A large part of patients’ confusion comes from the term “degenerative disc disease”, which sounds like a frightening condition which gets worse with time. In fact, disc degeneration is a natural part of the aging process and over time all people will experience changes in their discs. However, not all people will develop symptoms, which are variable in nature and severity.

Herniated disc

The natural degenerative process of our body begins around the age of 25. This process also involves the intervertebral discs. As the discs degenerate, they lose some mechanical properties, and they became thinner and dryer. In addition to the ageing process other factors such as improper lifting, bad posture and excessive weight are causes of degeneration of the intervertebral discs. The fibers of the annulus keep the softer material of the nucleus inside the disc holding it under pressure to prevent rupture of the disc (prolapse). When a disc becomes prolapsed due to degenerative disc disease the annulus becomes disrupted. In this condition, the center of the disc (nucleus) bulges out of its position, pushing outward and back from the two vertebrae producing pressure on the nerves (contained herniated disc). About 80% of cases of disc degeneration occur in the lumbar spine, because of the load that the lumbar spine has to bear.

There are three key phases in the prolapse of a disc:

1. The nucleus begins to lean out of its position, pushing backwards from between two vertebrae, but it is still contained inside of the disc (contained herniated disc)
2. In the extrusion phase too much pressure is applied on the annulus (outer part), provoking rupture of the annulus.
3. In the sequestration phase a portion of the nucleus’ material leaks outside the disc.

This condition may be dangerous because when the nucleus’ material pushes against the nerve roots situated along the spinal cord, this may provoke pain, weakness and numbness in the legs, feet or buttocks.
The contact between nerve and the disc’s material may provoke also a chemical reaction that affects the way in which the nerves work.
It is important to have early diagnosis of the herniated disc to allow intervention before the sequestration phase occurs.   

Sciatica

In the lumbar spine, the spinal cord becomes the cauda equina (or horses tail). The nerve roots here branch off toward the lower part of the body, from the back to the toes. The degeneration of the discs or the wear and tear of the lumbar spine can cause pressure on nerves that are directed to the legs. This means that even if the source of your condition comes from your back, you can feel pain in your legs or toes.  
The term sciatica is used to define the pain generated from a pinched root located along the sciatic nerve. This nerve travels from the lower back down to the legs.
Depending on which nerve is pinched, you will feel pain in a different part of the lower part of your body.

Generally the pain is located on one side of the lower part of the body. Symptoms of sciatica may be:

• Pain when sitting, in the rear and/or legs
• Tingling ,weakness, numbness or difficulty in moving the leg or foot
• A constant pain or shooting pain in one side of the rear
• Low back pain along with leg pain, but usually the low back pain is less severe than the leg pain