Hwee Weng Dennis Hey1, Kian Loong Melvin Tan2, Vikaesh Moorthy3, Eugene Tze-Chun Lau2, Leok-Lim Lau2, Gabriel Liu2, Hee-Kit Wong2. 1. University Orthopaedics, Hand and Reconstructive Microsurgery (UOHC), National University Health System, 1E Kent Ridge Road, NUHS Tower Block Level 11, Singapore, 119228, Singapore. dennis_hey@nuhs.edu.sg. 2. University Orthopaedics, Hand and Reconstructive Microsurgery (UOHC), National University Health System, 1E Kent Ridge Road, NUHS Tower Block Level 11, Singapore, 119228, Singapore. 3. Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Abstract
PURPOSE: To describe normal variations in sagittal spinal radiographic parameters over an interval period and establish physiological norms and guidelines for which these images should be interpreted. METHODS: Data were prospectively collected from a continuous series of adult patients with first-episode mild low back pain presenting to a single institution. The sagittal parameters of two serial radiographic images taken 6-months apart were obtained with the EOS® slot scanner. Measured parameters include CL, TK, TL, LL, PI, PT, SS, and end and apical vertebrae. Chi-squared test and Wilcoxon Signed Rank test were used to compare categorical and continuous variables, respectively. RESULTS: Sixty patients with a total of 120 whole-body sagittal X-rays were analysed. Mean age was 52.1 years (SD 21.2). Mean interval between the first and second X-rays was 126.2 days (SD 47.2). Small variations (< 1°) occur for all except PT (1.2°), CL (1.2°), and SVA (2.9 cm). Pelvic tilt showed significant difference between two images (p = 0.035). Subgroup analysis based on the time interval between X-rays, and between the first and second X-rays, did not show significant differences. Consistent findings were found for end and apical vertebrae of the thoracic and lumbar spine between the first and second X-rays for sagittal curve shapes. CONCLUSIONS: Radiographic sagittal parameters vary between serial images and reflect dynamism in spinal balancing. SVA and PT are predisposed to the widest variation. SVA has the largest variation between individuals of low pelvic tilt. Therefore, interpretation of these parameters should be patient specific and relies on trends rather than a one-time assessment.
PURPOSE: To describe normal variations in sagittal spinal radiographic parameters over an interval period and establish physiological norms and guidelines for which these images should be interpreted. METHODS: Data were prospectively collected from a continuous series of adult patients with first-episode mild low back pain presenting to a single institution. The sagittal parameters of two serial radiographic images taken 6-months apart were obtained with the EOS® slot scanner. Measured parameters include CL, TK, TL, LL, PI, PT, SS, and end and apical vertebrae. Chi-squared test and Wilcoxon Signed Rank test were used to compare categorical and continuous variables, respectively. RESULTS: Sixty patients with a total of 120 whole-body sagittal X-rays were analysed. Mean age was 52.1 years (SD 21.2). Mean interval between the first and second X-rays was 126.2 days (SD 47.2). Small variations (< 1°) occur for all except PT (1.2°), CL (1.2°), and SVA (2.9 cm). Pelvic tilt showed significant difference between two images (p = 0.035). Subgroup analysis based on the time interval between X-rays, and between the first and second X-rays, did not show significant differences. Consistent findings were found for end and apical vertebrae of the thoracic and lumbar spine between the first and second X-rays for sagittal curve shapes. CONCLUSIONS: Radiographic sagittal parameters vary between serial images and reflect dynamism in spinal balancing. SVA and PT are predisposed to the widest variation. SVA has the largest variation between individuals of low pelvic tilt. Therefore, interpretation of these parameters should be patient specific and relies on trends rather than a one-time assessment.
Entities:
Keywords:
EOS; Low back pain; Radiographic parameters; Sagittal spinal alignment; Serial imaging
Authors: Steven D Glassman; Keith Bridwell; John R Dimar; William Horton; Sigurd Berven; Frank Schwab Journal: Spine (Phila Pa 1976) Date: 2005-09-15 Impact factor: 3.468