Thoracoscopic Congenital Diaphragmatic Hernia Repair

Bochdalek Diaphragmatic Hernia

Bochdalek hernias develop in early gestation and are located in the posterolateral aspect of the diaphragm. They are associated with pulmonary hypoplasia and pulmonary hypertension. These two factors conspire to create the major morbidity of respiratory failure associated with this fragile patient group. The lungs of patients with Bochdalek CDH demonstrate a more immature histology, with decreased arterioles and airway branching. Although the mass effect exerted by the abdominal viscera in the chest can cause mediastinal displacement, the primary physiologic problems are pulmonary hypoplasia and associated pulmonary hypertension. The traditional operative approach to a Bochdalek CDH has been transabdominally through a subcostal incision or, less commonly, through a low lateral thoracotomy incision. The defect is closed primarily, if possible. If the diaphragmatic defect cannot be closed primarily, various synthetic materials, as well as muscle flaps, have been used to bridge the gap. Both the laparoscopic and thoracoscopic approaches for Bochdalek CDH repair have been described. We prefer the thoracoscopic approach because of the ease of reduction of the abdominal viscera using the CO ₂ insufflation, favorable sewing angles, and clear visualization of the hernia defect.

Indications for Workup and Operation

A Bochdalek CDH is often diagnosed prenatally. After the infant is born, a chest radiograph confirms the diagnosis. To prevent distension of the hollow viscera in the chest, early placement of an orogastric tube for decompression is important. Rarely, infants can be allowed to breathe with low levels of oxygen supplementation. Most require additional ventilatory support with endotracheal intubation. An experienced team focused on minimizing barotrauma and volutrauma is critical to successful management. The initial workup for infants with a posterolateral CDH includes an echocardiogram (ECHO) to evaluate for possible congenital heart disease and to quantify the degree of pulmonary hypertension. A baseline ultrasound of the head is also obtained in anticipation of the potential need for extracorporeal life support (ECLS). In the past, repairing this defect was thought to be a surgical emergency. The timing of repair is debated heavily in the literature, with some groups advocating early repair on ECMO and others (including our own) choosing delayed repair after the pulmonary hypertension has improved.

Clinical improvement includes a decreased oxygen requirement, minimal vasopressors, minimal ventilator support, and subsystemic pulmonary pressures as determined by ECHO. This is particularly important for the minimally invasive approaches to repair that use CO ₂ insufflation. If the patient requires ECLS, thoracoscopic repair is delayed until the patient is decannulated and on conventional respiratory support. Contrary to some opinions, it is our feeling that prior ECLS is not a contraindication to thoracoscopic repair. Thoracoscopic repair while the infant is cannulated on ECLS poses issues related to logistics and operative location and is regarded as unsafe because of the risk of perioperative bleeding.