Ultrasound evaluation of right diaphragmatic eventration and hernia

A hernia is due to a defect in the diaphragm. An eventration is due to a thinned diaphragm with no central muscle. Distinguishing right diaphragmatic hernia from eventration on chest radiographs can be challenging if no bowel loops are herniated above the diaphragm. Experience is limited with postnatal ultrasound (US) evaluation of diaphragmatic hernia or eventration.

To evaluate for specific US signs in the diagnosis of right diaphragmatic hernia and eventration.

We identified all patients (January 2007-December 2017) with right diaphragm US and surgery for eventration or hernia. We reviewed medical charts, and US images/reports for clinical presentation and diaphragm abnormalities. Surgical diagnosis was considered the reference standard.

Seventeen children (mean age: 5 months) had US examination before surgery for hernia (n=9) or eventration (n=8). The most common presentation was respiratory distress. In the US reports, hernia was correctly diagnosed in all patients and three patients with eventration were misdiagnosed as hernia, yielding 100% sensitivity and 62.5% specificity. In a retrospective evaluation of the US studies, a combination of folding of a free muscle edge with a narrow angle waist had 100% specificity for hernia and was seen in 7/9 children with hernia. Combination of a broad angle waist and hypoechoic strip of diaphragmatic muscle covering the waist had 100% specificity for eventration and was demonstrated in 4/8 children with eventration. Five of 17 patients (31.6%) had no specific sign that differentiated hernia from eventration.

On US, folding of the free edge of the diaphragm and a narrow angle waist are specific for hernia; a broad angle waist with muscle covering the elevated area is specific for eventration. Definitive differentiation between eventration and hernia may not be possible in about a third of patients.