Diagnosis/Clinical Examination

Diagnosing DCM early is challenging. This is partly because, due to current delays in diagnosis, the early diagnostic features of DCM are unknown; it is also partly because of the diversity of symptoms experienced by people with DCM [1].

Common features you should look out for include neck pain and stiffness, unilateral or bilateral limb or body pain, weakness or stiffness, unilateral or bilateral limb or body numbness, paraesthesia or sensory disturbance, loss of manual dexterity, balance and coordination, immobility, falls, and disturbance of normal bladder and bowel function [1]. Common misconceptions include the requirement for symptoms to be bilateral, or to involve the upper limb, or to include neck pain. This is not the case. 

In addition, many ‘under-recognised symptoms’ are increasingly linked to DCM, such as unusual often-uncomfortable sensory symptoms [2], chest tightness [3], respiratory dysfunction [4], hypertension [5] and headaches [6]. We term these symptoms ‘under-recognised’, as their link to DCM is less well reported, but their presence should not deter your suspicion of DCM.

The most consistent feature of DCM is an increase in the number of symptoms and their persistent progression over time [1]. A careful systems review at an early stage may help detect underappreciated symptoms that help to point to a problem in the cervical spinal cord. 

Remember, not all symptoms will be present and there is not a single, stereotyped presentation. Many relevant symptoms may not be recognised as related by the patient, who instead may focus on a specific feature, such as difficulty using their hand. In one series, 50% of people with DCM were initially diagnosed with carpal tunnel syndrome [7], and it is common for DCM to be mistaken for normal ageing [1]. 

Differential diagnoses, such as motor neurone disease, myasthenia gravis, myopathies, multiple sclerosis, tumours, vascular malformations, subacute combined degeneration of the cord, amongst many others, must be considered, but share similar investigation pathways [8].


Examination

Very much like the symptoms of DCM, any of these examination features of DCM, in any combination, may be present [1–3]. A comprehensive assessment of the upper and lower limbs is required.

Findings that you may elicit on examination of individuals with DCM include upper motor neuron signs in the upper and lower limbs: hyperreflexia, spasticity, clonus, a positive Babinski sign (upgoing plantar response), a positive Hoffman sign (flexion and adduction of the thumb after flicking the fingernail of the second digit downwards), a positive Trömner sign (flexion of the thumb and index finger on tapping the palmar side of the distal phalanx of the third digit), and Lhermitte’s sign (electric shock-like sensations going down the neck into the back and the upper limbs, especially on flexing the neck).

You may also identify weakness in a segmental pattern corresponding to the level of cord compression (likely due to involvement of exiting nerve roots and coexistent radiculopathy) or in a pyramidal pattern with extensors more affected in the upper limb and flexors more affected in the lower limb, due to compression of the lateral corticospinal tract fibres.

Although assessment of muscle weakness is one of the most frequently performed components of the neurological examination (probably because it is one of the most easily performed), muscle weakness is a difficult feature to accurately characterise [2]. The assessment of muscle strength by doctors is subjective, and often falsely reassuring. It also may not accord with the patient’s reported experience of muscle weakness, as their experience can be driven by other problems. For example, in DCM, problems such as fatigue or difficulty using the muscles may be construed as ‘weakness’ [4].

You may find sensory loss in the limbs and trunk, atrophy of the small muscles of the hand, and a broad-based, unsteady gait.

Importantly, you should remember that examination features in DCM have low sensitivity but high specificity. In other words, examination findings cannot exclude DCM, but abnormal findings are highly suggestive of DCM [1]. 


Imaging

Specialist imaging studies have recently shown that spinal cord damage occurs before the onset of symptoms and examination findings; therefore, a high index of suspicion is very important [1].

The most useful imaging modality is magnetic resonance imaging (MRI), which allows high-quality imaging of the neurological, bony and ligamentous structures within the cervical spine (Figure 1,[2]). Hyperintensity of the spinal cord on T2-weighted images and hypointensity on T1-weighted images are associated with greater clinical impairment, but this is not a consistent finding or a diagnostic hallmark [3, 4]. Likewise, the degree of spinal cord compression has been shown to correlate poorly with disease severity, meaning that even mild compression can cause severe disease [5–10]. Because MRI is conducted in a supine position and compression can be dynamic, it is recognised that imaging without visualised compression also is still compatible with DCM [11,12].

For people with progressive symptoms or symptoms that substantially affect their quality of life, you should refer for an urgent MRI scan; for people with mild and stable symptoms, you can refer for a non-urgent MRI [13].

How one accesses an MRI varies by region and country. If this cannot be arranged directly from primary care, a referral to a secondary speciality may be required. In the UK this would often be Neurology, or Musculoskeletal Services, an allied professional triage point for any concerns of the musculoskeletal system.

Figure 1: Sagittal T2 weighted MRI of the Cervical Spine. At C3 to C5, there is significant narrowing of the cervical canal; this can be appreciated by the loss of the ‘white’ CSF signal around the ‘grey’ spinal cord. The stenosis is driven anteriorly, by a large disc osteophyte complex, and posteriorly by thickening of the ligamentum flavum.


Electrophysiological Investigations

Clinical electrophysiological studies can be useful adjuncts to MRI imaging both in diagnosing DCM and in ruling out differential diagnoses such as isolated radiculopathy, peripheral neuropathy and motor neurone disease [1–3].

There are many different types of electrophysiological study, including electromyography (EMG), which examines the activity of the muscles, and nerve conduction studies (NCS), which examine the transmission of signals along neural pathways. Mostly these studies are performed only in the periphery, principally to assess for and localise a radiculopathy, or to rule out peripheral neuropathies, brachial plexopathy or peripheral nerve entrapment. Such an examination does not therefore diagnose DCM specifically, but can help by excluding alternative causes or informing the operative strategy [4].

More specialist versions of these tests can be performed, such as somatosensory and motor evoked potentials, which can detect the sensory and motor conduction impairment that occurs in the spinal cord in DCM [3].


Scoring Systems

There are several systems that you can use to measure the severity of DCM [1], as described in our Assessment Scales webpage.

The current international gold standard is the modified Japanese Orthopaedic Association (mJOA) scale [2]. This comprises 4 sub-components: upper limb motor function, lower limb motor function, upper limb sensation and sphincter function (Table 1). The mJOA is an 18-point scale, with a score of 15–17 representing mild, 12–14 moderate and 0–11 severe myelopathy [3].

These categories are useful to triage and inform immediate care; mild disease is generally stable, or very slowly progressive, whilst moderate to severe is more rapidly progressive for which urgent surgical treatment is recommended [2]. They also provide objective references for monitoring DCM over time.

Table 1: mJOA Scale

  1. Davies BM, Mowforth OD, Smith EK, Kotter MR (2018) Degenerative cervical myelopathy. BMJ 360 k186 
  2. Davies BM, Munro C, Khan DZ et al. (2020) Outcomes of Degenerative Cervical Myelopathy From The Perspective of Persons Living With the Condition: Findings of a Semistructured Interview Process With Partnered Internet Survey. Global Spine Journal 6 (22): 2192568220953811 
  3. Kobayashi H, Kikuchi S, Otani K et al. (2010) Development of a self-administered questionnaire to screen patients for cervical myelopathy. BMC Musculoskeletal Disorders 11 (1): 268 
  4. Bhagavatula ID, Bhat DI, Sasidharan GM et al. (2016) Subclinical respiratory dysfunction in chronic cervical cord compression: a pulmonary function test correlation. Neurosurgical Focus 40 (6): E3 
  5. Li Z, Zhao Y, Jia W et al. (2015) Surgical Treatment of Cervical Spondylotic Myelopathy Associated Hypertension–A Retrospective Study of 309 Patients. 10 (7): e0133828 
  6. Shimohata K, Hasegawa K, Onodera O et al. (2017) The Clinical Features, Risk Factors, and Surgical Treatment of Cervicogenic Headache in Patients With Cervical Spine Disorders Requiring Surgery. Headache 57 (7): 1109–1117 
  7. Behrbalk E, Salame K, Regev GJ et al. (2013) Delayed diagnosis of cervical spondylotic myelopathy by primary care physicians. Neurosurgical Focus 35 (1): E1 
  8. Tracy JA, Bartleson JD (2010) Cervical Spondylotic Myelopathy. The Neurologist 16 (3): 176–187 

 

Examination

  1. Davies BM, Mowforth OD, Smith EK, Kotter MR (2018) Degenerative cervical myelopathy. BMJ 360 k186 
  2. Hilton B, Tempest-Mitchell J, Davies B, Kotter M (2018) Assessment of degenerative cervical myelopathy differs between specialists and may influence time to diagnosis and clinical outcomes. PloS One 13 (12): e0207709 
  3. Cook CE, Wilhelm M, Cook AE et al. (2011) Clinical tests for screening and diagnosis of cervical spine myelopathy: a systematic review. Journal of Manipulative and Physiological Therapeutics 34 (8): 539-546 
  4. Davies BM, Munro C, Khan DZ et al. (2020) Outcomes of Degenerative Cervical Myelopathy From The Perspective of Persons Living With the Condition: Findings of a Semistructured Interview Process With Partnered Internet Survey. Global Spine Journal 6 (22): 2192568220953811 

 

Imaging

  1. Martin AR, Leener BD, Cohen-Adad J et al. (2018) Can microstructural MRI detect subclinical tissue injury in subjects with asymptomatic cervical spinal cord compression? A prospective cohort study. BMJ Open 8 (4): e019809 
  2. Nouri A, Tetreault L, Singh A et al. (2015) Degenerative Cervical Myelopathy: Epidemiology, Genetics, and Pathogenesis. Spine 40 (12): E675-93 
  3. Nouri A, Tetreault L, Zamorano JJ et al. (2015) Role of magnetic resonance imaging in predicting surgical outcome in patients with cervical spondylotic myelopathy. Spine 40 (3): 171-178 
  4. Tetreault LA, Dettori JR, Wilson JR et al. (2013) Systematic review of magnetic resonance imaging characteristics that affect treatment decision making and predict clinical outcome in patients with cervical spondylotic myelopathy. Spine 38 (22 Suppl 1): S89-110 
  5. Martin AR, Leener BD, Cohen-Adad J et al. (2017) Clinically Feasible Microstructural MRI to Quantify Cervical Spinal Cord Tissue Injury Using DTI, MT, and T2*-Weighted Imaging: Assessment of Normative Data and Reliability. American Journal of Neuroradiology 38 (6): 1257-1265 
  6. Tempest-Mitchell J, Hilton B, Davies BM et al. (2019) A comparison of radiological descriptions of spinal cord compression with quantitative measures, and their role in non-specialist clinical management. PloS One 14 (7): e0219380
  7. Nouri A, Tetreault L, Côté P et al. (2015) Does Magnetic Resonance Imaging Improve the Predictive Performance of a Validated Clinical Prediction Rule Developed to Evaluate Surgical Outcome in Patients With Degenerative Cervical Myelopathy? Spine 40 (14): 1092-1100 
  8. Wilson JR, Barry S, Fischer DJ et al. (2013) Frequency, timing, and predictors of neurological dysfunction in the nonmyelopathic patient with cervical spinal cord compression, canal stenosis, and/or ossification of the posterior longitudinal ligament. Spine 38 (22 Suppl 1): S37-54 
  9. Adamova B, Kerkovsky M, Kadanka Z et al. (2017) Predictors of symptomatic myelopathy in degenerative cervical spinal cord compression. Brain and Behavior 7 (9): e00797 
  10. Ost K, Jacobs WB, Evaniew N et al. (2021) Spinal Cord Morphology in Degenerative Cervical Myelopathy Patients; Assessing Key Morphological Characteristics Using Machine Vision Tools. Journal of Clinical Medicine 10 (4): 892 
  11. Tykocki T, Plessis J du, Wynne-Jones G (2018) Analysis of Morphometric Parameters in Cervical Canal Stenosis on Neutral and Dynamic Magnetic Resonance Imaging. World Neurosurgery 114 e317-e322
  12. Xu N, Wang S, Yuan H et al. (2017) Does dynamic supine magnetic resonance imaging improve the diagnostic accuracy of cervical spondylotic myelopathy? A review of the current evidence. World Neurosurgery 100: 474-479 
  13. Davies BM, Mowforth OD, Smith EK, Kotter MR (2018) Degenerative cervical myelopathy. BMJ 360 k186 

 

Electrophysiological Investigations

  1. Davies BM, Mowforth OD, Smith EK, Kotter MR (2018) Degenerative cervical myelopathy. BMJ 360 k186 
  2. Tracy JA, Bartleson JD (2010) Cervical Spondylotic Myelopathy. The Neurologist 16 (3): 176-187 
  3. Martin AR et al. (2022) Imaging and Electrophysiology for Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 9]. Global Spine Journal 12 (1 suppl): 130S-146S
  4. Fehlings MG, Tetreault LA, Riew KD et al. (2017) A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression. Global Spine Journal 7 (3 Suppl): 70S-83S 

 

Scoring Systems

  1. Davies BM, McHugh M, Elgheriani A et al. (2016) Reported Outcome Measures in Degenerative Cervical Myelopathy: A Systematic Review. 11 (8): e0157263 
  2. Fehlings MG, Tetreault LA, Riew KD et al. (2017) A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression. Global Spine Journal 7 (3 Suppl): 70S-83S
  3. Kopjar B, Tetreault L, Kalsi-Ryan S, Fehlings M (2015) Psychometric properties of the modified Japanese Orthopaedic Association scale in patients with cervical spondylotic myelopathy. Spine 40 (1): E23-8