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

Abstract

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° vs. 4.5±3.8°, P<0.001, TS P<0.001; post-correction: 7.6±7.2° vs. 4.1±3.3°, 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° vs. 4.1±3.3°, P=0.078; increased in LG: 6.3±4.9° vs. 7.6±7.2°, P=0.002). In patients with pre-corrective TS, CA after correction was decreased (post-correctively 11.9±10.0° vs. pre-correctively 13.9±6.0°, P=0.090). In addition, post-corrective CA was significantly decreased in EG (pre-correction 13.9±7.4° vs. post-correction 6.6±8.1°, P<0.001). However, post-corrective CA was increased in LG (pre-correction 13.8±4.5° vs. post-correction 16.7±9.2°, 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.

Keywords: Nuss procedure; Pectus excavatum (PE); scoliosis.

Figure 1

The CA (red arrow) is defined by the angle formed by the intersection of two lines drawn on a spinal radiograph of a patient suspected of having scoliosis. One line is drawn parallel to the lower surface of the lowest affected vertebral body, and the other is drawn parallel to the upper surface of the highest affected body. CA, Cobb angle.

Figure 2

There was a significantly positive correlation between age and CA, both pre-correctively and post-correctively (both P<0.001). From these findings, we assume that the thoracic scoliosis is aggravated with age in patients with PE. CA, Cobb angle; PE, pectus excavatum.