Subaxial cervical spine injury classification

The subaxial cervical spine injury classification (SLIC) system and severity score is a system for cervical spine trauma that helps guide treatment and predicts prognosis.

Classification

Three parameters are assessed, two being radiologic determined and the last being a clinical assessment ¹.

Injury morphology

• no abnormality: 0 points
• simple compression fracture: 1 point
• burst fracture: 2 points
• distraction (e.g. perched facet joint, hyperextension cervical injuries): 3 points
• rotation/translation (e.g. facet dislocation, unstable teardrop, or advanced flexion compression injury): 4 points

Discoligamentous complex

The discoligamentous complex comprises the intervertebral disc, anterior and posterior longitudinal ligaments, ligamentum flavum, interspinous and supraspinous ligaments, and facet joint capsules. Their integrity as a whole in one segment is rated as follows:

• intact: 0 points
• indeterminate (e.g. isolated interspinous widening, MRI signal change only): 1 point
• disrupted (e.g. disc space widening, facet perch, or dislocation): 2 points

More specifically, any of the following imaging findings indicate disruption ¹:

• abnormal facet alignment: articular apposition <50% or joint diastasis >2 mm
• abnormal widening of the anterior disc space
• abnormal widening of the posterior disc space with interspinous widening and relative angulation of >11° at the vertebral interspace
• high signal intensity horizontal through the nucleus and annulus of the disc on fluid-sensitive MR images

All distraction and translation bony injury morphologies imply discoligamentous disruption.

Neurological status

• intact: 0 points
• root injury: 1 point
• complete cord injury: 2 points
• incomplete cord injury: 3 points
• incomplete with ongoing cord compression: 4 points

Treatment

• ≤ 3 points: nonsurgical
• 4 points: indeterminate
• ≥ 5 points: surgical