Posterolateral congenital diaphragmatic hernia (CDH), also known as hernia of Bochdalek, occurs in approximately 1 in 4000 live births. A defect in the diaphragm allows abdominal organs, typically the intestines and stomach, to protrude into the thorax (Figure 1). The causative factors have yet to be elucidated. Children with this anomaly have variable degrees of both macroscopic and microscopic pulmonary hypoplasia as well as pulmonary arteriolar muscular thickening. The pulmonary hypertension and resultant shunt physiology are the most significant contributors to the life-threatening physiologic compromise that is seen initially in the majority of these patients.
A variety of methodologies including “gentle” ventilation strategies, delayed operative intervention, and extracorporeal life support have increased overall survival from 60% to greater than 80% at some centers. This improved survival has increased the likelihood that surgical repair of the diaphragmatic defect will be needed.
The thoracoscopic approach to CDH has several advantages over the traditional open transabdominal or transthoracic approaches. In addition to the obvious cosmetic benefits, there is decreased intraabdominal adhesion formation and thus a potential for decreased incidence of small bowel obstruction (seen in up to 18%–20% of patients who have undergone open transabdominal CDH repair). Additionally, minimally invasive techniques avoid significant thoracotomy-related complications including secondary scoliosis, shoulder girdle weakness, and chest-wall asymmetry.
The following criteria are used to determine if the thoracoscopic approach is feasible:
Absence of lethal chromosomal or cardiac abnormalities
Stable ventilatory status as defined by pre-ductal SaO2 >90% on less than 0.5 FiO2, and mean airway pressures ≤15 mm Hg on a nonoscillating ventilator
Lack of significant metabolic disturbances by blood gas analysis
Minimal or no need for vasoactive drips
Echocardiographic evidence of pulmonary pressures in the mild suprasystemic range or lower.
Early postnatal physiologic instability or use of extracorporeal membrane oxygenation (ECMO) in the preoperative period are not seen as contraindications, provided that the patient fulfills the above criteria prior to operative intervention. No specific preoperative anatomic or radiologic criteria are useful in determining the feasibility of the thoracoscopic approach.
A complete discussion of the preoperative care of these children is beyond the scope of this chapter. Once the child has stabilized sufficiently to otherwise be considered for operative repair, nursing staff is asked to reposition the child in the decubitus position for a minimum of 2 hours to mimic operating room positioning and confirm the child’s ability to tolerate dependency on the contralateral lung.
The risk of precipitous pulmonary hypertension defines much of the intraoperative management. Single-lung ventilation is not needed and may result in greater hypoxemia and increased risk of pulmonary hypertension. Oxygen saturations in the preductal and postductal positions are ...