title: Reliability of lateral bending and axial rotation with validity of a new method to determine axial rotation on anteroposterior cervical radiographs.
abstract: OBJECTIVE
  To investigate the reliability of a new radiographic measurement of axial rotation and lateral bending on anterior-posterior cervical views by using a computer and sonic digitizer.
  
  
  METHODS
  A blind, repeated-measure design was used. Anteroposterior cervicothoracic radiographs were presented to each of 3 examiners in random order. Each film was digitized, and 1 week later the films were randomized for a second run.
  
  
  METHODS
  Private, primary-care chiropractic clinic.
  
  
  METHODS
  The interclass and intraclass correlation coefficients (ICC) for intraexaminer and interexaminer reliability were calculated from measurements on radiographs for determining axial rotations (Ry) and lateral bending (Rz) of C3 to T3.
  
  
  RESULTS
  When the new axial rotation method was applied to small rotations of a C3 plastic model, the average error was less than 1 degrees. For the calculations of axial rotation (Ry), the ICC values were in the good to excellent range. For axial rotation, the intraclass correlation coefficients were ICCs > or =0.78, and the interclass correlation coefficients were ICCs > or =0.67. For lateral flexions (Rz) of C3 to T3, all intraclass and interclass correlation coefficients were in the excellent range (ICCs > 0.87).
  
  
  CONCLUSIONS
  Methods of calculating axial rotations in the spine have been reported for large angles (5 degrees to 30 degrees ) but not for smaller angles. A new method for determining axial rotations of the cervical segments on AP views, based on the chord across the arc displaced by the spinous-lamina junction, had reliability (ICC values) in the good to excellent range. Compared with measured rotations of a C3 model (-5 degrees to +5 degrees ), the new method had an average error of less than 1 degrees and approximately 11.5%. The reliability for the axial rotation measurements was in the good to excellent range, and the lateral bending measurements were all in the excellent range.
authors.affiliation: Senior Research Scientist, Time Domain, Inc, Huntsville, AL, USA.
authors.forename: T
authors.initials: T
authors.lastname: Janik
authors.forename: D E
authors.initials: DE
authors.lastname: Harrison
authors.forename: D D
authors.initials: DD
authors.lastname: Harrison
authors.forename: B
authors.initials: B
authors.lastname: Holland
authors.forename: R R
authors.initials: RR
authors.lastname: Coleman
authors.forename: M R
authors.initials: MR
authors.lastname: Payne
mesh_terms: D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology; D002684:Chiropractic / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D015588:Observer Variation; D011859:Radiography; D012016:Reference Values; D015203:Reproducibility of Results; D012399:Rotation; D016037:Single-Blind Method