Radiologic factors related to double-bar insertion in minimal invasive repair of pectus excavatum

Background: Pectus excavatum is the most common congenital chest wall deformity, with a high incidence in live births. This study aimed to evaluate the measured factors on CT images related to the number of pectus bars for surgical correction. Methods: A total of 497 patients who had undergone minimally invasive repair between April 2007 and July 2011 were classified into single-bar (n=358) and double-bar (n=139) insertion groups. We measured eight distinct distances and one angle on CT scans to reflect quantitative assessment. Univariate analysis and multivariate logistic regression analysis were performed to detect statistically significant association between radiologic measurements and the pectus bars required. Results: After adjusting for age and gender, the transverse distance (T), the transverse distance of the depression area (A), the inclined distance of the depression area (B), the AP distance of the depression area (C), the depression angle (G), and the eccentric distance of deformity (E) were significantly correlated with double-bar insertion. The regression model showed that age (P<0.0001), gender (P<0.0001), depression angle (G) (P<0.0001), direction of the depression (DD) (P<0.0001) and depression depth (D) (P<0.0001) were significantly associated with double-bar insertion. Conclusion: CT scan provides useful factors which can be of assistance in predicting the number of pectus bars for the surgical correction of pectus excavatum.