Computed tomographic findings of vacuum phenomenon in cervical intervertebral disks.

A gaseous collection in the intervertebral space, or the vacuum phenomenon, was observed on computed tomograms in as many as 30% of the patients with cervical disk disease. The condition most frequently occurred at the level of C5-6. The gas tended to accumulate more often at the marginal region of the intervertebral disks, the level at which marked degeneration was seen; thus, it may be related to cracks within not only the nucleus pulposus, but also in the annulus fibrosus.