title: Hidden discoligamentous instability in cervical spine injuries: can quantitative motion analysis improve detection?
abstract: OBJECTIVE
  Recent literature shows that occult discoligamentous injuries still remain difficult to diagnose in the first instance. Thresholds as indicators for discoligamentous segmental instability were previously defined. But, since supine radiodiagnostic is prone to spontaneous reduction of a displaced injury, and even some highly unstable injuries reveal only slight radiographic displacement, these criteria might mislead in the traumatized patient. A highly accurate radiographic instrument to assess segmental motion is the computer-assisted quantitative motion analysis (QMA). The aim was to evaluate the applicability of the QMA in the setting of a traumatized patient.
  
  
  METHODS
  Review of 154 patients with unstable cervical injuries C3-7. Seventeen patients (male/female: 1:5, age: 44.6 years) had history of initially hidden discoligamentous injuries without signs of neurologic impairment. Initial radiographs did not fulfill instability criteria by conventional analysis. Instability was identified by late subluxation/dislocation, persisting/increasing neck pain, and/or scheduled follow-up. For 16 patients plain lateral radiographs were subjected to QMA. QMA data derived were compared with normative data of 140 asymptomatic volunteers from an institutional database.
  
  
  RESULTS
  Data analysis of measurements revealed mean spondylolisthesis of -1.0 mm (-3.7 to +3.4 mm), for segmental rotational angle mean angulation of -0.9° (-11.1° to +17.7°). Analysis of these figures indicated positive instability thresholds in 5 patients (31.3 %). Analysis of center of rotation (COR)-shifts was only accomplishable completely in 3/16 patients due to limited motion or inadequacy of radiographs. Two of these patients (12.5 %) showed a suspect shift of the COR.
  
  
  CONCLUSIONS
  Our data show a high rate of false negative results in cases of hidden discoligamentous injuries by using conventional radiographic analysis as well as QMA in plain lateral radiographs in a trauma setting. Despite the technical possibilities in a modern trauma center, our data and recent literature indicate a thorough clinical and radiographic follow-up of patients with cervical symptoms to avoid secondary complications from missed cervical spine injuries.
authors.affiliation: Department for Traumatology and Sports Injuries, Paracelsus Medical University Salzburg, Muellner Hauptstrasse 48, 5020, Salzburg, Austria, mayermichi@yahoo.de.
authors.forename: M
authors.initials: M
authors.lastname: Mayer
authors.forename: J
authors.initials: J
authors.lastname: Zenner
authors.forename: A
authors.initials: A
authors.lastname: Auffarth
authors.forename: M
authors.initials: M
authors.lastname: Blocher
authors.forename: M
authors.initials: M
authors.lastname: Figl
authors.forename: H
authors.initials: H
authors.lastname: Resch
authors.forename: H
authors.initials: H
authors.lastname: Koller
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000293:injuries; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging* / Q000293:injuries; D007593:Joint Instability / Q000000981:diagnostic imaging*; D008023:Ligaments, Articular / Q000000981:diagnostic imaging* / Q000293:injuries; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009038:Motion; D019838:Neck Injuries / Q000000981:diagnostic imaging; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013124:Spinal Injuries / Q000000981:diagnostic imaging*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards; D055815:Young Adult