Traumatic subaxial cervical facet subluxation and dislocation: epidemiology, radiographic analyses and risk factors for spinal cord injury

Publication date: Available online 21 July 2017
Source:The Spine Journal
Author(s): Ryan D Quarrington, Claire F Jones, Petar Tcherveniakov, Jillian M Clark, Simon J I Sandler, Yu Chao Lee, Shabnam Torabiardakani, John J Costi, Brian J C Freeman
Background contextDistractive-flexion injuries (DFIs) of the subaxial cervical spine are major contributors to spinal cord injury (SCI). Prompt assessment and early intervention of DFIs associated with SCI is crucial to optimize patient outcome; however, neurological examination of patients with subaxial cervical injury is often difficult, as patients commonly present with reduced levels of consciousness. Therefore, it is important to establish potential associations between injury epidemiology and radiographic features, and neurological involvement.PurposeThe aim of this study was to describe the epidemiology and radiographic features of DFIs presenting to a major Australian tertiary hospital, and identify those factors predictive of SCI. The agreement and repeatability of radiographic measures of DFI severity were also investigated.Study design/settingThis is a combined retrospective case-control and reliability/agreement study.Patient sampleTwo hundred and twenty-six patients (median age 40 years [interquartile range ±34]; 72.1% male) who presented with a DFI of the subaxial cervical spine between 2003 and 2013 were reviewed.Outcome measuresEpidemiology and radiographic features of DFI, and risk-factors for SCI were identified. Inter- and intra-observer agreement of radiographic measurements was evaluated.MethodsMedical records, radiographs, computed tomography and magnetic resonance imaging scans were examined and the presence of SCI was evaluated. Radiographic images were analysed by two consultant spinal surgeons and the degree of vertebral translation, facet apposition, spinal canal occlusion and spinal cord compression were documented. Multivariable logistic regression models identified epidemiology and radiographic features predictive of SCI. Intra-class correlation coefficients (ICC) examined inter- and intra-observer agreement of radiographic measurements.ResultsThe majority of patients (56.2%) sustained unilateral (51.2%) or bilateral facet (48.8%) dislocation. The C6/C7 vertebral level was most commonly involved (38.5%). Younger adults were over-represented amongst motor-vehicle accidents, whilst falls contributed to a majority of DFIs sustained by older adults. Greater vertebral translation together with lower facet apposition distinguished facet dislocation from subluxation. Dislocation, bilateral facet injury, reduced Glasgow coma scale, spinal canal occlusion and spinal cord compression were predictive of neurological deficit. Radiographic measurements demonstrated at least "moderate" agreement (ICC>0.4), with most demonstrating "almost perfect" reproducibility.ConclusionsThis large-scale cohort investigation of DFIs in the cervical spine describes radiographic features that distinguish facet dislocation from subluxation, and associates highly reproducible anatomical and clinical indices to the occurrence of concomitant SCI.



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