title: The analysis of segmental mobility with different lumbar radiographs in symptomatic patients with a spondylolisthesis.
abstract: OBJECTIVE
  Lumbar flexion-extension radiographs in standing position (SFE) are the most commonly used imaging method to evaluate segmental mobility. Many surgeons use SFE to disclose abnormal vertebral motion and base their decision for surgical fusion on its results. We tested the hypothesis that imaging in standing and recumbent position (SRP) reveals a higher sagittal translation (ST) and sagittal rotation (SR) in symptomatic patients than with SFE.
  
  
  METHODS
  We analysed images of 100 symptomatic patients with a low-grade spondylolisthesis that underwent surgical fusion. To determine the ST and SR in SRP, we compared the images taken in the recumbent position in the CT with images taken in the standing position during the routine plain radiography.
  
  
  RESULTS
  The measurement of ST revealed an absolute value of 2.3 ± 1.5 mm in SFE and 4.0 ± 2.0 mm in SRP and differed significantly (p = 0.001). The analysis of the relative value showed an ST of 5.9 ± 3.9% in SFE and 7.8 ± 5.4% in SRP (p = 0.008). The assessment of ST in flexion and in a recumbent position (FRP) revealed the highest ST (4.6 ± 2.5 mm or 9.2 ± 5.7%). Comparison of SR showed the highest rotation in SFE (6.1° ± 3.8°), however, compared to SRP (5.4° ± 3.3°), it missed the level of significance (p = 0.051).
  
  
  CONCLUSIONS
  For evaluation of ST in symptomatic patients with spondylolisthesis SRP appears to be more suitable than SFE, while a pathological SR is better revealed in SFE. The analysis of SRP might offer a complementary method to detect or exclude pathological mobility in more cases.
authors.affiliation: Department of Neurosurgery, Charité, Universitätsmedizin Berlin, Hindenburgdamm 30, 12200 Berlin, Germany. mario.cabraja@charite.de
authors.forename: Mario
authors.initials: M
authors.lastname: Cabraja
authors.forename: Ellafi
authors.initials: E
authors.lastname: Mohamed
authors.forename: Daniel
authors.initials: D
authors.lastname: Koeppen
authors.forename: Stefan
authors.initials: S
authors.lastname: Kroppenstedt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011187:Posture; D013168:Spondylolisthesis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult