What is the name of the maneuver used to check for radiculopathy, characterized by a straightened knee and a curved forward torso and neck?

The Straight Leg Raise (SLR) Test is the Name of the Maneuver to Check for Radiculopathy

The Straight Leg Raise (SLR) test is the specific maneuver characterized by a straightened knee with curved forward torso and neck used to assess for radiculopathy, particularly lumbar radiculopathy.

Understanding the SLR Test

The SLR test is a neurodynamic test designed to place tension on the sciatic nerve roots and assess for radiculopathy. It involves the following components:

1. Patient positioning: The patient lies supine
2. Execution: The examiner lifts the patient's leg with the knee extended (straightened)
3. Positive finding: Reproduction of the patient's radicular pain, typically radiating down the leg
4. Variation: The test can be performed with the patient bending forward at the torso and neck to increase neural tension

Evidence Supporting SLR Test

Research has demonstrated that the SLR test has high specificity for detecting nerve root compression, particularly in lumbar disc herniations. According to Majlesi et al., the SLR test has a specificity of 0.89 in patients with lumbar disc herniations 1. This makes it particularly valuable for identifying patients who have herniations with root compression that may require surgical intervention.

Clinical Application and Interpretation

A positive SLR test occurs when:

• Pain radiates along the sciatic nerve distribution (posterior thigh, calf, foot)
• Pain is reproduced between 30-70 degrees of leg elevation
• Pain increases with ankle dorsiflexion (Bragard's sign)
• Pain is relieved with knee flexion

Related Tests for Radiculopathy Assessment

Slump Test

The Slump test is a variant of the SLR performed in the seated position and involves a progressive series of maneuvers:

• Patient sits with hands behind back
• Patient slumps forward (flexes spine)
• Examiner applies overpressure to maintain flexion
• Patient extends one knee
• Examiner dorsiflexes the ankle

The Slump test has higher sensitivity (0.84) compared to the SLR (0.52) but slightly lower specificity (0.83 vs 0.89) 1. It may be more useful as an initial screening tool due to its higher sensitivity.

Spurling Test (for Cervical Radiculopathy)

While the SLR primarily assesses lumbar radiculopathy, the Spurling test is used for cervical radiculopathy:

• Extension and lateral bending of the neck toward the affected side
• Application of axial compression
• Positive when radicular symptoms are reproduced

According to Shabat et al., the most effective variation of the Spurling test involves extension, lateral bending, and axial compression, which produces the highest pain scores and most distally elicited pain 2.

Diagnostic Accuracy Considerations

It's important to note that no single test has perfect diagnostic accuracy for radiculopathy:

• The SLR test is more specific than sensitive
• Combining multiple tests improves diagnostic accuracy
• Electrodiagnostic testing (EMG) complements physical examination with high specificity but modest sensitivity 3
• MRI is the most sensitive imaging test for detecting nerve root compression but should be correlated with clinical findings 4, 5

Potential Pitfalls

• False negatives may occur with the SLR test, particularly in higher lumbar radiculopathies (L1-L3)
• The test may be less accurate in chronic conditions
• Degenerative findings on imaging are common in asymptomatic individuals over 30 years of age and correlate poorly with neck pain 4, 5
• Overreliance on a single test may lead to misdiagnosis

The SLR test remains a cornerstone in the physical examination for suspected radiculopathy, particularly when combined with other neurodynamic tests and a thorough neurological examination.