Vitellointestinal Duct Anomalies

Abstract

The omphalomesenteric duct (OMD) is the embryonic structure connecting the primary yolk sac to the embryonic midgut. In normal circumstances it becomes a thin fibrous band, which eventually disintegrates and is absorbed spontaneously at the fifth to tenth week of gestation. The omphalomesenteric duct will continue to grow if it fails to disintegrate completely; failure of such closure may result in the OMD remnants. There are many mechanisms for small-bowel obstruction from a persistent omphalomesenteric duct; these include intussusception in the case of a patent omphalomesenteric duct, volvulus or internal hernia (closed-loop obstruction) from a patent omphalomesenteric duct or a fibrous connection between the umbilicus and the ileum. A patent OMD and Meckel’s diverticulum are clinically significant because they may lead to intestinal obstruction. In general, the most appropriate treatments of small-bowel obstruction as well as timing of surgery remain controversial. A lot of confusion exists not only in literatures but also in textbooks dealing with theses anomalies, about the presentation and classification, so we will try to explain each anomaly, in a simple way, with a new classification covering the common anomalies as well as the rare case reported. Midgut prolapse and congenital umbilical appendix are rare entities related to vitellointestinal duct anomalies, reported separately, but I included it herein with the other known anomalies.