Congenital diaphragmatic hernia sacs: prenatal imaging and associated postnatal outcomes

The presence of a hernia sac in congenital diaphragmatic hernia (CDH) has been reported to be associated with higher lung volumes and better postnatal outcomes.

To compare prenatal imaging (ultrasound and MRI) prognostic measurements and postnatal outcomes of CDH with and without hernia sac.

We performed database searches from January 2008 to March 2017 for surgically proven cases of CDH with and without hernia sac. All children had a detailed ultrasound (US) examination and most had an MRI examination. We reviewed the medical records of children enrolled in our Pulmonary Hypoplasia Program.

Of 200 cases of unilateral CDH, 46 (23%) had hernia sacs. Cases of CDH with hernia sac had a higher mean lung-to-head ratio (LHR; 1.61 vs. 1.17; P<0.01), a higher mean observed/expected LHR (0.49 vs. 0.37; P<0.01), and on MRI a higher mean observed/expected total lung volume (0.53 vs. 0.41; P<0.01). Based on a smooth interface between lung and herniated contents, hernia sac or eventration was prospectively questioned by US and MRI in 45.7% and 38.6% of cases, respectively. Postnatally, hernia sac is associated with shorter median periods of admission to the neonatal intensive care unit (45.0 days vs. 61.5 days, P=0.03); mechanical ventilation (15.5 days vs. 23.5 days, P=0.04); extracorporeal membrane oxygenation (251 h vs. 434 h, P=0.04); decreased rates of patch repair (39.0% vs. 69.2%, P<0.01); and pulmonary hypertension (56.1% vs. 75.4%, P=0.03).

Hernia sac is associated with statistically higher prenatal prognostic measurements and improved postnatal outcomes. Recognition of a sharp interface between lung and herniated contents may allow for improved prenatal diagnosis; however, delivery and management should still occur at experienced quaternary neonatal centers.