Discussion: Congenital diaphragmatic hernias (CDH) include hiatal, posterolateral (Bochdalek), and anteromedial (Morgagni) varieties. The Morgagni hernia is the rarest form of CDH, accounting for only 2-3%. Yet it is the most common cardiophrenic angle mass in children. The defect arises during embryogenesis between the third to the seventh week of development during the formation of the septum transversum, the structure that normally divides the the pleural and peritoneal cavities. CDH is commonly associated with other congenital anomalies.
With CDH there is the risk of pulmonary hypoplasia due to restriction of lung development by the encroachment of abdominal organs into the thorax. In pulmonary hypoplasia, there is a decrease in the number of alveoli and also a reduction in the number of airway generations. Pulmonary hypoplasia is almost always secondary to another congenital abnormality such as CDH or renal agenesis. There is no specific treatment for hypoplasia, only supportive measures such as mechanical ventilation and supplemental oxygen. Surgical correction of the anatomical defect in CDH is undertaken to improve ventilation. Outcomes can vary widely and are mostly dependent upon the degree of lung hypoplasia. Morgagni hernias are typically asymptomatic and are usually found incidentally on routine chest radiographs.
With respect to Morgagni hernias specifically, they can be surgically repaired using either the abdominal or transthoracic approach. The abdominal approach is used in cases where the diagnosis has been made preoperatively, thus eliminating the need for exploratory thoracotomy. Traditionally, these hernias have been repaired by laparotomy. However, with advances in endoscopic surgery, repairs may be performed laparoscopically or by video-assisted thoracic surgery (VATS). |