The most common causes of spinal cord injuries are

  • Motor vehicle crashes (48%)

  • Falls (16%)

The remainder of spinal cord injuries are attributed to assault (12%), sports (10%), and work-related accidents. About 80% of patients are male.

In the elderly, falls are the most common cause. Osteoporotic bones and degenerative joint disease may increase the risk of cord injury at lower impact velocities due to angulations formed by the degenerated joints, osteophytes impinging on the cord, and brittle bone allowing for easy fracture through critical structures.

Spinal cord injuries occur when blunt physical force damages the vertebrae, ligaments, or disks of the spinal column, causing bruising, crushing, or tearing of spinal cord tissue, and when the spinal cord is penetrated (eg, by a gunshot or a knife wound). Such injuries can also cause vascular injury with resultant ischemia or hematoma (typically extradural), leading to further damage. All forms of injury can cause spinal cord edema, further decreasing blood flow and oxygenation. Damage may be mediated by excessive release of neurotransmitters from damaged cells, an inflammatory immune response with release of cytokines, accumulation of free radicals, and apoptosis.

Vertebral injury

Vertebral injuries may be

  • Fractures, which may involve the vertebral body, lamina, and pedicles as well as the spinous, articular, and transverse processes

  • Dislocations, which typically involve the facets

  • Subluxations, which may involve ligament rupture without bony injury

In the neck, fractures of the posterior elements and dislocations can damage the vertebral arteries, causing a syndrome resembling a brain stem stroke.

Unstable vertebral injuries are those in which bony and ligamentous integrity is disrupted sufficiently that free movement can occur, potentially compressing the spinal cord or its vascular supply and resulting in marked pain and potential worsening of neurologic function. Such vertebral movement may occur even with a shift in patient position (eg, for ambulance transport, during initial evaluation). Stable fractures are able to resist such movement.