How should I evaluate and manage a patient with nerve root compression (e.g., from disc herniation, foraminal stenosis, tumor, or trauma)?

Evaluation and Management of Nerve Root Compression

MRI without IV contrast is the single best imaging modality for evaluating nerve root compression, correctly identifying the causative lesion in 88% of surgically confirmed cases—far superior to CT (50%), myelography (57%), or CT myelography (81%). 1, 2

Initial Clinical Assessment

Red Flag Symptoms Requiring Urgent Imaging

Do not delay imaging if any of the following are present: 1

• Trauma or prior spine surgery
• Malignancy (known or suspected)
• Infection risk: fever, IV drug use, elevated inflammatory markers (ESR, CRP, WBC)
• Progressive neurologic deficits or new-onset weakness
• Cauda equina symptoms: bowel/bladder dysfunction, saddle anesthesia
• Intractable pain despite conservative therapy
• Systemic disease: ankylosing spondylitis, inflammatory arthritis
• Vertebral body tenderness on palpation
• Autonomic instability: blood pressure fluctuations, syncope, sweating (suggests high cervical/thoracic cord compression) 3

When Conservative Management is Appropriate

Without red flags, most acute radiculopathy resolves spontaneously or with conservative treatment within 6 weeks. 1 Imaging is not required at initial presentation in these cases. 1

Proceed to imaging after 6 weeks if: 2

• Symptoms persist despite conservative therapy
• Patient is a surgical or interventional candidate
• New neurologic deficits develop

Imaging Algorithm

First-Line: MRI Without IV Contrast

Order MRI without IV contrast immediately for: 1, 3, 4, 2

• Cervical spine: suspected myelopathy, radiculopathy with red flags, or failed conservative therapy
• Lumbar spine: radiculopathy after 6 weeks conservative therapy, suspected cauda equina syndrome, or progressive neurologic deficits
• Thoracic spine: any suspected thoracic myelopathy (surgical emergency) 3

MRI protocol should include: 3, 4

• T2-weighted sequences (best for cord edema, disc herniation)
• Gradient-echo sequences (optimal for hematomas, bone fragments)
• Sagittal and axial planes with high spatial resolution

Image the entire spine when cord compression is suspected—20% of spine injuries have a second noncontiguous level. 3

When to Add IV Contrast to MRI

Add IV contrast only when: 4, 2

• Postoperative patients (distinguishes recurrent disc from scar/fibrosis) 1, 2
• Suspected infection (epidural abscess, discitis, osteomyelitis) 3, 4
• Known or suspected malignancy with new symptoms 3, 4
• Noncontrast MRI is nondiagnostic 2

Do not add contrast routinely for degenerative disease—it provides no benefit and increases cost/time. 4

Second-Line: CT Myelography

Use CT myelography when: 1, 4, 2

• MRI is contraindicated (non-MRI-safe implants, severe claustrophobia)
• MRI findings are equivocal or nondiagnostic 1, 2
• Significant metallic hardware artifact degrades MRI quality 1, 4
• Detailed visualization of lateral recess compression is needed 1, 2

CT myelography achieves 81% diagnostic accuracy for nerve root compression—superior to CT alone (50%) but inferior to MRI (88%). 4, 2

When CT Alone is Appropriate

Use CT without IV contrast for: 1, 4

• Acute trauma with suspected fracture (97% sensitivity for osseous fractures) 4
• Detailed bony anatomy for surgical planning (osteophytes, facet joints, uncovertebral joints) 1, 4
• Ossification of posterior longitudinal ligament (OPLL) assessment 4
• Postoperative fusion assessment 1

Critical pitfall: CT alone cannot exclude spinal cord pathology and is markedly inferior to MRI for soft-tissue evaluation. 3, 4 Never rely on CT alone when myelopathy is clinically suspected. 4

Plain Radiographs: Limited Role

Radiographs are inadequate for evaluating nerve root compression (only 49-62% sensitivity for thoracic fractures, 67-82% for lumbar). 3

Consider radiographs only for: 4

• Initial evaluation of chronic neck pain without neurologic deficits or red flags
• Screening for gross malalignment or instability
• Rheumatoid arthritis patients (though MRI is superior for odontoid erosions: 67.5% vs 12.5% for radiographs) 4

Management Considerations

Conservative Management

For patients without red flags, initiate: 1

• Physical therapy
• NSAIDs or acetaminophen
• Activity modification
• Reassess at 6 weeks

Surgical Referral Indications

Urgent neurosurgical consultation for: 3

• Cauda equina syndrome (bowel/bladder dysfunction)
• Progressive motor weakness despite conservative therapy
• Myelopathy with cord compression on imaging
• Autonomic instability with high cervical/thoracic compression 3

Elective surgical consideration after: 2

• 6 weeks of failed conservative therapy
• Persistent radiculopathy with MRI-confirmed nerve root compression
• Functional impairment affecting quality of life

Multidisciplinary Coordination

Pathologic fractures require coordination between interventional radiology, surgery, and radiation oncology. 3

Epidural abscess requires emergent MRI with contrast, neurosurgical consultation, and infectious disease involvement. 3

Critical Pitfalls to Avoid

1. Do not rely on physical examination alone: Physical exam tests correlate poorly with MRI evidence of cervical nerve root compression (high false-positive and false-negative rates). 1

2. Beware of imaging-clinical mismatch: Degenerative findings on MRI are common in asymptomatic patients >30 years old and correlate poorly with symptoms. 1, 2 The abnormal MRI level may not correspond to clinical examination findings. 2

3. Do not delay imaging for red flags: Progressive myelopathy with autonomic instability may require urgent surgical decompression. 3, 4

4. Do not use CT alone for suspected myelopathy: CT cannot visualize the spinal cord itself and misses 75% of ligamentous injuries and 100% of cord injuries detected by MRI. 3, 4

5. Consider extraforaminal pathology: Conventional axial and sagittal MRI may miss extraforaminal disc herniations—consider oblique sequences or 3D MR rendering if clinical suspicion is high despite negative standard imaging. 5, 6

6. Suspect conjoined nerve roots: If imaging shows a "disc herniation" but the patient presents with nerve root claudication (rather than typical radiculopathy) and minimal neurologic deficit, consider conjoined nerve root anomaly (5.8% incidence, mainly S1 and L5 levels). 7 Treatment requires laminectomy and foraminotomy, not simple discectomy. 7