Chapter 73: Abdominal Wall Defects

The normal abdominal wall is formed by infolding of the cranial, caudal, and two lateral embryonic folds. These folds form in the 4th week of development as a combination of the parietal layer of lateral plate mesoderm and overlying ectoderm. As they move ventrally to meet in the midline, rates of cell proliferation and fusion in the folds differ. This fusion process between the folds is complex, involving cell-to-cell adhesion, cell migration, and cell reorganization. Simultaneously, as the abdominal wall is forming, the rapid growth of the intestinal tract leads to its herniation through the umbilical ring into the yolk sac from the 6th to the 10th week of gestation. By the 10th to 12th week of gestation, the intestine returns to the abdominal cavity in a well-coordinated pattern. This results in normal intestinal rotation and fixation, followed by complete formation of the abdominal wall.¹

Abnormal formation of the abdominal wall can result in omphalocele and possibly gastroschisis, which are discussed in succession.

Gastroschisis

Patient Story

A term newborn infant is found to have protrusion of the abdominal wall, involving the viscera (Figure 73-1). A prenatal diagnosis of gastroschisis had been made by ultrasound and the mother was referred to a high-risk obstetrical service for management. The infant was born via vaginal delivery and upon delivery was taken to the neonatal intensive care unit for immediate resuscitation and management. The family had met with the pediatric surgeon and neonatal intensive care team prior to the delivery. The infant underwent successful surgical repair for the defect. After a 5-week hospital course, the infant was discharged home with good bowel function.

Introduction

Gastroschisis is a full-thickness defect in the abdominal wall, typically to the right of umbilical cord (Figure 73-1), where a variable amount of intestine and/or other organs may be herniated through the abdominal wall without a membrane or covering.^2,3

Epidemiology

• The incidence of gastroschisis seems to be increasing worldwide and is approaching 3 to 4 per 10,000 births in endemic areas.⁴

• Recent epidemiologic studies have found a strong association between the occurrence of gastroschisis and young maternal age. However, a clear cause of gastroschisis has yet to be determined.^4,5

Etiology and Pathophysiology

• The cause of a gastroschisis is unknown.

• Several theories have been proposed to explain the unique abdominal wall defect through which abdominal organs may ...