Myelopathy vs Radiculopathy: Key Clinical Distinctions
Myelopathy involves spinal cord compression causing upper motor neuron signs, gait disturbance, and loss of fine motor skills, while radiculopathy results from nerve root compression causing dermatomal pain, sensory changes, and lower motor neuron findings in a specific nerve root distribution.
Anatomic Location and Pathophysiology
Myelopathy affects the spinal cord itself, resulting from compression or intrinsic pathology within the spinal canal 1. The spinal cord dysfunction can arise from neoplastic, infectious, inflammatory, neurodegenerative, vascular, nutritional, or degenerative conditions 1.
Radiculopathy involves compression or irritation at the nerve root level as it exits the spinal canal 2. The pathophysiology includes both mechanical compression and chemical inflammation of the nerve root 3.
Clinical Presentation
Myelopathy Signs and Symptoms:
- Fine motor skill impairment in the hands (difficulty with buttons, writing) 4
- Gait disturbance and balance problems due to spinal cord involvement 4
- Upper motor neuron signs: hyperreflexia, positive Babinski sign, clonus
- Hand numbness (often bilateral and non-dermatomal) 4
- Neck stiffness and pain 4
- Stepwise deterioration is typical without treatment 3
Radiculopathy Signs and Symptoms:
- Dermatomal pain radiating down the arm in a specific nerve root distribution 4
- Sensory changes following dermatomal patterns 4
- Lower motor neuron signs: weakness in specific myotomes, diminished reflexes 4
- Muscle atrophy in chronic cases
- Pain often worse with neck movement or specific provocative maneuvers 2
Critical Pitfall: These conditions can coexist as "myeloradiculopathy," making clinical distinction challenging 5. When both are present, the myelopathic component should drive treatment urgency.
Diagnostic Approach
Imaging:
For Myelopathy:
- MRI of the entire spine is the mainstay due to superior spinal cord visualization 1
- Consider imaging the entire spine even with localized symptoms, as multilevel involvement is common 1
- Brain MRI may be useful as an adjunct in certain cases 1
For Radiculopathy:
- MRI cervical spine without contrast is the first-line imaging 2
- MRI correctly predicts 88% of surgical lesions versus 81% for CT myelography 2
- Important caveat: MRI shows frequent false-positives in asymptomatic patients, and abnormal levels may not correspond to clinical examination 2
- CT myelography is an excellent alternative for claustrophobic patients or when MRI is contraindicated 2
Electrodiagnostic Testing:
For Radiculopathy:
- Needle electrode examination (NEE) is the cornerstone, showing myotomal spontaneous activity and neurogenic motor unit changes 6
- Examine at least five proximal and distal limb muscles plus paraspinal muscles 6
- Preserved sensory nerve action potentials help localize to nerve root (versus peripheral nerve) 6
For Myelopathy:
- Electrodiagnostic studies are less useful and not routinely indicated 7
Natural History and Treatment Urgency
Myelopathy:
- Unlikely to show significant spontaneous improvement 3
- Typically shows stepwise deterioration without intervention 3
- Surgical decompression and stabilization should be strongly considered to prevent permanent disability 3
- Long-term compression can result in irreversible spinal cord damage affecting quality of life 4
Radiculopathy:
- Most patients improve with conservative management 3
- Natural history favors non-surgical treatment for the majority 3
- Some patients remain disabled by pain and become surgical candidates 3
- Conservative care includes medication, physical therapy, activity modification, patient education, supervised exercise, and manual therapy 8, 9
Treatment Algorithm
If myelopathy is suspected (upper motor neuron signs, gait disturbance, fine motor impairment):
- Obtain MRI of entire spine urgently
- Refer to spine surgery for evaluation
- Surgical decompression is typically indicated to prevent progression
If radiculopathy is suspected (dermatomal pain, lower motor neuron signs):
- Obtain MRI cervical spine without contrast
- Initiate conservative management: patient education about prognosis, activity modification, supervised exercise, manual therapy
- Reserve surgical evaluation for: progressive neurologic deficits, chronic/treatment-refractory symptoms (typically >6-12 weeks), or if myelopathy develops
Critical distinction: The presence of myelopathy fundamentally changes management from conservative to surgical consideration, as the natural history without intervention is progressive deterioration with potential permanent disability 3.