Intradiscal Gas and Disc Herniation

The development of air within the degenerated disc is secondary to the movements of the spine. Because of the negative intradiscal tension produced with hyperextension of the spine, the vacuum phenomenon increases with extension and decreases with flexion. The presence of air in the epidural space is more uncommon and may be associated with a disc herniation and even located within the herniated disc itself.We reviewed the clinical and CT findings of 750 patients. Intradiscal gas was found in 130 out of the 750 patients, 65 men and 65 women, whose age ranged from 17 to 81 years; 20 patients were under 40 years old. The gas was at a single level in 83 cases, mainly L5-S1 (43 cases) and L4-L5 (20 cases). In 22 other patients the gas collection was at a level other than disc herniation.