Using EOS Imaging Technique to Provide Reference Values for Proximal, Distal, and Total Thoracic Kyphosis in the Iranian Population

Background Objectives: EOS, as a new imaging technique, has several benefits over conventional radiography in measuring spinal curvatures. In this study, we aimed to use EOS to determine the normal values of thoracic kyphosis besides its association with the participants’ age and gender. Materials Methods: In this retrospective cross-sectional study, 100 individuals with no history of spinal abnormality were included. Spinal curvatures, comprising proximal thoracic segment, distal thoracic segment, and total thoracic kyphosis, were measured on EOS images using a Cob method. The demographic characteristics of the participants, such as age and gender were also extracted from medical profiles. Results: The study population included 31 males and 69 females with a mean age of 27.2 ± 17.4 years (range 6-66). The mean curvatures of proximal and distal thoracic segments were 14.5 ± 6.5º and 32.7 ± 7.5º, respectively. The mean total thoracic kyphosis was 47.2 ± 7.2º. Besides, distal and total thoracic kyphosis, but not proximal thoracic segment, were significantly more in participants aged over 40 years (p=0.03, p=0.04, and p=0.07, respectively). No significant association was found between the thoracic curvatures and participants’ sex. Conclusion: It seems that there is a direct relationship between distal and total thoracic kyphosis and aging; however, more studies are required in order to approve our results.