Pathologic vertebral compression in spinal malignancy secondary to intervertebral disk expansion.

A retrospective analysis of the MR appearance of the intervertebral disks in 17 patients with spinal malignancy was performed. Disk expansion, related to neoplastic structural weakening of the bone in the face of unaltered disk biomechanics, was present in 20% of all visualized disks in association with a 77% incidence of malignant involvement of the vertebral bodies studied. This compared with a frequency in benign disk expansion (i.e., osteoporosis) of 2% in the age-matched, but randomly selected, control group. On careful review, there was no strict correlation between disk expansion and patient symptoms. Although this finding may be seen in non-neoplastic conditions, it is felt that the higher incidence of disk expansion associated with osseous vertebral malignancy nevertheless reflects the underlying gravity of the pathologic changes accompanying neoplasia.