Exomphalos, also known as omphalocele, is a type of abdominal wall defect. This condition occurs when a baby’s abdominal wall does not fully close during development in the womb, leading to organs like the intestines outside the abdomen. The organs remain contained within a protective, translucent sac, with the umbilical cord inserting directly into this sac. This distinct covering differentiates exomphalos from other abdominal wall defects like gastroschisis, where the organs are exposed without a sac.
Causes and Diagnosis
Exomphalos arises from an anomaly during early fetal development. During this period, the intestines normally grow rapidly and temporarily extend into the umbilical cord before returning to the abdominal cavity. In cases of exomphalos, this natural process fails, and the organs do not fully retract, remaining outside the abdomen. The precise cause is often unknown. However, exomphalos can be associated with chromosomal factors or genetic conditions, and advanced maternal age may increase the risk.
The condition is identified during prenatal ultrasound scans, performed around the 12-week or 20-week gestation mark. A sonographer observes the midline sac with the umbilical cord inserting into its apex. Exomphalos is categorized based on the size of the defect and the organs involved: a minor exomphalos involves an opening less than 4-5 cm and contains only intestines, while a major or “giant” exomphalos is larger than 4-5 cm and may include the liver.
Associated Health Conditions
Exomphalos can occur as an isolated finding or as part of a broader spectrum of conditions. Associated anomalies are observed in up to 70% of cases, significantly influencing the baby’s health outlook.
Common co-occurring issues include congenital heart defects (up to 20% to 50% of cases) and various chromosomal abnormalities. These chromosomal conditions include Trisomy 18 (Edwards’ syndrome) and Trisomy 13 (Patau’s syndrome), linked to around 30%–50% of exomphalos cases. Beckwith-Wiedemann syndrome, a genetic overgrowth disorder, is also frequently associated with exomphalos, occurring in approximately 10% of cases.
If exomphalos is detected prenatally, further diagnostic tests like chorionic villus sampling (CVS) or amniocentesis may be offered. These invasive tests determine if chromosomal or genetic conditions are present, which assists in planning care and prognosis. The impact of these associated conditions outweighs the exomphalos itself in determining long-term health and survival.
Treatment and Management
When exomphalos is diagnosed during pregnancy, a planned delivery in a specialized hospital with a neonatal intensive care unit (NICU) is recommended. This ensures a multidisciplinary team is available for the newborn. The mode of delivery is determined by obstetric considerations, though a C-section may be suggested for large exomphalos defects to reduce the risk of sac rupture or liver injury.
Immediately following birth, care focuses on protecting the exposed sac, preventing fluid and heat loss, and decompressing the bowel. The sac is covered with a non-adhesive dressing. A gastric tube is inserted to decompress the bowel. Fluid resuscitation and temperature control are managed.
Treatment approaches vary based on the size of the defect and the baby’s overall health. For small exomphalos defects, a primary surgical repair is performed shortly after birth. In this procedure, the surgeon places the organs back into the abdominal cavity and closes the abdominal wall.
For larger defects where the abdominal cavity may not be large enough to accommodate all the organs immediately, a staged repair is employed. This involves creating a temporary external “silo” made of mesh to contain the organs. The silo is gradually tightened over days or weeks, slowly pushing the organs back into the abdomen as the abdominal cavity expands. Once the organs are fully reduced, a final surgery is performed to close the abdominal wall.
A conservative, non-surgical approach is an alternative for selected cases, particularly giant exomphalos or when a baby has significant co-morbidities that make immediate surgery risky. This method involves applying a topical antimicrobial agent to the sac to encourage the skin to grow over it. This process can take several months to years, allowing the abdominal cavity to expand before a delayed surgical closure.
Outlook and Long-Term Care
The prognosis for babies born with exomphalos varies considerably, depending on the size of the defect and the presence or absence of other health conditions. For infants with an isolated exomphalos, the survival rate is high, exceeding 90%. These babies recover well and can lead healthy lives.
When exomphalos occurs alongside other structural or chromosomal abnormalities, the outlook can be more complex. Survival rates are lower in these cases, particularly with severe cardiac defects or certain chromosomal conditions like Trisomy 13 or 18. Long-term care may involve monitoring for feeding difficulties, which can require tube feeding initially. Breathing support, including mechanical ventilation, may be necessary for a period, especially after repair of a giant exomphalos due to pulmonary hypoplasia. Children will have an abdominal scar from the repair, and some may develop hernias in the future. Regular follow-up with a pediatric surgical team is recommended to address any ongoing needs and ensure proper development.