Keywords

1 Introduction

Atresia of the colon is an uncommon entity distinct from congenital pouch colon, which is a more frequent occurrence in India and Asia and is associated with anorectal malformations. Although the underlying cause may be vascular insufficiency [1, 2], the association with particularly Hirschsprung’s disease [3,4,5] and the gross discrepancy between the proximal and distal bowel diameters militate against management strategies described for small bowel atresias.

2 Demographics

Atresia of the colon is a relatively rare form of intestinal atresia with an incidence of 1:40,000 to 1:60,000 live births and comprises less than 5% of the total number of gastrointestinal tract atresias (4.4% in our series of 248 bowel atresias distal to the duodenum) [6, 7]. There is no gender or racial predilection. There is an association with Hirschsprung’s disease, gastroschisis, malrotation/nonfixation of the bowel, and a more proximal atresia of the small bowel [6]. The association with cloacal exstrophy is well known but will not be described here.

3 Etiology/Pathophysiology

The etiology of colonic atresia remains a subject of debate. The association with gastroschisis and intestinal atresia is thought to be as a result of a vascular accident in utero [2, 8, 9]. Other insults affecting vascular supply such as volvulus and constriction of bowel in a closing umbilical ring have been suggested [10].

It is not clear why aganglionosis is found in some, but it is thought that either the dilated loop proximal to the transition to aganglionosis undergoes volvulus with bowel ischemic injury and the development of atresia or it may suggest an early event whereby migrating nerve cells are arrested in their progress to populate the distal gut [4, 5]. This implies an early gestational interruption. An unfixed mesentery is often noted in cases of colonic atresia coexistent with Hirschsprung’s disease suggesting intrauterine volvulus as a possible etiology [11, 12].

Colonic atresia can occur in any part of the colon with different case series showing predominance of the right or left colon. All types of atresia have been reported with type IIIa being more common in most series [6, 10, 13].

4 Clinical Presentation

4.1 History

Antenatal history may include that of polyhydramnios. Prenatal ultrasound may show a single dilated loop of bowel. Patients present with neonatal intestinal obstruction with gross abdominal distension if it is an isolated colonic atresia.

4.2 Physical

Aspiration of gastric content of a volume > 25 ml via orogastric or nasogastric tube or emesis which is bile stained along with abdominal distension and failure to pass normal meconium is suggestive of a distal bowel obstruction. Abdominal distension may not be so marked in cases with coexistent proximal jejunal atresia, a not infrequent association.

4.3 Investigations

The abdominal X-ray in isolated colonic atresia is typical in showing one or two very dilated gas and fluid-filled loops [13] (◘ Fig. 73.1).

Fig. 73.1
figure 1

AP abdominal radiograph showing a disproportionately large loop of bowel

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A pitfall to be avoided is the colonic atresia distal to a small bowel atresia. At laparotomy, the colon may look normal in outward appearance. It is, therefore, essential for the patency of the lumen of the colon to be evaluated in any small bowel atresia preferably preoperatively by contrast enema.

In addition, before the surgeon intends restoring colonic continuity, a preoperative contrast enema, which typically shows collapsed and disused distal colon (◘ Fig. 73.2), needs to be performed to confirm patency of the distal bowel.

Fig. 73.2
figure 2

Contrast enema of a patient with ileal atresia showing a sigmoid atresia and distal microcolon

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Biopsy of the bowel distal to the atresia showing normal innervation of the bowel to exclude Hirschsprung’s disease is mandatory, if primary anastomosis is contemplated [13]. Likewise, rectal suction biopsy is done prior to stoma closure.

4.4 Management

Management should include full investigation for associated anomalies, exclusion of Hirschsprung’s disease by biopsy of the bowel distal to the atresia [6], and exclusion of a second atresia or stenosis by contrast enema [14].

The appropriate management in terms of best operative strategy remains a debate, possibly because of small case series and limited institutional experience on which to base management options. There has been little consistency of methods in many of the reported series [15]. The fashioning of a stoma at the level of the atresia is the preferred initial treatment rather than an attempt at primary anastomosis – especially if distal patency has not been confirmed or there is a large discrepancy in proximal and distal bowel diameter (◘ Fig. 73.3). The gross dilatation of the blind end may need to be tapered to assist in fashioning a manageable stoma. This can then be followed with stoma closure once the baby is stable and thriving, and results of investigations on the distal bowel are determined.

Fig. 73.3
figure 3

Operative photograph of patient with colonic atresia at the hepatic flexure showing dilated ascending colon and collapsed transverse colon

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As with small bowel atresias, both proximal and distal colonic ends adjacent to the atresia may have abnormal innervation and vascularity, and hence, at the time of anastomosis, a portion of the proximal dilated and distal micro-colon should be resected before anastomosis [16].

Primary resection and anastomosis can only be performed in selected cases if the distal colon is normal and bowel patency has been established, depending on coexistent pathology [16,17,18]. Primary resection and anastomosis have had higher complication rates in some series, usually due to undiagnosed distal pathology [13, 19], while a better prognosis is reflected in other series where most cases have been managed with a primary stoma [14].

5 Postoperative Complications

Missed diagnosis should not occur if the above principles are followed. In our series of 14 cases, there was one mortality due to a second colonic atresia, which was missed in a patient presenting with a small bowel atresia, causing a leak from the more proximal anastomosis, peritonitis, and death [13].

6 Prognosis and Outcomes

Outcomes should be good but are limited by associated intestinal atresia with short gut and the extent of other anomalies. Mortality in various series ranges from 7% to 61% [14, 19]. The type of surgery and coexistent pathology are major determinants of outcome, with initial primary anastomosis frequently being associated with more complications and a worse outcome.

7 Ethical Issues

As in any resource-poor environment, the need for parenteral nutrition may be the major determinant for survival.

8 Evidence-Based Surgery

Available literature on colonic atresia is currently in the form of relatively small case series of between 9 and 15 cases and seeks to identify associated conditions, management options, and predictors of outcome. . Tables 73.1, 73.2, and 73.3 reflect current available literature.

Table 73.1 Evidence-based literature [13]
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Table 73.2 Evidence-based literature [20]
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Table 73.3 Evidence-based literature [21]
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Key Summary Points

  1. 1.

    A very large dilated loop with a fluid level on abdominal X-ray is suspicious.

  2. 2.

    Beware the second atresia in the colon of a patient with a small bowel atresia.

  3. 3.

    Exclude Hirschsprung’s disease of the bowel distal to the colon atresia.

  4. 4.

    Avoid primary anastomosis.

  5. 5.

    Note the association with nonrotation of the midgut.