The spine is composed of 33 vertebrae, uniquely aligned to support the body and provide a passageway for the spinal cord and nerves. At the top of the spine are seven cervical (neck) vertebrae, followed by 12 thoracic (chest) vertebrae from which the 12 pairs of ribs originate. Next are 5 lumbar (low back) vertebrae, followed by the 5 fused sacral bones (the back of the pelvis) and 4 fused bones of the coccyx (tailbone).
What is lumbar disc herniation?
Vertebrae are separated from each other by intervertebral discs which lie between the bony vertebral bodies of the spine, cushioning the vertebra and providing space for the nerves roots to exit the spinal canal. The disc and vertebral bodies are considered joints since there is motion.
The discs are composed of cartilage that have an outer wall of tough fibrous tissue called the annulus fibrosus, and a softer, inner portion called the nucleus pulposus. The nucleus pulposus is a jelly-like substance that contains water which, like a water-filled balloon, cushions the disc. If a disc degenerates (a herniated disc), it flattens and puts pressure on the spinal cord. Because the space between the vertebrae also becomes less, the bones may put pressure on the nerves.
What causes a lumbar disc herniation?
The natural curvature of the spine provides the skeleton with strength and stability. The curves act like a spring in a coil and distribute the mechanical stress as the body moves. Unfortunately, because the lumbar spine carries the bulk of the body's weight, it is more prone to injury. As discs age, they lose their water content and begin to degenerate. The annulus fibrosus (outer ring), may also be damaged through general wear and tear or by injury in which the nucleus, under extreme pressure, bulges out through the annulus fibrosus ring.
Can lumbar disc herniation be prevented?
Most lumbar disc herniations occur in 30 to 50 year-old people – who are physically active and busy, sometimes too busy to take care of themselves! Confining our physical activity to what our bodies are prepared for is a key to preventing injuries. Consistent and rational exercise, maintaining good body weight, good posture (especially holding the abdomen in) and good nutrition all support good back health. Accident prevention involves assessing risks – is your body prepared for the activity you are about to do?
What surgical treatment options are there for lumbar disc herniation?
- steroid injections
- discectomy, microdiscectomy, decompression
- discectomy - fusion and stabilisation
- disc replacements
The majority of patients with disc herniation that has not responded to conservative treatment (i.e. reduced activity, physical therapy, drugs) or have signs of progressive neurology (numbness, weakness, bladders symptoms) can be treated with surgery.
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