Can plain chest X-ray replace computed tomography for the follow-up of children who have undergone the Nuss procedure?

PURPOSE To establish whether new indices on plain chest X-ray (CXR) can replace those on computed tomography (CT) for the follow-up of children who have undergone the Nuss procedure. METHODS The subjects of this retrospective study were 45 children who underwent the Nuss procedure between 2000 and 2016. The Haller index (HI) was measured by preoperative CT. Preoperative and postoperative chest deformities were evaluated by two CXR measurements: the concave rate on the lateral view (CR; the depth of the concavity divided by the anterior-posterior diameter of the rib cage) and the tracheal bifurcation angle (TBA) on the anterior view. Data are expressed as the median with range. RESULTS The median age and HI of the children, when they underwent the Nuss procedure, was 9.3 (3.8-17.3) years and 4.5 (3.2-10.1), respectively. The preoperative CR was correlated significantly with the HI. The postoperative CR was significantly lower than the preoperative CR [pre: 0.17 (0.08-0.37), post: 0.09 (0.01-0.18), p < 0.05], and the low value was sustained after bar removal. The TBA decreased significantly after the Nuss procedure from 74.2° (55-104) preoperatively to 65.0° (45-92) postoperatively (p < 0.05). CONCLUSIONS These results suggest that CXR can replace CT for the follow-up of patients after the Nuss procedure, with lower radiation exposure.