Abdominal Wall Defects
Priscilla Joe, MD
Children’s Hospital and Research Center at
Oakland
Omphalocele
• Membrane sac arising from the umbilical cord
covers intestines
• Outer membrane layer consists of amnion and
inner lining of peritoneum
• Size ranging from small->giant defects containing
liver, small and large bowel, stomach, spleen,
ovaries, and testes
• Associated with foreshortened bowel and
malrotation
• Small abdominal cavity and pulmonary hypoplasia
Gastroschisis
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No membrane covering
Abdominal wall defect typically 2-4cm diameter
Lateral to the right side of the umbilical cord
Usually contains midgut and stomach
Thickened, atretic, and possibly ischemic bowel
Associated with malrotation
Embryology of Gastroschisis
• Failure of vascularization of the abdominal wall
due to abnormal involution of the right umbilical
vein or a vascular accident of omphalomesenteric
artery causes abdominal wall weakness and
subsequent rupture
• Rupture of a small omphalocele with absorption of
the sac and growth of a skin bridge between the
abdominal wall defect and umbilical cord
Embryology of Omphalocele
• Normally, midgut returns to the abdomen by
10th week of gestation
• Somatic layers of cephalic, caudal, and
lateral folds join to close abdominal wall
• With omphalocele, folds fail to close
Gastroschisis and Omphalocele
• Combined incidence of 1 in 2000 births
• Male-to-female ratio is 1.5:1
• Overall survival > 90%
Gastroschisis
• Increasing incidence
• Associated with young maternal age and
low gravida
• Associated with prematurity and low birth
weights
Omphalocele
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Incidence has remained constant
Increased risk with advanced maternal age
Probable genetic predisposition
Associated syndromes and anomalies (45-55%):
- gastrointestinal
- cardiac
- trisomy 13, 18, 21
- OEIS complex (omphalocele, bladder extrophy,
imperforate anus, spinal defects
- Beckwith-Wiedemann
- pentalogy of Cantrell
- cleft palate
- pulmonary hypoplasia
• May be associated with maternal use of valproic acid
Beckwith-Wiedemann
Pentalogy of Cantrell
Diagnosis
• AFP synthesized in fetal liver and excreted by
fetal kidneys and crosses placenta by 12 weeks
• Elevated maternal MSAFP in neural tube defects,
abdominal wall defects, duodenal or esophageal
atresia
• 40% false positive rate
• Fetal ultrasound after 14 weeks gestation
• Amniocentesis and fetal echocardiography
Treatment
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NGT to low intermittent suction
Use of bowel bags, saran wrap
Conservation of body heat and fluid losses
Antibiotics
Careful positioning to avoid kinking of
mesenteric vessels
• 1.5 times maintenance fluids with isotonic
fluids
Surgical Management
• Operative repair within 2-4 hours of birth
• Primary closure for smaller defects
• Delayed primary closure for large defects
– Avoid compromised ventilation and abdominal
compartment syndrome
– Use of silo with sequential reduction of
abdominal contents
– Later fascial closure
Mortality/Morbidity
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Short gut syndrome
NEC
Gut dysmotility and prolonged ileus
Sepsis
Complications from associated
anomalies/syndromes