What is the main cause of radiculopathy?

Main Causes of Radiculopathy

Radiculopathy is most commonly caused by mechanical nerve root compression from degenerative, metabolic, infectious, or neoplastic causes, with disc herniation being the predominant etiology. 1

Pathophysiology and Common Causes

Radiculopathy results from irritation and/or compression of nerve roots as they exit the spine. The primary causes include:

1. Disc Herniation:

   • Most frequent cause, particularly in lumbar and cervical regions
   • Accounts for majority of cases requiring surgical intervention (1-2% of all discectomies) 1
   • Often calcified (20-65%) in thoracic region 1
   • Typically occurs at L4-L5 and L5-S1 levels in lumbar spine 1

2. Degenerative Changes:

   • Facet joint spondylosis 2
   • Spinal stenosis, commonly from:
     • Disc herniations (especially below T7 in thoracic spine) 1
     • Facet arthropathy 1
     • Ligamentum flavum ossification 1

3. Other Causes:

   • Infectious processes affecting nerve roots
   • Neoplastic conditions compressing nerve roots
   • Metabolic disorders affecting nerve root function
   • Vascular pathologies 1

Clinical Presentation

The clinical manifestation varies by location but typically includes:

• Pain in the distribution of the affected nerve root (76% in thoracic cases) 1
• Motor/sensory deficits (61% in thoracic cases) 1
• Spasticity/hyperreflexia (58% in thoracic cases) 1
• Positive Babinski sign (55% in thoracic cases) 1
• Bladder dysfunction (24% in thoracic cases) 1

Diagnostic Approach

MRI is the gold standard for diagnosis of radiculopathy:

• Most useful for evaluating compressive myelopathy or radiculopathy 1
• Accurately depicts soft-tissue pathology and assesses vertebral marrow 1
• Can identify nerve root compression that correlates with clinical symptoms 1

CT myelography may be used when MRI is contraindicated:

• Provides high detail of spinal canal contents 1
• Useful for presurgical planning 1
• Requires lumbar puncture for contrast injection 1

Treatment Considerations

Most cases improve with conservative management:

• Non-surgical approaches show moderate evidence of effectiveness for lumbar disc herniation with radiculopathy 3
• Effective conservative treatments include patient education, McKenzie method, mobilization/manipulation, exercise therapy, and epidural injections 3

Surgical intervention is indicated for:

• Severe, intractable pain 1
• Progressive/severe myelopathy 1
• Clinically significant motor deficits 2
• Cauda equina syndrome, which presents with bladder/bowel dysfunction and saddle anesthesia 4

Key Pitfalls to Avoid

1. Misdiagnosis: Thorough clinical correlation is essential as imaging findings may not always correlate with symptoms. Up to 20-28% of asymptomatic individuals may have disc herniation on imaging 1.

2. Delayed Treatment: Cauda equina syndrome requires urgent MRI assessment and potential surgical intervention to prevent permanent neurological damage 1.

3. Over-reliance on Imaging: Clinical identification of affected nerve roots is as important as imaging findings for successful treatment outcomes 5.

4. Neglecting Red Flags: Symptoms suggesting malignancy, infection, or cauda equina syndrome require immediate evaluation and management 1.