Optimal Radiographic Views for Lumbar Radiculopathy
Standard anteroposterior (AP) and lateral standing radiographs of the lumbar spine are the appropriate initial plain film views when evaluating structural causes of radiculopathy, though radiographs alone have limited utility and should not delay or replace MRI when clinically indicated. 1, 2
Primary Imaging Recommendation
MRI lumbar spine without contrast is the gold standard and preferred first-line imaging modality for evaluating radiculopathy because it directly visualizes nerve roots, intervertebral discs, the thecal sac, and soft tissue pathology that plain radiographs cannot detect. 2, 3
- Plain radiographs are insensitive to the most common causes of radiculopathy including disc herniation, nerve root compression, and spinal canal stenosis 1, 2
- MRI provides superior soft-tissue contrast and precisely localizes intervertebral disc changes, neural foraminal narrowing, and ligamentum flavum thickening 2, 3
When to Obtain Plain Radiographs First
Obtain standing AP and lateral lumbar spine radiographs as initial screening when:
- Evaluating vertebral alignment, spinal curvature, and disc height as preliminary assessment 1
- Assessing for spondylolisthesis, which is best detected on standing lateral views 4
- Screening for primary bone tumors, fractures, or gross anatomic changes 1, 3
- Preoperative planning to evaluate segmental motion and functional alignment 2
Critical Radiographic Views and Their Utility
Standing Lateral View
- Standing lateral radiographs detect 40% of spondylolisthesis cases and show greater listhesis magnitude than supine views (6.5 mm vs 4.9 mm difference). 4
- This view is essential because all cases of stable spondylolisthesis ≥3 mm are detected on standing radiographs alone 4
Seated Lateral View
- Seated lateral radiographs perform equivalently to standing flexion views for detecting spondylolisthesis and show the greatest slip percentage (16.0%). 5
- This alternative view is particularly useful when standing flexion-extension views are difficult to obtain 5
Views to Avoid
- Oblique lumbar spine views should NOT be obtained—they double radiation dose without providing additional diagnostic information beyond standard AP and lateral views. 1
When Radiographs Are Insufficient
Plain radiographs should be bypassed entirely and proceed directly to MRI when:
- Red flag symptoms are present: cauda equina syndrome, progressive neurological deficits, suspected malignancy, infection, or significant trauma 2, 6
- Radicular symptoms persist beyond 6 weeks despite conservative management in a surgical candidate 2, 6
- Clinical examination reveals objective neurological deficits (motor weakness, reflex loss, sensory changes) 6
Common Clinical Pitfall
The most critical error is relying on plain radiographs alone to exclude significant pathology in radiculopathy patients—CT and plain films lack sufficient soft-tissue contrast to visualize most disc herniations and nerve root compressions that cause radicular symptoms. 2
- Up to 20-28% of asymptomatic individuals have disc herniations on MRI, so imaging findings must correlate with clinical presentation 2
- Normal radiographs do not exclude radiculopathy; MRI remains necessary when clinical suspicion is high 2
Alternative When MRI Is Unavailable
CT lumbar spine without contrast is an acceptable alternative when MRI is contraindicated (non-MRI-compatible implants, severe claustrophobia) or when delays exceed 2-4 weeks. 2