BRIEF ABOUT ARM (REF- O NEIL TEXTBOOK OF PEDIATRIC SURGERY)

1. RECENT TRENDS IN THE
EVALUATION AND MANAGEMENT
OF ANO RECTAL MALFORMATION
PRESENTER: DR. MANHARSINH RAJPUT
PGT GENERAL SURGERY

2. INTRODUCTION
• Anorectal malformations constitute one of the commonest congenital anomlies
encountered in the newborn.
• The enormity of the problem can be judged by the fact that 1 out of every 5000
newborn babies is liable to have this condition.
• Male>female (54%:46%)
• ARM are currently considered to be “multifactorial”, meaning that there are many
unknown factors involved. there are also many genes involved.
• Imperforate anus without fistula occurs in 5% of patients, but interestingly, half of
them also have Down's syndrome. Patient with Down's syndrome and anorectal
malformations have this type of defect 95% of the time.

3. • The most common defect in females is rectovestibular fistula, whereas the most
common defect in males is rectourethral fistula. Cloacal malformations are more
common than formerly thought, most likely because they were previously
misdiagnosed as rectovaginal fistulas.
• Cure in anorectal malformations encompasses anatomical restoration along with
functional effectiveness. It is a lifelong misery for a child to have an incontinent
opening in the perineum.
• It would be better, anytime, to have a permanent colostomy in the anterior
abdominal wall where at least a proper colostomy appliance can be fitted.

4. EMBRYOLOGY

5. • The caudal end of hindgut dilates to form the cloaca. The cloaca is connected to
the allantois (urachus) ventrally. It is closed caudally by cloacal membrane that
represents the opposed layers of ectoderm and endoderm.
• The mesoderm at the angle between the allantois and the hindgut proliferates
and invaginates the endoderm of the cloaca forming a septum, called urorectal
septum.
• The septum extends caudally to divide the cloaca into: i. Primitive urogenital
sinus ventrally & ii. Anorectal canal dorsally.
• Further extension of the urorectal septum caudally divides the cloacal membrane
into 2 parts; anterior part called urogenital membrane & posterior part called
anal membrane.

6. • Also, it raises the ectoderm between the previous membranes to form the
perineal body. Further proliferation of the mesenchyme around the anal
membrane creates an ectodermal depression around it, called proctodeum.
• Anorectal canal forms the mucosa of rectum and upper part of anal canal
(endodermal in origin). The lower part of anal canal is formed from the
proctodeum (ectodermal depression roofed by anal membrane).
• The anal membrane ruptures (at the 7th week of development) so that the 2
parts of anal canal become continuous together. Mesenchyme surrounding the
anorectal canal forms the musculature of rectum and anal canal.

7. • Blood supply of anal canal reflects its double origin, as follows:
• The upper part of anal canal that is endodermal in origin, being derived from the
endoderm of hindgut, is supplied by superior rectal artery which is the
continuation of inferior mesenteric artery .
• However, the lower part of anal canal that is ectodermal in origin, being derived
from the proctodeum (ectodermal depression roofed by anal membrane), is
supplied by inferior rectal arteries which are branches of internal pudendal
arteries.
• The line of fusion of the endodermal and ectodermal parts of anal canal is
marked by a line called pectinate line that lies below the anal columns. This line
marks the transition of anal canal lining from simple columnar to stratified
squamous epithelium.

12. WINGSPREAD CLASSIFICATION
BOYS GIRLS
ANORECTAL AGENESIS ANORECTAL AGENESIS
HIGH WITH RECTOVESICLE FISTULA WITH RECTOVAGINAL FISTULA
WITHOUT FISTULA WITHOUT FISTULA
RECTAL ATRESIA RECTAL ATRESIA
INTERMEDIATE RECTOBULBAR URETHRAL FISTULA RECTOVESTIBULAR/ RECTOVAGINAL
FISTULA
ANAL AGENESIS WITHOUT FISTULA ANAL AGENESIS WITHOUT FISTULA
LOW ANOCUTANEOUS FISTULA ANOVESTIBULAR/ANOCUTANEOUS
FISTULA
ANAL STENOSIS ANAL STENOSIS

13. ANATOMY AND PATHOPHYSIOLOGY
• Bowel control implies the ability to detect and retain flatus and stool until the
appropriate time for evacuation.
• It is the result of a complex interplay among sphincter function, anorectal
sensation, and colonic motility. All these factors are affected in children with
anorectal malformations.
Sphincter Mechanism
• The muscle groups of the sphincter mechanism are traditionally described as
including the voluntary striated muscles of the external sphincter, the levator
musculature and the involuntary, smooth muscle (internal sphincter).
• These muscles are innervated by the pudendal nerve,both motor to the
external sphincter and sensory to the skin around the anus and derived from
the sacral plexus roots S2 to S4, as well as the autonomic nervous system via
the nervi erigentes, also derived from segments S2 to S4 of the spinal cord.

14. • The posterior sagittal approach has demonstrated that the external sphincter
runs in a para median direction.
• In addition, the muscular boundaries of the external sphincter are fused and
thus the components of the external sphincter are indistinguishable.
• During posterior sagittal dissection, the junction of the levator musculature
with the external sphincter is defined by a vertical group of striated muscle
fibers called the muscle complex.
• Electrical stimulation of the upper end of the levator group pulls the rectum
forward. Stimulation of the muscle complex (vertical fibers) elevates the anus,
and stimulation of the para median fibers of the external sphincter closes the
anus.

15. • Children with anorectal malformations have varying degrees of striated muscle
development from almost normal-appearing muscle to virtually no muscle at all.
• In very high defects, the rectum may rest at the upper part of the funnel-shaped
muscle structure, and in lower defects, the rectum may traverse the base of the
muscular funnel.
• The characteristics and precise limits of the internal sphincter have not been
accurately described in normal individuals.
• In patients with anorectal malformations , this structure has been a matter of
speculation, and few attempts at scientific evaluation have been made.

16. Sensation and Proprioception
• Under normal circumstances, the anal canal is an exquisitely sensitive area. It
allows the individual to discriminate solids from liquids and even from gas. The
overwhelming majority of children with anorectal malformations are born
without an anal canal and therefore cannot discriminate like a normal individual
can.
• There is, however, another kind of sensation called proprioception. This is
described as a vague feeling that is perceived when the rectum is distended,
supposedly simultaneous with stretching of the voluntary muscle that surrounds
the rectum.
• proprioception seems to be present in different degrees in most patients with
anorectal malformations.
• The clinical implications are obvious. These patients lose control when they suffer
an episode of diarrhea. They have the ability to be toilet-trained when they can
form solid stool and can learn to perceive it.

17. Colonic and Rectosigmoid Motility
• Normally, it takes between 3 and 6 hours for the gastric contents to transit the
small bowel. The intestinal contents reach the cecum in a liquid state. It then
takes about 20 to 24 hours for that fecal material to reach the rectum and
become formed (solid).
• The rectosigmoid acts as a reservoir and keeps the fecal material for a variable
time. The anal canal (below the pectinate line) is usually empty because of the
action of the surrounding sphincteric mechanism.
• Occasionally, however, there are peristaltic waves that push the fecal material
toward the anus.

18. • The rectal contents move distally and touch the exquisitely sensitive tissue
of the anal canal, thereby providing the individual with valuable
information related to the nature of the rectal contents (gas, solid, liquid).
• The distention of the rectum produces a vague sensation of fullness or even
colicky pain( proprioception) but does not provide specific information
concerning the physical characteristic of the contents.
• Very little is known about the mechanism that triggers peristalsis of the
rectosigmoid to defecate, but it is clear that the degree of rectal fullness
has an important role.

19. • Thus, when the time comes, the rectosigmoid generates waves of peristalsis
aimed at emptying the lumen.
• Individuals can restrain this process temporarily by using the voluntary sphincter.
With a voluntary decision to allow the stool to come out, the sphincter is relaxed
and the individual waits for the next peristaltic wave.
• Normal defecation allows massive emptying of the rectosigmoid, followed by
another resting period of about 24 hours, during which the rectosigmoid again
acts as a reservoir.
• The importance of rectosigmoid motility and its relevance for bowel control have
largely been underestimated.

20. • Children subjected to surgical techniques that preserve the rectosigmoid suffer
from constipation. Constipation, one of the most important functional sequelae ,
is probably the result of hypomotility of the rectosigmoid.
• The hypomotility is self perpetuating and self-aggravating to the point that if left
untreated, megasigmoid develops. In extreme cases, fecal impaction and
encopresis or overflow pseudo incontinence may develop. It seems that
constipation is worse with lower defects.
• Knowing this and the fact that hypomotility can begin a vicious cycle leading to
megasigmoid, it is incumbent on the pediatric surgeon to avoid the cycle of
hypomotility, constipation, and megasigmoid.

21. • Aggressive patient follow-up plus dietary, mechanical, and pharmacologic
treatment prevents this cycle.
• Children with anorectal malformations who, for whatever reason, have lost their
rectosigmoid suffer from the exact opposite (i.e., tendency for diarrhea). These
children have no reservoir capacity, are highly sensitive to fruits and vegetables,
and worst of all, suffer from incontinence.

22. APPROACH TO A CASE OF ARM
• HISTORY OF NEONATE
• CLINICAL EXAMINATION
• INVESTIGATIONS

23. HISTORY:
• Muconuria may be present in rectovesical / rectobulbar fistula.
• Abdominal distension and non passage of stool per anus.
• Constipation in older patients as solidification of stool occurs by 3-4 months age.
GENERAL EXAMINATION OF NEONATE:
• Examination of spine
• Passage of rigid nasogastric tube
• Central cynosis
• Limb anomaly
• Examination of genitalia

24. EXAMINATION OF PERINEUM:
• Check all orifices.(Anus,vagina,urethra)
• meconeum from perineum.
• Associated anomalies.
BUTTOCK EXAMINATION:
• High anomalies -sacrococcygeal agenesis, Flat buttock
• Low/intermediate anomalies-Deeply pigmented puckering at the site where
normal orifice should have been.

25. IMAGINE STUDIES
• Invertogram
• Crosstable lateral radiograph
• USG W/A+KUB
• USG TRANSPERINEAL
• MCU,IVP
• CT SCAN ,MRI

26. INVERTOGRAM

27. Cross table lateral radiograph

28. CT SCAN:
• Mainly required before Definitive surgery.
• Clearly shows the anantomy of sphincter muscles.
• Delineates the rectal pouch and fistula.
• Clearly shows the relationship btw intestine and surrounding muscles.
MRI:
• Better than CT in soft tissue imagine and no radiation hazard.
• Clearly shows whether the pulled through intestine is within levator ani sling or
not.

29. MANAGEMENT
• During the first 24 hours, the baby should receive intravenous fluids, antibiotics,
and nasogastric decompression to prevent aspiration.
• The clinician should use these hours to rule out the presence of associated
defects such as vertebral anomalies, cardiac malformations, Tracheoesophageal
and/or esophageal atresia, renal anomalies,limb defects.(VACTERL)

32. POSTERIOR SAGITAL ANORECTOPLASTY
• When a low anomaly (perineal fistula) is diagnosed, the surgeon must decide
which procedure is appropriate. In the presence of a fistulous track to the
perineum, in which the anus is always located anterior to the sphincter
mechanism, a limited posterior sagittal anorectoplasty can be performed in the
newborn period.
• In babies who cannot undergo such a procedure in the newborn period because
they are ill and have significant associated anomalies, dilatation of the fistulous
tract is appropriate with a plan for repair in the future.
• Occasionally, such babies escape detection in the newborn period, and delayed
primary repair is then appropriate.
• It is advantageous to perform this operation in the first 48 hours of life .

33. • When such an operation is delayed and performed at several months of life, a
complete bowel preparation, including a postoperative period of parenteral
nutrition without oral intake, is recommended to avoid a perineal infection.
• For a limited posterior sagittal anorectoplasty, the baby is placed prone. In males,
a urinary catheter is inserted. The distal end of the rectum is intimately attached
to the posterior urethra, and urethral injury must be avoided.
• Multiple 6-0 silk sutures are placed at the muco-cutaneous junction around the
fistula orifice. An incision divides the posterior sphincter in half and is continued
circumferentially around the fistula.
• While traction is maintained on the bowel, a circumferential dissection is
performed to mobilize the bowel and reposition it within the limits of the
external sphincter. Mucosa is sutured to skin with fine, absorbable sutures under
slight tension. The perineal body is reconstructed.

34. COLOSTOMY
• Colostomy is usually performed as a first stage in a newborn with a high anomaly.
A descending colostomy is a relatively trouble-free stoma. It also leaves the
sigmoid colon entirely free for reconstruction.
• It is fashioned by making an oblique left lower quadrant incision. The ends of the
wound , the proximal part of the stoma is placed at the start of the sigmoid colon
, just after the colon comes off its left retroperitoneal attachment.
• Stomas placed in mobile portions of the colon are prone to prolapse . The distal
part of the stoma, in the upper sigmoid, is made intentionally small in an attempt
to prevent prolapse .
• The distal segment should be copiously irrigated to remove all meconeum. A
colostomy can result in significant morbidity, so it is vital to construct it
meticulously.

35. • Transverse colostomies often lead to prolapse, make cleaning the distal segment
difficult, make delineation of the downstream recto-urinary anatomy during the
distal augmented-pressure colostogram challenging, and can result in perforation
of the colonic segment." Such colostomies also lead to megarectosigmoid and a
left microcolon in the defunctionalized segment, particularly when the colostomy
is left in place for many months.
• A colostomy that is placed too low in the sigmoid can limit pull-through
maneuvers. A loop colostomy leads to distal contamination of the urinary stream
if there is a fistula and to a dilated megarectosigmoid from stool spillage.

36. LATER MANAGEMENT AFTER COLOSTOMY
• Before reconstruction, the anatomy of the anorectal malformation is delineated
by high-pressure distal colostography
• In patients who have not already undergone cystourethrography, the necessary
information may be gained during the distal colostogram .
• Patience is required when performing loopography,with slow distention of the
distal rectum. The muscles of the pelvis are normally contracted, and thus the
distal rectum is compressed and can at first appear flat at the pubococcygeal line.
• With gentle pressure, this flat line begins to bulge, and it is at this point that the
examiner can visualize the true extent of the rectum and the presence ofa
rectourinary fistula.

37. ANORECTAL RECONSTRUCTION
BASIC PRINCIPLES:
• The patient is placed in a prone position with the pelvis elevated.
• Special care must be taken to cushion all the pressure areas of the baby's body.
Two small bolsters must be used in front of each deltopectoral groove to avoid
hyperextension of the neck and shoulders.
• A Foley catheter is inserted into the bladder before the patient is positioned. The
catheter sometimes goes into the rectum through the fistula rather than into the
bladder.
• To avoid misplacement, the surgeon can direct the catheter with a lacrimal probe
inserted in the tip of the Foley catheter to function as a guide.

38. • A midline incision is created and the sphincteric mechanism is divided exactly in
the midline, with equal amounts of muscle left on each side.
• The rationale for this approach is based on the fact that important nerves or
vessels do not cross the midline. Everything seems to be terminal in the midline,
and there is even a midline raphe that helps the surgeon know that the opening
is exactly in the midline.
• The retractors should be placed superficially to avoid pressure damage to the
nerves that run close to the wound.

39. PSARP FOR ANOMALIES IN MALE
RECTOURETHRAL FISTULA
• The incision usually extends from the lower portion of the sacrum through the
center of the anal dimple; it is sometimes extended to the perineal body,
particularly in boys with a rectum-urethral bulbar fistula.
• The levator muscle is located deeper to the ischiorectal fat. This muscle is also
divided in the midline.
• In boys with a rectum-urethral bulbar fistula, the bowel is very evident and
prominent and extends toward the lower part of the incision. In boys with a
recto-prostatic fistula, the rectum is much smaller and located much higher in the
incision.

40. • The distal colostogram provides information that is valuable at this point for
determining where the location of the rectum can be expected. In the case of a
rectum bladder neck fistula, the rectum is not visible through a posterior sagittal
approach and should not be searched for.
• Temporary silk sutures are placed in the posterior rectal wall for traction, and the
rectum is opened exactly in the midline.
• Multiple 6-0 sutures are placed Above the fistula in a semicircular fashion.
• Once the rectum is fully separated from the urinary tract , circumferencial
perirectal dissection is performed to gain enough rectal length to reach
perineum.

41. • The vessels that hold the rectum are coagulated and divided until enough rectal
length has been achieved. The urethral fistula is closed using interrupted
absorbable sutures.
• The perineal body is reconstructed by bringing together the anterior limits of the
external sphincter. The posterior edge of muscle complex must be sutures
together in the midline.
• Anoplasty is performed by placing the rectum within the limits of the external
sphincter with the use of interrupted long-term absorbable sutures.

48. RECTUM BLADDER NECK FISTULA:
• In a patient with a rectum bladder neck fistula, an abdominal approach Via either
laparoscopy or laparotomy in addition to the posterior sagittal approach, is
necessary to mobilize the rectum.
IMPERFORATED ANUS WITHOUT FISTULA:
• In this patient the blind end of rectum is located at the same level as in a patient
with bulbar urethral fistula. The repair is performed as described for recto-
urethral fistula.

49. RECTAL ATRESIA AND STENOSIS
• Repair of rectal atresia and stenosis is straightforward. The goal of this procedure
is to connect the blind dilated end of the rectum proximally with the anal canal
distally.
• Both structures are usually separated by a few millimeters of fibrous tissue. The
rectum must be sufficiently mobilized to allow the performance of an end-to-end
anastomosis to the anal canal.
• The wound is then closed by reconstructing all the muscle structures, as
previously described.

50. PSARP FOR ANOMALIES IN FEMALE
VESTIBULAR FISTULA
• The complexity of this defect is frequently underestimated. Patients with a
vestibular fistula are born with the potential for bowel control. Thus, every effort
should be made to give these patients the best opportunity to undergo successful
reconstruction with a single operation.
• With the patient in the prone position, a midline incision is performed, but it is
not usually necessary to extend the incision as high as the middle portion ofthe
sacrum Which continues around the fistula into the vestibule; multiple 5-0
sutures are placed circumferentially at the fistula site.

51. • While traction is placed on these sutures, the rectum is dissected in a
circumferential manner. The posterior rectal wall can easily be identified, and the
dissection must start from the posterior aspect and be extended laterally.
• The last step, separation of the rectum from the vagina, is the most delicate part
of the dissection. The common wall between the rectum and vagina in this kind
ofdefect is long and extremely thin.
• The limits of the sphincteric mechanism are electrically determined and marked
with temporary silk sutures.

52. • The perineal body is then reconstructed by bringing together the anterior limit of
the external sphincter.
• The anterior edge of the muscle complex is reapproximated as described
previously for males. The levator muscle is not usually exposed and thus does not
need to be reconstructed.
• The muscle complex must, however, be reconstructed posterior to the rectum by
taking bites of the posterior rectal wall. The anoplasty and wound closure are
performed as described for males.

55. PERSISTENT CLOACA
• This female malformation is managed by a variation of posterior sagittal
anorectoplasty. It is considered separately because of its complexity.
• Repair of this defect has three main goals: achievement of bowel control, urinary
control, and sexual function.
• A long mid sagittal incision is made that extends from the middle portion of the
sacrum through the external sphincter and down into the single perineal
opening.
• There are two well characterized groups of patients with a cloaca. These two
groups represent different technical challenges and must be recognized
preoperatively.

56. • The first consists of patients with a common channel shorter than 3 cm.
Fortunately, this group represents the majority of those with cloacas . These
patients can usually be repaired via a posterior sagittal approach alone, without
laparotomy.
• The second group consist of patients with longer common channels. These
patients usually need laparotomy.

59. VAGINAL SWITCH
• A specific group of people are born with hydrocolpos and two hemivaginas .The
hemivaginas are very large and the two hemiuteri are separated,and the distance
between them being longer than the Vertical length of both hemivaginas. In this
case it’s wise to perform a maneuver called “vaginal switch”.
• The vaginal septum is resected and single vagina is created. Then what is used to
be the dome of hemivaginas, where the hemiuterus was resected is turned down
to the perineum.

62. GENERAL PRINCIPLES OF POSTOPERATIVE CARE
• In the absence of laparotomy oral feeding may begin in a matter of hours.
• Antibiotics are given for 48 hours.
• In male who had a rectourethral fistula, the urinary catheter should be left in
place for 7 days and in case of female with cloaca repair it is kept for 3 weeks.
• If a laparotomy was required for the repair, a suprapubic cystotomy or vesicotomy
is created.
• A dilatation program is begun 2 wks after surgery twice a day. Every week the size
of dilator is increased by 1 unit until the desired size is reached.

63. • Once the correct size is reached, the colostomy is closed.
• Dilatation must continue after closure. Once the dilator can be inserted easily, the
schedule is reduced to once a day for 1month, once a week for 1 month, and
then once a week for 3 months.
• A patient who has 1-3 bowel movements, and shows evidence of a feeling of
pushing during bowel movements has a good bowel movement pattern and
generally has a good prognosis.

64. Complications
• Constipation(m/c)
• Wound infection and retraction
• Rectal or vaginal strictures
• Rectal mucosal prolapse

65. CONTINENCE
• With the rational administration of bowel irrigation, diet, and drugs, most
patients, including those with severe fecal incontinence, are able to remain clean
for 24 hours.
• Only patients with severe diarrhea secondary to an absent or a short colon have
been candidates for a permanent colostomy.
• Patients suffer from fecal incontinence are evaluated and classified into those
with constipation and those with increased motility(tendency to have diarrhea).

66. • In the first group, bowel irrigation must be aggressive. A rubber tube is usually
introduced high into the sigmoid to clean the bowel. This program takes
advantage of the decreased bowel motility in constipated patients: they remain
clean for the next 24 hours. No laxatives or diets are given as part of this
protocol.
• The second group(patients who suffer from increased bowel motility because of
loss of the rectal reservoir) require a constipating diet, medication to decrease
bowel motility, and a program of colonic irrigation.

67. • The treatment is adjusted by trial and error over period of week, with 95% of
patients remaining clean and having an acceptable social life.
• However ,when the patient reaches at the age of 7-12 years more independence
is generally needed.
• At that point, creation of a continent appendicostomy (Malone procedure) is
recommended.
• This operation creates a communication between the abdominal wall and the
cecum through the appendix of the patient the valve mechanism created allows
catheterization the cecum but prevents leakage of stool. Patients are able to
administer their own enema while sitting on the toilet.

69. • The operation consists of plicating the cecum around the native of appendix of
the patient and exteriorizing the appendix in the deepest part of the umbilicus to
make inconspicuous.
• A significant number of patients do have an appendix.
• In such cases we make an appendix with a tubularized flap of he cecum and then
plicate the cecum around it.
• The stoma is also exteriorized through the umbilicus.

70. • Certain patients in whom the rectum was mislocated during the operation may
be candidates for reoperation. This is recommended in patients who were born
with a good sacrum , good sphincters, and a malformation with a good
prognosis. The results of this procedure vary, with continence achieved in 15%
to 46% of patients.
• Urologic problems in male patients and female patients without cloacas are rare.
In patients with a cloaca 28% with a common channel shorter than 3 cm require
intermittent catheterization or a continent diversion to empty their bladder.
Patients with common channels longer than 3 cm require intermittent
cathetersation.