What are the steps to diagnose cervical stenosis?

Diagnosis of Cervical Stenosis

The diagnosis of cervical stenosis requires MRI of the cervical spine without IV contrast as the first-line imaging modality, supplemented by clinical evaluation of neurological symptoms including pain, numbness, and motor weakness in the affected limbs. 1

Clinical Presentation and Initial Assessment

• Symptoms to evaluate:

  • Radicular pain (most common - 99% of patients)
  • Numbness/sensory changes (56% of patients)
  • Motor weakness in affected limbs
  • Possible myelopathic symptoms in severe cases:
    • Gait disturbance
    • Fine motor coordination problems
    • Bowel/bladder dysfunction 2, 3

• Physical examination findings:

  • Decreased cervical range of motion
  • Proprioception deficits (particularly in right lateral flexion and flexion)
  • Neurological deficits corresponding to compressed nerve roots
  • Positive Spurling's test (radicular symptoms with neck extension and rotation)
  • Hoffman's sign and hyperreflexia in myelopathy cases 3

Diagnostic Imaging Algorithm

1. MRI Cervical Spine Without IV Contrast

• Primary diagnostic tool for evaluating:
  • Foraminal stenosis
  • Central canal stenosis
  • Cord signal changes
  • Associated disc herniation
  • Bony osteophytes
  • Facet hypertrophy 1

2. CT Cervical Spine

• Secondary imaging option when:
  • MRI is contraindicated (pacemaker, metal implants, claustrophobia)
  • Better visualization of bony structures is needed
  • Detailed assessment of bony foraminal stenosis is required 4, 1

3. CT Myelography

• Reserved for cases where MRI is contraindicated and soft tissue detail is needed 4

4. Additional Imaging (When Indicated)

• CTA or MRA of the neck: If vascular pathology (vertebral artery dissection) is suspected
• MRI of the brain: If central nervous system pathology is suspected 1

Grading Systems for Cervical Stenosis

Kang MRI Grading System

• Grade 0: No stenosis
• Grade 1: Mild stenosis (obliteration of CSF space without cord deformity)
• Grade 2: Moderate stenosis (cord deformation without signal change)
• Grade 3: Severe stenosis (cord deformation with signal change) 2, 3

Measurement-Based Assessment

• Absolute stenosis: Canal diameter ≤10 mm
• Relative stenosis: Canal diameter <13 mm
• Torg-Pavlov ratio: Ratio of canal diameter to vertebral body width; ≤0.8 indicates stenosis 4, 5

Diagnostic Considerations

• T2 signal hyperintensity on MRI indicates edema, inflammation, or in chronic cases, neurodegeneration and demyelination 4

• Multiple level assessment is crucial as stenosis commonly affects multiple segments, with C5-C6 being the most frequently involved level 2

• Correlation with symptoms: Studies show strong agreement (K = 0.81) between Kang's grading system and the presence of clinical symptoms, with agreement being greatest in:

  • Female patients
  • Older patients
  • Those with longer duration of symptoms 2

• Differential diagnosis must rule out:

  • Central cord compression
  • Bilateral foraminal stenosis
  • Vascular causes (vertebral artery pathology)
  • Non-spinal neurological conditions 1

Pitfalls to Avoid

• Relying solely on imaging: Clinical correlation is essential as radiographic findings may not always correlate with symptoms 4

• Missing concomitant lumbar stenosis: Patients may have both cervical and lumbar stenosis, requiring careful assessment of both regions 5

• Overlooking natural history: CSM may manifest as slow, stepwise decline with periods of quiescence, affecting treatment decisions 4

• Ignoring proprioception deficits: The degree of cervical stenosis significantly affects cervical proprioception and range of motion, which should be assessed during clinical evaluation 3

By following this diagnostic algorithm and considering these key factors, clinicians can accurately diagnose cervical stenosis and determine its severity to guide appropriate management decisions.