Omphalocele is one of the most common abdominal wall defects. It allows abdominal contents to protrude into the umbilical cord, resulting in a membrane-covered defect. The incidence of omphalocele is approximately one in 5,000 births, according to specialists at the University Center for Fetal Medicine.
It is associated with advancing maternal age, with most mothers over age 30. In contrast to gastroschisis, patients with omphalocele have a high incidence of associated defects, ranging from 50 to 70 percent. The survival of patients with omphalocele is generally dependent on the severity of the associated defects.
The majority of omphaloceles are detected in the prenatal period by routine screening ultrasonography or as the result of obstetrical indications, such as an elevated maternal serum alpha-fetoprotein (MSAFP). If the omphalocele is ruptured (10 percent), it can be difficult to determine if the defect is gastroschisis or omphalocele, however, the presence of liver outside the abdominal wall is diagnostic of a ruptured omphalocele.
In addition, fetal MRI can provide better structural detail, aid in the diagnosis and evaluate for other anomalies. The fetal MRI (right) shows a giant omphalocele, indicated by the arrow. There is massive herniation of the fetal liver and bowel through the abdominal wall. A sac covering these structures is also seen.
Once the diagnosis of omphalocele is made, fetal echocardiography should be performed because of the high incidence of cardiac defects (50 percent) in patients with omphalocele. Fetal karyotype analysis also should be performed because of the 30 percent incidence of chromosomal anomalies with omphalocele.
Pregnancy checks with ultrasonography will continue monthly until 32 weeks gestation, followed by checks on a weekly basis. The goal is for patients with omphalocele to be delivered as close to term as possible to maximize lung development and growth.
There is no advantage to caesarean delivery over vaginal delivery unless the omphalocele is giant with liver herniation into the defect. In this instance, caesarean delivery would prevent abdominal dystocia or liver injury. Delivery should be in a hospital with pediatric surgeons on staff and a neonatal intensive care unit (NICU).
Following delivery, the newborn is transported to the NICU for close observation. The stomach is decompressed via an orogastric (OG) or nasogastric (NG) tube to prevent vomiting, aspiration and bowel distention. Intravenous (IV) lines are placed to give the newborn nutrients and antibiotics. The membrane covering the omphalocele is protected and dressed with non-adherent gauze to prevent injury.
If the omphalocele is ruptured, urgent bowel coverage, either by silo placement or mesh, is warranted. Once stabilized, a complete physical examination is performed and the plan for surgical repair of the omphalocele will be determined. The photo (right) shows a giant omphalocele with herniation of the liver and the majority of the abdominal contents through the abdominal wall and into the membrane sac.
Surgical repair is dictated by size of the defect, presence of other congenital anomalies or syndromes, and the stability of the baby. Surgical therapy ranges from primary repair for small omphaloceles, staged repair with sequential reduction of the sac contents into the abdomen, to a "paint and wait" strategy, which is used for giant omphaloceles in babies that are ill or have significant other disabilities. Pictured (right) is the abdomen affected by the giant omphalocele (pictured above) after staged repair of the defect.
The course of recovery is different for each patient. Length of hospital stay also varies and can range from a few weeks to several months.
Once the infant has met discharge criteria, he will be released to go home. Regular pediatrician visits should be scheduled for immunizations and assessment of normal growth and development. Follow-up appointments with the pediatric surgeon will be needed due to risk for complications, including gastroesophageal reflux disease (GERD), respiratory insufficiency, FTT and hernias.