title: The effect of age on sagittal plane profile of the lumbar spine according to standing, supine, and various sitting positions.
abstract: BACKGROUND
  The sagittal alignment of the spine changes depending on body posture and degenerative changes. This study aimed to observe changes in sagittal alignment of the lumbar spine with different positions (standing, supine, and various sitting postures) and to verify the effect of aging on lumbar sagittal alignment.
  
  
  METHODS
  Whole-spine lateral radiographs were obtained for young volunteers (25.4 ± 2.3 years) and elderly volunteers (66.7 ± 1.7 years). Radiographs were obtained in standing, supine, and sitting (30°, 60°, and 90°) positions respectively. We compared the radiological changes in the lordotic and segmental angles in different body positions and at different ages. Upper and lower lumbar lordosis were defined according to differences in anatomical sagittal mobility and kinematic behavior.
  
  
  RESULTS
  Lumbar lordosis was greater in a standing position (52.79° and 53.90° in young and old groups, respectively) and tended to decrease as position changed from supine to sitting. Compared with the younger group, the older group showed significantly more lumbar lordosis in supine and 60° and 90° sitting positions (P=0.043, 0.002, 0.011). Upper lumbar lordosis in the younger group changed dynamically in all changed positions compared with the old group (P=0.019). Lower lumbar lordosis showed a decreasing pattern in both age groups, significantly changing as position changed from 30° to 60° (P=0.007, 0.007).
  
  
  CONCLUSIONS
  Lumbar lordosis decreases as position changes from standing to 90°sitting. The upper lumbar spine is more flexible in individuals in their twenties compared to those in their sixties. Changes in lumbar lordosis were concentrated in the lower lumbar region in the older group in sitting positions.
authors.forename: Eui Seok
authors.initials: ES
authors.lastname: Lee
authors.forename: Cheol Woong
authors.initials: CW
authors.lastname: Ko
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Suh
authors.forename: Suresh
authors.initials: S
authors.lastname: Kumar
authors.forename: Il Kuy
authors.initials: IK
authors.lastname: Kang
authors.affiliation: Scoliosis Research Institute, Department of Orthopaedics, Korea University, Guro Hospital, Guro 2-dong, Guro-gu, Seoul, 152-703, South Korea. koreascoliosis@gmail.com.
authors.forename: Jae Hyuk
authors.initials: JH
authors.lastname: Yang
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D011859:Radiography; D013131:Spine / Q000000981:diagnostic imaging*; D055815:Young Adult