Laboratory Studies
For healthy children undergoing umbilical hernia repair or excision of omphalomesenteric or urachal remnants, routine laboratory tests are not needed. However, for infants with necrotizing fasciitis, who may be extremely ill, umbilical cultures and blood cultures are needed. Frequent hematologic, electrolyte, and blood gas analyses may be necessary.
Imaging Studies
Radiography is not indicated in most children with umbilical disorders. Umbilical hernias are diagnosed by means of physical examination.
Fistulography or sinography may be performed if a definitive opening is observed within the umbilicus. Fistulography can be performed by injecting water-soluble contrast medium into the opening at the base of the umbilicus. If the track is blind-ended, the child has a sinus; if it enters the intestine or bladder, a fistula is present.
Ultrasonography is helpful when a mass is present. It may be useful in identifying cysts of the umbilicus. Evaluating for a urachal cyst is useful; this cyst most commonly appears as a mass between the umbilicus and suprapubic area. Ultrasonography can also be used to identify a patent urachal fistula between the umbilicus and bladder.
Plain radiography may be useful in children with omphalitis. Air in the subcutaneous tissue or muscle planes is an ominous sign. An umbilical hernia may be incidentally observed on an upper gastrointestinal tract contrast study with small-bowel follow-through (see the image below).
Upper gastrointestinal contrast study showing incidental umbilical hernia in an infant. Red line outlines the umbilical hernia. The arrow shows contrast flowing into the intestine within the umbilical hernia. The umbilical hernia was easily reducible and no intervention based on this study was performed.
Cystography or cystoscopy may be indicated to identify bladder outlet obstruction in children draining frank urine from a urachal fistula. However, studies suggest that, in most cases, history and ultrasonography are sufficient for the diagnosis. [7]
Histologic Findings
The histology of umbilical remnants depends on the tissue of origin and may reveal intestinal or gastric mucosa. Examination of urachal remnants shows transitional or columnar epithelium.
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Cartoon illustrating the developing umbilical cord. (A) Embryonic disk: At this stage, the ventral surface of the fetus is in contact with the yolk sac. (B) The yolk sac narrows as the fetus grows and folds. The intracoelomic yolk sac forms the intestine and communicates with the extracoelomic yolk sac through the vitelline duct. The vitelline duct is also referred to as the omphalomesenteric duct and the yolk stalk. The allantois has begun to grow into the body stalk. (C) The yolk and body stalks fuse to become the umbilical cord.
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Umbilical region viewed from the posterior surface of the abdominal wall of an infant with the umbilical cord attached. UA: Umbilical artery; UV: Umbilical vein; RL: Round ligament (obliterated umbilical vein); UR: Umbilical ring; UL: Umbilical ligament; medial (obliterated umbilical arteries); median (obliterated urachus). Note fascial covering of surface and umbilical ring.
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Variations in the umbilical ring structure. (A) Usual configuration of the round ligament and urachus. (B) Less common configuration that can result in weakness at the umbilical ring.
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Preoperative photograph demonstrating umbilical hernia with redundant skin.
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Omphalomesenteric duct remnants. (A) Meckel diverticulum. Note feeding vessel. (B) Meckel diverticulum attached to posterior surface of anterior abdominal wall by a fibrous cord. (C) Fibrous cord attaching ileum to abdominal wall. (D) Intestinal-umbilical fistula. Intestinal mucosa extends to skin surface. (E) Omphalomesenteric cyst arising in a fibrous cord. The cyst may contain intestinal or gastric mucosa. (F) Umbilical sinus ending in a fibrous cord attaching to the ileum. (G, H) Omphalomesenteric cyst and sinus without intestinal attachments.
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Photograph of newborn with intestinal prolapse through a patent omphalomesenteric duct. Both the proximal and distal limbs of the intestine have prolapsed. The umbilicus was explored, the bowel was easily reduced, and the patent duct was excised. The child was discharged from the hospital 2 days later.
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Anatomic relationship between the umbilicus and its embryologic attachments.
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Laparoscopic removal of urachal cyst (U). L indicates the left medial umbilical ligament. R indicates the right medial umbilical remnant. B indicates the bladder. The distal attachment to the bladder is being grasped.
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Laparoscopic removal of urachal cyst. View is from left lower abdomen port. The umbilicus is on the right and the bladder on the left. The attachments or the urachal cyst to the bladder and the umbilicus have been clipped (not shown) and divided. Note the convergence of the right and left medial umbilical ligaments as they approach the umbilical ring on the right.
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Photograph of laparoscopically removed urachal cyst and its attachments.
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Urachal sinus with purulent drainage in midline below the umbilicus (black arrow). A laparoscope was placed in the supraumbilical crease (red arrow) for mobilization of the internal portion of the urachal remnant as depicted in the next image.
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Urachal cyst mobilized by the laparoscopic approach. Arrow demonstrates sinus communication through abdominal wall and skin 3 cm inferior to the umbilicus. See next image.
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External mobilization of urachal sinus through abdominal wall incision 3 cm inferior to umbilicus. Patient presented with recurrent drainage and infection from sinus. The internal portion was mobilized laparoscopically. See previous image.
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Neoumbilicus following umbilicoplasty.
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Upper gastrointestinal contrast study showing incidental umbilical hernia in an infant. Red line outlines the umbilical hernia. The arrow shows contrast flowing into the intestine within the umbilical hernia. The umbilical hernia was easily reducible and no intervention based on this study was performed.
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Laparoscopic view of urachal fistula, which extends from umbilicus above to bladder below. Image courtesy of Eugene S Kim, MD.
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Laparoscopic view of remnant fibrous band of omphalomesenteric duct, which extends from umbilicus to terminal ileum below. Image courtesy of Eugene S Kim, MD.
