TheburstfracturewasfirstdescribedbySirFrankHoldsworth in his classification of vertebral fractures as a stable injury resulting from axial impact.69,70 In his description of the injury mechanism based on the twocolumn spine, the nucleus of the intervertebral disc is forced through a fractured endplate into the vertebral body,whichconsequentlyshatters.Theinjurywascharacterized by the comminuted fracture pattern with displacement of bony fragments and the absence of posterior column injury. The existence of the unstable burst fracture, with complete disruption of the posterior elements and increased potential for neural injury, was described by Whitesides in 1977.148 In 1983, Denis expanded on the two-column model of Holdsworth by introducing a classification scheme based on three columns.32 In the three-column spine, the anterior column consists of the anterior longitudinal ligament (ALL) and the anterior portions of the anulus fibrosis and the vertebral body. The middle column is formed by the posterior longitudinal ligament (PLL) and the posterior portions of the anulus fibrosis and the vertebral body. The posterior column includes the posterior bony and ligamentous complex. According to Denis, acute instability ensues from rupture of both the middle column and the posterior ligamentous complex. In this classification, burst fractures occur from failure of the anterior and middle columns under compression; unstable burst fracturesadditionallyinvolvedisruptiontotheposteriorcolumn. This system has become the standard of assessing clinical stability.