Chapter 35

### Key Points

1. Umbilical hernia frequently resolves without operation.

2. When needed, persistent fascial defects (umbilical and epigastric hernias) should be repaired before 4 to 5 years of age.

3. Urachal and vitelline remnants often present with infection, and should be excised after the infection has resolved.

Umbilical abnormalities are among the most common reasons a child is referred to the pediatric surgeon. Periumbilical disorders that might require operation include abnormal granulation tissue, fistulas, masses, or herniation. While most umbilical conditions appear relatively nonacute, proper and concise diagnosis and management are necessary to avoid potentially serious, albeit infrequent, morbidity.

### Anatomic Considerations

Basic knowledge of the anatomical basis of umbilical disease is essential. The umbilical ring forms during the fourth week of gestation as a result of infolding of the lateral folds and migration and differentiation of the muscular and fascial mesoderm. The umbilical ring represents the transition from epidermis to amnion and contains the umbilical vessels, allantois, and vitelline (omphalomesenteric) duct. Primitive gut is connected to the yolk sac via the vitelline duct. The urachus is a vestigial canal between the allantoic stalk and the superior portion of the bladder (Fig. 35-1). During normal development, epithelium from both the urachus and the vitelline duct close as a result of apoptotic cell death. The involuted urachus becomes the median umbilical ligament. Absent or incomplete apoptosis gives rise to a range of urachal or vitelline ductal abnormalities including diverticuli, sinuses, cysts, or fistulae. Thus, there exists a delicate balance between cell proliferation and apoptotic cell death during this critical stage in fetal development.

###### Figure 35-1

Umbilicus and associated structures at 6 weeks' gestation. The embryo is attached to the developing placenta by a connecting stalk comprised of extraembryonic mesoderm through which the allantois, umbilical vessels, and vitelline duct pass.

The midgut, following initial herniation through the umbilical ring (as depicted in Fig. 35-1), returns to the abdominal cavity during the 10th week of gestation. Proper closure of the umbilical ring occurs as the lateral body wall (somatopleure) folds medially around the umbilical vessels, yolk stalk, and allantoic remnants. The rudimentary rectus abdominis muscles approach one another and, with subsequent narrowing, form the linea alba. Following birth and cord separation, the obliterated umbilical arteries (medial umbilical ligaments) also contribute to umbilical ring closure as their elastic fibers serve as a sphincter mechanism allowing for slow orifice contraction.

### Specific Disorders

#### Umbilical Hernia

The first umbilical hernia repair was mentioned by Celsus in the early first century. However, the majority of cases up to the 18th century were managed with abdominal binders. In 1890, Nota reported the first series of children undergoing hernia reduction and purse-string closure of the fascial defect. Mayo recommended transverse fascial closure in 1901 ...

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