Updated: Nov 26, 2020
Cervical spondylosis with cervical myelopathy, commonly referred to as cervical spondylotic myelopathy (CSM), refers to impaired function of the spinal cord caused by degenerative changes of the discs and facet joints in the cervical spine (neck).
This condition is the most common disorder causing dysfunction of the spinal cord (known as myelopathy) and results from compression of the spinal cord. Most patients with this condition are over 50 years of age, but the age of onset is variable depending on the degree of congenital spinal canal narrowing. The process that leads to spinal cord compression is a result of arthritis in the neck (also called cervical spondylosis or degenerative joint disease), which is incompletely understood and likely has a number of causes.
Factors That Lead to Cervical Spondylosis with Myelopathy
Factors that are thought to contribute to development of cervical spondylosis with myelopathy include:
Normal age-dependent changes of the intervertebral discs, most commonly manifested as cervical osteophytes (bone spurs) at the margins of the vertebrae
Arthritis in the neck leading to facet hypertrophy (enlargement of the facet joints).
Thickening of the ligaments surrounding the spinal canal, especially the ligamentum flavum, which parallels loss of disc height
Translational mechanical instability resulting in subluxation (or partial dislocation) of the vertebral bodies
Congenitally small spinal canal, which renders the patient's spinal cord more susceptible to compression
Repetitive wear and/or trauma leading to degenerative changes affecting the disc spaces and vertebral endplates.
These changes in the cervical spine produce narrowing of the spinal canal itself, leading to thickening of the posterior longitudinal ligament and bone spur (osteophyte) formation compressing the spinal cord, most commonly at the C4-C7 levels. The end result is chronic compression of the spinal cord and nerve roots leading to impaired blood flow and neurological deficit resulting in frank damage within the spinal cord itself.
A related condition that is more commonly being appreciated is ossification of the posterior longitudinal ligament (OPLL) that can also lead to chronic spinal cord compression.
Cervical Myelopathy Symptoms
Patients with cervical spondylotic myelopathy often have some combination of the following symptoms:
Weakness, numbness or clumsiness of the arms, hands, and/or fingers
Altered walking ability perceived as poor balance, weakness, heaviness or numbness in the legs
A painful, stiff neck
Variable degrees of radicular arm pain (pain that radiates down the arm and possibly into the fingers).
Though cervical spondylotic myelopathy is painless in more than 50% of patients, when pain is present it may be described as a stabbing, burning sensation or a persistent dull ache radiating throughout the arms to the forearms, at times to the fingers, associated with "pins and needles" paresthesias extending into the fingers.
Patients often comment about dropping objects accidentally or having trouble fastening their clothes. If prolonged, there may be associated muscle wasting and overt loss of sensation to vibration, pinprick sensation, and pain and thermal sensation.
In addition, on examination, the doctor may notice increased resting tone of the arms and legs, focal weakness of muscles supplied by affected nerve roots, unsteadiness of gait, and abnormally brisk deep tendon reflexes.
Coordination may be affected as well, including impaired fine finger movement, as well as difficulty with coordinated walking, such as seen with reverse tandem gait. Neck flexion may induce electrical-like sensations running down the spine (referred to as Lhermitte's phenomenon). Sexual function may be adversely affected as well.
As the impairment to spinal cord function (referred to as myelopathy) progresses, both legs weaken and become progressively spastic. Bowel and bladder sphincter control may then be altered. In advanced cases, gait will become progressively more difficult without aid by a cane or a walker.
Diagnosis of Cervical Myelopathy
The diagnosis of cervical myelopathy associated with cervical spondylosis depends to a large extent on the patient's history and the physical findings.
The diagnosis may then be confirmed by radiologic imaging, such as an MRI scan of the cervical spine demonstrating overt spinal cord and nerve root compression.
Additional Diagnostic Studies
Additional diagnostic studies often performed help provide further levels of detail and may aid in planning for treatment:
In certain instances (especially when the details of bone anatomy must be seen clearly), a cervical myelogram and post-myelogram CT scan may aid in determination of the anatomy associated with nerve root and spinal cord compression.
Advanced cases may show abnormal signal within the spinal cord on MRI imaging and/or atrophy of the spinal cord due to nerve cell loss. In such cases, referred to as "myelomalacia," surgical outcomes may not be as promising.
Flexion/extension cervical spine films to rule out translational instability of the cervical vertebral bodies, which can influence the choice of treatment as well as the extent of treatment.
Somatosensory evoked potentials (SSEPs) or motor evoked potentials (MEPs) to provide a measure of the electrical conductivity of the spinal cord across the compressed segments. Such testing may also be performed as a baseline in anticipation of monitoring of the spinal cord during surgery itself with the same studies.
To arrive at an accurate diagnosis, it is critical for the physician to consider other disorders that have similar symptoms as cervical spondylotic myelopathy (a "differential diagnosis").
Other conditions associated with neck pain and arm pain, motor-sensory-reflex changes, and signs of spinal cord dysfunction include:
Progressive forms of multiple sclerosis
Amyotrophic lateral sclerosis (Lou Gehrig's disease)
Hereditary spastic paraplegia
Sub acute combined degeneration of the spinal cord associated with vitamin B12 deficiency
Certain spinal cord tumors or vascular conditions, such as an AVM (anteriovenous malformation)
Combined system disease
Cervical Myelopathy Treatment
If a patient is having myelopathy symptoms (numbness, tingling, weakness etc) in addition to spondylosis symptoms (pain, Radiculopathy etc), then the main-stay of treatment in such cases is surgical decompression as soon as possible to prevent further and irreversible neurological damage.
Role of Non-Surgical Treatment
Conservative (non-surgical) treatment is aimed at decreasing pain by reducing spinal cord and nerve root inflammation, as well as improving the patient's function and ability to perform daily activities.
Treatment generally consists of a combination of temporary immobilization of the neck, steroidal and/or non-steroidal anti-inflammatory medications (such as COX-2 inhibitors or ibuprofen), as well as physical therapy.
Patients with overt spinal cord compression resulting in spinal cord dysfunction (myelopathy) may be referred directly for consideration of surgery. Patients exhibiting Myelopathy symptoms (as detailed above) should undergo surgery as soon as possible to prevent further damage to nerves and spinal cord.
These procedures are referred to as anterior or posterior cervical decompression and fusion operations. The surgeon may also use instrumentation (plates and screws) to provide immediate internal support for the cervical spine, and to promote bone graft healing.