The Intervertebral Discs
The intervertebral discs are a prevalent source of lower back pain as they are one of the most frequently injured spinal structures. The discs connect adjacent spinal vertebrae together and provide a degree of shock absorption in the torso.
- Disc Structure
- Causes of Injury
- Types of Disc Injury
- Symptoms of Disc Injury
- Treatment of Disc Injuries
The structure of the spinal disc resembles a jelly filled doughnut. The inner aspect of the disc contains a gel-like substance called the nucleus pulposus. Surrounding the nucleus are tough fibrocartilagenous fibers called the annulus fibrosis. These annular fibers contain the inner nuclear material similar to a basketball skin containing the air within.
Causes of Disc Injury
Disc injury occurs when the annular fibers of the disc are torn. Because the inner regions of the annulus lack "pain" innervation, injuries contained to the inner annulus occur without one's knowledge.
Common causes of annular disc tears include:
- uncorrected spinal misalignments
- prolonged sitting
- poor postural habits
- poor lifting habits
- improper workstation setup and ergonomics
- improper lifting techniques
- extended periods of vibratory forces (truck and auto drivers, jack hammer operators, etc.)
Other factors have been shown to increase the susceptibility of disc injury:
- inadequate diet and nutrition
- lack of physical activity
Types of Disc Injury
There are 3 main types of disc injuries. The first disc injury consists of annular fiber tears which do not extend to the outer aspects of the disc. Thus, the inner nuclear material is prevented from completely escaping the disc.
The second type of disc injury, commonly referred to as a disc herniation, consists of annular tears which run from the innermost aspects of the annulus (where the nucleus is) to the outermost aspects of the annulus. In this type of injury, the pressurized nuclear material can squeeze through the tears in the annulus and escape to the outside of the disc. When this occurs, the nuclear material may come in contact with nearby spinal nerves and even the spinal cord.
In the third type of disc injury, referred to as a disc bulge, the inner nucleus loses hydration; common in those with prolonged spinal stress and the elderly. This results in "bulging" of the disc much like a tire "bulges" when it contains inadequate amounts of air. Similar to the previous injury, the nearby spinal nerves and spinal cord may become impinged from the bulging disc.
Symptoms of Disc Injury
The symptoms of disc injury depend upon the location of the disc tears and whether or not the spinal nerves or spinal cord are affected.
When tearing of the annulus occurs within it's inner portion only, generally pain is not experienced. As previously stated, this is because the inner regions of the annulus lack pain receptors. When tearing of the annulus occurs in the outer annular fibers, mild to excruciating pain is felt in a generalized manner. If a lumbar disc is affected, for instance, diffuse low back pain with associated paraspinal muscle spasm is typical.
When numerous partial tears coalesce to form tears which run clear through the thickness of the annulus, the gel-like nucleus is able to escape the disc. If a spinal nerve or the spinal cord is contacted the individual may experience symptoms of pain, numbness, tingling and/or weakness within either or both lower extremities. In rare cases patients may lose the ability to control bowel and bladder functions. If this occurs, immediate medical intervention is required as the condition can become permanent.
Treatment of Disc Injuries
Many disc injuries respond favorably to chiropractic care. This is because chiropractic treatments focus on the dysfunctional spinal segments and not just the symptoms of the disc injury. Pain killers, anti-inflammatory and muscle relaxants can help relieve pain and muscle inflammation, but do not treat the cause of disc injuries and have been shown to induce further injury.
Chiropractic treatment may provide fast, effective, safe and long lasting relief from disc injuries. This is because the chiropractor's approach focuses on restoring spinal alignment, spinal function and overall spinal health, which are the primary factors responsible for the development of disc injuries.
Chiropractic doctors are experts in maintaining proper spinal alignment and function, both of which play a critical role in minimizing spinal stresses - the stresses that are responsible for injury and accelerated degenerative processes in spinal discs.