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TitleAnorectal Malformations in Children - A. Holschneider, J. Hutson (Springer, 2006) WW
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Page 2

Anorectal Malformations in Children

Page 238

225�� Rectal Atresia and Rectal Ectasia

condition [8,9]. Most techniques are of historical sig-
ni�cance [10�12] and are no longer adopted since the
popularization of the posterior sagittal anorectoplasty
(PSARP) approach.

�e authors prefer and suggest the following ap-
proach to manage babies with rectal atresia. A sig-
moid colostomy in the newborn period is mandatory,
except in cases with rectal stenosis, if they are able
to decompress e�ectively. Rectal stenosis can be man-
aged with anal dilatations in a gradual manner until
the desired lumen is achieved. For a rectal septum or
a membrane, the septum can be made to project at
the verge, with a Hegar�s dilator passed from the sig-
moid colostomy. �e septum is held with stay sutures
and divided under vision, and the edges can be su-
tured. Postoperative dilatation is maintained to avoid
stricture formation. For rectal atresia, an end-to-end
anastomosis with PSARP gives satisfactory results.
�e PSARP approach can also be used for patients
presenting with multiple (type V) atresia. Only in rare
instances, an additional abdominal approach may be
needed for a pull-through procedure.

Fluoroscopic string placement followed by pro-
gressive dilatation with Tucker�s dilators [13], abdom-
inoperineal pull-through similar to Swenson�s opera-
tion, and abdominoperineal endorectal pull-through
a�er stripping the mucous membrane of the distal
pouch have been described in the literature, but are
not popular. Transanal end-to-end rectorectal anas-
tomosis using an indigenously designed instrument,
was described by Upadhyaya with a successful out-
come [14,15]. Recently, a case has been described in-
volving the antenatal repair of the defect diagnosed in
conjunction with sacrococcygeal teratoma [16]. Post-
operative dilatation is very important and should be
continued for at least 3 months to achieve a normal
lumen and function. �e postoperative outcome is
good as the anal sphincter complex is normally de-
veloped and is usually not damaged by the surgical
approach. �e colostomy should be closed early so as
to allow the feces to dilate the new passage.

12.2 Rectal Ectasia

Rectal ectasia is not uncommon in the �eld of pe-
diatric coloproctology, either de novo or associated
with ARM [17]. Rectal ectasia is de�ned as a state of
massive dilatation of the rectum and sigmoid colon.
It may be primary (presenting at the time of birth) or
secondary (developing later as a result of distal ob-
struction or inadequate evacuation) [18].

Many confusing terminologies have been used in

the past to describe this entity. �ese include; bal-
loon-like rectum, colonic inertia, megarectum, termi-
nal fecal reservoir syndrome, pseudo-Hirschsprung�s
disease and rectal inertia [19,20]. Congenital pouch
colon, which was initially considered by some as a
part of this entity, has now been universally accepted
as a separate anomaly and is thus excluded from this
chapter.

12.2.1 Classification

Rectal ectasia can be broadly classi�ed into two types:
primary and secondary rectal ectasia. Primary rectal
ectasia is congenital in origin, and is attributable to a
mid-anal sphincter defect or a de�ciency of the rectal
musculature. �is excludes cases of congenital pouch
colon, which were previously included in this cat-
egory. However, 2�5% of cases of ARM present with a
congenital rectal ectasia that has a normal blood sup-
ply, unlike that in congenital pouch colon. �ere is
no known cause for primary rectal ectasia; however,
if the patient is symptomatic and investigated further,
the rectosigmoid region is found to be very capacious.
Secondary rectal ectasia, which develops a�er birth
and is usually associated with distal obstruction sec-
ondary to fecal impaction or surgery at the anorec-
tum. Dilatation of the rectum will depend upon the
degree and the duration of the obstruction.

Acquired ectasia develops a�er birth if the rectum
or anus is partially obstructed or if the colon distal
to a colostomy is cleansed inadequately, resulting in
a bolus of desiccated meconium or a hard fecaloma.
�e presence of a fecaloma in the rectum may initiate
a vicious cycle and worsen the dilatation further.

12.2.2 Embryogenesis of Primary Rectal
Ectasia

Many theories have been proposed to explain the de-
velopment of primary rectal ectasia.
1. �e cloaca is normally divided by the urorec-

tal septum into urinary and rectal passages. �e
cloaca in babies with ARM may be initially more
voluminous than normal before partition, with
consequent oversized passage or passages a�er
partition [18].

2. �e rectum is normally modeled into two ampul-
lae, one in the midrectum and one in the region
of the future anal canal. �e former becomes
the ampulla of the mature rectum and the latter
moulds into the anal canal. Primary rectal ectasia

Page 239

Devendra K. Gupta and Shilpa Sharma226

that occurs in association with ARM may be an
example of developmental overgrowth of the up-
per or lower primitive ampullae or both [18].

3. The tail gut is an extension of the undivided clo-
aca into the temporary tail of the human embryo.
It is initially quite voluminous, but becomes atro-
phic and disappears before partition of the cloaca
is complete. Incorporation and persistence of part
of the tail gut into the rectum may result in ano-
rectal ectasia [18].

4. It may be a variant of segmental dilatation of the
intestine, which is a well-known cause of obstruc-
tion [18].

5. Primary hypomotility of the distal rectum has also
been proposed [21].

6. Weakness of the posterior rectal wall or a defect
in the external anal sphincter has been suggested.
The authors have found a primary deficiency of
the musculature of the posterior rectal wall and
the external anal sphincter, resulting in rectal in-
ertia followed by rectal ectasia. This is well appre-
ciated on surgical dissection during the PSARP
procedure. Approximation of the defect improves
the clinical symptoms.

In 1984, Upadhyaya suggested a similar cause of
mid-anal sphincteric defect as the possible cause of
constipation in anterior perineal anus [22]. It may also
be possible that not much attention has been given to
this entity so far and many more cases may be diag-
nosed in future. This possible cause also explains the
clinically and radiologically evident posterior rectal
shelf in a few cases of primary rectal ectasia.

12.2.3 Pathophysiology

It has been shown that the primary pathology in the
causation of primary rectal ectasia is due to a defi-
ciency in the smooth muscle causing weakening and
dilatation of the rectal wall [17]. Secondary rectal ec-
tasia develops due to the response to the obstructed
rectum. The elasticity of the rectal wall permits the
normal rectum to expand to approximately double
the caliber, but it returns to its normal size. In the
newborn, ectasia beyond this diameter is predictive
of a primary developmental ectasia, which is made
even more apparent when overdistended by gas and
meconium content.

In the case of obstructive anorectal conditions, the
rectal caliber soon reverts to normal dimensions after
the relief of obstruction by surgery. If the rectal am-
pulla is developmentally ectatic, the dilatation may

persist and lead postoperatively to fecal accumula-
tion, further enlargement, troublesome constipation,
and soiling.

With high rectal anomalies, the terminal bowel is
frequently focally ectatic, and in many patients the
ectasia is primary or developmental. In others, hy-
pertrophy and dilatation may occur as reactions to
propulsive activity against an obstruction or upon
a retained meconium bolus in the terminus of the
bowel after a defunctioning colostomy [23]. Primary
and secondary rectal ectasia can be differentiated
histologically by examining rectal specimens: hyper-
trophy and hyperplasia of smooth muscle cells is evi-
dent in acquired cases, and are normal or smaller in
newborns with a primary or developmental anomaly.
Dysplastic nitrergic neurons in the rectum of a patient
with rectal ectasia have also been demonstrated [24].
Bowel activity after anorectal reconstruction for high
lesions is compatible with near-normal continence in
many children. Even when the sphincter muscles are
adequate for high-grade continence, the ectatic ter-
minal reservoir may overload and overflow, requiring
long-term treatment.

12.2.4 Clinical Features

The most common symptom is refractory constipa-
tion, either primarily or persistent after successful re-
constructive surgery for a known ARM. Rectal ectasia
predisposes to ampullary overloading and constipa-
tion. Patients usually present after 6 months of age,
the most common period being around 1–3 years.

Paradoxical diarrhea occurs when peristalsis re-
lentlessly pushes the column of feces against the pu-
borectalis sling and levator diaphragm. These mus-
cles fatigue, relax, and temporarily lose the important
sphincter functions that control the entrance to the
rectoanal canal. Soft feces are then massaged by peri-
stalsis over the fecal masses to escape constantly from
the anus (known as a “hold-back dyschesia cycle”
or “pseudoincontinence”), in spite of good surgery
[21,23].

The clinical significance of the anomaly is two
fold. First, following PSARP, the ectatic rectum may
become a passive reservoir for feces, which accumu-
lates and impacts; second, the large bulk of the walls
of the intact wide rectum may impair the reconstruc-
tion of the sphincter muscles at the time of the PSARP,
thus lessening the ultimate degree of continence.
Paradoxical diarrhea and incontinence resulting from
anatomically defective sphincters may be differenti-
ated by rectal examination. Digital palpation of the

Page 476

479Subject Index

� with spinal dysraphism 282
Sacral ratio
� in assessment of ARM 195�196
Sacral agenesis
� in Currarino syndrome 23
Sacral anomalies 208
� in cloaca 208
Sacrum 80
� agenesis of 80
� diagnosis of anomalies of 195�196
� dysgenesis of 80
� hypoplasia of 80
SALL1/GLI3/HLXB9/SHH
� human-mouse correlation 26
Secondary operations
� for continence 391�413
Scoring systems 349�357
� Kelly score (1972) 352
� principles 351�352
� Scott score (1960) 352
Self-help groups 460, 466�468
� bene�t for surgeon 466�467
� bene�t for patient 467
Secondary surgery
� functional outcome of 371�372
Sex distribution
� of ARM 33�34
Sex distribution
� of ARM 33
Sexual di�erentiation
� of perineum 55�56
Sexual function
� in adults 449�457
� in males a�er ARM 455
� in females a�er ARM 451
SD gene
� in ARM 59�60
� in Danforth mouse 59�60
SD mouse
� Abnormal development in 59
Sigmoid resection 418�419
Sirenomelia
� with ARM 22
Slow transit constipation
� dietary treatment of 389
Social impact
� of ARM 464
Smith, E Durham 6
Smooth muscle transplant 404�408
Sphincter
� internal anal 69�70
� external anal 71
Sphincter complex
� investigation of 195�196
Sphincter muscles

� photographic album of 87�142
Sphincter reconstruction 404
Spinal cord
� cauda equina of 81
� in ARM 81
� lipoma of 282�283
� on ultrasound 197
� tethering in ARM 281�285
Spinal cord anomalies
� in cloaca 208
Spinal deformities 267
Stephens� secondary pull-through 391�392
Stephens� secondary muscle complex repair 392�395
Stephens, F. Douglas 6
Stimulants in diet 387
Striated muscle complex 75�76
� anatomy of 68
� deep component of 76
� electrostimulation of 147
� super�cial component of 76
Support groups 460
Supralevator ARM 34
Surgical method
� role in prognosis 367
Syndrome
� Apert 39
� Cateye 20
� caudal regression 23
� Currarino 23
� Down 7, 20
� FG 21
� Pallister-Hall 21
� Pfei�er 39
� Townes-Brocks 21
Swenson, Ovar 6

T
Testicular feminization syndrome 445
Tethered spinal cord in ARM 281�285
� clinical features 281�282
� outcome 284�285
� pathophysiology 282�283
� prevalence 281
� surgery 284
Tourneux
� folds of 50
Total urogenital mobilization 309�310
Townes-Brocks Syndrome 20
True hermaphroditism 444

U
Ultrasonography
� of spinal cord 197
� transperineal 8
Ultrasound

Page 477

Subject Index480

— and position of colon 191
— infracoccygeal technique 191
Umbilical cord
— in normal development 53
Undesirable food
— in chronic constipation 388
Ureteric anomalies
— with ARM 272
Ureteric ectopia 272
Urethra
— common wall in ARM 75
— duplication of 236
Urethral anomalies 275
Urethrovaginal canal 255–257
Urinary anomalies
— with cloaca 272
Urinary incontinence
— In long-term 370
Urogenital anomalies
— in ARM 37
Urogenital sinus 53, 255
— in normal development 53–54
— variations of in cloacal anomalies 202, 204
Urological anomalies with ARM 269–279
— management 276–277
— long-term evaluation 277
Urorectal septum 50
— and cloacal membrane 53
— descent of 17
— fusion with cloacal membrane 57
Uterus
— development of 55

V
VATER association 7
— in ARM 22
VACTERL association
— in ARM 22, 37, 269
— incidence in ARM 165
Vagina 264
— agenesis of 256–257
— augmentation in cloacal anomalies 312
— colonic replacement 312
— common wall in ARM 75
— development of 55
— variations of in cloacal anomalies 202, 205
Vaginal anomalies
— embryology 441–442
— surgery for 441–448

Vaginal duplication
— in cloacal anomalies 307–308
Vaginal switch maneuver
— in cloaca 311–312
Vaginal atresia 444–447
— Mayer-Rokitansky syndrome 445
— testicular feminization syndrome 445
— acquired anomalies 445
— colovaginoplasty in 445–447
Vaginal reconstruction 441–448, 452–454
Vaginoplasty 453
Vesicointestinal fissure 239–249
— associated anomalies 241–243
— classification of 242
— embryology of 239–240
— genetics of 241
— incidence of 241–242
— management of 243–247
— results 247
— risk factors for 241
— surgery for 243–244
— surgery of
— — anorectal reconstruction 245
— — bladder turn-in 245
— — continence operations 245–246
— — gender management 246
— — gender assignment 246
— — genital reconstruction 246
— — gynaecology 248
— — psychosexual issues 248
— — urinary reconstruction 245
— — world experience 247
Vertebral anomalies
— in ARM 38
— incidence in ARM 165
Vesicoureteric reflux 272

W
Waldeyer’s fascia 332–334, 336
Wangensteen & Rice 5
— invertogram 5
Weaning
— in constipation treatment 389
Wingspread
— conference 8
— classification 8
Wingspread score (1988) 353–354
— — Peńa score (1995) 355
— other scores 355

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