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Invited Commentary

Double in Imperforate : A Diagnostic Conundrum for Paediatric Surgeons

Chen-Lung Steve Lin, Pek-Lan Khong1 and Paul K.H. Tam, Departments of and 1Diagnostic Radiology, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong.

Anal atresia, i.e. imperforate anus, is not an infrequently seen regularly performed for direct visualization of the distal rectal congenital anomaly with an average worldwide incidence of pouch.9 On the invertogram, the presence of an obstruction 1:5,000 live births.1 Congenital jejunoileal obstruction caused proximal to the , such as stenosis or atresia of the small by atresia or stenosis is also a relatively common cause of bowel or colon, will obviously result in a “high-held” terminal neonatal intestinal obstruction, with an incidence of 1:400 to gas shadow because the intraluminal gas would pause proxi- 1:1,500 live births.2,3 In contrast, colonic atresia is a rare cause mally without reaching the very terminal part of the rectum. of intestinal obstruction in neonates, with an incidence of However, there are still no reports in the literature regarding about 1:20,000 live births.4 Most neonates with imperforate MRI findings in anorectal malformation with concurrent anus have one or more abnormalities that affect other systems. intestinal atresia. Moreover, lower gastrointestinal (GI) con- However, only two of 172 patients with imperforate anus were trast study is certainly not applicable in patients with imperfo- reported to have an intestinal atresia below the duodenum,5 rate anus, and the absence of an antenatal history of polyhy- and only two of 246 patients had an absent colon.3 It is thus dramnios does not exclude the presence of intestinal atresia extremely rare to see a patient with an imperforate anus and either. Therefore, correct preoperative diagnosis in such pa- concurrent ileal stenosis and colonic atresia, as described by tients is difficult to make and inadequate initial manage- Asabe and Nagasaki in this issue of the Asian Journal of Surgery.6 ment often occurs as a consequence, as reported by Asabe and The aetiology of intestinal or colonic atresia is not clearly Handa.10 understood. The current consensus is that there is an in utero We recently encountered a patient with concurrent oeso- mesenteric vascular catastrophe, such as volvulus, intus- phageal atresia and imperforate anus, in whom preoperative susception, incarceration, or strangulation secondary to MRI clearly demonstrated the level of atresia in both segments. hernias, and embolic or thrombotic events,7 which results Division of the tracheo-oesophageal with primary in ischaemia and absorption of the necrotic bowel segment. oesophageal anastomosis and creation of colostoma for the The cause of imperforate anus is regarded as an event in the rectal atresia were successfully performed in the same setting. abnormal embryological development that results from However, emergency laparotomy was conducted the next day defects in the shape of the dorsal (posterior) and an because postoperative abdominal X-ray films showed persist- absence of the dorsal cloacal membrane.8 The lack of relation- ence of a bowel gas shadow with a progressively increasing ship between the causes of intestinal atresia and imperforate size at the right upper quadrant. Surgical findings confirmed anus may, thus, explain the rarity of their co-existence. that there was volvulus of the terminal ileum due to torsion The level of rectal atresia in imperforate anus has tradition- of Meckel’s diverticulum along the axis of the omphalo- ally been assessed by an invertogram, as in the reported case.6 mesenteric duct. In this case, volvulus of the ileum possibly In our institute, we rarely use the invertogram for the diagno- occurred only after GI continuity was re-established by sis of congenital anorectal malformation. Instead, magnetic oesophageal anastomosis which allowed air entry into the resonance imaging (MRI) of the in these patients is distal bowel.

Address correspondence and reprint requests to Dr. C.L. Steve Lin, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong. E-mail: [email protected]

© 2004 Elsevier. All rights reserved.

52 ASIAN JOURNAL OF SURGERY VOL 27 • NO 1 • JANUARY 2004 070/2001 ■ DOUBLE INTESTINAL ATRESIA IN IMPERFORATE ANUS ■

In summary, lower intestinal atresia associated with im- Ashcraft KW, eds. . Philadelphia: WB Saunders, perforate anus is difficult to diagnose preoperatively and 1980;331–45. 4. Benson CD, Lotfi MW, Brough AJ. Congenital atresia and stenosis often necessitates a second operation. It is therefore important, of the colon. J Pediatr Surg 1968;3:253–7. 6 as suggested by Asabe and Nagasaki, that a vigorous search 5. Lister J. Intestinal atresia and stenosis, excluding the duodenum. for the presence of another GI obstruction should be per- In: Lister J, Irving IM, eds. Neonatal Surgery, 3rd edition. London: formed at the first laparotomy when the terminal gas shadow Butterworth-Heinemann, 1990;453–73. 6. Asabe K, Nagasaki A. Double atresia of the hindgut with ileal on an invertogram is too high up in this group of patients. stenosis: a case report. Asian J Surg 2004; 27:49–51. 7. Santulli TV, Blanc WA. Congenital atresia of the intestine: References pathogenesis and treatment. Ann Surg 1961;154:939–48. 8. Kluth D, Hillen M, Lambrecht W. The principles of normal and 1. Stephens FD, Smith ED. Anorectal Malformations in Children. abnormal hindgut development. J Pediatr Surg 1995;30:1143–7. Chicago: Year Book Medical Publishers, 1971. 9. McHugh K, Dudley NE, Tam P. Pre-operative MRI of anorectal 2. DeLorimier AA, Fonkalsrud EW, Hays DM. Congenital atresia and anomalies in the newborn period. Pediatr Radiol 1995;25:S33–6. stenosis of the jejunum and ileum. Surgery 1969;65:819–27. 10. Asabe K, Handa N. Anorectal malformation with ileal atresia. Pediatr 3. Touloukian RJ. Intestinal atresia and stenosis. In: Holder TM, Surg Int 1997;12:302–4.

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