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Degenerative cervical myelopathy is often missed in the early stages due to the subtlety of its symptoms, and can be debilitating if left unmanaged. General practitioners (GPs) can help these patients achieve optimal treatment outcomes via a high index of suspicion and timely treatment. Find out what you should look out for and the latest treatment approaches.
Degenerative cervical myelopathy (DCM), previously referred to as cervical spondylotic myelopathy, is defined as spinal cord dysfunction from chronic compression of the cervical spinal cord.
DCM occurs when degenerative changes of the cervical spine cause narrowing of the cervical spinal canal. The pathophysiology of DCM consists of structural and functional abnormalities caused by both static and dynamic factors.
Static factors
The static degenerative cascade usually begins with degeneration of the intervertebral disc resulting in decreased disc height and disc bulges causing a narrowing of the spinal canal. This is made worse in many cases by hypertrophy of the ligamentum flavum.
Dynamic factors
Dynamic factors such as spondylolisthesis result in abnormal repetitive movement of the cervical spine. Excessive flexion may stretch and cause anterior compression of the spinal cord.
This causes irritation, compression, tethering and shearing of the spinal cord. Such mechanical irritation can result in vascular changes causing ischaemia and inflammation of the spinal cord. This may result in neuronal cell loss, degeneration of the posterior columns and anterior horn cells and endothelial damage. If severe enough, this may inhibit the electric conduction of the corticospinal tracts.1- 3
DCM may also occur in the setting of cervical radiculopathy – in which case, in addition to radicular arm pain, there may also exist signs of spinal cord dysfunction.
DCM is the most common degenerative, non-traumatic and non-infective form of spinal cord compression worldwide.
In North America, the annual incidence is 41 per one million, and the prevalence is 605 per one million.4 DCM patients typically present in their late 50s to early 60s. Men appear to be more commonly affected than women at a ratio of 3:1.5
DCM commonly involves multiple levels of the cervical spine with the C5/6 level being most common, followed by C6/7, and then C4/5. The literature suggests that 20-60% of patients treated nonoperatively will experience neurological deterioration over a period of three to six years.6
1. History and physical examination: What GPs should look out for
The diagnosis of DCM is largely clinical. Patients with DCM present with a spectrum of symptoms:
In the early stagesPatients may complain of neck pain with or without upper limb numbness or weakness.
As the condition progressesThey may complain of decreased hand dexterity affecting fine motor functions. This may manifest as difficulties with handwriting, buttoning clothes, and particularly in the Asian context, the use of chopsticks.
In more severe casesThey may start presenting with unsteady gait resulting in frequent falls. Bladder and bowel dysfunction are possible but very rare, portending severe disease.
A detailed description of a comprehensive physical examination for DCM is beyond the scope of this article. However, some physical signs may include:
2. Investigations
Beyond a comprehensive history and physical examination, various investigations can aid in the accurate diagnosis of DCM.
Plain radiographs
Even though plain radiographs do not show soft tissue detail, they can provide a wealth of information such as spinal cord narrowing, sagittal alignment (lordosis/kyphosis), osteophytes, and instability (on dynamic views).
MRI scans
Magnetic resonance imaging (MRI) is the preferred imaging modality for assessing patients with DCM as it allows detailed studies of soft tissue structures such as the intervertebral discs, ligaments and neural structures. MRI allows the clinician to localise the levels of disease and to a certain extent, allows quantifying the extent of spinal canal stenosis.
In severe DCM, MRI may reveal cord signal changes first in the T2 sequence, and then in the T1 sequences. This is believed to be a predictor of poor outcomes. On the other hand, improved functional outcomes are seen with postoperative T2 signal intensity regression.7
MRI is also helpful in excluding other disease processes of the cervical spine, such as neoplasm, demyelinating conditions and syringomyelia.
CT scans
In addition to MRI, computed tomography (CT) scans of the cervical spine are useful in further delineating bony architecture and the presence of ossification of posterior longitudinal ligaments, and allows surgical planning for instrumentation.
In some cases where MRI is contraindicated, a CT myelography can be considered.
Classification
There are several classification systems that guide the treatment of DCM. The modified Japanese Orthopaedic Association (mJOA) score is one such used grading system, which grades DCM into mild, moderate and severe cases.8
Clinical observation seems to be a reasonable option for patients with mild DCM, while surgery is the mainstay of treatment for patients with moderate or severe DCM.
Surgical approaches
The principles of surgery for DCM are adequate decompression and stabilisation where needed.
There is a myriad of surgical techniques beyond the scope of this article, but the surgical options can largely be divided into anterior and posterior approaches.
For anterior approaches, anterior cervical discectomy and fusion (ACDF) has long been considered the gold standard of treatment.
However, emerging data has suggested that motion preservation surgery in the form of cervical disc arthroplasty (CDA) may be a safe and even superior option to ACDF for the carefully selected patient.
Cervical disc arthroplasty
Compared to ACDF, CDA can potentially maintain physiological motion in the cervical spine and decrease the rates of reoperation arising from adjacent segment disease.9-11
Despite the promising results and increasing popularity of CDA, it should be noted that patient selection remains the key to successful surgical outcomes, as CDA is a more technically challenging procedure to perform and has far more stringent indications as compared to ACDF.
DCM is often missed in the early stages as its signs and symptoms are often subtle.
DCM is a progressive condition that can debilitate patients if not treated in a timely and appropriate manner.
A high index of suspicion of DCM in approaching the patient is needed to achieve optimal treatment outcomes by enabling timely referrals to the spine surgeon.
Neck pain with bilateral hand numbness, loss of finger dexterity and mild gait instability should raise a clinical suspicion and referral to a specialist spine surgeon or neurologist for further workup.
The mainstay of treatment for moderate-to-severe DCM is surgery. CDA is emerging as a safe and potentially superior alternative to fusion surgery, but stringent patient selection remains the key to successful treatment outcomes.
De Oliveira Vilaça C, Orsini M, Leite MA, de Freitas MR, Davidovich E, Fiorelli R, et al. Cervical spondylotic myelopathy: what the neurologist should know. Neurol Int. 2016;8(4):6330
Baptiste DC, Fehlings MG. Pathophysiology of cervical myelopathy. Spine J. 2006;6(Suppl 6):190S–7;
Fehlings MG, Skaf G. A review of the pathophysiology of cervical spondylotic myelopathy with insights for potential novel mechanisms drawn from traumatic spinal cord injury. Spine (Phila Pa 1976) 1998;23(24):2730–7
Yamaguchi S, Mitsuhara T, Abiko M, et al. Epidemiology and overview of the clinical spectrum of degenerative cervical myelopathy. Neurosurg Clin N Am. 2018;29(1):1-12; 1
Gibson J, Nouri A, Krueger B, et al. Degenerative cervical myelopathy: a clinical review. Yale J Biol Med. 2018;91(1):43-48; Nouri A, Tetreault L, Singh A, et al. Degenerative cervical myelopathy: epidemiology, genetics, and pathogenesis. Spine (Phila Pa 1976). 2015;40(12):E675-E693
Karadimas SK, Erwin WM, Ely CG, et al. Pathophysiology and natural history of cervical spondylotic myelopathy. Spine (Phila Pa 1976). 2013;38(22 suppl 1):S21-S36
Matsumoto M, Toyama Y, Ishikawa M, Chiba K, Suzuki N, Fujimura Y. Increased signal intensity of the spinal cord on magnetic resonance images in cervical compressive myelopathy: does it predict the outcome of conservative treatment? Spine (Phila Pa 1976) 2000;25:677–82
Tetreault L, Kopjar B, Nouri A, Arnold P, Barbagallo G, Bartels R, Qiang Z, Singh A, Zileli M, Vaccaro A, Fehlings MG. The modified Japanese Orthopaedic Association scale: establishing criteria for mild, moderate and severe impairment in patients with degenerative cervical myelopathy. Eur Spine J. 2017 Jan;26(1):78-84
Nunley PD, Hisey M, Smith M, Stone MB. Cervical Disc Arthroplasty vs Anterior Cervical Discectomy and Fusion at 10 Years: Results From a Prospective, Randomized Clinical Trial at 3 Sites. Int J Spine Surg. 2023 Apr;17(2):230-240. doi: 10.14444/8431
Janssen ME, Zigler JE, Spivak JM, Delamarter RB, Darden BV 2nd, Kopjar B. ProDisc-C Total Disc Replacement Versus Anterior Cervical Discectomy and Fusion for Single-Level Symptomatic Cervical Disc Disease: Seven-Year Follow-up of the Prospective Randomized U.S. Food and Drug Administration Investigational Device Exemption Study. J Bone Joint Surg Am. 2015 Nov 4;97(21):1738-47
Spivak JM, Zigler JE, Philipp T, Janssen M, Darden B, Radcliff K. Segmental Motion of Cervical Arthroplasty Leads to Decreased Adjacent-Level Degeneration: Analysis of the 7-Year Postoperative Results of a Multicenter Randomized Controlled Trial. Int J Spine Surg. 2022 Feb;16(1):186-193
Associate Professor Dinesh Shree Kumar is the Head of the CGH-NNI Integrated Spine Centre and SingHealth Duke-NUS Spine Centre. A neurosurgeon by training, he has subspecialised in spinal surgery and his current interests include cervical spine surgery, intradural tumour surgery and minimally invasive spine surgery with navigation/robotics.
GPs who would like more information about this procedure, please contact Prof Kumar at [email protected].
Dr Chew Zhihong is a Consultant Orthopaedic Spine Surgeon at the Department of Orthopaedic Surgery, Changi General Hospital and CGH-NNI Integrated Spine Centre. He recently returned from his fellowship under the Health Manpower Development Plan with Dr Michael Janssen at the Center for Spine and Orthopedics, Denver, Colorado, USA with a focus on cervical and lumbar disc arthroplasty.
GPs who would like more information about this procedure, please contact Dr Chew at [email protected].
GPs can call the SingHealth Duke-NUS Spine Centre for appointments at the following hotlines or click here to visit the website: Singapore General Hospital: 6326 6060 Changi General Hospital: 6788 3003 Sengkang General Hospital: 6930 6000 KK Women's and Children's Hospital: 6692 2984 National Neuroscience Institute: 6330 6363
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