Evaluation of the Normal Range of Thoracic Kyphosis and Lumbar Lordosis Angles Using EOS Imaging

Background: The use of EOS technology provides information about scoliosis and sagittal balance as well as pelvic parameters. Given that there are few studies about the normal range of kyphosis and lordosis angles in individuals through EOS imaging in Iran, the current study aims to evaluate the normal range of thoracic kyphosis and lumbar lordosis angles using EOS imaging. Material and methods: This cross-sectional descriptive-analytical study was conducted on adult males and females with low back pain who were referred to the Radiology Department of Shahid Sadoughi Hospital, Iran, for spinal imaging during 2016-2018. Kyphosis and lordosis angles were measured by EOS imaging. Information including sex and age were extracted from medical records. Results: In the current study, a total of 403 patients, of which 214 (53.1%) women and 189 (46.9%) men, were classified into four age groups (18-30, 31-40, 41-50 and 51-60 years old). The mean angle of lordosis and kyphosis was 32.42±6.29 and 43.55±6.44, respectively. The mean angle of lordosis in women was greater than men in all age groups. Comparison of kyphosis angle in men and women aged over 40 showed that men had greater values than women. Moreover, there was a significant relation between kyphosis and lordosis in men (r=0.286, p.0.001) and women (r=0.519, p.0.001), respectively. In men, no significant correlation was seen between age and lordosis (p=0.842) and kyphosis (p=0.459). In women, age was not notably associated with either lordosis (r=0.087, p=203) or kyphosis (r=0.010, p=0.123). Conclusion: Assessment of the angle of kyphosis and lordosis can be used to detect early spinal and pelvic anomalies. It is also used for standardization of the spinal column after fracture of the vertebrae or congenital and pathologic defects. Moreover, individuals' age did not affect the angle of kyphosis and lordosis. In addition, the mean angle of lordosis was sex-dependent.