Description

• Cervical spine injuries can result in vertebral fracture, ligamentous injury, or spinal cord injury.
• Vertebral and ligamentous injuries can cause cervical spine instability leading to cord injury.

Epidemiology

• An estimated 12,000/year new cases of spinal cord injury in the US, with >50% involving the cervical spine
• Affects young, active adults, and the elderly due to degenerative joint disease and increased risk of falls
• Average age at time of injury: 39.5
• Male-to-female ratio: 4:1

Risk Factors

• Degenerative joint disease (particularly, the elderly)
• Osteoporosis
• Spinal canal stenosis
• Spina bifida

Genetics
Inherited connective tissue disorders (e.g., familial cervical spondylosis, a spondylitis)

General Prevention

• Use seat belts and child safety seats.
• Treatment of osteoporosis and fall prevention for elderly

Pathophysiology

4 major vertebral and ligamentous injuries are classified by mechanism:

• Flexion:
  • Simple wedge compression fracture:
    • Anterior compression fracture of vertebrae
    • Nuchal ligament stretch, but not disruption
    • Diminished vertebral body height on x-ray
    • Stable fracture
  • Flexion teardrop fracture:
    • Anteroinferior vertebral body fracture
    • Displaced anterior fragment (“teardrop”)
    • Posterior and anterior ligamentous disruption
    • Extremely unstable; high risk of cord injury
  • Anterior subluxation:
    • Posterior ligament rupture without fracture
    • Rarely associated with neurologic deficit
    • Seen on flexion-extension views
    • Treated as unstable due to risk while in flexion, but not unstable by definition
  • Bilateral facet dislocation:
    • More severe anterior subluxation
    • Includes disruption of annulus, anterior, and posterior ligaments
    • Inferior facets move superior and anterior to the superior facets, causing displacement.
    • Neurologic injury related to disk herniation
  • Clay shoveler fracture:
    • Oblique fracture at base of spinous process
    • Occurs with abrupt flexion with simultaneous contraction of lower neck and upper body
    • Also occurs with blunt trauma
    • Avulsed fragment seen on lateral views
    • Stable fracture, low risk for neurologic deficit
• Flexion–rotation:
  • Unilateral facet dislocation:
    • Less anterior displacement than bilateral
  • Rotary atlantoaxial dislocation (C1–C2):
    • Specific type of unilateral facet dislocation
    • Asymmetry of the lateral masses of C1 seen
    • Considered unstable due to location
• Extension:
  • Hangman fracture:
    • Traumatic spondylolisthesis of C2
    • Bilateral fractures through C2 pedicles
    • Unstable fracture, but cord injury rare
  • Extension teardrop fracture:
    • Avulsion fracture from stretch on anterior longitudinal ligament, causing anteroinferior bony fragment
    • Commonly found at lower cervical levels
    • Cord injury possible due to ligamenta flava encroaching into spinal canal
    • Unstable fracture in extension
  • Fracture of C1 posterior arch:
    • Stable fracture
  • Posterior atlantoaxial dislocation (C1–C2):
    • Cord injury possible
• Vertical compression (from axial load):
  • Jefferson fracture:
    • Burst fracture of C1 ring
    • Instability determined by severity of transverse ligamentous disruption
    • Unstable if >25% loss of height
  • Occipital condyle fracture:
    • Can be avulsion or compression fracture
    • Associated with cranial nerve deficits
• Unclear mechanisms:
  • Odontoid (dens) fracture, part of C2 (axis):
    • Type I: Involving tip of dens
    • Type II: Involving base of dens
    • Type III: Extends into body of axis
    • Types II and III can become unstable.
  • Atlanto-occipital dislocation:
    • Brain stem stretch may cause immediate respiratory arrest and death.
• Spinal cord injury (SCI):
  • Complete cord injury: Characterized by complete loss of sensory and motor functions below injury through S4–S5. Can also present with priapism, urinary retention, and bladder distention.
  • Incomplete deficits: Sensory and motor functions partially preserved below injury. Sensory preserved to a greater degree because sensory tracts peripherally located. Incidence of incomplete cord injury has increased compared with complete injury with implementation of Advanced Trauma Life Support (ATLS) protocols for all trauma patients (1). Most SCI are mixed injuries, but there are some specific syndromes:
    • Central cord syndrome: Most common incomplete injury; motor deficits greater in upper than lower extremities. Sensory loss in the distribution of a “cape” and due to watershed injury affecting long fiber tracts; may be due to hyperextension
    • Anterior cord syndrome: Posterior columns spared; affects spinothalamic, corticospinal, anterior, and lateral columns; loss of pain, temperature, and motor with preserved vibration and position sense below the lesion
    • Posterior cord syndrome: Sensory deficits more pronounced than motor, due to contusion of posterior columns
    • Brown-Sequard syndrome: Ipsilateral motor loss and vibration sensation deficits with contralateral loss of pain and temperature sensation; hemisection of cord most often due to penetrating trauma

Etiology

Traumatic injury to the head or neck from:

• Motor vehicle accidents (MVAs) or falls
• Violence (e.g., gunshot wounds)
• High-risk or high-impact sports
• Diving injuries

Commonly Associated Conditions

• A second spinal injury (10–15% will have another injury at another level), hence careful immobilization and assessment of entire spine are important.
• Intracranial hemorrhage
• Cervical sprain and strain due to acceleration/deceleration, usually after a car accident (whiplash)
• Skull and facial fractures
• Thoracolumbar spine injury
• Other: Visceral/Extremities injuries in polytrauma