A retrospective study on the impact of bar flipping on the recurrence of pectus excavatum after the Nuss procedure

BACKGROUND: The Nuss procedure is widely used to correct pectus excavatum. Bar displacement is a common complication associated with this procedure. How the flipping of the bar affects pectus excavatum recurrence has not been reported. In our study, we discuss this and also offer an easier method to determine bar flipping. METHODS: This retrospective study analyzed pectus excavatum patients who underwent primary Nuss repair from August 2014 to December 2018. The preoperative and postoperative Haller indices were measured on chest radiographs (cxrHI). The slope angle of bar flipping (α) was measured on lateral chest radiographs. The improvement index after surgical repair was calculated by: ([preoperative cxrHI-postoperative cxrHI]/preoperative cxrHI × 100). The impact of α on the improvement index was analyzed using one-way analysis of variance and receiver operating characteristic tests. RESULTS: In this study, 359 adult and adolescent patients with an average age of 23.9 ± 7.7 years were included. We formed four subgroups based on the α value: α ≤ 10° (n = 131), α = 11–20° (n = 154), α = 21–30° (n = 51), and α > 30° (n = 23). The mean improvement indices in these groups were 27%, 28%, 26%, and 13%, respectively. Patients with α > 30° were associated with a significantly poorer improvement index than those from the other subgroups (p < 0.001). CONCLUSIONS: The α value is an alternative measurement method for presenting the radiological outcomes after the Nuss procedure. An α > 30° indicates a possible recurrence of pectus excavatum after the Nuss repair. Surgical revision may be considered in patients with an α > 30°, while monitoring should be considered in the other patient groups.