A human spine is made up of 33 bone segments that are referred to as vertebrae. The vertical vertebrae are connected through ligaments that are attached to the muscles by tendons. Between each vertebra are gel-like cushions called intervertebral discs. These discs are made up of nucleus pulosus – a semi-fluid matter – which is covered by a capsule of elastic fibers called annulus fibrosus.
Intervertebral disc damage in a person’s lumbar or the spine’s sacral region (lower back) is the most common cause for sciatica. An irritated, inflamed, or compressed sciatic nerve or nerve root results in sciatica. This often happens due to a ruptured, herniated, or slipped disk.
Pressure on the sciatic nerve root can also cause wear and tear on the vertebrae and lead to sciatica. Usual culprits of damaged vertebrae are aging and degenerative disc diseases like osteoarthritis. Sciatic nerve inflammation or compression that leads to sciatica may also happen due to:
- A pinched nerve that is caused from pressure by a surrounding bone, cartilage, muscle, or tendon
- Physical injury such as fractured pelvis
- Narrowing of the spinal column or spinal stenosis
- Spondylolisthesis, or when one vertebra slips out of line, resulting from degeneration or spinal defects like spinal bifida
There are rare cases when sciatica is caused by a metastasized cancer tumor or cyst. There are also sciatica conditions that are idiopathic, or those cases that occur without a known or identifiable cause.
These are factors that increase a person’s risk of developing sciatica:
- People who are between 30 and 50 years of age are more prone to developing sciatica
- Diabetes increases nerve damage that may lead to sciatica
- Genetics and any inheritable spine abnormalities
- Menopause leads to degenerative bone loss
- Physical activities that requires back twisting or heavy lifting such as golf
- Leading a sedentary lifestyle or occupations that involve long periods of sitting
If sciatica is left unresolved, it may result in permanent nerve damage. Immobility, partial, or complete loss of leg sensation, and recurring leg injuries are just some of the complications that may occur if sciatica’s underlying causes are left untreated.
