Congenital diaphragmatic hernia (CDH) is a developmental defect in the diaphragm associated with herniation of the abdominal viscera and ipsilateral pulmonary hypoplasia most pronounced on the ipsilateral side. In the current era, approximately 64% of cases in the United States will be diagnosed prenatally by midtrimester ultrasound, and the majority of the remaining newborns will present in the first few hours of life with varying degrees of respiratory distress. Herniation occurring later in gestation is associated with less-significant pulmonary hypoplasia and milder respiratory distress in the newborn period and is often not prenatally diagnosed. Prenatal diagnosis and advances in neonatal care have improved survival to 75% for isolated CDH. However, newborns with more severe CDH and those with other congenital anomalies or chromosomal defects continue to have a significant risk of death and morbidities, such as chronic lung disease, pulmonary hypertension, gastroesophageal reflux, failure to thrive, hernia recurrence, chest wall deformities, scoliosis, and adverse neurodevelopmental outcome.
A voluntary international registry for CDH infants was established in 1995 by Dr. Kevin Lally to collect data on infants with CDH with the goal of advancing the care and outcome for such infants.1 The CDH Study Group Registry now includes data from over 6000 patients from 93 centers in 10 countries and has provided important information regarding the efficacy of various therapies and predictors of outcome.
The birth prevalence of CDH in population-based studies ranges from 0.17 to 0.57 per 1000 live births.2,3 CDH is more frequent in males, with a ratio of 1.4 to 1, and less frequent among African Americans.3 Associated congenital anomalies occur in 25%, abnormal karyotype in 16%, and genetic syndromes in 5%. Cardiac malformations are the most frequent congenital anomalies seen in the CDH population, followed by anomalies of the ribs and sternum, brain, and spine. Chromosomal abnormalities seen include trisomy 18, 13, 21, 22, and 9 as well as other nontrisomy chromosomal anomalies.3 Fryns syndrome is the most common autosomal recessive syndrome seen in the CDH population, occurring in 1% to 10%, and is associated with a high mortality rate and extremely poor quality of life.4
The diaphragm is formed by fusion of the septum transversum and the pleuroperitoneal folds around the eighth week of gestation, thereby separating the pleural cavities from the peritoneal cavity. Failure of this closure will result in a diaphragmatic hernia, which most frequently appears in the posterior/lateral part, referred to as a Bochdalek hernia. Hernias in the anterior part of the diaphragm, known as Morgagni hernias, are less frequent. About 85% to 90% of diaphragmatic hernias occur on the left side and 10% to 15% on the right side. Bilateral hernias are uncommon (1%-2%). Most commonly, the defect is complete with a direct communication between the pleural and peritoneal cavities. In about 10% to 15%, ...