Your Vertebral Discs
Updated March 2016
Figure 4.1 illustrates a section of a healthy spine that is properly aligned. Supporting muscles groups that are balanced is ideal to maintaining optimal disc health. Here, there is an even distribution of force directed towards all sides of the disc.
When lifting an object or bending, the distribution should be maximized as the hips and knees function as to provide the flexibility needed to maintain the proper posture during the exertion. Specific muscle groups of the back, hip and legs are required to contract to accomplish this. Appropriate and effective lower back exercises help to maintain healthy discs.
Disc Problems and Factors
Many factors can cause bone and disc problems. It is vital to protect the vertebrae and discs by consciously maintaining a healthy posture. If this is not done, then the risk of chronic imbalances can lead to disc injury and even to the vertebrae itself. Most people are able to minimize the risks of injury in this situation. However, those suffering from lower back pain, usually will have a range of wear and tear to the vertebral discs and vertebrae themselves and corresponding muscle imbalances.
When the underlying problems with their spine and supporting muscles are not resolved, the discs become prone to wear, bulging, rupture or herniation. This is sometimes known as a “slipped disc”. Discs do not actually ‘slip’. This is a common misunderstanding. They do however bulge or herniate (tear, rupture).
Disc Bulge and Herniation
In figure 4.2, a disc has ruptured or herniated. This rupture occurs where the tough outer layer of cartilage of the disc has weakened due to excessive pressure or aging and has resulted in the softer inner layer of cartilage to protrude through. This creates a bulge that exits through an area of low resistance such as near the nerve root.
This is a common situation and a painful one. It is painful due to the bulge that is in contact or generating excessive pressure on the nerve. It can also be very painful if the rupture has released the contents within the discs to the surrounding tissues.
The contents contains very potent inflammatory proteins and markers that are meant to initiate the immune response to repair. The contents (or factors) are also known for generating inflammatory signals and pain through an attempted repair initiation and process. In many cases people have no symptoms of pain whatsoever but still have damage.
Discs will naturally rehydrate with rest and time. This is why you are taller in the morning after a nights sleep as compared to your height at bedtime.
Bulging or herniated discs will naturally heal over a period of weeks to months without any treatment except for rest. However, if underlying causes that place excessive wear and demand on your spine are not addressed, then a cycle of injury and temporary healing and relief will inevitably reoccur. This will result in progressive aging of the disc, where the disc loses is natural hydration, becomes thinner, and much less flexible as a result. It may also remain unable to reabsorb the herniated area of the disc resulting in a bulge that places constant pressure on the nerve roots that are near.
Figure 4.3 illustrates the progression of disc degeneration in the spine. A healthy disc is depicted at the top. This disc becomes thinner due to chronic bulging, herniation or from drying out.
When there is a bulge, the strong outer layer of cartilage known as the Annulus Fibrosis remains intact but the inner material of the disc known as the Nucleus Pulposus puts pressure thereby producing a disc bulge.
Depending on the severity of the bulge, there will be different pain signals that you will feel downstream from nerve compression. This can range from a mild tingling in the area just outside the spine, to sciatica, to full numbness. If the Annulus Fibrosis tears (annular tear) the inner material comes through creating a more focused injury to the disc. This material then pushes out onto a nerve.
Chronic Lumbar Issues
Chronic bulging, tearing and rupturing, along with healing as mentioned above may eventually lead to thinning as repair becomes poorer and less effective. Because the disc is thinner, your flexibility becomes progressively limited. This is because the initial disc height allowed for the most flexibility for your lower back.
The vertebrae on either side of the thinned disc are now physically closer. When these bones mover closer and you bend, the edges of the vertebrae become more likely to touch. When they do come in contact, there is wear to the bone. This damage triggers additional irritation and inflammatory repair.
The immune system tries to repair this area with a method of bone tissue repair. This can appear on an X-ray or MRI as osteophyte formation. This can become so advanced that it irritates the surrounding tissues and nerves, causing pain. This formation can build and limit your flexibility. For some, their discs become so badly degenerated that the vertebrae develop enough repair formation to fuse themselves together in order to stabilize and control the joint.
The lowest disc (and also the most prone), known as the L5-S1 in figure 4.3, has reached this point. Here, the person has endured so much discomfort that surgery may be considered to permanently fuse the vertebrae to restrict further movement to control pain.
The Facet Joint
There are special joints that are part of each vertebrae of your spine, called facet joints. They connect, align and protect each vertebrae and disc involved. The joint capsules in between provide lubrication and flexibility. This joint gives the articulated flexibility needed to distribute pressure evenly along the spine and on the discs and to keep the vertebrae aligned.
When the discs in between become too thin as in the case of disc degeneration or thinning, the facet joint and the capsule in between bear a heavier than normal load. This causes advanced wear to the capsule. Eventually the capsule becomes badly worn or destroyed. Bone on bone contact occurs leading to arthritis of the joint and corresponding pain.
Facet joint pain can create another symptom of lower back pain and further reduces mobility for the sufferer. The irritation and inflammation in this joint triggers the back muscles to spasm and lock in order to protect the spine from further movement. This is known as ‘muscle guarding’.
Although guarding helps to prevent further injury, it is not precise and leads to possible muscle imbalances that contributes to more injury on the discs nearby.
Figure 4.5 illustrates some of the different possible types of injury to the discs in your spine. As we age, it is natural to have wear and tear on the spine, especially to the lumbar discs. Herniated discs are very common and do reabsorb and repair over time.
Because discs require extensive periods of time to heal from a tear or rupture (weeks to months), they tend to lose height as a result during the repair process. In most cases, pain has already become manageable before this process is complete. Unfortunately, we will usually return to our daily activities before healing is complete. This increases the likelihood of an incomplete and poor repair process, thereby accelerating the aging process.
Discs become thinner as we age and the very limited blood supply to the discs that provide nutrients disappear after time. Therefore it would be typical to receive a diagnosis as we age that some of your discs have what is termed as “degenerative disc disease” or “DDD”.
As unsettling as it sounds to receive a diagnosis of a disease in an area which causes pain, it is generally the most common way to describe the aging process of your discs. Sometimes, it is described as ‘degenerative disc disorder’.
DDD diagnosis is sometimes graded as mild, moderate or severe. Almost everyone over the age of 30 is diagnosed with the ‘mild’ form. The L5-S1 disc (the last disc) that sits in between our lumbar column and pelvis is usually to first to exhibit this type of wear. This ‘disease’ or ‘disorder’ is what we need to be concerned about as we should try to delay or prevent this aging process with our discs.
What you do with your back on a daily basis will affect the acceleration of this aging process.
For most of us with low back pain, the aging process has already begun and our main concern is to slow it down as much as possible.
There are many treatments offered to help address the aging of our discs. Some range from dietary changes, disc decompression to physiotherapy and of course exercises for the lower back. With the right treatment you can successfully address this problem.
The Low Back Pain Program and eBook helps to address the physical limitations, imbalances and needs of our supporting muscle groups in order help prevent low back pain and ways to improve it with lower back exercises.
We can improve it to provide support and relief for our lower back in order that we may achieve not only pain relief but to use our muscles properly. This gives us more opportunity to perform the daily exercises and tasks that instead of contributing to our back pain, will help condition and protect it instead.