What is spinal stenosis ?

Spinal stenosis is composed of two words, spinal and stenosis. Spinal refers to the spine which protects the spinal cord and stenosis refers to narrowing or abnormal thinning of a lumen of something.

Therefore, this is a term used to denote abnormal narrowing of the spinal canal or the vertebral column which compresses the spinal cord and thus causes a variety of symptoms and problems.

The spinal cord is an important organ of the central nervous system and transmits and receives nerves from and to the brain. It acts as a conduit for all the nerves. This is why, if any part of the spinal cord is compressed due to any disease or injury, the nerves that are compressed will not work properly and cause pain and neurological deficit.

Spinal stenosis is classified according to the site of stenosis and compression of the spinal cord. The vertebral column is divided into cervical, thoracic, lumbar and sacral vertebrae.

Cervical vertebrae are located in the neck. Thoracic vertebrae are located behind the ribs and lumbar in the lower back area. Stenosis is named according to the location. Stenosis of the Cervical, thoracic and lumbar parts are known as cervical stenosis, thoracic stenosis and lumbar stenosis respectively.

Spinal stenosis affects different parts of the spinal canal and produce unique symptoms. Stenosis may occur at the following three locations : Spinal Stenosis

  1. The space in the centre of the vertebrae or bones of spine through which the spinal cord and nerves run.
  2. The space between different vertebrae or the bones of the spine.
  3. The space between the vertebrae where the nerves come out of the vertebral column.

If any of these spaces become narrow due to any pathology it results in the compression of the spinal cord and the nerve roots, causing pain and numbness among other symptoms. The severity of symptoms depends on the space that has been affected by the narrowing process. Small narrowing might not present as a big problem and might only cause a little pain on movement, while narrowing which is extensive and covers a lot of area will produce numbness, severe pain and even paralysis.

The most common sites where spinal stenosis occurs are the cervical and lumbar areas. Thoracic stenosis is the least common of all stenosis of the spinal canal. Cervical stenosis is the most dangerous because it might compress the spinal cord and might lead to general body weakness and even paralysis of the whole body.

Spinal stenosis causes

There are many factors that can cause spinal stenosis. These include normal aging processes, certain inflammatory diseases, hereditary predisposition, certain tumours, trauma and some pathologies of the vertebral column.

1. Aging – Old age is one of the major risk factors in the occurrence of stenosis. People who are aged above 50 are prone to develop spinal stenosis as their body ages and certain degenerative changes start to occur. These include thickening of ligaments that bind the vertebrae together, growth of bones and their edges, bulging out of the sides of bones into the narrow spaces in the vertebral column. All these degenerative changes narrow the spinal canal and start compressing the spinal cord and the nerves.
2. Inflammatory diseases – Inflammatory diseases of the joints and bones might cause spinal stenosis. These diseases include rheumatoid arthritis and osteoarthritis.

  •  Osteoarthritis is one of the most prevalent forms of arthritis and it usually occurs during late stages of life. It involves almost all of the joints of the body including intervertebral joints. Osteoarthritis mostly destroys cartilages that keep the vertebrae in place due by Inflammation. This causes the vertebrae to dislocate and produce pressure on the spinal cord and thus produce spinal stenosis.
  • Rheumatoid arthritis affects younger people and is an autoimmune disease. This disease also affects joints of the body and causes them to swell up. Intervertebral joint are also affected and although it does not usually cause spinal stenosis but when it does, it causes extensive disease.

3. Hereditary and genetic causes –  Some people have genetic predisposition to spinal stenosis. This is due to smaller spaces that are formed by birth in the vertebral column in such people therefore causing this disease during old age.

4. Tumors – Tumors of the spinal cord and the vertebral column can cause spinal stenosis by compressing the spinal cord or the nerve roots. These space occupying tumours and cancers compress the spinal cord and damage it by creating pressure on it.

5. Trauma and Disc slip – Trauma to the backbone and the vertebral column can dislocate the vertebrae and cause spinal stenosis. This can also happen in a condition called disc slip in which the cartilages in between the bones of the vertebrae are dislocated and cause pressure on the vertebral column.

Spinal Stenosis can be treated by treating the underlying cause or by surgery. The surgery cuts away the space occupying lesion or any other cause of compression on the spinal cord, thus relieving the symptoms.

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