O Teste de Lasegue: Indicações e Interpretação

The Lasegue Test: Indications for Performing the Test

The Lasegue test, also known as the straight leg raising test, is a widely used neurological assessment that seeks to identify lumbosacral nerve root irritation in patients with lower back pain. This test is commonly attributed to Dr. Charles Lasegue, although it was first described by Dr. Lazar Lazarevic in 1880. The Lasegue test is particularly valuable for detecting lumbar disc herniation, which is the most common cause of a positive test. Here are some indications for performing the Lasegue test:

1. Suspected Disc Herniation: The Lasegue test is primarily used to assess for lumbar disc herniation, which can cause radiculopathy (pain radiating down the leg). If a patient reports sciatic pain (radiculopathy) when the straight leg is raised between 30 and 70 degrees, the test is considered positive, and a herniated disk may be a possible cause of the pain.

2. Neurological Symptoms: Other neurological symptoms such as tingling, burning, or shooting pain along the leg may also indicate a positive Lasegue test result. This test is often used in conjunction with other neurodynamic tests to assess for lumbar radiculopathy or sciatica symptoms.

3. Crossed Straight Leg Raise Test: The crossed straight leg raise test is a variation of the Lasegue test that involves testing the unaffected leg while the patient reports symptoms on the affected side. This test is considered positive if symptoms are reproduced in the opposite leg.

4. Assessment of Functional Leg Strength: The Lasegue test can also be used to assess functional leg strength, particularly the rectus femoris element of the quadriceps. In this case, the test is performed actively by the patient, who raises their leg against resistance from the examiner.

While the Lasegue test is a valuable diagnostic tool, it is essential to consider other factors when interpreting the results. The test's sensitivity is reported to be 91%, but its specificity is relatively low at 26%. Additionally, the test's results can be influenced by factors such as age, gender, and the presence of comorbidities. As with any diagnostic test, the Lasegue test should be used as part of a comprehensive clinical evaluation and in conjunction with other diagnostic methods.