1. Tyler Golden
MSAT 6502
Professor Donahue
February 2, 2015
Evidence Based Medicine for Low Back Nerve Pain
Low back pain can arise from many different sources and can cause radiating pain
down to the lower extremities. When these symptoms in can cause severe dysfunction
and decrease in quality of life for those afflicted. One of the issues with low back pain is
its causes are many making it difficult for some clinicians to create rehab programs
geared toward the specific needs of their patients. When it comes to back pain relating to
nerve-related pathologies clinicians can use two special tests to help differentiate pain
symptoms. Two tests that can be utilized are the straight leg raise (SLR) and slump test.
The purpose of this paper is to discuss the sensitivity and specificity of these tests and to
lay a foundation for their uses in clinical settings.
To understand back pain is to understand its anatomy and function in the body.
Clinicians need to be aware of the structures involved in the lumbar and sacroiliac
regions in order to provide relief to their patients. The spinal column is a collection of 24
individually segmented vertebrae that interact with each other to provide the body with a
dynamic foundation for the stresses placed upon it.1 The lumbar region of the spinal
column consists of five vertebral bodies with the fifth (L-5) interacting with the sacrum.
The sacrum begins as five segmented bones before fusing together as we grow to become

2. one solid bone. Besides its articulation with the L-5 vertebrae the sacrum also interacts
and articulates with the two iliac bones of the pelvis. It is at this sacroiliac joint where
patients will experience a variety of different low back pain symptoms.1 Another aspect
of the spinal anatomy is the intervertebral discs that separate the individual vertebral
bodies. Each of the discs contains a gelatinous core which is surrounded by a fibrous
tissue.1 Theses discs provide cushion against the shock that can be placed upon the body.
Strong ligaments help hold the vertebral bodies in place as the body performs dynamic
movements such as bending, twisting, and straightening motions.1 The reason for the
multiple stabilizing structures of the spine is because the spinal column houses the spinal
chord which helps transmits information from the brain to all aspects of the body. Nerve
roots arise from the spinal chord and pass by the vertebral bodies.1 Besides carrying
information out to the periphery of the body the dorsal horn of the spinal chord is where
sensations from the peripheral systems enter to make their way up to the higher
processing centers of the brain.1
The low back is subject to severe stresses due to its role of being a part of our core
as well allow pivot point for the flexible positions of bending and twisting. The low back
also acts as a base of a lever for the arms when we lift heavy objects.1 Poor lifting
techniques can exacerbate the issue causing further stress on the low back. The role of
the low back in athletics varies as well. Through explosive movements and contact sports
the low back is subject to high amount of stress, which is why injuries to the low back
can be debilitating. Because of this the causes of low back pain especially relating to
nerve symptoms need to be monitored closely. The causes of low back pain can range

3. from simple spasms and strains to more severe such as bulging discs and pinched nerves.1
The problem with low back pain though is over 70% is non-specific pain.1 This can make
it difficult for clinicians to decipher is the pain is secondary to a psychosocial factor or if
the pain is arising from a single issue such as a degenerated disc. Some of the most
intense low back pain stems from nerve related issues. Besides causing pain in the low
back affected nerves in the low back can have radiating pain to other areas in the body.
In older patients 4% of herniated discs cause pain in the low back as well as radiating
pain down the sciatic nerve.1 Another cause of nerve pain can be narrowing of the spinal
canal via arthritis.1 When this occurs it can pinch the nerve and send pain down the
buttocks. In the young athletes such issues as muscle imbalances, inflexibility, growth
spurts, and spondylolysis can cause low back pain.2 Clinicians can also see acute disc
herniation in young athletes but it occurs only around 11% of the time.2 When this
happens examination findings include decreased amount of flexion, reflexes in lower
extremity, and strength in the lower extremities.2
When examining low back pain it is important to take into account what the
patient activities of daily living are and monitor how and the timeline in which their
symptoms occurred. For example when examining young athletes clinicians need to be
aware of factors such as poor technique, over training, and rapid growth spurts.2 Some
symptoms of nerve pain during examination are inability to sit for 30 min, lower
extremity paraesthesia, and pain distal to the knee.3 The trouble with diagnosing low back
nerve-related pathologies is there is not a definitive gold standard test. Common tests
include X-rays and MRI’s but they are still not accurate enough in determining what is

4. causing the pain. Even though you are able to get a clear picture of the low back with an
MRI but have several issues including worsening of pain symptoms, claustrophobia and
they can be slightly too sensitive.1 One study used a clinical improvement after removing
the “pain generator” such as disc lesions, but an issue they had was with comorbidities’
that could have caused pain symptoms.4 Because of this clinicians should be able to use
two special tests in order to establish a baseline of symptoms and reevaluate after
interventions with same tests to look for improvement. Two tests that can be used are the
Slump test and straight leg raise.
The straight leg raise test (SLR) or sometimes referred to as the (ASLR) was test
that was originally developed for pregnant patients with pelvic pain.5 The function of the
test was to see if the patient’s sacroiliac joints could transfer weight from the pelvis and
legs.5 After a while clinicians began to examine its effectiveness is examining abnormal
neurological symptoms. The test consists of having the patient lay supine and actively
raise their leg to about 20cm while maintaining a neutral pelvis.5 Due to its new use
studies began to investigate certain factors such as inter-rater agreement, sensitivity,
specificity, and likelihood ratios in order to determine its effectiveness in non-pregnant
populations. One study that examined the ASLR found the test to have a high inter-rater
agreement and high specificity, but a low sensitivity score. The Kappa score for inter-
rater agreement was 0.76, sensitivity of .25 & .20 (for each examiner), and a specificity
of .84 and .86.5 This study concluded that even with the high inter-rater agreement and
specificity the issue of the low sensitivity cannot be overlooked. They concluded that
more study needs to be done to determine its clinical effectiveness.5 A second study

5. examined the SLR for examining sciatic nerve entrapment in the gluteal region.3 This
study used a wide range for the participants’ age, which allows for a good representation
of how effective this test can be for different populations. In their study the authors
found results similar to the other studies with a specificity rate .95, but a low sensitivity
rate .15.3 One of the reasons they had for the results they received with the SLR was the
SLR examines the movement of the sciatic nerve in the sagittal plane versus isolating its
entrapment.3 They concluded that for their study the SLR did not have enough diagnostic
value to help diagnose those with sciatic nerve entrapment.3 With so many different
studies using the SLR a systematic review was done in order to verify the diagnostic
value of the SLR. In order to be accepted the review only accepted articles that reported
pain only in order to gain better accuracy of the diagnostic value.6 They found their
results to be surprising and inconsistent.6 Looking at the studies reported the sensitivity
and specificity rates were varied by wide margins. Due to the issue of such wide ranging
findings the review concluded that when looking at pain as a positive finding the SLR is
not accurate diagnositically.6
Most nerve pain can be a result of physical abnormality from another structure, a
by-product of misalignment, or disc degeneration. Sometimes though there could be an
issue with the nerve itself. The Slump test is used during low back examinations to help
identify abnormalities in the neural tissue.7 The slump test is similar to other test such as
SLR and Lasegue’s test. In order to perform the special test the patient is first instructed
to sit at the edge of the table with the back straight, the first step then is to instruct the
patient to slump by letting their thoracic spine fall into flexion.7 After this the patient with

6. extend the knee and flex the hip (similar to a SLR), but the difference now is the patient
will dorsiflexion the foot creating increased tension on the neural tissue.7 If any one of
these points the patients reports radicular pain, the clinician can reverse the steps to see if
that is able to reduce the pain. Some studies believe that this test is much more effective
during an evaluation. One study found a sensitivity rate of 0.84 and a specificity rate of
0.83.7 This study also compared the Slump test to the SLR and concluded that the Slump
test more likely to be a better diagnostic evaluation tool than the SLR.7 Another study
found good results of a variation of the slump test called the slump knee bend test. They
reported having a sensitivity percent of 100%, specificity percent of 83%, and a
predictive positive value of 67%.8 It should be mentioned that their study did only have
16 patients that could help explain the overwhelming good results. A final study found a
high rate of inter-rater agreement for the slump test. They reported high reliability for the
agreement between to raters with a kappa score of 0.71.9 Due to this the authors believe
that the slump test is a good predictor of neural tissue mechanosensitivity.9
When it comes to low back pain the causes are many, from disc degeneration,
neural sheath abnormalities, and psychosocial issues clinicians may have trouble
diagnosis what the cause of the pain is. Two special tests used often, Slump test and
SLR, are two of the many that clinicians have available during an evaluation. After
looking at several studies that describe several factors of the tests I believe that these test
should be used during an evaluation. These two tests should be used in conjunction with
palpation of painful areas as well as neurological testing to help better identify the source
of back pain. Strength testing myotomes associated with the patient’s pain patterns

7. should also be performed to focus the clinician evaluation. Despite the low numbers in
sensitivity, especially with the SLR, the ease of performing these tests can help clinicians
formulate a plan for further treatments. It allows for a starting point to work from and
should be one tool in the toolbox for clinicians to use.
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3. Martin HD, Kivlan BR, Palmer IJ, Martin RL. Diagnostic accuracy of clinical tests
for sciatic nerve entrapment in the gluteal region. Knee Surg Sports Traumatol
Arthrosc Off J ESSKA. 2014;22(4):882-888. doi:10.1007/s00167-013-2758-7.
4. Carragee EJ, Lincoln T, Parmar VS, Alamin T. A gold standard evaluation of the
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5. Bruno PA, Millar DP, Goertzen DA. Inter-rater agreement, sensitivity, and specificity
of the prone hip extension test and active straight leg raise test. Chiropr Man Ther.
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diagnosis of lumbar disc herniation, lumbar radiculopathy, and/or sciatica: A
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DOI
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7. Majlesi J, Togay H, Ünalan H, Toprak S. The Sensitivity and Specificity of the Slump
and the Straight Leg Raising Tests in Patients With Lumbar Disc Herniation: JCR J
Clin Rheumatol. 2008;14(2):87-91. doi:10.1097/RHU.0b013e31816b2f99.
8. Trainor K, Pinnington M. Reliability and diagnostic validity of the slump knee bend
neurodynamic test for upper/mid lumbar nerve root compression: a pilot study.
Physiotherapy. 2011;97(1):59-64. doi:10.1016/j.physio.2010.05.004.
9. Walsh J, Hall T. Agreement and Correlation Between the Straight Leg Raise and
Slump Tests in Subjects With Leg Pain. J Manipulative Physiol Ther. 2009;32(3):
184-192. doi:10.1016/j.jmpt.2009.02.006.