Update in Subaxial Cervical Trauma: What the Clinician Needs to Know Roy Riascos, MD Eliana Bonfante, MD Claudia Cotes, MD Clark Sitton, MD Maria Gule-Monroe, MD Harry Papasozomenos, MD Neurorradiology The University of Texas Health Science Center – Houston

Blunt trauma of the cervical spine is a common presentation to emergency departments with more than 1 million cases per year % of these cases will demonstrate injury to the cervical spine. Greater than 60% of all cervical spine fractures and more than three-fourths of the dislocations are sub axial. The major cause of cervical spine injury in the young population are motor vehicle accidents, acts of violence, and sports injuries. Falls or other low energy mechanisms are more common in the geriatric population. Imaging of the trauma patient has evolved in recent years, with multidetector CT being ordered as part of the initial management of these patients. MRI is a potential modality for problem solving but its use remains controversial. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Review the anatomy of the Subaxial cervical spine. To provide a review of the subaxial injuries in terms of anatomy and currently used. Identify the role of imaging in the prognosis and treatment of subaxial injuries. Purpose Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

The subaxial cervical spine extends from the inferior border of C2 to the superior endplate of T1. Ligaments: The anteior longitudial ligament connects the anterior aspects of the vertebral bodies. The posterior logitudinal ligament connects the posterior aspects of the vertberal bodies. The ligamentum flavum connects the adjacent laminae. The interspinous ligament connects the spinous processes. Joints The intervertebral discs connect the vertbral bodies The apophyseal facets communicate throgh synovial joints on both sides. Anatomy. Intervertebral disc Vertebral body Facet joint Anterior longitudinal ligament Posterior longitudinal ligament Interspinous ligament Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Indications for Imaging – Plain Films Three views: anteroposterior (AP), lateral, and odontoid view. Low cost and fast. Should be used when the suspicion of injury is low since it may fail to demonstrate lesions that are normally visible in other modalities. Dynamic views, which include flexion and extension views, demonstrate unstable cervical spine lesions. However, range of motion may be limited in the acute setting. Lateral (a), AP (b), od0ntoid (c), flexion (d) and extension views(e) of the cervical spine. a b c d e Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Indications for Imaging – CT Study of choice when injury of the cervical spine is suspected. Multiplanar, reformatted sagittal and coronal reconstruction provide high quality images that improve interpretation. The recommended slice thickness for sagittal and coronal reconstructions is 1.25 mm. Although newer scanners have decreased radiation exposures, these are higher compared to plain film. CT should be limited to patients at high risk of cervical spine injury. Axial, sagital and coronal CT images in bone reconstruction. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Indications for Imaging – MR Suspected myelopathy. Treatment planning for the mechanically unstable spine. Patients who can not be clinically evaluated for more than 48 hours, patients with neurological deficits, or suggested ligamentous injury. The main role of MR is detection of the type and extent of spinal cord injury which impacts patient management. MR is better suited for exclusion of spinal cord lesions than detection of ligamentous or other soft tissue injuries. T2 Sagittal without and with fat saturation are used in cervical trauma for evaluation of the soft tissues in trauma. Axial T2 sequences can help evaluate the spinal canal and the spinal cord. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Indications for Imaging – Magnetic Resonance (MR) MR performs slightly better in detection of clinically significant lesions. No studies compare more current MR technology with cadaveric studies; but MR has only a slightly advantage in the detection of occult instability injuries not detected on CT. MR does not provide any additional clinically relevant information in patients who are alert, neurologically intact, and younger than 60 years of age.* *Pourtaheri et al Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary T2 Sagittal without and with fat saturation are used in cervical trauma for evaluation of the soft tissues in trauma. Axial T2 sequences can help evaluate the spinal canal and the spinal cord.

Classifications Allen and Fergusson Cervical Spine Injury Severity Score (CSISS) Sub-axial Injury Classification (SLIC ) Controversy concerning the affect classification systems have on clinical outcome, most imagers have resorted to using descriptive terminology to describe patterns of injury. Recent efforts to further classify subaxial lesions have been made giving rise to the subaxial ligamentous injury (SLIC) and the cervical spinal severity score (CSISS) classifications. This exhibit will review the two classifications and discuss the clinical implications of them. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

more than 60% of all cervical spine fractures. Many classifications Based on mechanisms of injury the cervical fractures are divided in the following groups: Compressive flexion Vertical compression Distractive flexion Compressive extension Lateral flexion Limited clinical use Rarely currently utilized Still of great value in the comprehensive analysis of spectrum of injuries during diagnostic interpretation of images. Allen and Fergusson Classification Most widely utilized system for description of fractures in the past. This system does not quantify the severity of a lesion or guide treatment which is considered a limitation. Harris et al (1) expanded this classification in the mid 1980s. Today this expansion is used rarely in clinical practice. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Moore et al in 2006 Assess cervical stability and translate that into the likelihood of considering surgery as a treatment option Imaging only System considers the bony and the ligamentous components Spine is divided into four columns: anterior, posterior right pillar and left pillar Cervical Spine Injury Severity Score (CSISS) Diagram of a cervical spine (A) The spine is divided into four columns: anterior, posterior right pillar and left pillar. CSISS Classification (B). Adapted from Anderson et al Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Cervical Spine Injury Severity Score (CSISS) The anterior column includes the vertebral body, intervertebral disc, the anterior and posterior longitudinal ligaments. The posterior column includes the spinous process, the interspinous ligament, the lamina and ligament flava. The lateral pillars include the pedicle the pars articularis, the joint facet with the capsules and the transverse process. Diagram of a cervical spine (A) The spine is divided into four columns: anterior, posterior right pillar and left pillar. CSISS Classification (B). Adapted from Anderson et al Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Cervical Spine Injury Severity Score (CSISS) For each column, a score of 0 to 5 is given, 0 representing no injury and 5 representing the most severe fracture or dislocation possible for that column see image. The numerical value is summed of all four columns resulting in a final score of 0 to 20 for each level. This classification has yet to be compared with prognosis. The authors found that most patients with scores greater than 7 likely received surgical intervention, while only 3 of 20 patients with score lower that 7 required surgical reduction Diagram of a cervical spine (A) The spine is divided into four columns: anterior, posterior right pillar and left pillar. CSISS Classification (B). Adapted from Anderson et al Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Proposed by Vaccaro et al in 2007 Beyond mechanism of injury Components Injury morphology Disco-ligamentous complex (DLC) integrity Neurological status of the patient Guide towards management strategies Better inter-rater reliability than the Allen and Fergusson Sub-axial Injury Classification (SLIC) Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Simple Compression Anterior Column DLC disruption Laminar fractures Non-displaced lateral mass fracture Diagrams demonstrating simple compression morphology. The lesions show a loss of anterior column height. They can affect the anterior column, be accompanied by DLC disruption or laminar fractures. Non displaced lateral mass or facet fractures are also considered simple compression injuries. Adapted from, Vaccaro et al, Spine. 32(21): , October 1, Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Simple Compression Anterior column compression with Epidural Hematoma: Anterior compression fracture of C3 (white arrow head), Increased signal in the interspinous ligament (black arrow head) and spinal canal stenosis due to a posterior epidural hematoma (arrows). Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Simple Compression Anterior column with DLC Disruption: Fracture of the inferior endplate of C5 that extends to the interverterbal disc (arrows). An anterior epidural hematoma causes narrowing of the spinal canal with increased signal in the spinal cord (arrow heads). Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Simple Compression Laminar Fractures CT shows spinous fractures of C7 and T1 (arrows), slight compression fractures of the C7 verterbal body are noted (arrow head). Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Simple Compression Non displaced lateral mass fracture: CT shows a non displaced fracture of the right lateral mass of C6 (white arrow). MR STIR WI shows bone marrow edema at the fracture site. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Burst. Burst fracture: severe compression lesion that involves the whole vertebral body and can be associated with retropulsed fragments. Lateral (A) and sagittal (B) diagrams of the cervical spine. Adapted from, Vaccaro et al, Spine. 32(21): , October 1, Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Burst. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary Burst Fracture Burst compression fractures of C5 and C6 with posterior retropulsed fragments and a disc extrusion which narrows the spinal canal (arrow heads). Hyperintensity is noted in the spinal cord (arrows).

CircumferentialFacet dislocation Anterior distraction with extension Anterior distraction with flexion Distraction Distraction morphology. Diagrams demonstrating distraction morphology. Lesions are characterized by dissociation of the vertical axis involving the disc-ligamentous complex. Lesions may be circumferential and associated to facet dislocations. Anterior distraction in hyperextension may be associated to spinous process fractures. Distraction in hyperflexion can be associated to posterior ligamentous injury. Adapted from, Vaccaro et al, Spine. 32(21): , October 1, Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Distraction Anterior distraction with flexion CT shows laminar fractures with fractures of the spinous processes (arrow). Disruption of the ligamentum flavum- interspinous ligament is present (arrow heads) Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Anterior Distraction with Extension: Widening of the C5-6 intervertebral disc space with DLC compromise and interuption of the ALL (arrow). Sagittal T1 and axial GRE WI show an anterior epidural hematoma (arrowhead). Distraction Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Anteiror Disruption with Extension: Disruption of the anterior longitudinal ligament at C5-6 (white arrow) with a prevertebral hematoma and fluid in the C5-6 intervertebral disc consistent with disruption of the DLC. The spinal cord is compressed (arrow head). Distraction Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Translation in sagittal plane Translation with pedicle fracture Translation with facet fracture Rotational injury Translation/Rotation Translation/rotation morphology. Diagrams demonstrating translation and rotation injuries. These injuries are characterized with complete DLC disruption. Translation can happen in the sagittal plane, associated to pedicle fractures or joint facet fractures. Rotational injuries can also be present in addition to the axial translation. Adapted from, Vaccaro et al, Spine. 32(21): , October 1, Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Translation/Rotation Translation in the saggital plane. Slight translation in the sagittal plane (black arrow head) with incresaed signal in the spinal cord ((white arrow). Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Translation with pedicle fracture Translation with pedicle fracture: Anterior displacement of C6 on C7 with complete overlap. Fracture of the spinous process of C6 (white arrow head, and compression of the spinal cord is noted (white arrow). The interspinous soft tissues show edema (black arrow). Fracture of the pedicle of C6 is noted (black arrow head) Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary Translation/Rotation

Translation with facet fracture: CT before reduction and MR after reduction show widening of the C6-7 interverterbal space with fluid occupying the space (black arrowhead). The interspinous space in widened (white arrow); fracture of the superior joint facet in present (white arrow head). Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Diffuse Idiopathic Skeletal Hyperostosis: Patient with DISH shows fracture of the anterior bridging osteophytes with a preverterbal hematoma and of the transverse process of C7. bone marrow contusion isn the lower cervical bodies, consistent with bone contusions. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

The three categories of the SLIC system are identified and reported as seen in table 1. The report should include the spinal level, the injury level morphology, the bony injury descriptor, the DLC status and descriptors, the neurological status, and confounding factors (presence of ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis, osteoporosis, previous surgery, spondylosis, etc). A numeric value is assigned to each category and the numerical sum is the SLIC score. Higher scores indicate more significant injury and an increased need for surgical intervention. If multiple injuries occur at different levels, each level is assigned a separate score. How to use the classification What the Clinical needs to know SLIC- Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Although great improvement have been made using these new classification systems, challenges in the evaluation of subaxial cervical injuries remain. Some of these are: The signal changes in the cervical spinal cord don’t always correlate with the findings in the neurological exam. The cord abnormalities are not included in the scoring system, however they are extremely relevant for patient care, especially in non responsive patients. Challenges of the Classifications Overlap exists in parameters of the new classifications and we find it difficult to isolate the lesions to single categories of the proposed systems. The evaluation of other traumatic soft injuries such as acute disc herniations or epidural hematomas is not considered in the scoring systems, yet has a strong clinical impact. Image quality limitations are not taken into account, which are usual in acute traumatic injuries. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

The subaxial ligamentous injury (SLIC) and the cervical spinal severity score (CSISS) classifications are a new effort to classify subaxial traumatic cervical injuries. Neuroradiologists should be aware of the clinical implications of using these classifications, and how they can provide improvement in patient outcomes. The SLIC classification integrates imaging and neurological findings, and has shown a strong correlation with treatment planning. Radiologists should actively be included in evolving new classifications systems for subaxial injuries. Summary Although the Allen and Fergusson Classification has limited clinical utility, it is still of great value in the comprehensive analysis of spectrum of injuries during diagnostic interpretation of images. Non ligamentous soft tissue injuries such as the presence of epidural hematomas and cord compression are not included in these classifications. Radiologists must know which system is used at their institutions to be able to know what is the pertinent information to include in their reports. Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary

Vaccaro, A. R. et al. The subaxial cervical spine injury classification system: a novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex. Spine 32, 2365–2374 (2007). 78.Allen, B. L., Jr, Ferguson, R. L., Lehmann, T. R. & O’Brien, R. P. A mechanistic classification of closed, indirect fractures and dislocations of the lower cervical spine. Spine 7, 1–27 (1982). 79.Marcon, R. M. et al. Fractures of the cervical spine. Clin. São Paulo Braz. 68, 1455–1461 (2013). 80.Stone, A. T. et al. Reliability of classification systems for subaxial cervical injuries. Evid.-Based Spine- Care J. 1, 19–26 (2010). 81.Harris, J. H., Jr, Edeiken-Monroe, B. & Kopaniky, D. R. A practical classification of acute cervical spine injuries. Orthop. Clin. North Am. 17, 15–30 (1986). 82.Kwon, B. K., Vaccaro, A. R., Grauer, J. N., Fisher, C. G. & Dvorak, M. F. Subaxial cervical spine trauma. J. Am. Acad. Orthop. Surg. 14, 78–89 (2006). 83.Anderson, P. A. et al. Cervical spine injury severity score. Assessment of reliability. J. Bone Joint Surg. Am. 89, 1057–1065 (2007). References Introduction Purpose Anatomy Indications for imaging Plain Films CT MRI Classifications Allen and Fergusson CSISS SLIC Morphology Simple compression Burst Distraction Translation How to use Summary