Spinal canal stenosis

Definition Spinal Canal Stenosis

Spinal canal stenosis (narrowing of the spinal canal) is a degenerative (wear-related) disease of the spinal column with a narrowing of the spinal canal and the resulting pressure on the spinal cord and nerve roots. A distinction is made between a cervical spinal canal narrowing affecting the cervical spine, a thoracic spinal canal narrowing affecting the thoracic spine and a lumbar spinal canal narrowing affecting the lumbar spine. The spinal canal runs in the spinal column between the vertebral body and vertebral arch as a cavity, also known as the spinal canal, formed by the individual vertebral holes (foramen vertebrale).

The clinical picture of spinal canal stenosis occurs predominantly in older age, beyond the age of 60. Spinal canal stenosis mostly affects the lumbar spine. In the following description, therefore, the spinal canal stenosis of the lumbar spine is the main symptom.

Cause of spinal canal stenosis

The pathogenesis of spinal canal stenosis has to be seen in connection with other degenerative spinal diseases. The wear and tear of the intervertebral discs as the cause of spinal canal stenosis begins as early as in the 20’s of a person. This can lead to a bulging or prolapsed intervertebral disc (nucleus pulposus prolapsus).

The increasing water loss of the intervertebral discs leads to a decrease in height of the intervertebral body section (osteochondrosis). The consequences are an overload of the small vertebral joints, a malfunction of the spinal ligaments and a creeping instability of the spinal motion segment, consisting of two vertebral bodies and the intervertebral disc between them. The base and top plates of the vertebral bodies are subjected to more stress due to the lowered intervertebral disc.

The body reacts to this by compressing the bone in the area of these structures (sclerotherapy), which can be seen on X-rays. The body tries to counteract the creeping instability of the spinal column by producing bony attachments on the vertebral bodies (osteophyte exophytes), which seek support in the surrounding area. In very advanced instability, a wear-related curvature of the spinal column can develop, further weakening the statics of the spinal column (degenerative scoliosis).

The altered spinal column statics also changes the points of origin and attachment of the muscles and ligaments of the spinal column, with some muscles and ligaments becoming too close and shortened and others being stretched too much. Both of these factors lead to the weakening of these structures through the loss of function. Painful muscle hardness (muscle hard tension/myogelosis) can develop.

An incongruent position of the vertebral body joints in relation to each other leads to premature cartilage abrasion of the joint partners. The same processes that are well known for knee joint arthrosis or hip joint arthrosis then take place. This leads to joint inflammation, swelling and thickening of the capsules, and even more quickly than in the large joints, to joint deformation.

The overall picture of a vertebral joint arthrosis (spondylarthrosis) has been created. can eventually lead to a considerable narrowing of the spinal canal (spinal canal stenosis) and press the spinal cord itself or the outgoing nerve roots. Recessus stenosis refers to a pressure on the nerve root in the lateral recessus, usually caused by degenerative changes in the upper vertebral joint process (superior articular process).

• Displacements of the vertebral bodies due to instability (pseudospondylolisthesis)
• Thickening of the vertebral joint structures
• Bony spinal canal attachments
• Disc protrusions and
• Thickening of the spinal ligaments (Ligamentum flavum)