Effects of Nuss procedure on thoracic scoliosis in patients with pectus excavatum

Background: The objectives of this study are to investigate the association between pectus excavatum (PE) and thoracic scoliosis (TS) and to analyze the effects of the Nuss procedure on the thoracic spinal curvature in patients with PE. Methods: A total of 468 patients who underwent the Nuss procedure and pectus bar removal for PE from March 2011 to January 2015 were assessed and included into the present study. Results: TS prevalence was 9.4% pre-correctively and 9.8% post-correctively. There was a positive correlation between age and Cobb angle (CA), pre-correctively and post-correctively (both, P<0.001). The late correction group (LG, age >= 10 years) had a higher CA and more frequent TS than the early correction group (EG, age < 10 years) (pre-correction: CA 6.3 +/- 4.9 degrees vs. 4.5 +/- 3.8 degrees, P<0.001, TS P<0.001; post- correction: 7.6 +/- 7.2 degrees vs. 4.1 +/- 3.3 degrees, P<0.001, TS P<0.001). The post- corrective changes in CA were different according to the time of correction (decreased in EG: 4.5 +/- 3.8 degrees vs. 4.1 +/- 3.3 degrees, P=0.078; increased in LG: 6.3 +/- 4.9 degrees vs. 7.6 +/- 7.2 degrees, P=0.002). In patients with pre-corrective TS, CA after correction was decreased (post-correctively 11.9 +/- 10.0 degrees vs. pre-correctively 13.9 +/- 6.0 degrees, P=0.090). In addition, post- corrective CA was significantly decreased in EG (pre-correction 13.9 +/- 7.4 degrees vs. post- correction 6.6 +/- 8.1 degrees, P<0.001). However, post- corrective CA was increased in LG (pre-correction 13.8 +/- 4.5 degrees vs. post- correction 16.7 +/- 9.2 degrees, P=0.053). The number of patients with TS after correction was decreased in EG (P=0.194) and significantly increased in LG (P=0.028). There were both pre-corrective and post-corrective predictive factors for TS (Pre-corrective: age P<0.001, severity P=0.016, and BMI P=0.046; post-corrective: age at the time of correction P<0.001, weight P=0.046, and pre-corrective CA P<0.001). Conclusions: The Nuss procedure had some significant effects on the thoracic spinal curvature, with early correction able to reduce TS in patients with PE.