Straight leg raise
The Straight leg raise also, called Lasègue sign or Lasègue test, is a test done during the physical examination to determine whether a patient with low back pain has an underlying herniated disk.
Technique
With the patient laying down on a table, the examiner lifts the patient's leg while the knee is straight.
Variations
If the examiner also dorsiflexes the foot, this is the Lasègue sign.
Another variation is to lift the leg while the patient is sitting.[1] However, in one study this reduces the sensitivity of the test from 67% to 41%.[2]
Another variation in the sitting position is the slump test.[3] In the Slump test:
- the patient sits looking straight ahead
- then is encouraged to slump in order to flex the thoracic and lumbar spines
- then fully flex the cervical spine, continuing to look straight ahead
- then the patient extends the leg at the knee
- then the examiner dorsiflexes the foot
In one study, the sensitivity of the Slump test was 84% and specificity was 83% while the [sensitivity and specificity|sensitivity]] of the SLR test was 52% with specificity of 89%.[3]
Interpretation
"The straight leg raise test is positive if pain in the sciatic distribution is reproduced between 30° and 70° passive flexion of the straight leg." [4]
A meta-analysis reported the accuracy is[5]:
- sensitivity 91%
- specificity 26%
If pain below the knee only occurs below the know after more than 70°, this may indicate "sciatic nerve compression outside the spinal canal."[3]
If the raising the opposite leg causes pain (cross straight leg raising):[5]
- sensitivity 29%
- specificity 88%
References
- ↑ Waddell G, McCulloch JA, Kummel E, Venner RM (1980). "Nonorganic physical signs in low-back pain". Spine 5 (2): 117-25. PMID 6446157. [e]
- ↑ Rabin A, Gerszten PC, Karausky P, Bunker CH, Potter DM, Welch WC (2007). "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". Archives of physical medicine and rehabilitation 88 (7): 840-3. DOI:10.1016/j.apmr.2007.04.016. PMID 17601462. Research Blogging.
- ↑ 3.0 3.1 3.2 Majlesi J, Togay H, Unalan H, Toprak S (April 2008). "The sensitivity and specificity of the Slump and the Straight Leg Raising tests in patients with lumbar disc herniation". J Clin Rheumatol 14 (2): 87–91. DOI:10.1097/RHU.0b013e31816b2f99. PMID 18391677. Research Blogging.
- ↑ Speed C (2004). "Low back pain". BMJ 328 (7448): 1119-21. DOI:10.1136/bmj.328.7448.1119. PMID 15130982. Research Blogging.
- ↑ 5.0 5.1 Devillé WL, van der Windt DA, Dzaferagić A, Bezemer PD, Bouter LM (2000). "The test of Lasègue: systematic review of the accuracy in diagnosing herniated discs". Spine 25 (9): 1140-7. PMID 10788860. [e]