Cervical Myelopathy:
When the Spinal Cord in the Neck Is Squeezed

What cervical myelopathy actually is

"Myelopathy" means dysfunction of the spinal cord itself. In the neck (the cervical spine), the most common cause in adults is gradual narrowing of the spinal canal by age-related changes — bulging or degenerated discs, bone spurs, thickening of the ligaments behind the cord, and slippage between vertebrae. Specialists now group these under the umbrella term degenerative cervical myelopathy (DCM), which includes cervical spondylotic myelopathy, disc-related compression, and ossification of spinal ligaments (Nouri et al., Spine, 2015).

This is different from cervical radiculopathy, in which a single nerve root is pinched as it leaves the spine, typically causing pain down one arm. In myelopathy, the cord — the main cable carrying signals to and from the arms, trunk, and legs — is under pressure. Symptoms can therefore involve both hands and both legs, and they are often less about pain and more about lost dexterity, balance, and coordination.

OPLL: a cause that is especially relevant in Japan

One cause deserves special mention for readers living in Japan: ossification of the posterior longitudinal ligament (OPLL), in which the ligament running along the back of the vertebral bodies — directly in front of the spinal cord — gradually turns into bone. OPLL has long been recognized as more common in East Asian populations. In a study of whole-spine CT scans from 1,500 Japanese adults attending a health-screening center, cervical OPLL was found in 6.3% of people (8.3% of men and 3.4% of women) (Fujimori et al., Spine, 2016). Most people with OPLL on a scan have no symptoms, but when the ossified ligament becomes thick enough, it can compress the cord. In Japan, OPLL is designated as an intractable disease (指定難病), and patients with more advanced disease may be eligible for medical-expense support.

How common it is

Degenerative cervical myelopathy is considered the most common cause of spinal cord impairment in adults worldwide. Precise numbers are hard to pin down because many cases go unrecognized; a narrative review estimated minimum incidence and prevalence in North America of 41 and 605 per million people, respectively, while acknowledging these are likely underestimates (Nouri et al., Spine, 2015).

Compression seen on MRI is far more common than symptomatic myelopathy. In the population-based Wakayama Spine Study in Japan, MRI showed some degree of cervical cord compression in 24.4% of 977 community residents (mean age 66), more often in men and increasing with age. Most of these people did not have classic myelopathic signs on examination, although those with compression did tend to perform slightly worse on tests of hand function and walking (Nagata et al., Spine, 2012). In other words, "cord compression" on a scan does not automatically mean disease — the diagnosis depends on symptoms and examination findings that match the imaging.

Symptoms — and why they are easy to miss

Myelopathy usually develops gradually, and early symptoms are subtle. Common complaints include:

Because these changes creep in slowly and resemble ordinary aging, arthritis, or peripheral nerve problems, diagnosis is often delayed. In one hospital series of 42 patients who eventually had surgery, the average time from first symptoms to a diagnosis of cervical myelopathy was 2.2 years, and most patients had first seen a family doctor or orthopaedic surgeon before the diagnosis was made by a spinal specialist (Behrbalk et al., Neurosurg Focus, 2013).

How the diagnosis is made

A specialist will ask about hand function, walking, balance, and bladder symptoms, and perform a neurological examination. Signs that suggest the spinal cord is involved include brisk reflexes in the arms and legs, a positive Hoffmann sign (a flick of the middle fingertip causing the thumb to twitch), a positive Babinski sign, difficulty with rapid hand grip-and-release, and trouble walking heel-to-toe. Severity is commonly graded using the modified Japanese Orthopaedic Association (mJOA) score — a scale developed in Japan and now used internationally — with scores of 15–17 considered mild, 12–14 moderate, and below 12 severe.

MRI is the key test for confirming compression of the cord and for looking at signal change within the cord itself, which can indicate injury. Other tests may be added depending on the clinical picture.

Method	Strengths	Limitations
MRI	Shows the spinal cord, discs, and ligaments; can reveal signal change within the cord; no radiation	Compression is common in people without symptoms, so findings must match the examination
CT	Best for bone detail; clearly shows OPLL and its thickness; helpful for surgical planning	Radiation exposure; less detail of the cord itself
X-ray (including flexion/extension views)	Quick and inexpensive; shows alignment, canal size, and instability with movement	Cannot show the cord or soft-tissue compression directly
Nerve conduction / EMG	Helps distinguish myelopathy from carpal tunnel syndrome, peripheral neuropathy, or other nerve disorders	Does not show anatomy; normal results do not exclude myelopathy

Several other conditions can look similar and may need to be ruled out, including carpal tunnel syndrome, peripheral neuropathy (for example, related to diabetes or vitamin B12 deficiency), and neurological diseases such as amyotrophic lateral sclerosis or multiple sclerosis.

What the evidence says about treatment

Unlike radiculopathy, which often improves on its own, the natural course of myelopathy is variable: some people remain stable for years, while others gradually or stepwise worsen. Because damage to the spinal cord may not fully recover, decisions about treatment are generally based on severity and on whether symptoms are progressing.

The goal of surgery is primarily to stop further damage to the spinal cord; improvement in existing symptoms is possible but varies from person to person.

For milder disease, the question of whether to operate early has been tested directly, though only in a small number of patients.

The choice between anterior and posterior surgery depends on the number of levels involved, the alignment of the neck, the location and thickness of any OPLL, and the individual's health. This is a decision made with a spine surgeon based on detailed imaging.

When to see a specialist

It is reasonable to seek a spine specialist's assessment if you notice progressive clumsiness in both hands, numbness in both hands that doesn't fit a typical carpal tunnel pattern, unexplained unsteadiness while walking, or if you have been told an MRI or CT shows cord compression or OPLL. If you already know you have a narrow canal or OPLL, it is worth learning the warning signs and taking sensible steps to reduce fall risk. As noted above, rapid worsening, new bladder or bowel problems, or new symptoms after a fall or neck injury warrant prompt evaluation.