Disc Injuries and Conditions

Some of the most common disc injuries and conditions of the intervertebral discs of the spine include bulging discs and herniated discs.

A number of disc conditions that cause back pain may cause you to have enough pain to disrupt your life and significantly lose your mobility. Some disc injuries and conditions that may affect your mobility include herniated discs, bulging discs, and degenerative disorders of the discs. Degenerative changes to the discs may begin when the gel core on the inside of the disc loses some of its mass, when the outer envelope tears from the inside out, or both of these changes may occur simultaneously. The inner part of the disc, the nucleus pulposus, can be best described as a gel pack. This gel pack can be squeezed downwards when we apply pressure to this section of the spine, absorbing energy to protect the other structures of the spine. The outer part of the disc is the tough covering of the disc - the annulus fibrosus. This annulus fibrosus is made up of tough collagen fibers that criss-cross each other to produce a strong outer covering that protects the materials of the nucleus from oozing out. Pathology to the discs may occur when either the wall of the annulus becomes torn or the water content of the nucleus pulposus decreases shrinking the disc.

Pathology to one section of the disc may negatively affect the other section, as well as the nerves and other soft tissues of the spine. Weakening or the thinning of the wall may cause to wall to bulge outwards, or tear, if there is still enough material in the nucleus pulposus to cause enough pressure on the annulus. If the wall of the annulus fibrosus bulges outwards, the condition is known as a bulging disc. If the wall tears completely, the condition is known as a herniation, or a herniated disc. When there is a disc herniation, the gel material of the nucleus may squirt through the wall, possibly causing pain and other symptoms. Patients are most likely to experience symptoms as a result of disc herniations if the materials project towards the back of the spine, where the posterior spinal ligaments and nerve roots are located.

Previously, it was thought that bulging and herniated discs only caused back pain if the adjacent nerve roots were compressed at that level of the spine. It was thought that discs themselves were not supplied with nerve fibers to react to these disc injuries and conditions. More recently, however, researchers have discovered pain-specific nerve terminals, called C-Fibers, within the discs.

Disc injuries are very perplexing conditions in back pain medicine because they appear to be the cause of back pain in a significant percentage of cases, yet many people with bulging and herniated discs do not experience any symptoms. As we begin to learn more about how changes in the anatomy of the spine affect us, we have learned a few things up to this point. We have learned that bulging and herniated discs may not be the cause of back pain and reduced mobility if they don't cause significant compression of the nerve root or spinal ligaments. We have also learned there are nerve fibers in the discs themselves that may respond to degenerative changes of the discs.