Published on in In Utero Insights
Abdominal wall defects (AWD) are rare, complex anomalies whose causes are unknown. Optimal outcomes depend on the ability to orchestrate many factors: early and accurate diagnosis, close prenatal monitoring, precisely-timed delivery with immediate neonatal resuscitation, expert surgical repair, and vigilant long-term follow-up. The Center for Fetal Diagnosis and Treatment is one of a few programs with the breadth of expertise and extensive experience to provide comprehensive management of these defects — from early in gestation well into childhood. Pediatric surgeons, obstetricians, neonatologists, anesthesiologists, advanced practice and surgical nurses, social workers, nutritionists, and many others collaborate seamlessly in the care of our patients.
Diagnosis and prenatal care
Most abdominal wall defects are initially identified by alpha-fetoprotein screening. Once referred to our Center, diagnosis is confirmed through high-resolution ultrasound and fetal echocardiography to identify cardiac issues; for omphalocele, an ultra-fast fetal MRI is also performed. These techniques not only help us distinguish gastroschisis from omphalocele, they allow us to determine the severity of the omphalocele defect. While gastroschisis is usually an isolated defect, omphalocele is associated with increased incidence of cardiac, central nervous system, GI and genito-urinary abnormalities. Additional screening for genetic syndromes and chromosomal abnormalities is essential.
Abdominal wall defects require meticulous surveillance for the pregnancy’s duration. Because gastroschisis is associated with increased risk of intrauterine fetal demise in the third trimester, our Center routinely monitors mothers beyond 30 to 32 weeks' gestation with twice-weekly sonograms, biophysical profiles and non-stress testing, keeping a close watch for signs of fetal distress, oligohydramnios or polyhydramnios, sometimes signaling an intestinal atresia. For omphalocele, serial sonographic evaluation helps us detect developing issues throughout the pregnancy, such as intrauterine growth restriction or abnormalities such as Beckwith-Wiedemann syndrome. “It’s one of the hallmarks of our Center that we follow mothers and babies so closely,” says Executive Director Lori Howell, RN, MS.
Delivery and postnatal care
Many AWD pregnancies now deliver at Children’s Hospital’s Garbose Family Special Delivery Unit (SDU), the world’s first birth facility for mothers carrying babies with diagnosed birth defects. Here, interaction between the obstetric, neonatal and surgical teams unfolds seamlessly.
For gastroschisis, delivery is usually vaginal and often takes place between 35 and 37 weeks’ gestation. The baby is immediately handed to the neonatal team in an adjacent resuscitation room for assessment, placement of an NG tube to decompress the intestine, and to intube for ventilatory support if needed. Throughout, careful positioning of the neonate to protect the exposed bowel from infarction is critical. A spring-loaded silo is placed around the bowel, and the baby is transported to the Newborn/Infant Intensive Care Unit (N/IICU). In the ensuing days, at the bedside, the surgeon reduces the bowel into the abdomen as abdominal capacity gradually increases. Once the bowel is properly in place, pediatric surgeons remove the silo and close the defect in the operating room.
Omphalocele deliveries may be vaginal or cesarean depending on the size and contents of the sac. Liver-containing omphaloceles are delivered by C-section. Protection of the sac and liver is paramount, as rupture or bleeding significantly increases the risk of mortality. These neonates are immediately stabilized and the omphalocele sac is placed in a sterile wrap. Particular attention is paid to ventilation, as babies with giant omphalocele typically have extremely small lungs. Pediatric surgeons may close a small omphalocele with an immediate primary repair. For large or giant omphalocele, mesh sheeting is sewn to the fascia (Schuster procedure), allowing the abdominal contents to be reduced gradually over the course of days or even weeks, until final closure can safely take place in the OR.
N/IICU stays for babies with abdominal wall defects can range from several days to several months. The highest level of medical and nursing care is essential during this period, both before and after final closure, as infants must gradually meet milestones of breathing and feeding without support, and be monitored for complications such as late necrotizing enterocolitis (a risk after gastroschisis repair). During this time, the team helps to educate and reassure families about caring for their babies after discharge.
Long-term follow-up care
For children with giant omphalocele, pulmonary hypoplasia represents a significant and long-term health threat. CHOP has created a Pulmonary Hypoplasia Program to focus multidisciplinary attention on the specific needs of these children, following them for years after initial repair.
“It’s a continuum of care,” says neonatologist Natalie Rintoul, MD. “Every piece is essential for these babies — and that’s where many layers of expertise make the difference.”
Our Center's experience with abdominal wall defects - 1995-2010
- Prenatal referrals: 527
- Neonatal surgeries: 267
Categories: In Utero Insights Winter 2011