Fractures and dislocations of the spine
Before we delve into the fractures that each part of the spinal cord can get it is important to consider the ‘Three-Column Concept of Spinal stability’. This is a simple concept, it basically divides the spinal column into three columns and if more than one column is involved in the fracture then instability usually occurs.
This concept was devised by Francis Denis and is often referred to as the Denis classification. We have listed the contents of each column below:
- Anterior
- Anterior longitudinal ligament
- Anterior ⅔ of vertebral body
- Anterior ⅔ of intervertebral disc (annulus fibrosus)
- Middle column
- Posterior ⅓ of vertebral body
- Posterior ⅓ of intervertebral disc (annulus fibrosus)
- Posterior longitudinal ligament
- Posterior column
- Pedicles
- Facet joints and articular processes
- Ligamentum flavum
- Neural arch and interconnecting ligaments
Off the back of this, Denis listed five types of fracture:
- A
- Fracture of both end plates without kyphosis
- Caused by pure axial load
- Predilection for lower lumbar region
- B
- Fracture of superior endplate
- Most frequent burst fracture, caused by axial load and flexion
- Predilection for thoracolumbar region
- C
- Fracture of the inferior endplate (rare)
- Caused by axial load and flexion
- No particular site pattern
- D
- Burst rotation fracture - burst fracture with comminution of vertebral body, loss of posterior height and bone retropulsion into spinal canal
- Caused by axial load and rotation
- Predilection for mid lumbar region
- E
- Burst lateral flexion fracture, fractured posterior wall of vertebral body with fragment extrusion towards side of flexion
- Caused by axial load and lateral flexion
Cervical spine injuries
Some interesting things to note here. Once the spine has been damaged there is a protective muscular spasm that tries to protect the patient if they are conscious. As such, it is very unlikely that careful handling of a conscious patient can do any further damage. This however is not true for the unconscious patient, and special care must be taken for such patients.
Cervical spine injuries can be caused in one of four ways:
- Flexion
- Extension
- Vertical compression
- Rotation
Flexion injuries are the most common cause of cervical injuries and are generally seen in the C4-C7 region. The lesions that can be caused include:
- Crush injuries - as the cervical spine rapidly flexes, the superior vertebral body compresses the body below causing a crush fracture of the lower body
- Symptomatic treatment with four post collar or cast