Vacuum phenomena involving the intervertebral discs are a result of the accumulation of gas (principally nitrogen) within the crevices of the intervertebral discs of adjacent vertebrae. It is a common finding in a degenerative intervertebral disc. Other processes can lead to discs containing gas: vertebral osteomyelitis, Schmorl node formation, spondylosis deformans, and vertebral collapse with osteonecrosis.