Seated or Supine Straight Leg Raise Test: Does It Matter?
Low back pain can shoot down the leg, a symptom called sciatica. The cause of the leg pain is pressure on (or irritation of) the spinal nerve. The pressure usually comes from a protruding disc, bone spur, or other degenerative changes in the spine.
Any time a nerve is damaged or irritated in this way, the condition is called lumbar radiculopathy. Besides sciatica, radiculopathy can also be accompanied by numbness and tingling down the leg. Weakness and loss of sensation can occur. Deep tendon reflexes such as the patellar tendon reflex and the ankle jerk may be changed (increased, decreased, or absent).
One test used most often to test for lumbar radiculopathy is called the straight raise leg (SLR). This test can be done in the sitting position or with the patient lying down (supine). The examiner lifts the patient's leg to 90 degrees while keeping the knee straight.
Normally, the test movement causes the nerve to glide. A positive test occurs when the test causes or reproduces the patient's pain and other symptoms. The gliding nerve is pressed and pulled against the disc causing pain.
In this study, both test positions (sitting and supine) were compared for sensitivity and accuracy. How likely is it that the patient has a disc problem based on the SLR test? Does it matter if the patient is sitting up or lying down when the test is done?
All patients included had a positive MRI for lumbar disc herniation. The imaging was done before the two SLR tests were done. The results of testing showed that the supine SLR was a much better test of lumbar radiculopathy compared to the sitting test.
The authors caution anyone conducting SLR tests to be aware that the seated test may not detect the presence of lumbar radiculopathy when it's present. More studies are needed to compare these two test positions before suggesting we disband the seated test.
Alon Rabin, DPT, MS, et al. The Sensitivity of the Seated Straight-Leg Raise Test Compared with the Supine Straight-Leg Raise Test in Patients Presenting with Magnetic Resonance Imaging Evidence of Lumbar Nerve Root Compression. In Archives of Physical Medicine and Rehabilitation. July 2007. Vol. 88. No. 7. Pp. 840-843.