What is the sensitivity of the straight leg raise test for disk herniation?

• A. 0.91
• B. 0.72
• C. 0.58
• D. 0.35

Answer: (A)

The straight leg raise test is commonly used to assess for lumbar disc herniation and is a useful clinical tool in diagnosing sciatica. Sensitivity refers to the test's ability to correctly identify those with the condition (true positives). A sensitivity of 0.91 indicates a very high probability that patients with a disc herniation will have a positive result on the straight leg raise test.

In this specific context, a sensitivity of 0.91 means that the test correctly identifies 91% of patients who truly have a lumbar disc herniation. This high sensitivity makes it a reliable initial screening tool. The straight leg raise tests the integrity of the structures around the lumbar spine and the sciatic nerve, providing valuable information about the presence of nerve root tension, which can be affected by a herniated disc. When the nerve root is compressed by a herniated disc, raising the leg can elicit pain, confirming the diagnosis.

Other options present lower sensitivity values, which indicate a reduced rate of correctly identifying individuals with the condition. This lower sensitivity means that those options would not be as effective in confirming a diagnosis of disk herniation compared to the sensitivity associated with the straight leg raise test.