Summary

Herniation of viscera through defects of the abdominal watt can be categorised into gastroschisis, omphalocele, and the rarer bladder or cloacal exstrophy. Many of the principles of diagnosis and management are similar for these conditions. Gastroschisis is a small defect positioned to the right of the umbilicus. The herniated viscera are not covered by a membrane. Gastroschisis is usually an isolated abnormality, but these infants frequently have significant intestinal dysfunction. Omphalocele is a defect of the umbilical cord itself and can be small to very large. The herniated organs are covered by a sac. Associated abnormalities are frequent and significantly affect outcome. Most abdominal watt defects are diagnosed prenatally. Location and route of delivery can then be chosen to facilitate postnatal management. Initial treatment consists of coverage of the viscera and fluid resuscitation. Several options are then available for definite surgical management, depending on the size of the defect, the condition of the underlying viscera, and the status of the baby. Most infants have good long-term prognosis.

KEYWORDS

Gastroschisis; Omphalocele; Exompahalos; Exstrophy

Introduction

The various congenital defects of the abdominal wall seem to be essentially different, although they have similar appearances. (1) These defects can be broadly categorised into gastroschisis, omphalocele, and the rarer exstrophy of the bladder or cloaca. Art involve herniation of viscera through a defect in the upper or lower abdominal watt. Although there are significant differences between these conditions, many of the principles of diagnosis and management are similar. This review will focus mainly on the more common conditions of gastroschisis and omphalocele, but will briefly mention the exstrophies as well.

Description of the conditions

Gastroschisis

Gastroschisis is generally a small (3-5cm) defect in the anterior abdominal wall positioned lateral and usually to the right of the umbilical cord (Fig. 1). The eviscerated small bowel, colon, stomach, ovary, or testis has no covering membrane. The intestine is shortened and has a thick inflammatory peel over it. This bowel damage has been attributed to a variety of factors such as contact with amniotic fluid and constriction of the bowel at the small abdominal wail defect. (2-5)

Gastroschisis is usually an isolated lesion and is rarely associated with chromosomal abnormalities. Structural anomalies are associated with gastroschisis in 5-15% of cases, the most common of which is intestinal atresia. (6,7) Intestinal atresia has been considered a poor prognostic feature (8) and results in additional surgical procedures, delayed establishment of enteral feedings and prolonged hospital stay. (9) Neonates with gastroschisis also frequently have significant intestinal hypomotility and absorptive dysfunction that result in delay in starting and reaching full enteral feeds, with longer duration of TPN support compared with neonates with omphalocele. (10)

Omphalocele

In contrast to gastroschisis, omphalocele (also called exomphalos) is a defect of the umbilical cord itself and can be anywhere from 2 cm in size to very large (Fig. 2). The herniated bowel, liver and sometimes other organs are covered by a sac that consists of translucent coverings of the umbilical cord (amnion, Wharton's jelly, and...