What is radiculopathy and how is it assessed?

Radiculopathy: Definition and Assessment

Radiculopathy is pain that radiates in a dermatomal distribution with or without accompanying sensory loss or motor loss, reflecting spinal nerve root compression or irritation. 1 This condition commonly manifests as pain radiating from the spine into the distribution of the affected nerve root, often accompanied by sensory changes, weakness, and reflex abnormalities.

Definition and Pathophysiology

Radiculopathy occurs due to:

• Compression or irritation of nerve roots in the spine
• Most commonly caused by:
  • Degenerative disc disease
  • Facet joint spondylosis
  • Herniation of intervertebral discs 2

The condition differs from plexopathy, which involves abnormalities in a network of nerves (plexus) and affects multiple peripheral nerve distributions 1.

Clinical Assessment

Key Symptoms to Evaluate

• Pain radiating in a specific dermatomal pattern
• Sensory changes (numbness, tingling) in the affected dermatome
• Motor weakness in muscles innervated by the affected nerve root
• Diminished deep tendon reflexes (particularly triceps in cervical radiculopathy) 3

Physical Examination

1. Motor Strength Testing:

   • Test specific muscle groups corresponding to affected nerve roots
   • Grade strength on a 0-5 scale 4

2. Sensory Testing:

   • Assess light touch, pinprick sensation in specific dermatomes
   • Document areas of hypoesthesia or hyperesthesia 4

3. Reflex Testing:

   • Check deep tendon reflexes (biceps, triceps, brachioradialis for upper extremities; patellar, Achilles for lower extremities)
   • Note any diminished or absent reflexes 4

4. Special Tests for Cervical Radiculopathy:

   • Spurling test: Extension and lateral rotation of neck toward affected side reproduces symptoms
   • Shoulder abduction test: Relief of symptoms when placing hand on top of head
   • Upper limb tension test: Reproduction of symptoms with specific arm positioning 3

5. Special Tests for Lumbar Radiculopathy:

   • Straight leg raise: Reproduction of radicular pain when raising the affected leg
   • Crossed straight leg raise: Pain with contralateral leg raise (highly specific)
   • Femoral nerve stretch test (for upper lumbar radiculopathy) 5

Diagnostic Workup

When to Order Imaging

• Initial presentation: Imaging is not required unless there is:

  • History of trauma
  • Persistent symptoms despite conservative treatment
  • Red flags for malignancy, myelopathy, or abscess 3

• Timing: Consider MRI after 6 weeks of failed conservative management if symptoms persist 4

Imaging Modalities

1. MRI:

   • Most sensitive test for detecting nerve root compression, disc herniation, and soft tissue injuries
   • First-line advanced imaging for radiculopathy 4

2. X-rays:

   • Initial imaging to rule out fracture or instability
   • Limited value for soft tissue evaluation 4

3. CT or CT Myelography:

   • Alternative when MRI is contraindicated
   • Can provide detailed bony anatomy 4

Electrodiagnostic Testing

• EMG/NCV: Not needed if diagnosis is clear but useful when:
  • Clinical picture is ambiguous
  • Peripheral neuropathy is a likely alternative diagnosis
  • Multiple levels of involvement are suspected 3

Clinical Correlation

A critical step in diagnosis is correlating clinical findings with imaging results. The American College of Radiology emphasizes that abnormalities on imaging are common in asymptomatic individuals, making clinical correlation essential 4. The diagnosis requires:

• Symptoms in a dermatomal distribution
• Corresponding physical examination findings
• Supportive imaging findings when indicated

Pitfalls to Avoid

1. Overreliance on imaging: Abnormalities are common in asymptomatic individuals 4
2. Incomplete neurological examination: May miss specific nerve root involvement 4
3. Confusing radiculopathy with plexopathy: There is considerable overlap in clinical presentations 1
4. Neglecting to assess for serious pathology: Always evaluate for red flags suggesting cauda equina syndrome, malignancy, or infection

By systematically assessing symptoms, performing a thorough neurological examination, and appropriately utilizing diagnostic studies, clinicians can accurately diagnose radiculopathy and implement effective treatment strategies.