Evaluation of the intervertebral disk angle for the assessment of anterior cervical diskoligamentous injury

Novel Grading Scales for Static and Flexion-Extension Magnetic Resonance Imaging in Patients with Cervical Spondylotic Myelopathy

BACKGROUND

Flexion-extension magnetic resonance imaging (MRI) has potential to identify cervical pathology not detectable on conventional static MRI. Our study evaluated standard quantitative and novel subjective grading scales for assessing the severity of cervical spondylotic myelopathy in dynamic sagittal MRI as well as in static axial and sagittal images.

METHODS

Forty-five patients underwent both conventional and flexion-extension MRI prior to anterior cervical discectomy and fusion from C4 through C7. In addition to measuring Cobb angles and cervical canal diameter, grading scales were developed for assessment of vertebral body translation, loss of disc height, change in disc contour, deformation of cord contour, and cord edema. Data were collected at all levels from C2-C3 through C7-T1. Variations in measurements between cervical levels and from flexion through neutral to extension were assessed using Mann-Whitney, Kruskal-Wallis, and two-way ANOVA tests.

RESULTS

Cervical canal diameter, vertebral translation, and posterior disc opening changed significantly from flexion to neutral to extension positions (P < 0.01). When comparing operative versus nonoperative cervical levels, significant differences were found when measuring sagittal cervical canal dimensions, vertebral translation, and posterior disc opening (P < 0.01). Degenerative loss of disc height, disc dehydration, deformation of ventral cord contour, and cord edema were all significantly increased at operative levels versus nonoperative levels (P < 0.01).

CONCLUSIONS

Flexion-extension MRI demonstrated significant changes not available from conventional MRI. Subjective scales for assessing degenerative changes were significantly more severe at levels with operative cervical spondylotic myelopathy. The utility of these scales for planning surgical intervention at specific and adjacent levels is currently under investigation.

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

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.

Diagnostic Imaging in Spinal Cord Injury

In the evaluation of spinal trauma, diagnostic imaging is of paramount importance. Computed tomography (CT), flexion/extension radiographs, and MRI are complementary modalities. CT is typically obtained in the initial setting of spinal trauma and provides detailed information about osseous structures. MRI provides detailed information about structural injury to the spinal cord. Diffusion tensor imaging provides microstructural information about the integrity of the axons and myelin sheaths, but its clinical use is limited. Novel imaging techniques may be better suited for the acute clinical setting and are under development for potential future clinical use.