Thoracolumbar spine fractures – McAfee classification

Classification

Wedged compression fracture

• Isolated failure of the anterior column
• Wedge-shaped vertebral body
• Mechanism of injury: Forward flexion

Stable burst fracture

• Anterior and middle columns fail
• No loss of integrity of the posterior elements
• Mechanism of injury: Compressive load

Unstable burst fracture

• Anterior and middle columns fail in combination with disruption of the posterior column
• Posterior column may fail in compression, lateral flexion, or rotation, but not in distraction
• Tendency for post-traumatic kyphosis and progressive neural symptoms

Note: The importance of differentiating compression from burst fractures lies in the higher frequency of neurologic deficits associated with the latter.

Chance fracture

• Horizontal avulsion injury of the vertebral body
• Mechanism of injury: Flexion about an axis anterior to the anterior longitudinal ligament
• Entire vertebral segment is pulled apart by strong tensile forces

Flexion-distraction injury

• Compressive failure of the anterior column while the middle and posterior columns fail in tension
• Mechanism of injury: Flexion about an axis posterior to the anterior longitudinal ligament
• Tensile failure of the middle column results in tear or attenuation of the posterior longitudinal ligament
• If the zygoapophyseal joint capsules are disrupted, subluxation, dislocation of the facet joints, or fracture of the facets can occur
• Most varieties of this injury are potentially unstable because the ligamentum flavum, interspinous ligament, and supraspinous ligament usually are torn

Translational injury

• All three columns have failed in shear
• Displacement in the transverse plane with alignment disruption of the spinal canal
• Includes Holdsworth’s slide fractures, rotational fracture-dislocations, and pure dislocations

Explanation

The classification of acute traumatic spinal injuries by McAfee and colleagues is based on the three column concept of the spine. CT is mandatory for accurate assessment.

Figures

Insert figures illustrating the classification

Reference(s)

Provide the citation for the landmark article and recent review articles describing the classification