Omphalocele and gastroschisis

Learning objectives

Omphalocele and gastroschisis are congenital abdominal wall defects resulting in intestinal herniation from the abdominal cavity
Resulting from major defects in the closure of the abdominal wall → exposure of abdominal viscera
Main difference: There is no sac covering the intestines in gastroschisis
Both can be detected antenatally using fetal ultrasound → allows timing, location, and mode of delivery to be planned in advance
- Omphalocele: Deliver at term
- Gastroschisis: Benefit from early delivery (37 weeks gestation) to limit bowel damage from exposure to amniotic fluid
Both are associated with prematurity and low birth weight

Omphalocele

Herniation of abdominal contents through the middle of the abdominal wall at the umbilicus
- The skin, muscle, and fibrous tissue are missing
- The intestines herniate through the opening and are covered by a thin sac
- The sac is formed from an outpouching of the peritoneum and protrudes in the midline, through the umbilicus
Commonly occurs with other congenital defects (e.g., heart and kidney defects), chromosome abnormalities (e.g., Down syndrome, trisomy 18, trisomy 13), and genetic syndromes (e.g., Beckwith-Wiedemann syndrome)

Gastroschisis

Herniation of abdominal contents from a defect lateral to the umbilicus (usually right-sided), but not directly over it
Protruding organs are not covered by a thin sac → damage due to direct contact with amniotic fluid in the uterus → inflammation
Rarely have other congenital defects, seldom associated with chromosome abnormalities or genetic syndromes

Omphalocele

Omphalocele minor: Minor herniation into the umbilical cord, small 5-8 cm defect
Omphalocele major: Large defect, including the liver, with poorly developed abdominal and pulmonary hypoplasia
Intestine looks normal

Gastroschisis

The intestine wall may be thickened, with a fibrin “peel” due to exposure to amniotic fluid
May involve the stomach, bladder, uterus, and rarely liver

Intrauterine growth retardation
Underdevelopment of the lungs → respiratory insufficiency may require mechanical ventilation
Feeding difficulties
Poor gut motility
Malrotation
Intestinal atresia
Volvulus
Stenosis
Gastroesophageal reflux
Short bowel syndrome → dehydration

Sequelae of an open abdomen

Initial post-delivery treatment

Fluid resuscitation
Care of herniated bowel/viscera and their blood supply: Cover exposed organs with a sterile dressing to keep them moist and protected
Bowel decompression using a nasogastric tube
Temperature regulation: Nurse in an incubator to reduce heat loss
Omphalocele: Inspect the sac to check whether or not it is ruptured
IV antibiotics to minimize the risk of infection

Single vs staged surgery

Surgery typically takes place shortly after birth
Omphalocele: Semi-urgent surgery unless sac is ruptured
Gastroschisis: Urgent surgery
Required to replace the intestines in the abdomen and to close the opening
Single stage surgery: Omphalocele minor
- Intestines are moved back in the abdomen, and the opening is closed during the same surgery
Staged surgery: Omphalocele major and gastroschisis
- Wrap intestines in a protective covering (i.e., silo)
- Gradually move intestines back into the abdomen over several days or weeks
- Surgically close the opening once all intestines are back in the abdomen

Neonates are highly susceptible to dehydration and heat loss before repair of the abdominal wall defect → fluid resuscitation and temperature control
Repair surgery may be primary or staged
Improved survival is associated with optimal pre- and postoperative care