Burst-shear flexion-distraction injuries of the lumbar spine

Seven cases of a previously undescribed lesion of the lumbar spine consisting of a burst fracture of the vertebral body associated with a posterior subluxation of the adjacent lower level facet joints are described. The lesion is due to a flexion-distraction mechanism. All seven cases reported involve a burst fracture (four upper burst, one burst-split, and two complete burst fractures). The dislocation line goes through the upper end-plate, through the posterior wall of the fractured vertebra, through the spinal canal, and through the caudal facet joints. The caudal disk is not destroyed primarily, but is involved in cases of burst-split or complete burst fractures. The treatment is surgical: reduction of the posterior subluxation, reduction of the burst fracture with anterior distraction (e.g., AO internal fixator or any other pedicle system allowing anterior distraction and reduction of the burst fracture), transpedicular bone grafting of the burst fracture if necessary, and fusion of the destroyed motion segment(s).