What causes cervical spinal stenosis?

The occurrence of cervical spondylosis will actually lead to a series of problems. For example, the common cervical stenosis may also appear after cervical spondylosis. There are several causes of cervical spinal stenosis, such as unstable spinal stenosis, ossification of the posterior longitudinal ligament of the cervical spine, compensatory spinal stenosis, etc. If you have any problems with your cervical spine, you should go to a regular hospital for examination in time.

Instability of spinal stenosis

Cervical instability mostly occurs in middle-aged and older patients, due to degeneration or damage of tissues such as the cervical intervertebral disc, ligaments and joint capsules. Younger patients may suffer from cervical subluxation due to neck trauma. In a small number of patients, after cervical spondylosis surgery, adjacent cervical vertebrae become unstable due to increased compensatory activity. In patients with flexion injury of the cervical spine, due to damage to the transverse ligament of the atlas, the atlas shifts forward when flexed, and the distance between the atlas and the teeth reaches 3 to 10 mm. During extension activities, the unstable cervical vertebra may shift posteriorly by 1 to 4 mm, and the lower posterior edge of the vertebral body of the shifted cervical vertebra and the upper edge of the vertebral arch of the next cervical vertebra form a spinal canal stenosis area. In patients with more severe symptoms, neck extension is often limited, and the muscle tension in the back of the neck increases or the muscles spasm. Some patients experience numbness in the limbs and trunk and muscle cramps in the lower limbs when extending the neck. This is a pathological phenomenon due to compression of the cervical spinal cord.

Ossification of the posterior longitudinal ligament of the cervical spine

The posterior longitudinal ligament is attached to the back of the cervical vertebral body. After the ligament ossifies, its volume increases, which can cause the anterior-posterior diameter of the spinal canal to narrow. Lesions in the upper cervical segment often involve C2 to C4, and lesions in the lower cervical segment often involve C5 to C6. The spinal canal of the upper cervical spine is relatively wide, and ossification of the posterior longitudinal ligament often does not cause obvious symptoms of spinal cord compression. In cases with more complete ossification, local stability is achieved, and dynamic pathogenic factors are eliminated. In cases with milder symptoms, although the degree of stenosis of the anterior-posterior diameter of the spinal canal reaches 10 to 11 mm, most of them do not show serious spinal cord injury.

Compensatory spinal stenosis

The physiological lordotic curve of the cervical spine may manifest as a compensatory lesion due to spinal lesions. Clinically, excessive cervical extension can be caused by the following causes.

① When the transverse ligament of the vertebra is injured and the odontoid process of the axis is underdeveloped, the atlas often undergoes anterior dislocation; there is a congenital fusion deformity of the atlanto-occipital vertebrae, and the foramen magnum is narrowed, which compresses the lower medulla oblongata and upper cervical spinal cord. In order to alleviate the above nerve tissue damage, the body presents a compensatory cervical hyperextension position, and the neck and shoulder muscle tension increases.

② To adapt to normal physiological anatomy and maintain the balance of the human body's center of gravity, the cervical, thoracic and lumbar vertebrae have certain physiological curves. The thoracic spine may become kyphotic due to certain pathological changes, and the patient may develop a compensatory cervical hyperextension curve.

The degree of compensatory cervical extension is severe in some patients. The lateral cervical X-ray film shows obvious overlapping of the vertebral arches. The upper edge of the vertebral arches may protrude into the spinal canal, and the anterior-posterior diameter of the spinal canal becomes narrow.