The "Flat Diaphragm": Does the Degree of Curvature of the Diaphragm on Postoperative X-Ray Predict Congenital Diaphragmatic Hernia Recurrence?

Abstract

The appearance of the diaphragmatic curvature and the rib insertion level of the diaphragm on postoperative chest X-ray (CXR) may predict recurrence. Our purpose was to examine the relationship between the curvature of the diaphragm on postoperative CXR and recurrence. We performed a retrospective review of left-sided, Bochdalek congenital diaphragmatic hernia (CDH) surgical repairs from 2004 to 2015 at a single institution. We developed a tool to measure the flatness of the diaphragm on postoperative CXR, termed the diaphragmatic curvature index (τ). The primary outcome of interest was recurrence after surgical repair. Of the 127 patients identified, 54% (n = 69) had a primary repair, while 46% (n = 58) required a patch repair. The overall recurrence rate was 21.3% (n = 27). There was no difference in median lateral rib insertion level in patients with and without recurrence or those who had a primary or patch repair. The overall median diaphragmatic curvature index was 6.29 (interquartile range [IQR] 5.30-8.09) and was not significantly different among patients who had a recurrence (6.00, IQR 5.34-8.24) and those who did not (6.46, IQR 5.24-8.07) (P = .853). Within the primary repair group (6.34 versus 6.93, P = .84) and the patch repair group (5.59 versus 6.18, P = .46), the median diaphragmatic curvature index was not different among patients who had a recurrence and those who did not. A flat appearance of the diaphragm on postoperative CXR as measured by the median diaphragmatic curvature index (τ) is not associated with recurrence. The shape of the diaphragm on CXR after CDH repair may not be predictive of recurrence as previously thought.