Incidence:

Seen in 1 out of 5000 newborns. Posterolateral (Foramen of Bochdalek) hernia is more common with incidence of almost 80% (L > R). Anteromedial (Foramen of Morgagni), Esophageal hernia and Bilateral hernias are less common. Overall mortality (with modern treatment) is 50% and morbidity remains high.

Associated conditions seen with Congenital Diaphragmatic hernia:

Development of the Diaphragm:

Diaphragm is composed of several components:

Septum transversum - forms the central tendon
Pleuroperitoneal membrane - forms the dorsolateral portion
Intercostal muscle group - forms the posterior lateral portion
Esophageal mesentry - forms the dorsal crura

In 7th week of gestation, peritoneal folds extend medially to fuse with central tendon. If the fusion is incomplete, the defect is well established by 10 to 12 weeks of gestation.

Size of the defect varies from 2 cm to complete agenesis of the diaphragm.

In CDH, there is interruption of bronchial airway branching at 10 weeks gestation. The ipsilateral lung development is retarded at 12th - 14th generation. Contralateral lung development is retarded at 16th - 18th generation. Development of Type 1 alveolar epithelium is arrested.