Burst Fracture of the Lumbar Spine

General Considerations

• Burst fractures result from axial loading most often secondary to motor vehicle accidents and falls
• The axial load drives the intervertebral disk into vertebral body below
• Usually produces a comminuted, vertical fracture through the vertebral body
• Fragments may be retropulsed into the spinal canal injuring the cord
• Burst fractures may resemble flexion-teardrop fractures
• In a classical flexion-teardrop fracture, there is an avulsed anterior, inferior triangular bony fragment that is displaced anteriorly
• Both the anterior and posterior ligamentous structures are injured, which may not be the case in a burst fracture
• Burst fractures, however, can have associated injury to the posterior ligamentous structures, especially if there is a combination of axial loading and flexion at the time of injury
• Most common site of injury to the spine is the thoracolumbar junction

Clinical Findings

• Back pain
• Numbness or parasthesia
• Weakness

Imaging Findings

• On conventional radiography
• Lateral view of the spine on conventional radiograph should show a comminuted fracture of the vertebral body
• The anterior portion of the body will be wedged
• Retropulsion can be inferred if the posterior surface of the vertebral body is convex towards the spinal canal, as the normal cervical vertebral body has a concave posterior surface
• Injury to the posterior ligamentous structures can be inferred by forward subluxation of the fractured body on the one below it
• CT will show the comminuted fracture and the retropulsed fragment and provide additional information on the compromise of the spinal canal

Treatment

• Some controversy exists as to best treatment
• Large number of thoracolumbar and lumbar fractures can be treated conservatively while some fractures require surgery
• Principles of treatment include neural decompression, stabilization and fusion
• Unstable fractures include a neurologic deficit
• Loss of 50% of vertebral body height
• Fracture associated with dislocation
• Thoracolumbar burst fracture: angulation of the thoracolumbar junction > 20 degrees or canal compromise > 30 percent

Burst Fracture of Lumbar Spine. Sagittal reconstruction of CT of the lumbar spine demonstrates a comminuted vertical burst fracture through the body of L1 (white arrow). The posterior surface of L1 is displaced posteriorly toward the spinal canal (yellow arrow).
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