Omphalocele

Definition

• Direct abdominal defect that causes a portion of the intestines and other abdominal organs to herniate WITH a covering membrane/peritoneal sac
• Typically located midline, and can be anywhere along the upper/mid/lower abdomen.
• Approximately 50–70% of cases are associated with additional congenital anomalies
  • ASDs, VSDs and Tetralogy of Fallot are most common
  • Also associated with Beckwith-Wiedemann Syndrome, Marshal-Smith, Meckel Gruber, and Pentalogy of Cantrell
  • Chromosomal abnormalities (Trisomy 13, 14, 15, 18, 21) are common

Diagnosis

• Identified via ultrasound during prenatal screening
• Elevated AFP can help confirm the diagnosis
  • Levels of AFP tend to be higher in Gastroschisis compared to Omphalocele

Epidemiology/Prognosis

• Occurs in 1.5-3 per 10,000 births
• Outcomes are variable, but are dependent on the level of other comorbidities
  • Survival rates are > 40-70%

Embryology

• During normal embryologic development, the intestinal tract physiologically herniates into the umbilical cord at approximately the sixth week of gestation, with expected return to the abdominal cavity by around the twelfth week.
• In Omphalocele, bowel fails to return into the abdomen and remains in the umbilical cord.

Surgical/Medical Management

• The initial resuscitation for patients with Omphalocele is quite similar to those with Gastroschisis.
  • Frequently delivered via cesarean section to minimize the risk of additional bowel injury during passage through the vaginal canal, although the mode of delivery may ultimately be individualized based on obstetric considerations.
  • The overarching treatment goal is reduction of the herniated intestinal contents into the abdominal cavity, followed by closure of the fascial and skin defects.
  • Management strategies are influenced by several factors, including the size and type of the defect, the size and gestational maturity of the infant, and the presence of associated comorbidities.
• The key differences for Omphalocele compared to Gastroschisis include:
  • A decrease urgency to operatively close the defect
  • Instead, the goal is to initially cover the sac to protect the herniated contents
  • Then you can let them epithelialize over time with silver sulfadiazine (if a primary closure if not permitted). Once the sac has completely epithelialized and the sac is well formed, the surgical team can reduce the abdominal contents and perform a ventral hernia repair. This can be typically done around 6-12 months of age.

Anesthetic Considerations

Preoperative

• Obtain a CBC, CMP and T&S
  • Blood loss is typically unexpected however there will be lots of evaporative losses than sometimes may be best treated with blood
  • Evaluate whether there are any electrolyte issues
• NGT placement to decompress the stomach and decrease the risk of aspiration
• Address any other comorbidities (VACTERL) associated with the pathology
  • Can be valuable to get a preoperative echocardiogram due to the rate of ASDs, VSDs, and TOFs

Intraoperative

• Standard ASA Monitors
  • Temperature will be particularly important given the large amount of heat loss from the open abdomen
• Induction
  • Position the patient in reverse trendelenberg to minimize the pressure from the abdominal contents on the lungs
  • RSI to minimize aspiration risk
• Lines
  • PIVs for resuscitation
  • Arterial Line
  • Central Lines for CVP monitoring and postoperative parenteral nutrition administration
• Maintenance
  • Patient can be maintained w/ either volatile or IV anesthetics
  • Avoid N2O due to risk of bowel distension
  • Maintain paralysis to help with abdominal closure
  • When surgical team is closing the abdomen, have close discussion with surgical team as this may cause decreased diaphragmatic excursion, compression of the lungs, increased airway pressures.
    • If at any point there are an increase in the peak inspiratory pressures > 35 or intra-abdominal pressure > 20, there should be an active discussion with the surgical team about reopening and performing a staged repair.

Postoperative

• Disposition to the NICU
• Anticipate post operative ventilation requirements
• Continue to monitor intra-abdominal pressures
• Early enteral feeding and TPN discontinuation can decrease length of stay and infection risk

Resources

• Gropper M, et al. Miller's Anesthesia. Chapter 77: Pediatric Anesthesia. Section: Omphalocele and Gastroschisis. 9th ed.

• Ledbetter DJ. Gastroschisis and Omphalocele. Surg Clin North Am. 2006;86(2):249-60. PubMed