◊Clearing of the cervical spine on clinical grounds has become the standard of care in alert adult patients.

Factors associated with higher risk of fracture:

1. Glasgow Coma Score <14
2. Neck tenderness
3. Loss of consciousness
4. Neurologic deficit
5. Drug ingestion
6. Specific mechanism of injury: motor vehicle accident, fall from a height >3 m

Indications for screening CT of cervical spine:

• high-risk adult patients (= >5% pretest probability of injury) defined by:
  1. High-speed (>35 mph) motor vehicle accident
  2. Crash resulting in death at scene of accident
  3. Fall from height >3 m (10 feet)
  4. Significant closed head injury (intracranial hemorrhage seen on CT)
  5. Neurologic signs / symptoms referred to C-spine
  6. Pelvic / multiple extremity fractures

Frequency: 1–3% of all trauma cases;

C2, C6 >C5, C7 >C3, C4 >C1

◊Cervical spine trauma accounts for ⅔ of all spinal cord injuries!

• neurologic / spinal cord damage (39–50%)

Location:

1. upper cervical spine = C1/2 (19–25%): atlas (4%), odontoid (6%)
2. lower cervical spine = C3–7 (75–81%)
3. cervicothoracic junction (9–18%)
4. multiple noncontiguous spine fractures (15–20%)

Site: vertebral arch (50%), vertebral body (30%), intervertebral disk (25%), posterior ligaments (16%), dens (14%), locked facets (12%), anterior ligament (2%)

Associated with injury to:

• head (70%), thoracic spine (15%), lumbar spine (10%), thorax (35%), pelvis (15%), upper extremity (10%), lower extremity (30%)

N.B.: 5–8% of patients with fractures may have normal radiographs!

• Most missed fractures involve C2 (34%), C6-7 (14%), C4 (12%), C1 (8%), occipital condyles
• C7–T1 space not visualized in at least 26% of all trauma patients

Normal range of motion: 10–20° during flexion and extension; 4–12° of lateral tilting

Cx: neurologic deterioration with delay in diagnosis

1. HYPERFLEXION INJURY (46–79%)
   1. Odontoid fracture
   2. Simple wedge fracture (stable)
   3. Flexion teardrop fracture = avulsion of anteroinferior corner by anterior ligament (unstable)
      • Most severe + unstable injury of C-spine
      
      Location: C5, C6, C7
      • triangular fragment in soft tissues anterior to vertebral body
      • retrolisthesis
      • widening of facets
      • narrowing of spinal canal
      • mild kyphosis
      
      Associated with: ligamentous tears, spinal cord compression
      

      Subaxial Injury Classification and Scoring (CT Severity Score for Entire Spine, 2007)*

      Injury Category Point Value Injury Morphology Compression 1 Burst 2 Distraction 3 Translation / rotation 4 Discoligamentous complex Intact 0 Indeterminate 2 Disrupted 3 Neurologic status Intact 0 Root injury 1 Spinal cord injury incomplete 2 complete 3 Cord injury + ongoing compression 4 Total Score:≤3 manageable without surgery 4 indeterminate; ≥5 need for surgical intervention

      * a separate score is given to each injured level

      
      ◊Triangular teardrop fracture without posterior element distraction / vertebral body translation should be characterized as (1) compression or (2) burst injury.
   4. Anterior subluxation
   5. Bilateral facet lock = interlocking of articular surfaces (unstable)
      • anterolisthesis of affected vertebra by ½ vertebral body width
      • mild focal kyphosis
      • soft-tissue swelling
      • no rotation
   6. Anterior disk space narrowing
   7. Spinous process fracture = clay shoveler's fracture
      = sudden load on flexed spine with avulsion fracture of C6 / C7 / T1 (stable)
   8. Flexion instability = isolated rupture of posterior ligaments
      • Dx may be missed without delayed flexion views
      • no fracture
      • interspinous widening
      • loss of facet parallelism
      • widening of posterior portion of disk
      • anterolisthesis >3 mm
      • focal kyphosis
2. HYPEREXTENSION INJURY (20–38%)
   Mechanism: impact on forehead / face, whiplash
   • High risk for neurologic deficit!
   • Radiographs may be completely normal!
   1. Hyperextension dislocation
      followed by immediate realignment
      • upper extremity paresthesia to complete quadriplegia
      • disruption of anterior longitudinal ligament, annulus, intervertebral disk, lig. flavum
      • prevertebral swelling ← hemorrhage + edema
      • stripping of posterior longitudinal ligament
      • tears of paraspinal muscles
      • widening of disk space anteriorly
      • avulsion of anteroinferior endplate
      • transverse dimension of anteroinferior avulsion fragment greater than vertical dimension
   2. Extension teardrop fracture
      = avulsion of intact fibers of anterior longitudinal ligament off anteroinferior endplate
      Location: C2, C3
      • acute central cord syndrome (in up to 80%)
      • vertical dimension of triangular fragment greater than transverse dimension
   3. Neural arch fracture of C1 (stable fracture = anterior ring + transverse ligament intact)
      • vertically oriented fracture of posterior arch (stable if isolated / part of Jefferson burst fracture)
   4. Anterior arch fracture of C1
      • biomechanically stable
      • transverse fracture through inferior pole / midportion at attachment of atlantodental lig. / longus colli m.
   5. Uni- / bilateral laminar fracture commonly part of a burst fracture / pedicolaminar fracture-separation / flexion teardrop fracture
      • extension into adjacent spinous process (frequent)
   6. Subluxation (anterior / posterior)
   7. Hangman's fracture
3. FLEXION-ROTATION INJURY (12%)
   1. Unilateral facet lock (oblique views!, stable fracture)
      • anterolisthesis <¼ vertebral body width
      • “bow-tie” sign = the 4 rotated facets on LAT view
      • decrease in spinolaminar space
      • rotation of spinous process (on AP view)
      • “naked facet” (on CT)
4. VERTICAL COMPRESSION (4%)
   = axial loading
   1. Jefferson fracture
   2. Burst fracture = intervertebral disk driven into vertebral body below (fracture may be stable / unstable)
      • loss of posterior vertebral body height with several fragments:
        • sagittal fracture component extending to inferior endplate
        • retropulsed fragment from posterior superior margin in spinal canal
        • interpedicular widening
        • posterior element fracture
      
      Associated with: widening of apophyseal joints, fracture of posterior vertebral arches
5. LATERAL FLEXION / SHEARING (4–6%)
   1. Uncinate fracture
   2. Isolated pillar fracture
   3. Transverse process fracture
   4. Lateral vertebral compression