[The intravertebral vacuum phenomenon or gaseous dissection of the vertebral body].

The intravertebral vacuum phenomenon is rather uncommon. It is determined by the collapse of the body of the vertebra with successive aspiration ex vacuo of gas (nitrogen) from the surrounding tissues, which collects under the endplates, causing them to appear disconnected. To date, the one who has reported the highest number of cases is Maldague, with sixty examples. Our report concerns four cases seen during the past five years. According to the most widely accepted pathogenetic theory, this phenomenon represents, together with vertebral collapse and increased bone density, a pathognomonic sign of ischemic osteonecrosis of the vertebrae, similar to osteonecrosis of the head of the thigh bone and, like this, favored by many different factors, such as old age, repeated traumas, alcoholism, rheumatoid arthritis, arteriosclerosis and corticosteroid therapy.