Colonic Atresia: A Series of Four Cases with Two Rare Variants

INTRODUCTION

Colonic atresia (CA) is one of the rarest causes of congenital intestinal obstruction. It occurs in between 1.8% and 15% of all patients affected by atresia of the bowel.^[1–11] The management of CA remains controversial.^[1–4] Treatment ranges from diversion to primary anastomosis. The treatment depends on the type of atresia, the site of atresia, and associated abnormalities. Delayed diagnosis and associated Hirschsprung’s disease further complicate the issues in management. We report a series of four cases of CA. One case was an ileocecal valve atresia, while the other was associated with a distal cystic colonic duplication and proximal colonic web with Hirschsprung’s disease. These two are very rare varieties of CA.^[9–11]

MATERIAL AND METHODS

This was a retrospective study over a period of 2 years, from March 2022 to March 2024. We collected data for all cases of CA operated on by us during the period. We operated on four cases of CA recorded in all patients: age, sex, birth weight, gestational age, symptoms and signs, diagnostic procedures, location and type of atresia, associated anomalies, operative details, and treatment outcomes [Table 1].

RESULTS

We operated upon four term neonates who presented between 2 and 4 days of age with symptoms and signs of distal bowel obstruction but no other gross external anomalies. The weight range was 2.2–3.2 kg, and three were males, while one case was female. All were delivered outside and were referred to us with a history of intolerance to feeds and progressive abdominal distension. In two cases, there was a definite history of infrequent passage of meconium, while in two, the attendants were unaware.

An abdominal radiograph showed dilated bowel loops with a large dilated loop with an air-fluid level [Figure 1]. In all cases, we did a contrast enema to confirm microcolon, confirming a diagnosis of bowel atresia [Figure 2].

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Figure 1:

Abdominal radiograph showing dilated bowel loop with air fluid level.

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Figure 2:

Contrast enema showing microcolon.

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We found type IIIa CA in two patients and type I in one patient. In one case, there was both type IIIa and type I atresia [Figure 3]. One case was type I atresia in the form of an isolated ileocecal valve atresia [Figure 4]. In two cases of type IIIa CA, the atresia was located on the right side of the colon or proximal to the splenic flexure. In one case of type IIIa CA, the atresia was located on the left colon, while there was an additional colonic web at the level of the splenic flexure. The proximal end was distended and bulbous with a terminal, less distended part [Figure 3]. When opened, there was a mucosal web with a perforation in the middle. This case also had a colonic duplication cyst attached to the distal atretic bowel [Figure 3].

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Figure 3:

Intraoperative findings for Case 3; (a) Schematic diagram of anatomy and (b) Figure showing dilated colon with duplication cyst.

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Figure 4:

Intraoperative findings of ileocecal valve atresia; (a) Showing dilated ileum and microcolon and (b) Decompressed ileum opening ileocecal web.

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In two cases of type IIIa, the proximal 10 cm of the dilated colonic segment was excised and sent for biopsy, and a colostomy with a distal mucus fistula was fashioned. This was done to rule out aganglionosis and to avoid ileus due to a dilated bowel.

The mucus fistula was used to flush out contents and to dilate the distal bowel before establishing bowel continuity. A biopsy was taken from the distal bowel too for ascertaining ganglionic status.

In the case of left-sided CA, a colostomy was fashioned, and the distal bowel cystic duplication was excised and sent for biopsy, along with multiple levelling biopsies. The length of the distal colon was 5 cm, and two biopsies were taken: one from the site of the mucus fistula and one just above the peritoneal reflection.

In the case of ileocecal valve atresia, the common web between the dilated ileum and colon was excised [Figure 4]. Appendicectomy was done, and the enterotomy thus created was used to access the colonic web. The excised appendix was sent for biopsy, which had ganglion cells [Figure 5]. This excision of the colonic web was sufficient in this case.

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Figure 5:

Figure showing normal appendix with ganglion cells stained with hematoxylin and eosin with 40x magnification.

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Postoperatively, feeds were introduced between postoperative days 2 and 4. Additionally, parenteral nutrition (only amino acids and dextrose, no lipids) was given to all four patients till they achieved half of the full oral feeds. Average time to full feeds was 8 days (6–12 days). All the patients survived and were kept in follow-up for weight gain and stoma care.

A definitive procedure was completed for all the cases subsequently, except for the case of ileocecal valve atresia, where web excision proved definitive. In the two cases with right-sided CA, bowel continuity was established after 2 months, as the distal bowel was found to be ganglionic. In the case associated with the duplication cyst, the biopsies from the distal bowel and the excised cyst were both aganglionic, while the proximal colon had ganglion cells.

An abdomino-perineal pull-through was done after 4 months for this case. In this procedure, we excised the distal rectum and the distal aganglionic colon through a combined abdominal and perineal route and brought the ganglionic proximal colon to complete the coloanal anastomosis just above the dentate line. Till the recent follow-up, all the cases are doing well without any significant complaints. Operative details are not clear.

DISCUSSION

CA is one of the rarest causes of neonatal intestinal obstructions, comprising 1.8%–15% of all gastrointestinal atresias.^[1–12] Surgical technique, whether to proceed with ostomy in all cases or to individualise the operative procedure to the location of the atresia and the condition of the patient, is still controversial.^[1–4] The presence of Hirschsprung’s disease associated with CA has further complicated the surgical protocol to be followed.^[3]

The classical etiologic factor of most CA is intrauterine extrinsic mesenteric vascular obstruction associated with internal hernia, volvulus, intussusception, or strangulation in tight gastroschisis.^[1,2] Pressure due to intrauterine choledochal cysts has also contributed as evidence for the ischaemic theory.^[5] Other theories in vogue are that intraluminal vascular obstruction due to a placental embolus reaching the foetal mesenteric circulation may cause intrinsic, disturbed morphogenes and, rarely, foetal infection with varicella.^[6–8]

CA has been found to be associated with various anomalies like proximal intestinal atresias, choledochal cysts, gastroschisis, appendiceal duplication, caecal perforation, pelviureteric junction obstruction, anorectal malformations, tracheo-oesophageal fistula, etc. A review of 224 cases of CAs had various other anomalies associated, but none similar to those reported in our case, which was associated with a colonic duplication.^[1] Only 10 cases of isolated ileocecal valve atresia have been previously reported.^[9]

CA is rarely associated with Hirschsprung’s disease.^[1,3] CA with Hirschsprung’s disease usually presents as intestinal anastomosis failure or persistent obstruction after successful restoration of intestinal continuity.^[12] The coexistence of Hirschsprung’s disease with CA can be due to defective caudal migration of ganglion cells beyond the atretic colon.^[12] Another hypothesis, however, suggests that pre-existing antenatal Hirschsprung’s disease (HD) results in a dilated proximal bowel impacted with meconium. This dilated bowel is prone to segmental volvulus, which results in a CA. A third hypothesis labels the association as a disorder of common genetic origin.^[12]

There have been around 20 cases reported in the literature.^[1,3] Of all these, two died due to multiple surgeries and late diagnosis. Only two cases were diagnosed before the definitive procedure, with others diagnosed after complications with the primary procedure.^[1] The scenario, however, has improved recently with the increasing knowledge of the association.^[1,3]

It is reported that 80% of newborns with CA have associated gastrointestinal anomalies, particularly rotation and fixation anomalies.^[8] Of the twenty cases of CA with Hirschsprung’s disease, only 12 cases mention the retroperitoneal fixation of the distal colon.^[1] Of these, two had normal retroperitoneal fixation of the distal colon, while the remainder had a non-fixed, coiled, foreshortened colon.^[1,3] Thus, in a case of CA, HD should be ruled out during the primary operation by rectal and distal and proximal colonic biopsies.^[1–4]

Most of the cases of CA present as distal bowel obstruction, and thus diagnosis is often delayed.^{[1–4,9–11]} The common presentation is abdominal distension associated with feed intolerance.^[1] An initial abdominal X-ray often reveals dilated small bowel loops along with a dilated colonic segment with or without air-fluid levels.^[9–11] Many neonates have a dubious history regarding the passage of meconium. A contrast enema demonstrating a microcolon is diagnostic of an atresia. However, it is difficult to differentiate between a distal ileal and CA, and most are diagnosed intraoperatively.

The optimal management of CA is controversial. Some aim at a primary anastomosis; others recommend a staged approach.^[1–4] Others advocate tailoring the surgical approach according to the location of the atresia and condition of the infant.^[1–4] The classical surgical approach to CA was primary anastomosis in the right CA proximal to the splenic flexure and colostomy with delayed anastomosis distal to this point.^[4] In case of ascending CA, an alternative method of a proximal ileostomy, with mucous fistulas of both the atretic and the distal colon, has been recommended in order to preserve the IC junction.^[4] The proximal and distal ends adjacent to the CA are abnormal in both innervation and vascularity, and thus, a part of both should be resected.^[1–4] In cases with left-sided atresia and associated Hirschsprung’s disease, an initial colostomy with levelling biopsies followed by a pull-through or anastomosis, depending upon the ganglionic status of the distal bowel, was routine.^[1,3] The same was done in our case.

In most of the early cases of isolated ileocecal valve atresias, the dilated ileum along with the cecum was excised, followed by ileocolic anastomosis.^[9–11] However, in a recent few cases, an ileocecal valve reconstruction with preservation of the valve has been successful and is recommended by us too.^[9–11] Mousavi and Sarparast also advised tapering of the dilated ileum for better functioning.^[11]

CONCLUSION

CA is a rare pathology. The treatment should be individualised according to the patient’s condition, level of atresia, and presence of aganglionosis. Delayed recognition of simultaneous colonic aganglionosis is associated with significant morbidity and mortality. Hirschsprung’s disease should be suspected in all cases of CA, regardless of distal colonic orientation, and should be ruled out by biopsies before definitive treatment.