The radiographic characterization of burst fractures of the spine.

A retrospective review of 75 burst fractures of the spine was performed to define the radiographic features found on high-resolution CT, polytomography, and plain radiography and thereby allow full characterization of this uncommon spinal injury. Characteristic components of the injury include: centripetally oriented disruption of the vertebral body, unilateral or bilateral laminar fractures that abut the spinous process, marked anterior wedging, vertically oriented vertebral fracture emanating from the basivertebral foramen, increased interpediculate distance, and significant spinal canal narrowing by characteristic retropulsed fragments. Nearly all bursts occurred from T9 to L5; double bursts were present in less than 10% of cases. The usually present neurologic deficit nearly always corresponded to the level of the burst rather than to the frequently found noncontiguous associated spine fracture. Recent literature suggests that these complex fractures, which were initially thought to represent stable injuries, are often unstable. A subcategorization of burst fractures and their variants is proposed to explain this instability. An approach to the radiographic diagnosis of the spinal burst is proposed, and plain film clues to distinguish the burst fracture from the more common compression fracture are discussed. Representative cases are illustrated.