral nerve pressure
• Excessive pressure on the groin during a
posterior sagittal operation can lead to this
problem, which can be avoided by adequate
cushioning of the patient’s pelvis while in the
prone position.

Neurogenic bladder
• Neurogenic bladder following a posterior sagittal
approach in patients with favorable anatomy can occur
due to nerve damage during the rectal dissection.
• In addition, placing Weitlander’s retractors deeper than
is necessary may compress the nerves that come from
the sacral area,causing a neurogenic bladder.

Management of complication
Minimal to no potential for bowel control
• These are patients who have a under developed
sacrum, associated spinal problem, poor
sphincters, a very high defect, and a poor bowel
movement pattern.
• The best treatment for these patients is a bowel
management program with success rate of 95%

• Patient in this group are divided in to 2
category,
Constipated
• These patients have undergone a procedure in
which the rectum was preserved.
• Contrast study shows a megarectosigmoid.
• Management consists of the use of enemas with
volumes of fluids large enough to clean a large
rectosigmoid colon.
• These patients don’t need any strict diet
recomandation

Patients with a tendency to have loose stool
• This group of patients has undergone a type of
procedure in which their original rectosigmoid
colon was resected.
• A contrast enema shows that the colon runs
straight from the splenic flexure down to the anus.
• Management consists of a small enema, a very
strict constipating diet and agents that slow
colonic motility, such as loperamide and water-
soluble fiber.

Potential for bowel control
• These patients were born with a favorable
type of defect (rectovestibular fistula,
rectoperineal fistula, rectourethral bulbar
fistula), a good sacrum, a normal spine, and a
good sphincteric mechanism, and underwent
an operation that placed the rectum in the
correct position.

• In addition, these patients have a good bowel
movement pattern.
• Management of this patient requires
behavioral modification (to have voluntary
bowel movement) and sometimes stimulant
laxatives.

Candidates for a reoperation
• These patients were born with a favorable
type of defect.
• They underwent an operation that placed the
rectum in the wrong place or left it strictured
or prolapsed.
• Management of this patient requires
repositioning of rectum with in sphincter
mechanism.

REFERENCES
• Bischoff A, Tovilla M. A practical approach to the management of pediatric
fecal incontinence. Seminars in Pediatric Surgery 2010; 19: 154–9.
• Falcone RA, Levitt MA, Peña A, Bates MD. Increased heritability of certain
types of anorectal malformations. Journal of Pediatric Surgery 2007; 42: 124–
8.
• Hong AR, Rosen N, Acuña MF et al. Urological injuries associated with the
repair of anorectal malformations in male patients. Journal of Pediatric
Surgery 2002; 37: 339–44.
• Peña A, Grasshoff S, Levitt MA. Reoperations in anorectal malformations.
Journal of Pediatric Surgery 2007; 42: 318–25.
• Peña A, Migotto-Krieger M, Levitt MA. Colostomy in anorectal malformations a
procedure with serious but preventable complications. Journal of Pediatric
Surgery 2006; 41: 748–56.
• Shaul DB, Harrison EA. Classification of anorectal malformations – initial
approach, diagnostic tests, and colostomy. Seminars in Pediatric Surgery 1997;
6: 187–95.

• Pena A, Devries PA: Posterior sagittal anorectoplasty: important technical
considerations and new applications. J Pediatr Surg 1982, 17(6):796-811.
• Pena A: Posterior sagittal approach for the correction of anorectal
malformations. Adv Surg 1986, 19:69-100.
• Pena A, Hong A: Advances in the management of anorectal
malformations. Am J Surg 2000, 180(5):370-376.
• Rintala RJ, Lindahl HG: Posterior sagittal anorectoplasty is superior to
sacroperineal-sacroabdominoperineal pullthrough: a long-term follow-up
study in boys with high anorectal anomalies. J Pediatr Surg 1999,
34(2):334-337.
• Pena A: Anorectal Malformations: Operative Pediatric Surgery Edited by:
Ziegler, Azizkhan. Gauderer & Weber. Boston: Appleton & Lange; 2005.
• Pena A: Cloacal Repair. In Atlas of Pediatric Urologic Surgery. Chapter63
Edited by: Hinman F. Philadelphia, PA: W.B. Saunders Company; 1994:322-
324.

• Pena A, Levitt M: Anorectal malformations. In Pediatric Surgery and
Urology: Long term outcomes 2nd edition. Edited by: Stringer M, Oldham
K, Mouriquand PDE. Cambridge: Cambridge University Press; 2007:401-
415.
• Levitt MA, Pena A: Pitfalls in the management of newborn cloacas. Pediatr
Surg Int 2005, 21(4):264-269.
• Rosen NG, Hong AR, Soffer SZ, Rodriguez G, Pena A: Rectovaginal fistula: a
common diagnostic error with significant consequences in girls with
anorectal malformations. J Pediatr Surg 2002, 37(7):961-965.
• Levitt MA, Stein DM, Pena A: Gynecologic concerns in the treatment of
teenagers with cloaca. J Pediatr Surg 1998, 33(2):188-193.

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