The diagnosis of CDH is associated with a mortality rate of 40% to 50% depending on the population being studied. CDH patients tend to have multisystem disease processes that must be considered when planning an operation later in life. Up to 50% of CDH patients also have associated additional congenital malformations. These early malformations include intestinal atresias, congenital cardiovascular disease, and chromosomal anomalies. High-risk patients who undergo cardiorespiratory failure and are cannulated for ECMO are also at risk for serious neurologic sequelae related to peri-cannulation hypoxemia, thromboembolus, or intraventricular hemorrhage, all of which can have life-long neurologic implications.
Overall, outcomes of patients with CDH are dependent on both the inherent pathophysiological process of the disease as well as the different treatment options used for their treatment. Complications include but are not limited to the following: (1) nerve palsies; (2) recurrence of CHD; (3) chylothorax; (4) small bowel obstructions; and (5) persistent pulmonary hypertension. Long-term sequelae include issues with the thoracic/chest wall and GERD.
Nerve palsies are common following repair of the CDH. The diagnosis can be made in the usual fashion with a follow-up x-ray. This specifically complicates an already dysplastic residual diaphragm. In general, it is important to continue to monitor pulmonary function tests and remaining residual functional capacity; often it is the use of inappropriate high pressure ventilatory strategies in the hypoplastic lung parenchyma that cause long-term sequelae.
Chylothorax can present in as many as 28% of CDH patients following surgical repair. Risk factors include prosthetic patch use, prenatal diagnosis, and ECMO cannulation.2 Long-term sequelae include and are not limited to nutritional deficiencies, immunologic dysfunction, and the potential for further interventions to correct the persistent loss of proteinaceous and often lymphocyte-rich fluid.
CDH patients are likely to undergo further operations during their lifetime after initial hernia repair. Recurrence is not uncommon following repairs of diaphragmatic hernias. Recurrence may follow both open and thoracoscopic repairs (Fig. 153-7A,B). Recurrence may also follow both primary and prosthetic patch repairs. According to Guner et al., the incidence of recurrence in all CDH patients ranges from 2% to 45%, where the highest incidence occurs in patients who undergo open repair with patch material.3 Recurrence likely occurs from the inherent growth of the child, patch stability, and inherent pathophysiology of the diaphragm itself. Up to 50% of patients who receive a patch repair have subsequent recurrence by 3 years of age.4 ECMO recipients are more likely than their non-ECMO counterparts to undergo subsequent procedures, including antireflux operations, recurrent diaphragmatic hernia repair, Ladd's procedure, tracheostomy, and chest wall reconstruction.5 Occasionally ECMO patients require an umbilical silo to permit the abdominal space to decompress into the silo, and, therefore, reduce pressure on the repair.5 These silos can be placed at the time of defect repair, or following closure to relieve abdominal compartment syndrome. Patients with CDH uniformly have intestinal malrotation. Small bowel obstruction occurs in 4% to 20%, attributed to midgut volvulus, incarcerated CDH recurrence, or intestinal adhesions.4,6 Laparotomy for small bowel obstruction is the second most commonly performed procedure for CDH patients other than repair of hernia recurrence.5
A. Small late recurrence after thoracoscopic patch CDH repair. B. After thoracoscopic repair of recurrence.
Long-term data categorizing outcomes for CDH patients are lacking. CDH patients who require ECMO embody a high-risk patient group. In general, the degree of pulmonary hypoplasia and pulmonary hypertension are the most significant sources of potential morbidity. These patients more commonly have larger defects, which predisposes them to greater risk of recurrence, scoliosis, and chest wall dissymmetry. Up to one-third of CDH patients may exhibit reduced FEV1 and FVC values compared to otherwise healthy counterparts on pulmonary function testing. CDH patients who are on mechanical ventilation for more than 7 days have significantly lower FEV1 and VC than patients who were on the ventilator for less time, likely reflecting both their underlying disease severity and effects of ventilator-induced barotrauma.7 There are few studies documenting the influence of pulmonary hypertension in CDH survivors later in life. While some patients exhibit normal exercise capacity and gas exchange parameters in adulthood,7 studies have shown approximately one half of children survivors demonstrate evidence of right ventricular hypertension on electrocardiogram.8