II. Technique
- Perform in two positions (findings should be consistent in both positions)
- Supine Low Back Exam (flex hip toward 90 degrees)
- Sitting Low Back Exam (extend knee)
III. Interpretation: Criteria for positive test
- Sciatic Pain at 30 to 70 degrees
- Aggravation of pain with dorsiflexion of the foot
- Relief of pain by knee flexion
IV. Interpretation: What patient experiences
- Radiating pain into the legs
- Suggests radiculopathy
- Higher likelihood findings suggesting radiculopathy
- Excruciating Sciatica-like pain
- Pain occurs at 30 to 40 degrees of leg elevation
- Pain radiates into opposite leg (Crossed Straight Leg Raise)
- Indicates severe impingement
- Almost always is due to a large disk Herniation
V. Modifications
- Crossed leg testing (see efficacy below)
- Lasegue's Test
- Dorsiflex foot while performing Straight Leg Raise
- Slump Test
- Patient sits upright and then flexing at waist with head to knees, in slumped position
- Patient lifts leg
VI. Efficacy: Predicting Lumbar Disc Herniation
- Straight Leg Raise
- Test Sensitivity: 80-98%
- Test Specificity: 40-60%
- Positive Likelihood Ratio: 2.0
- Negative Likelihood Ratio: 0.2 to 0.5 (high Negative Predictive Value)
- Crossed Straight Leg Raise
- Test Sensitivity: Up to 35-43%
- Test Specificity: 90-98%
- Positive Likelihood Ratio: 3.5 to 4.3 (high Positive Predictive Value)
- Negative Likelihood Ratio: 0.72