Cervical spondylosis is a term for degenerative changes (wear and tear) of the vertebral discs of the cervical spine. It is considered to be a normal part of aging. It is not symptomatic in many people but may cause recurring neck pain.
In cervical spondylosis, the edges of the vertebrae often develop small, rough protrusions of the bone (osteophytes) which are in response to thinning of discs.
Mostly asymptomatic, these osteophytes may cause compression on nearby muscles, ligaments, or nerves to cause pain in the neck and surrounding area. Involvement of a nerve leading to pain and other symptoms in the upper limb is called cervical radiculopathy.
Cervical spondylotic myelopathy refers to changes in the cord due to cervical spondylosis that causes weakness of the hands and other parts of the body.
Cervical spondylotic myelopathy is discussed separately as its presentation is quite different.
Causes of Cervical Spondylosis
Age-related wear and tear is the biggest factor for the development of cervical spondylosis. However repeated occupational trauma like carrying loads, professional dancing, gymnastics etc. which put repeated strains on the neck may contribute.
Familial cases have also been reported suggesting possible genetic factors also. Smoking is another suggested risk factor.
Conditions that cause increased mobility or instability to a segment of the cervical spine like congenitally fused spine, cerebral palsy, Down syndrome etc may be risk factors for cervical spondylosis.
Pathophysiology of Cervical Spondylosis
Cervical spondylosis is the result of disc degeneration. With age, intervertebral discs lose water, fragment, and collapse. This causes increased mechanical stress at the cartilaginous endplates. This further causes bone formation under the periosteum. This is an attempt by the body to stabilize adjacent vertebrae.
Osteophytes may cause narrowing of the intervertebral foramina [A canal through which the nerve root comes out of spine] and irritation of nerve root. Degradation of intervertebral discal proteoglycans also causes irritation of nerve root. This would lead to cervical radiculopathy.
Cervical spondylotic myelopathy occurs when the changes in cord occur because of degenerative changes causing mechanical compression, spinal cord ischemia and stretch injury to the spinal cord. Patients with narrow spinal canal are predisposed to developing cervical spondylotic myelopathy. Space may be further worsened by hypertrophy of the ligamentum flavum, thickening of bone, degenerative kyphosis, and subluxation.
Presentation of Cervical Spondylosis
Intermittent neck and shoulder pain is the most common complaint in cervical spondylosis. The pain usually comes and goes but may persist in some persons with occasional exacerbation.
The pain is often accompanied by stiffness, with radiation into the shoulders or skull. A headache, unilateral or bilateral upper limb may be involved. The pain may stop at the shoulder or occur till the fingers.
Paresthesiae may accompany pain in the cervical region, the upper limb, shoulder or interscapular region. Radiation to the chest may also occur.
Physical examination reveals neck stiffness and numbness in the affected root.
Laboratory values are mostly normal in cervical spondylosis.
Routine anteroposterior x-rays of the cervical spine demonstrate loss of cervical lordosis, disc space narrowing, osteophytes, facet joint osteoarthritis etc.
CT and MRI are no routinely done for cervical spondylosis. MRI may be indicated in cases where radiculopathy is not amenable to treatment or in cases of spondylotic myelopathy to assess cord damage.
Treatment of Cervical Spondylosis
The pain of cervical spondylosis and Cervical radiculopathy usually resolves without intervention. The treatment includes neck immobilization, drug treatments, lifestyle modifications and physical modalities like traction, manipulation, and exercises.
Soft collar, Philadelphia collar, rigid orthoses, and Minerva jacket are commonly used for immobilization of the neck. The collar is worn as long as possible during the daytime. With the improvement of symptoms, the wearing of collar should be during strenuous activity. Prolonged use of collar may reduce muscle tone and cause neck stiffness from disuse.
Nonsteroidal anti-inflammatory drugs are the mainstay of drug treatment for reducing inflammation and pain. Patients with chronic symptoms should receive tricyclic antidepressants like amitriptyline.
Muscle relaxants such as thiocolchicoside, tizanidine, carisoprodol, and cyclobenzaprine may help patients with neck spasms.
Use of opioid drugs is restricted to patients who are not relieved with above drugs or do not tolerate nonsteroidal anti-inflammatory drugs or have moderate-to-severe pain due to significant structural spondylosis.
Lifestyle modifications include posture improvements, ergonomic changes in the workplace, relaxation techniques to avoid strain on the cervical spine.
Surgery is indicated in patients with
- Intractable pain [Pain that is not responding to treatment]
- Progressive neurologic deficits
- Documented compression of nerve roots or of the spinal cord
The aim of surgical treatment is decompression of the neural structures/spinal cord and fusion of the unstable spine.
The surgeries done are foraminotomy, anterior cervical discectomy with fusion, cervical disc replacement etc.