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Intervertebral disk vacuum phenomenon secondary to vertebral collapse: prevalence and significance.

PURPOSE
To evaluate the prevalence of the intervertebral vacuum phenomenon in disks adjacent to vertebral collapses of various causes.


MATERIALS AND METHODS
The authors retrospectively studied 310 consecutive patients who had at least one vertebral collapse. The vacuum phenomena were divided into collapse-related (ie, adjacent to a collapse) and degenerative (ie, not associated with a vertebral fracture) ones. Plain radiography was performed in all patients, and, in addition, conventional tomography, computed tomography, and/or magnetic resonance imaging was performed in 175 patients.


RESULTS
Collapse-related vacuum phenomena were seen in 15% of patients with plain radiography and in 21% when all of the imaging modalities were considered. They occurred in association with all of the causes of collapse (ie, osteoporosis, multiple myeloma, metastasis, acute trauma, and vertebral osteomyelitis), although the prevalence was lower in association with metastasis or trauma (P = .008). The occurrence of collapse-related vacuum phenomenon was correlated with age (P = .001) and with the coexistence of degenerative disk-related vacuum phenomenon in the same patient (P = .0002).


CONCLUSION
Occurrence of a vacuum cleft in disks adjacent to a vertebral collapse is common and appears as the second cause of vacuum phenomenon after degenerative disk disease.