Can you tell me what's the difference between disc herniation and disc protrusion? I saw two different surgeons for an opinion on what's causing my back pain. One told me it is a disc herniation. The other said it was a disc protrusion. Are they the same thing or do I have two different problems?

People often refer to a disc herniation as a slipped disc. The disc doesn't actually slip out of place. Rather, the term herniation means that the material at the center of the disc has squeezed out of its normal space.

Between the vertebral bones of the spine is an intervertebral disc. The discs provide a cushion or shock absorber for the spine. Each disc is made up of two parts. The center, called the nucleus, is spongy. It provides most of the disc's ability to absorb shock. The nucleus is held in place by the annulus. The annulus is a series of strong ligament rings around the nucleus.

Herniation occurs when the nucleus in the center of the disc pushes or protrudes out of its normal space. The nucleus presses against the annulus, causing the disc to bulge or prolapse outward. The bulged disc material is still contained within the annulus.

But in some cases, the nucleus pushes completely through the annulus and squeezes out of the disc. This is called a disc herniation or protrusion. Herniation and protrusion are two words for the same thing.

If a piece of the disc breaks off, it's called a sequestered fragment. Surgery is almost always needed for sequestration. The loose piece can enter the spinal canal and put pressure on the spinal cord or spinal nerve roots causing serious problems.

J. N. Weinstein, et al. Either Surgery of Nonoperative Treatment Led to Improvement in Intervertebral Disc Herniation. In Journal of Bone and Joint Surgery. May 2007. Vol. 89-A. No. 5. Pp. 1139.