Cervical myelopathy: symptoms and early diagnosis

Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction in adults over 50. Despite its prevalence, it is frequently diagnosed late — on average two to three years after the first symptoms appear — because its early signs are gradual, non-specific, and all too easily attributed to normal ageing or other conditions. This delay has serious consequences: unlike peripheral nerve damage, spinal cord injury is not fully reversible. The longer cord compression persists, the greater the risk of permanent neurological disability. Dr Christian Dimitriu, spine neurosurgeon in Paris, explains the early warning signs, clinical examination findings, scoring systems and imaging criteria that allow a timely diagnosis — before irreversible cord damage occurs.

What is cervical spondylotic myelopathy?

Cervical spondylotic myelopathy (CSM) results from progressive compression of the spinal cord at the cervical level, caused by age-related degenerative changes: disc degeneration and protrusion, osteophyte formation, hypertrophy of the ligamentum flavum and facet joint arthropathy. As the intervertebral foramen and spinal canal narrow over years, the spinal cord is gradually squeezed within an increasingly confined space.

Unlike a lumbar disc herniation, which compresses peripheral nerve roots (which can regenerate), cervical myelopathy compresses the spinal cord itself — part of the central nervous system, which regenerates only to a very limited degree. The compression causes direct mechanical damage to axons, as well as ischaemic injury from compromise of the cord’s microvasculature.

The condition typically progresses in one of three patterns:

• Gradual stepwise deterioration: the most common pattern — slow progression punctuated by occasional acute episodes of deterioration, often triggered by minor trauma (such as a fall or whiplash)
• Slow continuous decline: steady, insidious worsening over months and years without acute episodes
• Static or episodic course: less common — symptoms remain relatively stable for long periods with occasional exacerbations

Regardless of the course, spontaneous significant improvement does not occur. The natural history of untreated myelopathy is unfavourable: without decompression, most patients deteriorate over time.

Early symptoms: the warning signs that are too often missed

The early symptoms of cervical myelopathy are subtle and insidious. They are not painful in the early stages — pain is a late feature — which is one reason why patients delay seeking medical attention. The three cardinal early symptoms are:

1. Clumsy hands

This is often the first symptom of cervical myelopathy and the one most frequently overlooked. Patients report progressive difficulty with fine motor tasks:

• Difficulty buttoning a shirt or doing up a coat — a task that suddenly requires more concentration and time
• Difficulty writing legibly — handwriting becomes slow, small or tremulous
• Difficulty typing accurately at a keyboard — frequent errors, slower speed
• Difficulty picking up small objects — coins, pills, pins
• Difficulty using cutlery precisely

These difficulties arise because the lateral corticospinal tract fibres controlling intrinsic hand muscles (the fine dexterity muscles of the fingers) are the most superficially located within the cervical cord and are therefore the first to be compromised by external cord compression. A patient who reports that their hands “don’t do what they’re told” or that they have become “all fingers and thumbs” is describing early myelopathy until proved otherwise.

2. Gait disturbance

The second characteristic early symptom is an unsteady, wide-based gait. Patients describe it in vivid terms: “walking as if on a boat”, “my legs feel like someone else’s”, or “I never feel safe on my feet.” They may stumble on uneven pavement, have difficulty navigating stairs (particularly descending), and feel insecure in crowds or on escalators.

The gait disturbance in myelopathy is spastic-ataxic in character: the legs are stiff (due to pyramidal tract involvement) and coordination is impaired (due to posterior column dysfunction). This distinguishes it from the pure ataxia of cerebellar disease and the sensory ataxia of peripheral neuropathy, both of which are important differential diagnoses.

A simple bedside test — the tandem gait test (walking heel to toe in a straight line) — is highly sensitive for early myelopathic gait disturbance. Patients with early myelopathy often cannot complete more than a few steps without stepping off the line or needing to use their arms for balance.

3. Heavy or cotton-wool legs

The third early symptom is a subjective sensation of heaviness, stiffness, or “cottony” texture in the lower limbs. Patients describe legs that feel difficult to lift, as if weighted down, or that feel disconnected from their body. Climbing stairs requires more effort than expected. The sensation worsens with fatigue and prolonged walking.

This symptom reflects early corticospinal tract dysfunction producing subclinical spasticity — an increase in muscle tone and reduced flexibility that has not yet reached the threshold of clinical spasticity detectable on examination.

Advanced symptoms: signs of established myelopathy

As cord compression progresses untreated, symptoms become more prominent and easier to recognise on clinical examination. Advanced myelopathy produces the following signs:

• Spasticity: increased muscle tone in the lower limbs, causing a stiff, scissor-like gait; the legs resist passive movement
• Hyperreflexia: exaggerated deep tendon reflexes in the lower limbs (knee jerk, Achilles jerk) — sometimes with spreading or polykinetic responses
• Clonus: a sustained rhythmic oscillation of the ankle when the foot is rapidly dorsiflexed — a sign of upper motor neurone lesion
• Bladder urgency and difficulty voiding: an important sign of advanced myelopathy, reflecting involvement of the descending autonomic pathways controlling bladder function; this sign often appears late but is highly significant when present
• Upper limb weakness: grip strength reduction, difficulty with repetitive hand movements (e.g., rapidly opening and closing the fist)

Pathognomonic clinical signs: Lhermitte and Hoffmann

Lhermitte’s sign

Lhermitte’s sign is elicited by asking the patient to flex the neck forward. A positive sign consists of a sudden electric shock or intense tingling sensation that shoots down the spine and radiates into one or both arms and/or legs at the moment of neck flexion. It is caused by mechanical deformation of the compressed cord during flexion, transiently irritating the posterior columns.

Lhermitte’s sign is pathognomonic of spinal cord involvement. In adults over 50 with progressive neurological symptoms, it virtually confirms the presence of cervical cord compression. Its presence should prompt immediate MRI of the cervical spine.

Hoffmann’s sign

Hoffmann’s sign is the upper limb equivalent of the Babinski plantar response. It is elicited by rapidly flicking the nail of the patient’s middle finger downward (the middle phalanx is held between the examiner’s index finger and thumb, and the distal phalanx is flicked downward). A positive Hoffmann sign consists of reflex flexion of the thumb and index finger in response to the flick. It indicates a corticospinal tract (pyramidal) lesion above the cervical cord level tested.

A positive Hoffmann sign in a patient with upper limb symptoms is a reliable indicator of upper motor neurone dysfunction and strongly suggests cervical cord compression. It is part of the standard neurosurgical examination for any patient in whom myelopathy is suspected.

The mJOA score: quantifying severity

The modified Japanese Orthopaedic Association (mJOA) scale is the internationally accepted scoring system for grading the severity of cervical myelopathy and guiding treatment decisions. Endorsed by the AOSpine Myelopathy Clinical Practice Guidelines (2017), it is used in virtually every published clinical trial on cervical myelopathy surgery.

The three severity categories and their clinical and treatment implications are:

• Mild myelopathy (mJOA ≥ 15): minor symptoms without significant functional impairment; close neurological surveillance with annual MRI; surgery may be deferred but should be reconsidered if any deterioration occurs
• Moderate myelopathy (mJOA 12–14): meaningful impairment of hand function and/or gait; surgery strongly recommended; outcomes are good when the mJOA is still above 12 pre-operatively
• Severe myelopathy (mJOA < 12): significant disability; urgent surgical evaluation; post-operative recovery is often incomplete but surgery remains beneficial to halt further deterioration

The mJOA score is also used to calculate the recovery ratio after surgery, which expresses the proportion of maximum possible improvement achieved: (post-operative mJOA − pre-operative mJOA) ÷ (18 − pre-operative mJOA) × 100. A recovery ratio of 50% or more is generally considered a good surgical outcome.

MRI findings: what to look for

MRI of the cervical spine is the definitive investigation for cervical myelopathy. A standard protocol includes sagittal and axial T2-weighted sequences and sagittal T1-weighted sequences as a minimum. The following findings are assessed:

Degree of canal stenosis

Cervical stenosis is measured on axial T2 images. Clinically significant compression is generally defined as a reduction of the spinal canal to an anteroposterior diameter below 10 mm, or a reduction in the cross-sectional area of more than 50% compared with the normal adjacent level. However, the correlation between the degree of stenosis and clinical severity is imperfect: some patients with apparent severe stenosis have few symptoms, while others with moderate stenosis are significantly disabled. The clinical presentation and mJOA score must be interpreted alongside the MRI findings.

T2 intramedullary hyperintensity

The most clinically significant MRI finding in cervical myelopathy is the presence of a T2 hyperintensity within the spinal cord at the level of maximum compression. This bright signal on T2-weighted MRI represents one or more of the following pathological processes: oedema, gliosis (reactive scar tissue), demyelination, or axonal loss within the cord parenchyma. Its presence indicates that the cord is not merely mechanically compressed but is actively injured.

The T2 hyperintensity is one of the strongest prognostic factors in cervical myelopathy surgery. Patients with a focal, mild T2 signal typically recover well after decompression. Those with an intense, multi-level or “pencil-like” T2 signal have more established cord damage and recover less completely, even after technically successful surgery.

T1 hypointensity

A T1 hypointensity (dark signal) within the cord at the stenotic level is a more ominous finding than a T2 hyperintensity. It indicates myelomalacia — established cord softening, cavitation or cyst formation — corresponding to irreversible tissue loss. When T1 hypointensity is present, surgical decompression can still halt further deterioration but is unlikely to produce significant neurological recovery of function already lost.

Multi-level versus single-level disease

Cervical spondylotic myelopathy most commonly involves multiple levels. The most frequently affected segments are C3-C4, C4-C5 and C5-C6, reflecting the sites of greatest mechanical stress in the mid-cervical spine. MRI allows precise localisation of each compressive lesion and of the intramedullary signal changes, which is essential for planning whether an anterior or posterior surgical approach is most appropriate.

Differential diagnosis: conditions that can mimic myelopathy

Not every patient with gait disturbance and hand clumsiness has cervical myelopathy. The following conditions must be excluded before a diagnosis of myelopathy is confirmed:

It is worth noting that cervical myelopathy and peripheral neuropathy can coexist — a condition known as cervical myelopathy with superimposed peripheral neuropathy, or “double crush syndrome”. In such cases, the clinical picture may be atypical (absent rather than brisk reflexes), and the diagnosis requires a combination of MRI and neurophysiological studies (EMG/nerve conduction) to disentangle the contributions of each level.

The importance of early diagnosis and specialist referral

The fundamental principle of managing cervical myelopathy is that cord damage is irreversible. Unlike a fractured bone or an inflamed joint, a compressed and injured spinal cord cannot simply be repaired and fully restored to its pre-injury state. Surgical decompression achieves two goals: it halts the progressive deterioration, and it allows the cord to partially recover the function that has been suppressed by compression (as opposed to the function that has been permanently destroyed by established axonal loss).

The consequences of late diagnosis are measurable in outcomes data. Fehlings MG et al. (Global Spine J, 2017), reporting on over 750 patients in the prospective AOSpine North America and International myelopathy studies, found that patients with moderate or severe myelopathy who underwent surgery achieved highly significant improvements in mJOA score and quality of life at 24-month follow-up. The benefit was greatest in those operated before cord damage had progressed to the point of T1 hypointensity on MRI. Similar findings were confirmed by the AOSpine Myelopathy Clinical Practice Guidelines group (Fehlings MG et al., Global Spine J, 2017), who concluded that surgery is recommended for moderate and severe myelopathy and should be offered promptly once the diagnosis is made.

The message for patients and referring physicians is clear: do not wait. A patient reporting hand clumsiness, gait instability, or electric shock sensations in the neck deserves urgent MRI of the cervical spine and, if cord compression is confirmed, early neurosurgical assessment.

Management approach: surveillance or surgery?

Once the diagnosis of cervical myelopathy is established and severity is quantified using the mJOA score and MRI, the management approach depends on the clinical and imaging picture:

• Mild stable myelopathy (mJOA ≥ 15, no T2 hyperintensity): annual neurological review + annual MRI surveillance; patient educated on warning signs requiring urgent reassessment; contact sports and activities with high risk of cervical trauma are contra-indicated
• Mild myelopathy with T2 hyperintensity: strong recommendation for surgery, regardless of mJOA score, as the cord is already injured; further delay increases the risk of establishing irreversible deficits
• Moderate myelopathy (mJOA 12–14): surgery strongly recommended; 6-month deferral may be acceptable in unusual circumstances (patient preference, anaesthetic risk) but should not be exceeded
• Severe myelopathy (mJOA < 12): urgent surgical referral; surgery remains beneficial to halt deterioration, even if complete recovery is unlikely
• Any acute neurological deterioration: relative surgical emergency — assessment within days; if falls or minor trauma have precipitated acute-on-chronic deterioration, earlier intervention is warranted

Conservative measures — analgesics, anti-inflammatories, a soft cervical collar during the acute phase — provide symptomatic relief but do not decompress the spinal cord and cannot prevent neurological progression. They should not be used as a substitute for timely surgical assessment in patients with moderate or severe myelopathy.

Frequently asked questions

Sources: Fehlings MG et al. J Neurosurg Spine 2017 — AOSpine Myelopathy CPG 2017 (Global Spine J) — EANS, EuroSpine, SFNC guidelines.