The spine provides axis to the whole body and the anatomy of the spine includes strong bones, flexible ligaments and tendons, large muscles and sensitive nerves. The most notable feature of the spine is the vertebral column or the spinal column. It is made up of block-shaped bones called vertebrae that typically total 33 at birth but later become 26 bones because some of the lower vertebrae fuse to form the sacrum and the coccyx or the tailbone.
The spine is connected to the head, shoulders, ribs and the hips. Each vertebra, except the first and second cervical vertebrae, is separated by an inter-vertebral disc. These discs are made of a tough fibro- cartilaginous material with elastic capabilities. These discs act as shock absorbers between the vertebrae and protect the bones from the adverse impact of jumping from heights, tough sports and certain forms of exercise. The spine derives its stability and inherent mobility from these discs.
Each disc has 2 parts:
Inter-Vertebral disc disease is not a disease pre se but a medical condition because one or more discs have slipped out in part or as a whole from their respective location in the spinal column. The portion of the disc extending out of the normal alignment impinges upon the nerve root and causes pain. The condition could be attributed to damage and wear and tear to the inter-vertebral disc due to old age or other causes.
Due to the degenerative changes, the spinal discs become anatomically altered after losing water content and become thinner. The outer layer of the spinal disc may tear, resulting in expulsion of the contents of the inner core of the disc through the outer covering, a condition known as a herniated disc. These protrusions may press on nerves, causing pain in the back and leg that can range from mild to excruciating.
Although patients with degenerative disc disease will find that their discs continue to degenerate over time, most do not experience a corresponding increase in pain.
Degenerative disc disease occurs when wear and tear on the inter-vertebral discs between the bones (vertebra) in the spinal column cause deterioration that eventually results in pain. It is caused by old age and is among the most common sources of back pain in people who are middle-aged or older.
As one grows older inter-vertebral discs or spinal discs suffer from damage. These discs stabilize spine by providing flexibility and provide cushioning effect by acting as shock absorbers.
Due to old age, usually the spinal discs slowly become flat, deteriorate, lose water content and acquire a thin and brittle texture. These deteriorative changes make the discs render them vulnerable to the condition called degenerative disc disease.
Generally the outer layer of the disc develops a tear. The contents of the inner core may burst / leak out through the tear. This condition of the disc is called herniated disc. The disc matter protruding out may, sometimes, press on the nerves emanating from the spine and cause pain. This pain could ne in the leg or the back and could range from mild to severely excruciating.
The symptoms of degenerative disc disease may appear over a long time in several phases spread over a decade or more. In initial stages the severity of the back pain may render normal movements very difficult. Subsequently, the area becomes inflamed and the pain may sometimes disappear completely and again come back. Eventually, the condition stabilizes since the disc loses the protein substances that initially caused the pain, inflammation and discomfort.
These changes are caused by aging. Everyday, right from morning, the spine supports the body weight of an individual. The effect of resultant daily stress and minor wear and tear and un-noticed injuries gets accumulated over time and brings about structural changes in the discs. The primary role of the discs is to absorb these very stresses and protect the bones from injury.
The annulus or the outer part of the disc is the first to get damaged. Tears may appear on the annulus due to excessive pressure or injury. The natural healing process of the body creates scar tissue formation to repair the tears. Repeated tears and scar tissues formation greatly reduces the original strength of the annulus, making it vulnerable. This may result in damage to the inner core or nucleus pulposus and water content of the core is lost. This weakens the disc further and the proteins contained in the inner core may leak out. This inflames the nerves and cause pain and other symptoms.
Repeated wear and tear may accumulate to the point that the discs begin to deteriorate. Over time, spinal discs usually begin to flatten, lose water content, thin out and become more brittle. In addition, injuries and wear and tear suffered during sports or other strenuous activities can sometimes lead to disc damage.
Pain is the main symptom associated with degenerative disc disease. This pain tends to be concentrated in the lower buttocks and upper back. Pain that radiates down into the leg or foot is usually minimal. Depending on the location of the injured disc, neck pain may also occur.
The pain begins slowly and gradually but increases with prolonged sitting or standing. The pressure load on the inter-vertebral discs is around 3 times while sitting as compared to standing. The pain, thus, is more severe while sitting and relief may be felt while standing upright, moving about, walking or lying in fetal position. Any movement with bending, twisting or lifting makes the pain worse.
Pain caused by degenerative disc disease may range from mild to severe. Also, the pain may not be felt always but may come and go. The pain may disappear for sometime and reappear for a few days to a few months. Damage to nerves caused by the damaged discs may result in weakness in the leg muscles or foot.
As with any other disease the physician starts the diagnostic process by recording the medical history of the patient with specific details about back pain being sought. The patient may be asked:
Degenerative disc condition can be treated without any surgery in most cases. Non-surgical techniques available are:
It is essential to consult a physician before taking any medicine. Medicines provide effective relief from pain and inflammation but can not stop the degenerative changes caused by this disease.
Spinal fusion eliminates some spinal flexibility, which can be beneficial if movement between spinal segments is the source of a patient’s pain.
Other surgical options may include:
Disc disease is condition that is caused by old age and other factors. Many of the cause are controllable and some steps taken in time can prevent the onset of this disease or improve the condition. Some of thee could be:
Degenerative disc disease may cause total or irreversible damage to a disc or the disc may be damaged due to trauma / injury. In such situations the disc needs to be removed. The options available after removal of the inter-vertebral disc are not many and fusion of the two vertebrae is carried out. Fusion, however, cause some amount of mobility and flexibility loss. Replacement of the damaged disc by an artificial disc is the other option available in such cases.
The procedure involves removing the damaged disc and the new artificial inserted. This artificial disc is made of metal and plastic and its size is about the size of a quarter coins.
It is believed that ideal candidates for this surgery have the following characteristics:
So far, studies indicate that patients who have this surgery recover more quickly and have fewer complications than patients who have more traditional forms of surgery.
Other prostheses are also being developed, including some that replace only a disc’s inner core or the nucleus pulposus. Attempts towards tissue engineering and regeneration are also being made.