title: Segmental lumbar spine instability at flexion-extension radiography can be predicted by conventional radiography.
abstract: OBJECTIVE
  To identify plain radiographic findings that predict segmental lumbar spine instability as shown by functional flexion-extension radiography.
  
  
  METHODS
  Plain radiographs and flexion-extension radiographs of 215 patients with clinically suspected lumbar spine instability were analysed. Instability was classified into anterior or posterior sliding instability. The registered plain radiographic findings were traction spur, spondylarthrosis, arthrosis of facet joints, disc degeneration, retrolisthesis, degenerative spondylolisthesis, spondylolytic spondylolisthesis and vacuum phenomena. Factors reaching statistical significance in univariate analyses (P < 0.05) were included in stepwise multiple logistic regression analysis.
  
  
  RESULTS
  Degenerative spondylolisthesis (P = 0.004 at L3-4 level and P = 0.017 at L4-5 level in univariate analysis and odds ratio 16.92 at L4-5 level in multiple logistic regression analyses) and spondylolytic spondylolisthesis (P = 0.003 at L5-S1 level in univariate analyses) were the strongest independent determinants of anterior sliding instability. Retrolisthesis (odds ratio 10.97), traction spur (odds ratio 4.45) and spondylarthrosis (odds ratio 3.20) at L3-4 level were statistically significant determinants of posterior sliding instability in multivariate analysis.
  
  
  CONCLUSIONS
  Sliding instability is strongly associated with various plain radiographic findings. In mechanical back pain, functional flexion-extension radiographs should be limited to situations when symptoms are not explained by findings of plain radiographs and/or when they are likely to alter therapy.
authors.affiliation: Departments of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland. marja.pitkanen@kuk.fi
authors.forename: M T
authors.initials: MT
authors.lastname: Pitkänen
authors.forename: H I
authors.initials: HI
authors.lastname: Manninen
authors.forename: K-A J
authors.initials: KA
authors.lastname: Lindgren
authors.forename: T A
authors.initials: TA
authors.lastname: Sihvonen
authors.forename: O
authors.initials: O
authors.lastname: Airaksinen
authors.forename: S
authors.initials: S
authors.lastname: Soimakallio
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging; D007593:Joint Instability / Q000000981:diagnostic imaging*; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D013122:Spinal Diseases / Q000000981:diagnostic imaging*; D025242:Spondylarthropathies / Q000000981:diagnostic imaging; D013168:Spondylolisthesis / Q000000981:diagnostic imaging