Evaluation of subjective anterior disc space widening on trauma cervical spine CT as a potential sign of ligamentous injury

Abstract

Introduction: MRI is commonly accepted as the gold standard imaging technique for identification of isolated discoligamentous injury to the cervical spine. Widening of the anterior disc space (ADW) has been suggested as signs of injury to the anterior longitudinal ligament (ALL). The purpose of this study aimed to assess the accuracy of ADW reported on CT as a sign of ligamentous injury compared. Methods: The study was performed at a level 1 trauma centre. All patients over a 5-year period from 1 January 2015 to 31 January 2019 who underwent a cervical CT scan for the indication of trauma and who subsequently received a cervical spine MRI during the same admission were included if no fracture was found on the initial CT. Demographic data were collected along with mechanism of injury and time period between CT and MRI. Presence or absence of subjective CT-ADW along with presence or absence of ALL injury on MRI was recorded by retrospective review of the radiology reports. Sensitivity, specificity and positive and negative predictive values were then calculated. Results: Over a 5-year period, 1,305 patients fulfilled the study criteria. CT-ADW had a sensitivity, specificity and positive predictive value of 8.2% (95% CI: 2.7-18.1%), 96.2% (95% CI: 95.3-97.4%) and 10.2% (95% CI: 3.4-22.2%) respectively. Conclusion: Subjective CT-ADW is a poor predictor of ALL injury as assessed by MRI and should not be relied upon in isolation to diagnose ligamentous injury of the cervical spine in the setting of trauma.