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A. K. Mackow
complex and require careful endoscopic evaluation, as well as contrast studies, to evaluate the
urinary and genital tracts in addition to the distal
colostomy. Following separation of the rectum
from the urogenital sinus, the entire urogenital
tract is mobilized away from the clitoris and the
common channel is divided in the midline to create aps to help create the neovagina and reconstruct the introitus (Fig.4.5). For patients with a
longer common channel, this total urogenital
sinus mobilization will be insufcient to achieve
sufcient length for reconstruction. These infants
should receive a total body preparation because
a
they will require a laparotomy to mobilize the
genital tract. This dissection is exceedingly complex and may require cystotomy with cannulation
of the ureters, as these reside in the long common
wall between the bladder and vagina. Depending
on the anatomy of the genital tract, vaginal reconstruction may then be undertaken with the use of
a duplicated hemivagina (called the vaginal
switch maneuver by Peña) or portions of the gastrointestinal tract. If the distal rectum is wide
enough, it is possible that a well-vascularized
segment of the distal rectum can be separated (for
use as a vaginal replacement) from the remainder
Fig. 4.5 Illustration of operative steps to repair cloacal
malformation—(a) Total urogenital sinus mobilization
(cloaca with a short common channel, <3 cm). (b) The
rectum is separated from the urogenital sinus. (c) Sutures
are placed around the urogenital complex for uniform
traction to facilitate mobilization of the urogenital sinus.
Reprinted with permission from [6] © 2012 Elsevier
4 Congenital andPediatric Anorectal Conditions
71
of the rectum tapered for use in the anorectoplasty. If this is not possible, using a portion of
the mobile rectosigmoid or even the distal colostomy can be considered, with the small bowel
used as the least favorable option. If the vaginal
tract opens directly into the bladder neck or trigone, a vesicostomy should be created, with consideration for eventual continent urinary diversion
vs a bladder neck reconstruction; vaginal replacement can be done as otherwise described [6].
Laparoscopic-Associated Anorectoplasty (LAARP)
The laparoscopic approach has been mainly
applied to the higher anorectal malformations
(such as rectobladder neck or rectoprotatic stulas, or even cloacal anomalies) [20–27].
Georgeson described this technique in 2000, as
he initially developed the technique of a laparoscopic pull-through for Hirschsprung’s disease
and then applied it to anorectal malformations
[22]. The dissection is undertaken at the level of
the peritoneal reection to identify and divide the
mesorectum, staying on the rectal wall until the
stula can be clipped and divided. The rectum is
then retracted out of the pelvis to reveal the pelvic musculature. Approaching the perineum
externally, with use of an electrical stimulator to
identify the sphincter complex, an 8mm incision
is made over the complex. Gentle blunt dissection in the midline is undertaken, guided by the
intrapelvic light from the laparoscope. Following
this, a Veress needle, with a sheath for a 10mm
radially-dilating port, is introduced through the
midline of the sphincter complex under direct
visualization. Once the needle is optimally positioned, the port can be introduced through the
sheath and the end of the rectum brought out as
the port is removed. The anorectoplasty is then
fashioned and the rectum tacked to the presacral
fascia under laparoscopic guidance [22].
Direct comparison of the LAARP and PSARP
has been attempted in several instances, with the
suggestion that outcomes are comparable [23, 26,
27]. Ming reported that there were more morbidi-
ties for the PSARP, including wound infection
and recurrent stula, but that rectal prolapse
occurred in 7.5% of the patients undergoing
LAARP [23]. Another study reports a higher
incidence of posterior urethral diverticula with
LAARP [26], while a different study reported
more surgical complications (including damage
to the vas deferens and urethra) with LAARP
[27]. Perhaps the greatest challenge in comparing
the two procedures, however, is a lack of specicity in the description of the LAARP technique
and a lack of standardization in comparing results
of the two procedures [26].
Bowel Management
Although constipation can be a major issue for
some patients, the issue that is considered most
important to most patients and families is that of
long-term bowel control or continence. When
evaluating a patient with fecal incontinence, of
primary importance is the distinction to be made
between patients with pseudoincontinence and
true incontinence. Pseudoincontinence refers to
fecal impaction with overow incontinence,
which requires disimpaction followed by a regimen of laxatives. Patients who fall into this group
tend to be patients with anorectal malformations
with a good prognosis for continence (perineal
stulas, rectovestibular or rectobulbar stulas,
cloacas with common channel <3cm and imperforate anus without stulas), as well as some
patients with Hirschsprung’s with ongoing with
constipation. These patients will need to be kept
on a laxative regimen (e.g., senna-based), sometimes requiring the aid of a bulking agent to make
stool more formed before it is passed [28, 29].
Patients with true fecal incontinence have no
potential for bowel control, having been born
with anorectal malformations with poorer prognosis for continence (bladder neck stulas, cloacas with longer common channel, an abnormal
sacrum, large sacrococcygeal teratoma, spina
bida, or Hirschsprung’s disease in which the
dentate line was not preserved during the
pull-through). Relying on the fact that colon transit takes up to 24 h, a bowel management program uses daily enemas to empty the descending
colon and rectosigmoid in order to maintain
patient cleanliness. The type of enema relies on
72
A. K. Mackow
whether the colon appears dilated or nondilated
on initial contrast enema, as the latter suggests a
hypermotile colon that may require loperamide
and a bulking diet to prevent small amounts of
stool to be emitted in between enemas. The former type of colon will require a larger volume
enema that can be graduated in concentration
from normal saline to an enema containing soap
or Fleets phosphosoda [28, 29]. A well-established method of determining the right amount
and concentration of this enema was rst demonstrated by the group at Cincinnati Children’s
Colorectal Center, utilizing a week-long trial,
with daily assessment utilizing abdominal lms
to titrate the enemas.
The enemas as described above, are administered utilizing a Foley balloon to allow full
administration of the enema over 5min, followed
by a “dwell time” of 10min, then 45min of sitting on the toilet to allow for evacuation. The
enema concentration and volume are adjusted
based on whether the enema achieves evacuation
of the full stool burden, and whether the patient is
having “accidents” between enema administrations [28]. Once the enemas have been established as an effective maneuver for maintaining
cleanliness, and when the child is of sufcient
age and ability to cooperate, the patients may be
offered an appendicostomy or cecostomy to facilitate self-administration of antegrade enemas.
These may be accomplished through use of a
tube appendicostomy (such as a Chait tube) that
can be created laparoscopically [30], or a continent appendicostomy brought up through the
umbilicus utilizing a cecopexy to create a valve
mechanism allowing administration of the ush
without backow of the enema [31].
Hirschsprung’s Disease
nize the pathologic signicance of these differences. The understanding that this was related to
a lack of ganglion cells in the myenteric and submucosal plexuses of the bowel was not recognized until 1948, despite an apt description of the
lack of nerve cells in the myenteric plexus by
Tittel in 1901 [33].
Hirschsprung’s disease is diagnosed in
approximately one out of every 4400 patients
[34, 35]. Hirschsprung’s incidence has been
thought to be relatively low in premature infants,
reported from 4 to 8% [36]. However, Baxter’s
review revealed a rate of 19% in 132 pre-term
patients [37], who were more likely to be diagnosed after 30days of age, undergo staged procedures and have presentations with Hirschsprung’s
associated enterocolitis (HAEC) than their fullterm counterparts. The reason for delay in diagnosis may be related to the usual development
and onset of function of the enteric nervous system—although the craniocaudal neural crest cell
migration may be complete within the rst
13weeks of gestation, the activity of this system
does not start until late in gestation [38].
As with anorectal malformations, there is an
association between Hirschsprung’s and Down’s
syndrome, or Trisomy 21. Over time, there has
been increasing recognition of this association, as
2.7% of children with Down’s also have
Hirschsprung’s disease [39], and the overall incidence of Down’s in the Hirschsprung’s population has been estimated from below 3% to up to
16% [39–41]. These patients tend to have more
severe disease—long segment involvement, more
episodes of Hirschsprung’s associated enterocolitis and worse outcomes with respect to longterm constipation [41]. In addition to Down’s
syndrome, Hirschsprung’s is associated with
congenital heart disease, and congenital central
hypoventilation syndrome (Ondine’s curse) [42].
Harald Hirschsprung, a Danish pediatrician, is
credited with the most complete, although not the
rst, description of two children with what he
termed as congenital megacolon [32, 33],
Although his report described the outward
appearance of the dilated bowel and non-dilated
rectum in both of these patients, he did not recog-
Pathophysiology
The characteristic pathologic nding is a lack of
ganglion cells in the submucosal (Meissner) and
myenteric (Auerbach) plexus [33, 43], associated
with an increase in hypertrophied nerve trunks
4 Congenital andPediatric Anorectal Conditions
73
[44]. It appears that the lack of ganglion cells
leads to an excess of acetylcholinesterase activity
in the lamina propria and muscularis mucosae
[45], which has been well-demonstrated by
pathologic staining. The aganglionic segment
involves the distal-most colon and extends proximally; notably, 75–80% involve the rectum and
sigmoid colon [40, 46]. The lack of normal neural transmission in the distal bowel causes an
inability of that segment to undergo normal peristalsis, resulting in functional obstruction and
dilation of the normal bowel proximal to this
point.
Presentation
Neonatal Obstruction
The classic teaching is that the vast majority of
Hirschsprung’s patients fail to pass meconium
within the rst 24h, but this is does not necessarily correlate with a high incidence of diagnosis
during the initial newborn period [40, 42, 46].
Despite the incidence of presentation with failure
to pass meconium within 24h (90%), abdominal
distention (92%) and bilious emesis (75%), in
Grosfeld’s experience [46], only 38% were diagnosed as neonates, while 36% were infants
(22 days to 2 years) and 26% children
(2–18 years). Over time, recognition of
Hirschsprung’s in the early neonatal period has
improved to the point that the average age of
diagnosis decreased from almost 18.8months of
age in the 1960s to 2.6months in the 1980s [36].
Multicenter outcomes data in 2003 suggested
that ~60% of neonates are diagnosed with
Hirschsprung’s within the rst month of life [47];
more recent studies utilizing the National
Inpatient Sample suggest that presentation within
the rst week is rare (6.5%) and grows to 60% by
a year of age [48].
Childhood Constipation
Workup for constipation in the pediatric population should include rectal biopsy and barium
enema. Per Swenson, these children generally
present with abdominal distention and, depending on the length of affected intestine, either an
empty rectum if they have long segment disease
or palpable stool and fecal impaction if a shorter
segment was involved [40]. Klein’s report also
corroborated that 80% of those presenting outside the newborn period had abdominal distention [36].
Hirschsprung’s-Associated Enterocolitis (HAEC)
A severe form of enterocolitis that presents specically in Hirschsprung’s disease was wellcharacterized by Bill in 1962, when they
described severe, explosive, watery diarrhea that
could be fatal [49]. Patents may present with
enterocolitis in 6–29%, while 5–42% may
develop post-pull-through enterocolitis [47, 50].
HAEC is theorized to be related to a partial
obstruction leading to stasis and mucosal ischemia in the ganglionic segment, eventual bacterial translocation and severe systemic
inammatory response [50]. Teitelbaum characterized the primary risk factors as being presentation after 1week of age and Down’s syndrome
[47]. When present, HAEC requires prompt
attention to effecting stool egress with rectal irrigations (10–20mL/kg), use of intravenous uids
for resuscitation and antibiotics. Metronidazole
has become the antibiotic of choice and can be
used by mouth or intravenously, as warranted by
the clinical presentation. The life-saving potential of irrigations or colostomy to halt the systemic insult cannot be underscored enough.
Diagnosis
Contrast Enema
When abdominal x-ray suggests the diagnosis
with dilated loops of bowel, or air-uid levels in
the rectum, these ndings are generally corroborated with an unprepped contrast enema. The study
is considered diagnostic with demonstration of a
transition between dilation of normal bowel proximal to the aganglionic segment (Fig. 4.6).
However, the radiographic transition point has a
reported sensitivity of 65–80% and specicity of
60–76% [51, 52], and does not always correlate
with the pathologically-determined level [53].
74
Fig. 4.6 Contrast enema in patients with Hirschsprung’s
disease with transition zone between descending and sigmoid colon
Another diagnostic sign is reversal of the normal
recto-sigmoid ratio—the caliber of the rectum
should be larger at rest than that of the sigmoid, as
the rectum acts as a reservoir, distending until defecation occurs. However, the reliability of contrast
enema with respect to both transition zone and rectosigmoid ratio has been shown to be age specic,
with a higher sensitivity and specicity shown in
infants and older children than in neonates [54].
Another helpful adjunct is that of the retention of
rectal contrast on a 24-h delayed lm, with a specicity of 85% for Hirschsprung’s disease [55].
Anorectal Manometry
Manometric evaluation of the anorectum was rst
undertaken by Swenson in 1949, with the characteristic nding of higher anorectal resting tone
and loss of the usual recto-anal inhibitory reex
(RAIR) displayed when stool presents to a rectum
not yet lled for defecation [56]. Interestingly,
although loss of RAIR is characteristic of
Hirschsprung’s disease, anorectal manometry can
also present false negative results. Anorectal
manometry is therefore considered more effective
at ruling out the diagnosis in constipated children
than in making a denitive diagnosis itself [56].
A. K. Mackow
Rectal Biopsy
Suction vs. Full-Thickness
The gold standard of diagnosis is rectal biopsy.
Work done on characterizing these pathologic
specimens showed that the paucity of ganglion
cells extended further caudally in the submucosal
plexus than in the myenteric plexus [43], which
validates the diagnostic ability of suction rectal
biopsy [57]. Introduction of a suction biopsy device
per rectum relies on the application of sufcient
negative pressure to provide standardized pieces
of mucosa and underlying submucosa. Biopsies
should be undertaken at least 1–2cm proximal to
the dentate line as there is a normal “anal transition
zone” in which there are no ganglion cells present
[43]. Additional diagnostic conrmation is provided by identication of hypertrophied nerve
trunks [44], and acetylcholinesterase staining
showing heightened activity in the lamina propria
and muscularis mucosae [45].
Such biopsies can be accomplished at bedside,
with centimeter markings along the barrel of the
device facilitating proper levels—at least 2 cm
from the anal verge for newborns. Generally
speaking, these should be taken at 3 points, posteriorly; specimens may require careful separation from the device using a ne hypodermic
needle, before placement into separate formalin
containers for pathologic analysis.
In older children, suction rectal biopsy cannot
provide adequate sampling of the submucosa.
These children are taken for a rectal examination
under anesthesia, with the child in lithotomy position, using a nasal speculum to visualize placement
of separate 3-0 or 4-0 absorbable sutures at 2, 4 and
6cm from the dentate line to provide traction exposure. The intervening mucosa can be biopsied
down to the muscularis in wedge-shaped fashion,
placed on a non-adherent material and sent separately in formalin; the proximal suture to the biopsy
can then used to close the mucosal defect.
Management
The principal of denitive operative management
of these patients is to bring the normal ganglionic
4 Congenital andPediatric Anorectal Conditions
75
bowel to the anus while preserving sphincteric
function. Swenson rst proposed this in 1949 as
a full thickness resection of the aganglionic
bowel starting 2.5–3cm proximal to the dentate
line [58]. Prior to this, other management strategies had been proposed, including resection of
the dilated bowel leaving a normal-appearing
rectum in place, and attempts at sympathectomy
because physiologic studies suggested increased
sympathetic tone in the affected bowel. Once
Swenson noted that colon function and size normalized after colostomy creation, he suggested
bringing normal bowel down to the anus in order
to bypass a functional obstruction in the rectosigmoid colon [58]. Initial experience with the
Swenson technique intimated that mortality was
higher in the neonatal population, and due to this
and other morbidities [59], other techniques
were proposed in the next 15–20years: a retrorectal pull-through by Duhamel [60] and a submucosal pull-through by Soave [61]. These
techniques have all been modied over time,
with some of the primary innovations including
the initiation of primary pull-throughs in the
neonatal population to obviate the need for a
colostomy, starting in 1980 [62] and conrmed
to be a safe alternative to staged procedures by
Teitelbaum in his report in 2000 [63]. Following
this, Georgeson’s described a laparoscopic
pull-through in 1995 [64] and a completely
transanal dissection was proposed by Langer in
1999 [65]. Current practice among pediatric surgeons tends to favor the completely transanal or
laparoscopic-assisted transanal approach to an
endorectal pull-through of either the Soave or
Swenson technique [66, 67].
Surgical Approaches
Swenson
The classic description by Swenson began as a
closed division of bowel 12cm proximal to the
visible transition zone via laparotomy, with
mobilization of the normal bowel to a tensionfree anastomosis. Following this, he everted the
distal end through the anus and divided the aganglionic bowel 2.5cm proximal to the sphincter,
completing the pull-through in two layers after
gently pulling through the end of the normal
bowel (Fig.4.7a) [58, 59].
Duhamel
Duhamel considered his pull-through to be a
modication of Swenson’s technique. The purpose of the modication was to avoid potential
urinary and sexual dysfunction that could result
from the full thickness dissection of the rectum in
the pelvis, and some complications related to the
end-to-end anastomosis, such as structuring. He
detailed his technique as resecting the aganglionic segment at the level of the peritoneal reection, leaving a Hartman’s pouch of aganglionic
bowel. The proximal bowel was mobilized and
the retro-rectal space dissected to pass the normal
colon posterior to the aganglionic segment. He
then turned to the perineal dissection, utilizing a
posterior incision at the anocutaneous junction to
dissect in the plane between the anal mucosa and
the external sphincters until the pull-through segment could be sutured to the anal mucosa cranial
to the external sphincter. Two Kocher clamps
were then applied to the apposed walls of the
aganglionic native rectum anteriorly and the
pull-through segment posteriorly, creating a
crush-clamp anastomosis (Fig. 4.7b) [60].
Currently, a stapler is used to complete the anastomosis. This technique is often used as a
“rescue” for a failed Swenson or Soave
pull-through and is thought to cause problems
with constipation [69].
Soave
Soave’s technique was initiated with hydrodissection, injecting lidocaine into the seromuscular
layer to facilitate its separation from the mucosal
layer, from the level of the peritoneal reection.
The subsequent perineal dissection was undertaken after dilation of the anus, followed by circumferential incision of the mucosa 1 cm
proximal to the dentate line, proceeding proximally until the two planes of dissection were
joined. The normal colon was then pulled down
to the level of the mucosal dissection and the cut
seromuscular edge sewn to the proximal colonic
wall after a pelvic Penrose drain was introduced
76
A
A
FG
A. K. Mackow
a
B
C
b
E
B
C
D
Fig. 4.7 Depiction of three main pull-through types: (a)
Swenson pull-through—a: Resection of the aganglionic
and dilated bowel. b: Pull-through of normal ganglionic
bowel. c: Operation nished. (b) Duhamel pull-through—
a: Resection of dilated portion and part of the aganglionic
segment. b: Presacral, rectorectal dissection. c: Pull-through
of normal ganglionic bowel. d: Incision of the posterior rectal wall. e: Pull-through of normal ganglionic bowel
through the window in the posterior rectal wall. f: Creating
a wide anastomosis between normal ganglionic and aganglionic segment. g: Finished operation. (c) Soave pullthrough—A: Resection of dilated colon plus intraperitoneal
aganglionic segment. B: Endorectal intrapelvic dissection.
C: Resection of the mucosal aganglionic segment down to
the pectinate line. D: Pull-through of normal ganglionic
bowel through the muscle cuff and anastomosis 1cm above
the pectinate line. Reprinted with permission [68] © 2006
Springer
4 Congenital andPediatric Anorectal Conditions
c
A
77
B
C
Fig. 4.7 (continued)
between layers. He left the pull-through segment
exteriorized and completed the anastomosis in
delayed fashion, using a rectal tube for post-operative decompression until normal function was
regained. After several weeks, daily dilations
would then be undertaken for several postoperative months (Fig.4.7c) [61].
Modern modication of this technique has led
to splitting the posterior muscular cuff, immedi-
D
ate completion of the anastomosis, and adoption
of a totally transanal approach for rectosigmoid
and short segment disease [65, 67].
Modern Approach
Georgeson proposed a laparoscopic procedure
combined with a submucosal transanal dissection. Laparoscopy was undertaken initially, with
mobilization of the colon and rectal dissection
78
A. K. Mackow
into the pelvis. Transanal approach was then
facilitated by hydrodissection [64]. Langer’s
modication initiated the dissection transanally,
taking intraoperative frozen sections to conrm
the level of aganglionosis before completing
resection and pull-through of a segment several
centimeters proximal to the transition zone [65].
An initial evaluation of long-term outcomes of
the Soave showed concerning ndings that a
transanal approach had worsened outcomes with
continence, but lower rates of HAEC than the
transabdominal approach [70]. However, further
evaluation with a multicenter trial showed that
the transanal pull-through had fewer initial complications and no difference in terms of continence or stooling patterns [71].
Generally, preoperative preparation includes
rectal irrigations (10–20mL/kg of normal saline),
and often enteral neomycin and erythromycin. In
the operating room, laparoscopy can be utilized
to obtain intraoperative frozen sections if desired
for assistance of the transanal dissection. Biopsies
are generally taken at the transition point and
proximally; while pathology is being evaluated,
the mesentery is divided and the proximal segment mobilized. Indeed, transanal dissection can
also be initiated if the transition zone appears
quite obvious, but may interfere with the maintenance of pneumoperitoneum for further biopsies
and mobilization if necessary.
Long-Segment Disease
Long-segment or total colonic disease occurs in
2–13% of patients and present a particular diagnostic and treatment challenge [72]. The aganglionosis may even extend into the small bowel,
which may result in treatment for intestinal failure requiring total parental nutrition and a proximal stoma, with all the concomitant risks [42].
Operative treatment may involve modication
of Duhamel to utilize a longer segment of aganglionic bowel to take advantage of the increased
motility of the small bowel and the reservoir
function of the retained aganglionic rectum [42,
73]. These patients have a high-risk of preopera-
tive (20%) and postoperative HAEC (55%), but
have surprisingly reasonable long-term
outcomes [73].
Complications
Post-operative complications from a pull-through
can be grouped into the following three categories—incontinence, constipation and HAEC.
Incontinence
The major diagnostic dilemma is determining
whether the incontinence is a true incontinence due
to lack of rectal sensation or overow incontinence
deriving from fecal impaction. If a pull-through is
performed too close to the dentate line, the removal
of the native rectal mucosa—able to sample rectal
contents and determine whether they are solid, liquid or gas—leads to incontinence that must be
treated with a bowel management program. If,
however, the problem is related to fecal impaction,
then more workup ought be undertaken [69].
In long-term studies, incontinence does appear
to be a signicant issue in 12–32% of Hirschsprung’s
patients [74, 75], with a larger number of patients
experiencing “incomplete continence,” or a worsened stooling pattern compared to age-matched
normal patients in 71–75% [74]. These outcomes
appear to improve over time as shown by a study of
long-term outcomes in 107 patients over 22years—
48% of patients under 5years old reported problems with continence, compared to 8% in patients
over 15years old [76], These results were corroborated by Aworanti based on continence scores in a
cohort followed after pull-through [77].
Constipation
Persistent problems with stooling occur in
10–13% of patients overall [74], do not seem to
improve as much as continence [76, 77]. Some of
the problems are anatomic, such as anastomotic
stricture, a “spur” following Duhamel—which
may require reoperation—or a tight muscular
cuff following a Soave [69, 78, 79] Some patients,
particularly those with longer segment disease,
may have motility issues affecting the proximal
bowel (based on a “Sitz” marker study) that lead
to a diagnosis of intestinal neuronal dysplasia
[79]. Other issues may be related to an inadequate
pull-through due to acquired or retained aganglionosis that require redo pull-through [69].
Internal anal sphincteric achalasia, if preset, has a
Having constipation/ recurrent
Clinical response?
4 Congenital andPediatric Anorectal Conditions
79
reasonable response to botulinum toxin A
(Botox®) injection [79, 80]. A nal category,
diagnosed by exclusion, is that of functional
megacolon, characterized as stool-holding behavior unresponsive to botulinum toxin injection and
requires long-term bowel management [69, 79].
HAEC
As noted above, HAEC may be present at initial
diagnosis, or occur post-operatively in 5–42% [47,
81]. Postoperative HAEC may lead to anastomotic
stricture with treatment including dilations, or even
a redo pull-through if recalcitrant to dilation alone.
HAEC may respond to botulinum toxin injections
to relax the internal anal sphincter or with posterior
myectomy if the episodes become recurrent.
Although prevention is the best treatment for
HAEC, a randomized controlled trial of the use of
post-pull-through probiotics did not show it to be
effective in decreasing its incidence [82].
Reoperation
There are different reoperative algorithms for
patients with ongoing issues following pull-through
(Fig. 4.8) [69]. The least invasive is progressive
serial anal dilation, as for strictures; if the stricture
proves unresponsive, a limited stricturoplasty or
redo pull-through would be the next step.
Botulinum toxin can be used as an intersphincteric
injection of 3–5mg/kg in divided doses, and may
require multiple reapplications, as effects may only
last 3–6months. Posterior myotomy or myectomy
may be employed in the presence of recurrent
enterocolitis or severe constipation with a normal
rectal biopsy, or potentially selectively with a
shorter retained segment of aganglionic bowel [69,
81]. A redo pull-through requires careful planning
and evaluation, as it is fraught with greater risks
due to obscured planes from previous dissection
and scarring, as well as an increased risk of bleeding and other morbidity (Fig.4.9) [69].
Fig. 4.8 Algorithm for treatment of post-pull-through complications. Modied from [69]
Contrast enema
Colon dilated
Try botulinum
toxin
Yes
Posterior
myectomy,
consider
ostomy
enterocolitis following pull-through?
Rectal exam
Colon twisted
?
No
improvement
Stricture
Dilations
No improvement
pull-through
Redo
Rectal biopsy
Ganglia present
Constipation Enterocolitis
Clinical response?
No
?
No
improvement
Ganglia absent
Try
botulinum
toxin
YesNo
Posterior
myectomy