Several aspects of your leg's strength and stability can be determined with a straight leg raise test (SLR). A doctor performs a straightforward leg test by lying the patient flat on a bed and raising their legs while adding light resistance. The purpose of conducting this test is to review muscle and nerve function to get a better picture of the leg's functionality.
This test is popular for patients who suffer lower back pain. Defining part of a patient's treatment strategy begins with a positive SLR result. Read on to discover some key elements of a straight leg raise test and common questions you should consider asking your physician.
What is a Straight Leg Raise Test?
A common test physicians use to identify impairments in disc pathology or lumbosacral nerve irritation, the Straight Leg Raise test or Lasegue test, is also crucial in detecting disc herniation and neural compression. This test can also be used for neurodynamic evaluation and to detect compression or tension on a nerve root. It is performed on people with lower back pain, and there are various conditions for a positive test.
Some of these reasons include:
- Facet joint cysts
- Lumbar disc herniation
This orthopedic examination test provides essential information to a physician who must decide if a patient should be referred to a specialist. When a physician attempts to determine whether your pain is nerve-related or mechanical (muscle and joint pain), this is often the first orthopedic test they perform and will help them determine the structures causing pain.
Before starting the test, expect your physician to ask you some questions, including when the pain began, how long you've had it, how you would describe it, and whether it's been getting worse or better. Answering these questions honestly and to the best of your ability will provide your physician with a basis to discover the potential cause of your pain. Although physicians typically perform this test on the patient as they're lying on their back, if this causes discomfort, you should talk to your doctor about changing positions.
Straight Leg Raise Test Technique: How the Test is Performed
While seated or lying down, your physician will check the range of motion on the unaffected side. Next, with your knee straightened, they will passively flex your hip. Both legs are tested individually, and as your physician slowly raises the leg on the side where you experience pain, be sure to advise them when you begin to feel any discomfort. Along with lifting your legs, your physician may ask you to extend your foot and flex your neck to stretch your nerve roots.
Some other tests used to test for lumbar radicular syndrome include:
- Slump Test
- Crossed Straight Leg Raise Test
- Bowstring Test
- Prone Knee Bending Test
A physician performs a crossed straight leg raise test the same way as a straight leg raise test, the only difference being that the test is only conducted on the unaffected leg. It is considered a positive result if symptoms are reproduced on the other leg while your doctor lifts the opposite leg. The test is negative when no symptoms are felt on the opposite leg.
During a seated straight leg raise test, your physician will have you sit on the exam table with your knees bent to 90 ° and slowly extend one of your knees from that starting point. Until you begin to feel pain, your doctor will continue to gently raise your knee until full extension is reached. Upon maximal extension, the test is negative if no pain is felt.
A reversed SLR test or prone knee bending test is often performed by your physician to check for possible neurological dysfunction in the lumbar spine. During this test, your doctor I'll ask you to lay on your stomach and then passively flex your knee as far as possible or until your heel rests against your buttock. A positive prone knee bending test suggests that you may be experiencing irritation of nerve roots L2-L3.
What to Do After a Positive Straight Leg Raise Test
Seeking care from your doctor if your SLR test is positive is recommended. Physical therapy or visiting a chiropractor can shorten your recovery time and decrease your chances of experiencing the same pain. If your doctor determines through the test that sciatica is the source of your pain, they will typically advise that you manage symptoms with relative rest and avoid or limit activities that may aggravate your condition.
A physician may prescribe pharmaceuticals or recommend spinal injections for patients with severe symptoms. When some are experiencing changes in bowel and bladder habits, surgery may be an option. However, most people diagnosed with sciatic often see an improvement in their symptoms in as little as six weeks with proper rest.
Straight Leg Raise Test Positive
The aim of adding modifications to this test is to stretch the sciatic nerve to find your source of pain and determine if a compressed or irritated nerve route is causing you to experience sciatic, spinal stenosis, or disc herniation. If doing this makes your pain worse or causes it to go away suddenly, it is generally considered a positive straight leg raise test. Additionally, apart from feeling tightness in your hamstring muscle, any pain you feel below your knee is considered a positive test. Your doctor will make note of the degree of hip flexion where you report pain. It is considered a positive result if you experience a reproduction of your regular symptoms between 30 and 70 degrees.
Straight Leg Raise Test Negative
A negative result may indicate to your physician that additional diagnostic is necessary to pinpoint the source of your pain. For instance, you may receive a non-positive result if you are only experiencing lower back pain and aren't experiencing any pain below your knee. With an SLR, your physician will be able to determine the best treatment for any conditions affecting the function of your quadriceps muscles or a nerve condition. Disruption of the patellar tendon, quadriceps tendon, or kneecaps may result in an inability to perform an SLR test.