Fractures of the spine in diffuse idiopathic skeletal hyperostosis.

Fractures of the spine in diffuse idiopathic skeletal hyperostosis (DISH) have rarely been reported. Only four cases could be found in the world literature. Eight new cases with nine fractures are reported in this study. The critical features are the frequent delays in diagnosis (three of eight patients) and the high rate of immediate and delayed neurologic deficit (seven of eight patients). Two fracture patterns occurred in this group. The first type occurred through the midportion of an ankylosed segment of the spine and involved the vertebral body (five fractures). The second type occurred at the top or bottom of a fused segment (four fractures). The latter were disk disruptions or odontoid fractures. This is a marked difference from spinal fractures in ankylosing spondylitis, in which the majority are transdiskal fractures. The difference can be explained on the basis of the different pathology of these two disease processes. Careful evaluation of patients with DISH who sustain trauma is critical. Treatment of this rare injury should be early stabilization of the spine to avoid complications of nonunion, deformity, neurologic injury, and death.