EARLY recognition of diaphragmatic hernia in newborn infants and prompt treatment are responsible for the progressive lowering of the mortality rate associated with this developmental defect.1 Whereas expectant treatment was more popular at one time, this practice has been abandoned in favor of early surgical corrective measures.
A consideration of the surgical treatment of this defect requires an understanding of the embryology involved.2 The ventral division of the diaphragm takes its origin from the septum transversum, which divides the abdominal viscera from the heart. This septum migrates caudally from the neck region to a station at the level of the 12th rib. There is a union at this point of the thickened mesodermal cells of the dorsal mesentery. There is an opening which remains, however, in each posterolateral section of the diaphragm, the pleuroperitoneal canal, until the end of the fourth week, at which time a membrane from