What are the differences in diagnosis and treatment between myelopathy and radiculopathy?

Myelopathy vs Radiculopathy: Diagnostic and Treatment Differences

MRI is the gold standard imaging modality for both myelopathy and radiculopathy, with distinct clinical presentations requiring different management approaches based on severity and progression of neurological deficits. 1, 2

Clinical Presentation Differences

Myelopathy

• Definition: Pathology affecting the spinal cord itself
• Key clinical features:
  • Bilateral symptoms (often)
  • Spasticity/hyperreflexia (58% of cases)
  • Positive Babinski sign (55%)
  • Bladder dysfunction (24%)
  • Gait disturbances
  • Motor/sensory deficits (61%)
  • Progressive neurological deterioration 1, 3, 4

Radiculopathy

• Definition: Compression or irritation of nerve roots as they exit the spinal canal
• Key clinical features:
  • Usually unilateral pain in a dermatomal distribution
  • Sensory loss in specific nerve root distribution
  • Motor weakness in specific myotomal pattern
  • Positive straight leg raise test (91% sensitivity, 26% specificity)
  • Positive crossed straight leg raise (88% specificity, 29% sensitivity)
  • Typically affects a single nerve root 1, 2

Diagnostic Approach

Imaging for Myelopathy

1. MRI without contrast: First-line imaging

   • Best visualizes cord compression, signal changes within cord
   • Identifies structural causes: disc herniation, spinal stenosis, OPLL
   • Evaluates for inflammatory, infectious, vascular, or neoplastic etiologies 1, 4

2. CT myelography: When MRI is contraindicated

   • Superior for assessing patency of spinal canal/thecal sac
   • Excellent for differentiating ventral cord herniation from dorsal arachnoid web/cyst
   • Higher resolution for presurgical planning 1

3. CT without contrast: For preoperative planning

   • Delineates osseous structures with high resolution
   • Aids in trajectory planning for hardware fixation 1

Imaging for Radiculopathy

1. MRI without contrast: First-line imaging

   • Visualizes nerve root compression
   • Identifies disc herniation, foraminal stenosis
   • Recommended for persistent symptoms after 6 weeks of conservative management 1, 2

2. Electrodiagnostic studies (EMG/NCS):

   • Differentiates radiculopathy from peripheral neuropathy
   • Localizes site of nerve compression
   • Confirms clinical findings 2

3. CT myelography: Alternative when MRI contraindicated

   • Useful for diagnosing foraminal stenosis and bony lesions 2

Treatment Approach

Myelopathy Treatment

1. Moderate to severe myelopathy:

   • Surgical intervention is strongly recommended
   • Decompression of spinal cord is primary goal
   • Approach (anterior vs posterior) depends on:
     • Location of compression
     • Number of levels involved
     • Presence of instability 1, 5

2. Mild myelopathy:

   • Surgical intervention or supervised structured rehabilitation
   • Convert to surgery if:
     • Neurological deterioration occurs
     • No improvement with conservative management 5

3. Non-myelopathic patients with cord compression:

   • Without radiculopathy: Close observation recommended
   • With radiculopathy: Higher risk of developing myelopathy; consider surgery or close follow-up 5

Radiculopathy Treatment

1. Initial management (first 6 weeks):

   • NSAIDs as first-line medication
   • Physical therapy
   • Activity modification 1, 2

2. Persistent symptoms (>6 weeks):

   • Targeted epidural steroid injections under fluoroscopic guidance
   • Consider surgical intervention for:
     • Progressive neurological deficit
     • Significant disc herniation with corresponding radiculopathy
     • Failed conservative management 1, 2

Prognostic Factors

Myelopathy Prognosis

• Earlier intervention improves outcomes in moderate/severe cases
• Severity of preoperative myelopathy is strongest predictor of outcome
• Signal changes on MRI indicate more advanced disease 5, 6

Radiculopathy Prognosis

• 50% of patients may have residual or recurrent episodes up to 1 year
• Poor prognostic factors include:
  • Female gender
  • Older age
  • Coexisting psychosocial pathology 1, 2

Common Pitfalls to Avoid

1. Misdiagnosing myelopathy as radiculopathy:

   • Both can present with pain and neurological symptoms
   • Myelopathy has bilateral symptoms and upper motor neuron signs
   • Radiculopathy typically has unilateral symptoms in a dermatomal pattern 3, 4

2. Overlooking red flags requiring urgent evaluation:

   • Cauda equina syndrome (urinary retention has 90% sensitivity)
   • Progressive neurological deficits
   • Cancer (history of cancer has positive likelihood ratio of 14.7)
   • Infection 1, 2

3. Relying solely on imaging findings:

   • High rate of asymptomatic degenerative changes on imaging
   • Clinical correlation is essential
   • Psychosocial factors are strong predictors of outcomes 1, 2

4. Delaying treatment for severe myelopathy:

   • Can lead to irreversible neurological damage
   • Surgical intervention should not be delayed in progressive cases 5