title: Lumbar Spine Alignment in Six Common Postures: An ROM Analysis With Implications for Deformity Correction.
abstract: METHODS
  A cross-sectional study of prospectively collected data.
  
  
  OBJECTIVE
  To compare lumbar spine alignment in six common postures, and estimate loss in range of motion (ROM) relative to standing.
  
  
  BACKGROUND
  Ideal position for fusion of lumbar spine remains unknown. Although surgical fusion is necessary for deformity correction and symptom relief, the final position in which the vertebrae are immobilized should provide maximum residual function.
  
  
  METHODS
  Data were collected prospectively from 70 patients with low back pain recruited over a year. All subjects had x-rays performed in slump sitting, forward bending, supine, half squatting, standing, and backward bending postures. ROM quantified in terms of sagittal global and segmental Cobb angles was measured from L1 to S1. Loss of ROM relative to standing was calculated for each posture. Analysis of variance and unpaired t tests were used to identify differences in alignment between postures.
  
  
  RESULTS
  Slump sitting gives the greatest lumbar flexion followed by forward bending, and supine postures (P < 0.001). Backward bending produces greater lumbar extension than standing (P = 0.035). Half-squatting and standing postures were not significantly different (P = 0.938). For all postures, L4-5 and L5-S1 segments remained in lordosis, with L4-5 having greater ROM than L5-S1. L1-2 turns kyphotic in lying supine, L2-3 at forward bending, and L3-4 at slump sitting in the form of a "kyphosing cascade." Should the entire lumbar spine be fused in standing position from L1-S1, there would likely be a mean loss of 47.6° of lumbar flexion and 5.9° of lumbar extension.
  
  
  CONCLUSIONS
  The present study demonstrates the extent of flexibility required of the lumbar spine in assuming various postures. It also enables comparison of the differences in degree of motion occurring in the lumbar spine, both across postures and across segments. Significant loss in ROM, particularly flexion, is anticipated with fusion modeled after the lordotic standing lumbar spine.
  
  
  METHODS
  2.
authors.affiliation: University Orthopaedics, Hand and Reconstructive Microsurgery (UOHC), National University Health System, Singapore, Singapore.
authors.forename: Hwee Weng Dennis
authors.initials: HWD
authors.lastname: Hey
authors.forename: Eugene Tze-Chun
authors.initials: ET
authors.lastname: Lau
authors.forename: Kimberly-Anne
authors.initials: KA
authors.lastname: Tan
authors.forename: Joel L
authors.initials: JL
authors.lastname: Lim
authors.forename: Denise
authors.initials: D
authors.lastname: Choong
authors.forename: Leok-Lim
authors.initials: LL
authors.lastname: Lau
authors.forename: Ka-Po G
authors.initials: KG
authors.lastname: Liu
authors.forename: Hee-Kit
authors.initials: HK
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000503:physiopathology; D017116:Low Back Pain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D000077708:Sitting Position; D016683:Supine Position / Q000502:physiology