Keywords
Hirschsprung disease - enterocolitis - pull-through
Case Report
You are presented with a 2-year-old boy with a history of Hirschsprung disease (HD)
who has previously undergone a newborn ileostomy, and then a colectomy and pull-through
at 10 months of age, and has subsequently had four episodes of enterocolitis. You
review a contrast enema study that was completed after the patient recovered from
the enterocolitis ([Fig. 1]).
Fig. 1 A contrast enema study.
Discussion
Hirschsprung associated enterocolitis (HAEC) is a feared complication in patients
with HD, which typically presents as abdominal distension, fever, and diarrhea.[1] It can occur both prior to and after HD surgery and can develop when there is stasis,
bacterial overgrowth, and bacterial translocation. Although the exact physiology of
HAEC is unknown, causes for obstruction should be routinely evaluated in patients
who have undergone corrective surgery and thereafter have recurrent HAEC.
Obstructive symptoms in HD patients post pull-through have been reported between 8
and 30% postoperatively, and HAEC has been reported between 25 and 37%.[2] There are five potential explanations for persistent obstructive symptoms after
pull-through:
Initial evaluation with a contrast enema and an examination under anesthesia can help
identify the presence of a mechanical obstruction.[1]
[4] The contrast study provides the answer to the anatomic problem with this case's
pull-through. It is likely that the recurrent enterocolitis episodes are due to mechanical
obstruction caused by a Duhamel spur. We will discuss the Duhamel spur in addition
to the other common causes of mechanical obstruction.
In the case of this 2-year-old boy, the contrast enema shows what appears to be his
rectal pouch compressing the bowel just proximal to it ([Fig. 2]). At 10 months of age, this boy underwent colectomy and ileo-Duhamel pull-through;
however, the Duhamel pouch and pulled-through ileum were not adequately united into
a single lumen, leading to a Duhamel spur. Accumulation of stool in the pouch eventually
causes compression and obstruction of the ileum, leading to stasis and recurrent enterocolitis.
The treatment is to remove the spur. This can be done with an endovascular stapler
placed transanally. In this case, the staple line was extended, thus removing the
spur, and the patient began to stool better and has not had another episode of enterocolitis.
If this maneuver is not possible or does not improve symptoms, then resection of the
pouch and a redo operation with conversion to ileo-anal anastomosis is in order.[3]
[5]
Fig. 2 Contrast enema study showing Duhamel spur. (A) Aganglionic pouch. (B) Ileum pull-through segment.
Other mechanical issues that can be wrong with an HD pull-through include an obstructing
seromuscular cuff, an anastomotic stricture, and a twist of the pull-through.[6] An obstructing seromuscular cuff is a complication from a Soave procedure and occurs
when the residual aganglionic sleeve of the intentionally preserved muscular layer
causes narrowing around the pull-through. This is thought to occur due to a constant
contracted state of the aganglionic muscle[7] and may occur if the cuff is not split, is not split adequately, or rolls up. To
reduce the occurrence of this, many surgeons who perform the Soave pull-through have
modified it so that the amount of residual cuff is limited to just 1 to 2 cm from
the beginning of their dissection.[7] One could affectionately refer to this modification as a “Soave-son” as it is approaching
the Swenson technique. A long obstructing cuff can sometimes be treated with intraperitoneal
division of the obstructing cuff using a laparoscopic approach.[6] Such an approach is most relevant for very long cuffs, or cuffs that were created
during a transabdominal Soave procedure, rather than one done transanally. A redo
transanal pull-through with removal of the muscular cuff and any proximally dilated
colon is also an effective strategy.[7] In the case of anastomotic stricture, these can usually be addressed with serial
dilations although if unsuccessful, resection, and redo pull-through may also be required.[3] A twisted pull-through requires a redo. In addition to mechanical problems with
a pull-through, the distal aspect may be in transition zone which leads to obstructive
symptoms and requires a reoperation.[8]
If no anatomic or pathologic problem is identified, a nonrelaxing motility disorder—even
with an anatomically and pathologically correct pull-through—is a rare occurrence
and is best evaluated by colonic manometry. A functional megacolon should respond
to laxative therapy.
Conclusion
Mechanical obstruction is common after a pull-through procedure in patients with HD.
An anatomic or pathologic cause for obstruction can lead to recurrent enterocolitis,
as well as other obstructive symptoms such as chronic abdominal distension and failure
to thrive. These patients and should be evaluated with a contrast enema and an examination
under anesthesia. It is important for the surgeon to recognize that different complications
exist depending on the pull-through procedure that was initially performed and warrant
different surgical approaches in management. Although some less invasive techniques
exist to address these issues, patients may require a redo of their pull-through to
resolve the obstructive symptoms.
