Clinical practice guidelines recommend clinicians use the passive straight leg raise (SLR) test to assist in detecting radicular pain in low back pain patients, while a positive crossed SLR may indicate pain secondary to a lumbar disc herniation. When performed, the SLR mechanically provokes irritated lumbosacral nerve roots, resulting in radicular pain. However, when performing the SLR, symptoms related to the irritation of non-neural tissues may also occur, and structural differentiation techniques are required to help distinguish symptoms arising from neural tissue vs non-neural tissue irritation.

 

Despite clinical practice guidelines recommending the use of SLR testing, systematic reviews suggest that the SLR performs poorly when diagnosing lumbar radicular pain. One possibility for this is insufficient reliability, which may contribute to inconsistent patient categorization and lead to inaccurate expectations about the management of these patients’ symptoms.