Cervical Spondylotic Myelopathy


Cervical Spondylotic Myelopathy, Cervical Myelopathy, Degenerative Cervical Myelopathy, Degenerative Myelopathy, Myelopathy, Lhermitte Sign

  • Definitions
  1. Myelopathy
    1. Spinal Cord Injury and compression resulting in UMN and LMN neurologic deficits
  2. Cervical Myelopathy
    1. Cervical Spinal Cord Injury and compression with neurologic deficits (most commonly due to degenerative disease)
  • Epidemiology
  1. Cervical Spondylotic Myelopathy is the most common spinal cord disorder in adults
  2. Onset age 50-60 years (mean presenting age 64 years old)
  3. Incidence: 4 to 60 per 100,000 (U.S. per year)
  4. Gender: Male (by 3:1 ratio)
  • Pathophysiology
  1. Axial loading during neck hyperflexion or hyperextension (in acute Trauma)
    1. Normal lordosis of the Cervical Spine is protective, dissipating axial load across cervical structures
    2. However, Spinal Cord Injury is at risk with axial loading at end range of motion, and with underlying degeneration
  2. Spinal cord compressed by degeneration (discs and facets) as well as ligamentous hypertrophy and ossification
    1. Includes hard disc lesions with Cervical Spondylosis (chronic) in older patients
    2. Pressure of posterior osteophytes at anterior cord
    3. Cervical spinal canal narrows to 13 mm in cervical steonsis and Myelopathy (>=15 is normal)
    4. Results in combined nerve root (Lower Motor Neuron) and cord compression (Upper Motor Neuron) symptoms
  3. Lower extremities are typically more affected than lower extremities
    1. Lower extremity tracts are more peripheral in cord and susceptible to injury than upper extremity tracts
  4. Lateral spinal cord tracts are more susceptible to initial injury
    1. Spinothalamic Tract (pain and TemperatureSensation) and Lateral Corticospinal tract (motor) are susceptible to injury
    2. Dorsal columns (ipsilateral vibration and proprioception) are less affected in the posterior cord
  5. Distribution
    1. C5-6 (most common)
    2. C6-7 and C4-5 are also common
  1. Static
    1. Congenital spinal stenosis
    2. Degenerative disc disease
    3. Ligamentum flavum ossification
    4. Posterior longitudinal ligament ossification
    5. Cervical Spondylosis
    6. Vertebral osteophytes
  2. Dynamic
    1. Degenerative Spondylolisthesis
    2. Spinal cord straining or Stretching from cervical flexion or extension
    3. Physiologic spinal canal narrowing
  • Risk Factors
  • Noncompressive Factors (e.g. physiologic spinal canal narrowing)
  • Symptoms
  1. Cervical Nerve root related symptoms (radicular symptoms and Lower Motor Neuron Deficits at level of lesion)
    1. Neck Pain (50%)
    2. Neck stiffness
    3. Upper extremities are more affected than lower extremities
      1. Radicular symptoms such as Shoulder or arm pain, Paresthesias or numbness (38%)
      2. Upper extremity weakness or atrophy (corresponding to affected spinal level of compression)
      3. Decreased hand fine motor activity (writing)
  2. Spinal cord related symptoms (Upper Motor Neuron Deficits)
    1. Balance or Gait difficulty and falls
    2. Leg weakness and spasticity
    3. Ascending Paresthesias (first lower extremity, then upper extremity)
    4. Decreased hand dexterity and altered handwriting
    5. Autonomic Dysfunction
      1. Erectile Dysfunction
      2. Urine retention or stool retention (44%)
      3. Urine Incontinence or Stool Incontinence
  • Signs
  1. See Neck Exam
  2. Cervical Nerve root related signs (proximal lesion related and Lower Motor Neuron)
    1. Painful Cervical Spine range of motion
      1. Neck flexion stretches the spinal cord over Vertebral osteophytes
      2. Neck extension may force ligamentum flavum towards cord, narrowing spinal canal
    2. Lhermitte Sign
      1. Passive neck flexion results in electrical Sensation down spine or arms
    3. Hoffman Sign
      1. Tapping or flicking the third Fingernail down results in involuntary flexion of the thumb or index finger
      2. Normally present in 3% of patients without cord compression or Upper Motor Neuron disease
    4. Spurling Test
      1. Axial compression reproduces symptoms
    5. Upper extremity weakness (corresponding to affected spinal level of compression)
    6. Hyporeflexia (specific to affected nerve root)
      1. C6: Biceps Reflex and Brachioradialis Reflex
      2. C7: Triceps Reflex
  3. Spinal cord related symptoms (Upper Motor Neuron Deficits)
    1. Upper Motor Neuron Deficits
      1. Hyperreflexia
      2. Pathologic reflex spread
      3. Ankle Clonus
      4. Spasticity
      5. Babinski Reflex (or Brissaud Reflex)
      6. Intrinsic Hand Muscle atrophy and weakness
      7. Wide-based ataxic gait
      8. Romberg Test
      9. Hoffman Sign
        1. Flick the distal tip of the third or fourth finger
        2. Results in thumb abduction and flexion at the distal phalanx
    2. Synkinesis
      1. Involuntary limb movement occuring with voluntary other limb movement
    3. Pyramidal Weakness
      1. Flexion is stronger in the upper extremity
      2. Extension is stronger in the lower extremity
    4. Specific Findings for C5-6 Spinal Cord Compression
      1. Inverted Brachioradialis Reflex Positive (Supinator Test)
      2. Biceps Reflex Absent (C5)
      3. Brachioradialis Reflex (C6)
      4. Hyperreflexia at Triceps Reflex (C7)
  • Grading
  • Modified Japanese Orthopedic Association Scoring System of Cervical Myelopathy Severity (mJOA)
  1. Motor Scoring
    1. Score 0-4: Upper Extremity (unable to move hands=0, able to button shirt with slight difficulty=4)
    2. Score 0-7: Lower Extremity (complete motor loss=0, no dysfunction=7)
  2. Sensory Scoring
    1. Score 0-3: Upper Extremity (complete hand sense loss=0, no sensory loss=3)
    2. Score 0-3: Sphincter Dysfunction (unable to urinate voluntarily=0, normal urination=3)
  3. Interpretation (total of all 4 criteria from motor and sensory)
    1. Total >=15: Mild
    2. Total 12-14: Moderate
    3. Total <=11: Severe
  4. Resources
    1. Full Scale (PDF)
      1. https://operativeneurosurgery.com/doku.php?id=modified_japanese_orthopaedic_association_scale
  • Grading
  • Nurick Scoring of Cervical Myelopathy Severity
  1. Scoring (select one)
    1. Score 0: Root involvement symptoms and signs but NO spinal cord findings
    2. Score 1: Spinal cord findings but no difficulty with walking
    3. Score 2: Slight walking difficulty, but does not prevent full time employment
    4. Score 3: Able to walk without assistance, but walking difficulty limits full-time work and house work
    5. Score 4: Only able to walk with assistance or with use of walker or other similar device
    6. Score 5: Chairbound or bed bound
  2. Interpretation
    1. Score 0: Mild
    2. Score 1-2: Moderate
    3. Score >=3: Severe
  • Imaging
  1. See Cervical Spine Imaging in Neck Pain
  2. MRI Cervical Spine with and without contrast
  3. CT Myelogram
    1. Alternative to MRI, when not available
  4. XRay Cervical Spine
    1. Consider while awaiting advanced imaging
    2. Defines spinal canal narrowing, osteophytes, ligament ossification
    3. Identifies significant cervical lordosis or kyphosis
  • Management
  1. Conservative Management
    1. See Cervical Disc Disease
    2. Cervical Spine Immobilization
      1. Cervical Collar in slight flexion
      2. Prevent further Spinal Cord Injury
    3. Symptomatic management
      1. NSAIDs
      2. Corticosteroids
      3. Physical Therapy
      4. Massage
      5. Foraminal injections or epidural steroid injections
    4. Cervical Traction
      1. Avoid unless recommended by spine specialist
      2. Risk of spinal ischemia complications
  2. Surgical Management
    1. Procedures: Options for spinal cord decompression and stabilization
      1. Posterior cervical fusion
      2. Anterior cervical Discectomy and fusion
      3. Corpectomy
      4. Laminectomy
      5. Disc arthroplasty
    2. Indications
      1. Moderate to severe, or progressive Cervical Myelopathy
      2. Mild to moderate Cervical Myelopathy refractory to conservative management
    3. Contraindications
      1. Asymptomatic cord compression incidental on imaging (surgery NOT recommended)
        1. Cervical stenosis is a common finding on imaging (see above)
    4. Complications
      1. Residual neurologic deficits are common (e.g. pain, spasticity, neurogenic Bladder or bowel)
      2. C5 Nerve injury (30%)
      3. Recurrent laryngeal nerve injury (2.7%)
      4. Superficial laryngeal nerve injury (1.3%)
      5. Vertebral Artery injury (4.1%)
    5. Prognosis: Predictors of best outcome
      1. Younger patients with fewer comorbidities
      2. Non-smokers
      3. No gait dysfunction
  • Course
  1. Gradual onset at age 50 with slow progression
  2. Surgical management needed for severe symptoms in 20-60% of patients at 3-6 years from onset