Special Tests: Lower Body Neurodynamic Tests

Special Tests Covered in this Lesson:

• Neurodynamic Tests
  • Straight Leg Raise Test (SLR) and Well Leg Raise Test
  • Slump Test
  • Femoral Nerve Neurodynamic Tests

Neurodynamic tests aid in ruling-out whether the sciatic nerve, femoral nerve, or dorsal nerve structures are involved in patient's complaints. Generally, these complaints are related to low back pain, and correlated with a diagnosis of a herniated disk, nerve root irritation, or lumbar radiculopathy. The straight leg raise test (SLR) (a.k.a. Lasègue’s sign) is likely the most often performed test, and is an indicator of sciatic nerve involvement. During the SLR, slump test, or femoral nerve test, hip and ankle joint actions may be used to aid in implicating specific nerves; for example, ankle dorsiflexion during the SLR may bias the test toward tibial nerve involvement. Additionally, pain on the opposite side of the low back or lower extremity during a lower extremity neurodynamic test, may be more indicative of hernatid disk. Note, the SLR also lengthens the hamstring and posterior thigh muscles, and it is common for patients to report SLR symptoms as "hamstring tightness." The most accurate neurodynamic tests have been included in this course, and lesser tests have been excluded. Clinical movement professionals (physical therapists, physical therapy assistants, chiropractors, occupational therapists, athletic trainers, etc.) should be aware of these tests, as their skillset is often the safest and most effective option for treating mild to moderate nerve irritation (e.g. manual therapy, certain modalities, and corrective exercise).

Summary:

The body of research regarding lower extremity nerve tension tests continues to grow; however, additional research is needed to answer clinically relevant questions. Studies have demonstrated the validity of these tests, but perhaps not the specificity. That is, neurodynamic testing results in the lengthening and gliding of nerves (22-25); however, more research is needed to demonstrate that each test results in the lengthening or gliding of the intended nerve.

Generally, neurodynamic tests have demonstrated higher sensitivity than specificity for related diagnoses (4 - 21, 29 - 31); however, a few studies imply specificity increases when various modifications are added to the Straight Leg Raise Test (SLR) (8-11, 17 - 21). More consideration needs to be given to what diagnoses are associated with a "positive test" (lumbar herniation, radiculopathy, neurogenic symptoms, etc.), as diagnoses vary between studies which contributes to the wide range of reported accuracies. Although a considerable number of studies have been performed on these tests, more research is needed to answer these key questions.

Brookbush Institute Recommendation:

The Brookbush Institute recommends that all clinical professionals (physical therapists, physical therapy assistants, chiropractors, occupational therapists, athletic trainers, etc.) are aware of these lower extremity neurodynamic tests. Because these tests demonstrate good sensitivity but do not provide information regarding the cause of symptoms, the Brookbush Institute recommends these tests are used as screens; that is, a negative test "rules-out" a nerve's involvement.

For an Introduction to Special Tests

• For an introduction to Special Tests including definitions of specific terminology, what special tests measure, accuracy (specificity, sensitivity, reliability, etc.), how we chose the tests in each special test course lessons, and best practice recommendations:
• Special Tests: Introduction

Courses covering Special Tests for the Lumbo Pelvic Hip Complex

• Special Tests: Sacroiliac Joint (SIJ)
• Special Tests: Hip Joint
• Special Tests: Lower Body Neurodynamic Tests