Straight Leg Raise Test (SLR test) : Several aspects of your leg’s strength and stability can be determined with a straight leg raise test (SLR). A doctor performs a straight leg raise 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.

The straight leg raise (SLR) test is a physical examination maneuver used by healthcare professionals, particularly in orthopedics and neurology, to assess the integrity of the lumbar nerve roots and the presence of sciatic nerve irritation or compression. The test primarily evaluates for signs of herniated discs, lumbar radiculopathy, and other lower back and leg-related conditions.

Dynamics of the Straight Leg Raise Test:

1. Patient Position: The patient typically lies down flat on their back on an examination table, with both legs fully extended.
2. Performance: The examiner slowly lifts one leg off the table while keeping the knee straight. The leg is raised until the patient experiences pain, or until the examiner detects resistance or limitation in the range of motion. The unaffected leg remains flat on the table during the test.
3. Findings: If raising the leg causes pain between 30 to 70 degrees of elevation, it suggests a positive SLR test, which may indicate irritation or compression of the sciatic nerve or its nerve roots. This pain may radiate from the lower back, through the buttock, and down the back of the leg.
4. Bilateral SLR Test: If the SLR is positive on one leg, the examiner may perform the test on the other leg as well to compare findings and gather more information about the patient’s condition.

History of the Straight Leg Raise Test: The straight leg raise test was first described by Lasègue in 1864, a French physician and one of the founders of modern neurology. The test was originally used to diagnose sciatica, a condition characterized by pain along the path of the sciatic nerve, which runs from the lower back down the back of each leg. Lasègue’s original description involved raising the leg while the patient was seated, and the test was later modified to the supine (lying down) position, as it is commonly performed today.

Since its introduction, the SLR test has become a valuable diagnostic tool in the assessment of various conditions affecting the lower back and the sciatic nerve. However, it is essential to note that the SLR test is not specific to a particular condition and is usually used in combination with other clinical tests and imaging studies to arrive at an accurate diagnosis. Additionally, it should be performed with care and within the limits of the patient’s tolerance to avoid exacerbating any existing conditions. Therefore, if you suspect any issues with your back or legs, it’s crucial to consult a healthcare professional for a comprehensive evaluation.

The Straight Leg Raise (SLR) test is a cornerstone in the field of orthopedics and neurology, aiding healthcare professionals in diagnosing various lower back and leg-related conditions. This simple yet effective diagnostic maneuver has a fascinating historical background, dating back to the 19th century. In this article, we will delve into the origins and evolution of the SLR test, highlighting its significance in modern medicine.

Origins of the SLR Test

The SLR test owes its inception to the pioneering work of a French physician named Charles Lasègue. In 1864, Dr. Lasègue introduced the test as part of his efforts to diagnose and understand sciatica—a condition characterized by pain along the path of the sciatic nerve. His early work with the seated version of the test involved raising the leg of the seated patient to determine the presence of pain or discomfort along the sciatic nerve.

The Shift to Supine Position

As medical knowledge advanced and the examination techniques improved, the SLR test underwent a significant transformation. The shift from a seated to a supine (lying down) position occurred during the late 19th and early 20th centuries. This change not only made the test more comfortable for patients but also allowed for better control and consistency during the examination.

Contributions of Joseph Babinski

Another notable figure in the development of the SLR test is the French neurologist Joseph Babinski (1857-1932). Babinski expanded on Lasègue’s work and introduced what is now commonly known as the Babinski sign or response. This neurologic phenomenon involves the upward movement of the big toe and fanning of the other toes in response to stroking the sole of the foot. The Babinski sign is often used in conjunction with the SLR test to assess spinal and neurological conditions.

Diagnostic Significance

Throughout the 20th century, the SLR test gained recognition as a valuable diagnostic tool, helping healthcare professionals identify the underlying causes of lower back pain and leg discomfort. By observing the patient’s pain threshold during leg elevation, doctors can assess the presence of herniated discs, lumbar radiculopathy, and other conditions related to the lumbar nerve roots.

Limitations and Advancements

While the SLR test has undoubtedly stood the test of time, it is not without its limitations. Its specificity in diagnosing a particular condition remains relatively low. In response to this, medical researchers and clinicians have continued to refine and improve the test’s diagnostic accuracy.

Modern imaging technologies, such as magnetic resonance imaging (MRI) and computed tomography (CT), now provide complementary information to the SLR test, allowing for a more comprehensive assessment of the patient’s condition. Additionally, a combination of other clinical tests, such as the Braggard test and the Bowstring test, are often employed alongside the SLR test to enhance diagnostic reliability.

Some of the key applications of the SLR test

The Straight Leg Raise (SLR) test is a valuable component of the medical assessment in various clinical settings, particularly in orthopedics, neurology, and physical therapy. Its primary use lies in evaluating conditions affecting the lower back and legs, with a focus on lumbar nerve roots and the sciatic nerve. Below are some of the key applications of the SLR test in medical assessment:

1. Diagnosing Lumbar Radiculopathy: Lumbar radiculopathy is a condition where the nerve roots exiting the lumbar spine are irritated or compressed, causing pain, weakness, and sensory changes in the legs. The SLR test is one of the main tests used to assess for the presence of lumbar radiculopathy. A positive SLR test (reproduction of leg pain between 30 to 70 degrees of elevation) may suggest nerve root irritation or compression.
2. Identifying Herniated Discs: Herniated discs occur when the soft center of a spinal disc pushes through a crack in the tougher exterior casing, potentially impinging on nearby nerves. The SLR test can provide clues to the presence of herniated discs, as the elevation of the leg might aggravate pain caused by nerve compression.
3. Assessing Sciatica: Sciatica refers to pain that radiates along the path of the sciatic nerve, which runs from the lower back through the buttocks and down the back of each leg. The SLR test is a valuable tool in identifying or ruling out sciatic nerve involvement in cases of lower back and leg pain.
4. Monitoring Nerve Impairment: The SLR test allows healthcare professionals to monitor the severity of nerve impairment or compression over time. By comparing the patient’s pain response during subsequent examinations, practitioners can gauge the progression or improvement of the condition.
5. Differentiating between Causes of Lower Back Pain: Lower back pain can arise from various sources, including muscular strain, joint dysfunction, or nerve-related issues. The SLR test, in conjunction with other clinical assessments, can help differentiate between these potential causes, guiding treatment planning accordingly.
6. Physical Therapy and Rehabilitation: Physical therapists use the SLR test to evaluate a patient’s baseline functional status and monitor their progress during rehabilitation. It assists in determining appropriate exercise regimens and assessing the patient’s response to therapy.
7. Screening for Neurological Dysfunction: The SLR test is an essential component of a comprehensive neurological examination. Abnormal findings may prompt further neurological investigations to diagnose and treat underlying conditions.
8. Preoperative Assessment: In cases where surgery is being considered to address lower back or leg issues, the SLR test provides crucial preoperative data. It helps surgeons understand the extent of nerve involvement and contributes to treatment planning.

It’s important to note that the SLR test should be performed carefully and gently to avoid exacerbating any existing conditions or causing unnecessary discomfort to the patient. As with any medical assessment, the SLR test is best utilized as part of a comprehensive evaluation, along with a thorough patient history, physical examination, and potentially other diagnostic imaging or tests, to arrive at an accurate diagnosis and appropriate treatment plan.

Introduction

The Straight Leg Raise (SLR) test is a simple yet valuable physical examination technique used by healthcare professionals to evaluate lower back and leg pain. This test provides important diagnostic information, helping to identify the presence of nerve root irritation or compression in the lumbar spine. In this blog post, we will explore the application of the Straight Leg Raise test, its significance, and provide a few examples to better understand its practical use.

Understanding the Straight Leg Raise Test

The Straight Leg Raise test involves raising one leg at a time while the patient is lying flat on their back. The examiner gently lifts the leg, keeping the knee straight, until the patient experiences pain or discomfort. The angle at which pain occurs is noted, and this information can be crucial in diagnosing the underlying cause of the patient’s symptoms.

Anatomy and Physiology of SLR test

The Straight Leg Raise (SLR) test is closely related to the anatomy and physiology of the lumbar spine, nerve roots, and the sciatic nerve. Understanding the relevant anatomical structures and their physiological implications is crucial for interpreting the test results and diagnosing conditions related to the lower back and legs. Let’s explore the key anatomy and physiology related to the SLR test:

Anatomy:

1. Lumbar Spine: The lumbar spine consists of five vertebrae (L1 to L5) located in the lower back. The intervertebral discs between these vertebrae act as shock absorbers and facilitate movement in the spine.
2. Nerve Roots: Emerging from the spinal cord, the lumbar nerve roots are responsible for transmitting sensory and motor information between the lower extremities and the central nervous system. These nerve roots exit the spinal cord through small openings on the sides of the vertebrae called intervertebral foramina.
3. Sciatic Nerve: The sciatic nerve is the largest and longest nerve in the body. It is formed by nerve roots from the lumbar spine (L4 to S3) and continues down the back of each leg. The sciatic nerve provides motor control and sensation to the muscles and skin on the back of the thigh, leg, and foot.

Physiology:

1. Neural Tension: During the SLR test, as the leg is raised, tension is applied to the sciatic nerve and its lumbar nerve roots. This tension is transmitted along the entire length of the nerve, from the lumbar spine down to the leg. If there is any irritation, inflammation, or compression along the nerve’s pathway, it may cause pain, tingling, or numbness, which is observed during the test.
2. Nerve Irritation and Compression: Various conditions, such as herniated discs, spinal stenosis (narrowing of the spinal canal), and foraminal stenosis (narrowing of the intervertebral foramina), can lead to nerve irritation or compression. These conditions can be identified by the SLR test when raising the leg reproduces symptoms or pain due to the increased pressure on the affected nerve roots or the sciatic nerve.
3. Disc Herniation: The intervertebral discs, located between the vertebrae, consist of a tough outer layer called the annulus fibrosus and a gel-like inner core called the nucleus pulposus. If the annulus fibrosus weakens or tears, the nucleus pulposus can bulge or herniate out of its normal position, potentially compressing nearby nerve roots or the sciatic nerve.
4. Radiculopathy: Radiculopathy refers to the symptoms that arise from the irritation or compression of a nerve root. In lumbar radiculopathy, the SLR test is particularly useful as it can provoke pain or symptoms associated with specific nerve roots, aiding in the diagnosis and localization of the condition.

Application of the Straight Leg Raise Test

1 ) Evaluating Lumbar Disc Herniation

One of the primary applications of the SLR test is assessing for lumbar disc herniation. When the sciatic nerve or its root is compressed or irritated due to a herniated disc, raising the leg will cause pain. The point at which pain is felt and the reproduction of the patient’s symptoms can indicate the level and location of the herniation.

2) Assessing Nerve Root Irritation

The SLR test can also help identify nerve root irritation caused by conditions such as spinal stenosis or spondylolisthesis. By reproducing pain in a specific leg position, the examiner can determine which nerve root is affected, aiding in the diagnosis and subsequent treatment planning.

3) Monitoring Progress and Treatment Effectiveness

The SLR test can be used as an objective measure to monitor a patient’s progress and the effectiveness of treatment. By comparing the range of motion and pain response before and after interventions such as physical therapy, spinal manipulation, or surgery, healthcare professionals can gauge improvements or the need for alternative approaches.

Examples of the Straight Leg Raise Test

Example 1: A 45-year-old patient complains of severe lower back pain radiating down the back of the leg. The SLR test is performed, and at an angle of 45 degrees, the patient experiences significant pain. Based on this finding, the healthcare provider suspects a lumbar disc herniation and orders further imaging studies to confirm the diagnosis.

Example 2: A 60-year-old individual presents with symptoms of numbness and tingling in the leg. The SLR test is performed, causing pain and paresthesia at 30 degrees. The test suggests nerve root irritation, leading the healthcare professional to suspect lumbar spinal stenosis. Subsequently, appropriate treatment options can be discussed.

The Straight Leg Raise test is a valuable tool in the diagnostic process for lower back and leg pain. By reproducing symptoms and assessing the range at which pain occurs, healthcare professionals can pinpoint the underlying cause and tailor treatment plans accordingly. From identifying lumbar disc herniation to evaluating nerve root irritation, the SLR test plays a crucial role in the management of various musculoskeletal conditions. As with any diagnostic tool, proper interpretation and integration with the patient’s clinical history and other examination findings are essential to reach an accurate diagnosis and provide optimal care.

The Straight Leg Raise (SLR) test, also known as the Lasègue test, has a rich history and has undergone modifications over time to enhance its diagnostic utility. It was first described by a French physician, Charles Lasègue, in 1864, as a means of assessing sciatic nerve irritation. Since then, the test has become an integral part of the physical examination for patients presenting with lower back and leg pain.

Differential Diagnosis which can be possible through slr test

The Straight Leg Raise (SLR) test is a valuable clinical tool that can help healthcare professionals narrow down the differential diagnosis for various conditions affecting the lower back and legs. By observing the patient’s pain response during leg elevation, doctors can gain insights into the possible underlying causes of their symptoms. Below are some of the conditions that can be considered in the differential diagnosis based on the SLR test results:

1. Lumbar Radiculopathy: Radiculopathy refers to the irritation or compression of a nerve root as it exits the spine. A positive SLR test, with reproduction of leg pain between 30 to 70 degrees of elevation, suggests the possibility of lumbar radiculopathy. The specific nerve root involved can be inferred from the side of leg pain reproduction.
2. Lumbar Disc Herniation: Herniation of an intervertebral disc, particularly in the lumbar region, can lead to nerve root compression. The SLR test can provoke pain or symptoms due to the increased pressure on the affected nerve root when the leg is raised.
3. Sciatica: Sciatica is a condition characterized by pain that radiates along the path of the sciatic nerve, which runs from the lower back through the buttocks and down the back of each leg. A positive SLR test, with pain radiating down the back of the leg, can suggest sciatic nerve involvement.
4. Lumbar Spinal Stenosis: Spinal stenosis is a narrowing of the spinal canal, leading to compression of the spinal cord or nerve roots. The SLR test can provoke symptoms in patients with lumbar spinal stenosis.
5. Piriformis Syndrome: The piriformis muscle, located in the buttock, can irritate or compress the sciatic nerve. The SLR test, along with other clinical tests, can help differentiate between piriformis syndrome and other causes of sciatica.
6. Sacroiliac Joint Dysfunction: Dysfunction or inflammation of the sacroiliac joint, which connects the sacrum to the ilium bones of the pelvis, can cause lower back and leg pain. The SLR test may be used to help rule out or implicate the sacroiliac joint as a source of symptoms.
7. Muscle Strain or Spasm: Muscular issues in the lower back or buttock region can also cause pain during the SLR test. However, these issues usually do not cause specific radiating pain patterns down the leg like nerve-related conditions.
8. Hip Pathologies: In some cases, hip joint problems, such as hip osteoarthritis or labral tears, can refer pain to the thigh or buttock region, which might be mistaken for lower back or sciatic nerve-related pain.

It is essential to note that the SLR test is not specific to a single condition and should be used in conjunction with other clinical assessments, patient history, and imaging studies to arrive at an accurate diagnosis. Additionally, the test should be performed with care and within the patient’s tolerance to avoid exacerbating any existing conditions. Therefore, a comprehensive evaluation by a healthcare professional is necessary to determine the appropriate diagnosis and treatment plan based on the patient’s specific symptoms and clinical findings.

when to use slr test ?

The Straight Leg Raise (SLR) test is a valuable diagnostic maneuver that can be used in various clinical scenarios to help assess and identify conditions affecting the lower back and legs. Healthcare professionals, particularly those in orthopedics, neurology, and physical therapy, may utilize the SLR test in the following situations:

1. Evaluation of Lower Back Pain: The SLR test can be employed as part of a comprehensive assessment to determine the cause of lower back pain. It helps differentiate between nerve-related issues, such as lumbar radiculopathy or sciatica, and musculoskeletal causes like muscle strains or joint dysfunction.
2. Suspected Lumbar Radiculopathy: When patients present with symptoms such as radiating pain, tingling, or numbness in the legs, the SLR test can be used to assess the involvement of specific nerve roots in the lumbar spine.
3. Sciatica Assessment: The SLR test is valuable in evaluating patients with sciatica, a condition characterized by pain along the sciatic nerve’s distribution. It helps determine if the sciatic nerve is involved and, if so, which nerve root may be affected.
4. Preoperative Screening: Before considering surgery for conditions like disc herniation or spinal stenosis, the SLR test can aid in assessing the extent of nerve involvement and guiding treatment decisions.
5. Monitoring Progression: For patients undergoing physical therapy or conservative management for lower back or leg-related issues, the SLR test can be used to track progress and determine the effectiveness of the treatment plan.
6. Differential Diagnosis: When the cause of lower back or leg symptoms is unclear, the SLR test, along with other clinical assessments, can help narrow down the potential differential diagnosis, guiding further investigations or referrals if needed.
7. Identifying Nerve Impairment: The SLR test is useful in identifying nerve impairment, such as nerve root compression, which may be caused by conditions like disc herniation or spinal stenosis.
8. Pre-employment or Sports Assessments: The SLR test can be used in pre-employment or sports evaluations to assess an individual’s physical fitness and detect any pre-existing lower back or leg issues that may impact their performance or job requirements.

It’s essential to perform the SLR test with care and within the patient’s tolerance, especially in cases where there may be suspected nerve compression. Additionally, the SLR test should be interpreted in conjunction with other clinical findings, patient history, and potentially imaging studies to arrive at an accurate diagnosis and treatment plan.

Overall, the SLR test is a valuable tool in the medical assessment of lower back and leg-related conditions, aiding healthcare professionals in providing appropriate care and management for their patients.

Original Straight Leg Raise Test

In its original form, the SLR test involved the patient lying supine while the examiner raised the patient’s leg with the knee extended. Pain experienced by the patient during leg elevation was used as an indicator of nerve root compression or irritation. The angle at which pain occurred was noted, and this information aided in determining the severity and location of the underlying pathology.

Modifications of the Straight Leg Raise Test

Over time, modifications to the SLR test have been introduced to enhance its diagnostic accuracy and minimize patient discomfort. Some of the notable modifications include:

1. Passive Straight Leg Raise Test: This modification involves the examiner performing the leg elevation, allowing for better control of the movement and reducing variability. It also allows the examiner to assess the range of motion and observe any associated signs such as muscle tension or reflex changes.
2. Active Straight Leg Raise Test: In this variation, the patient actively raises their leg with the knee extended, without assistance from the examiner. This modification helps assess the patient’s ability to generate force and reproduces symptoms in a more functional context.
3. Slump Test: The slump test is a modification of the SLR test that incorporates cervical spine flexion. The patient sits with their legs hanging off the edge of a table and slumps forward, flexing the thoracic and lumbar spine. Then, the examiner performs the SLR while maintaining the slump position. This modification allows for the evaluation of neurodynamic mobility and can be helpful in identifying neural tension originating from the cervical or thoracic spine.
4. Modified SLR Test with Dorsiflexion: This variation involves combining ankle dorsiflexion with the SLR. The examiner elevates the patient’s leg while simultaneously dorsiflexing the ankle, which places additional tension on the sciatic nerve. This modification can be useful in differentiating between sciatic nerve and hamstring tightness as the source of pain.
5. Well-leg Raise Test: This modification is performed by elevating the asymptomatic leg while keeping the affected leg extended on the table. It helps differentiate between true sciatic nerve irritation and non-specific pain due to muscle strain or other causes.

These modifications allow for a more comprehensive evaluation of neurogenic pain and help differentiate between various sources of lower back and leg pain. They provide additional information for healthcare professionals to arrive at a more accurate diagnosis and develop targeted treatment plans.

The Straight Leg Raise test has evolved since its inception, with various modifications introduced to enhance its diagnostic accuracy and clinical utility. From passive and active variations to incorporating cervical spine flexion or ankle dorsiflexion, these modifications allow for a more thorough evaluation of neurogenic pain and provide valuable information for diagnosis and treatment planning. By utilizing the appropriate modification of the SLR test, healthcare professionals can gain insights into the underlying pathology and deliver effective care to patients presenting with lower back and leg pain.

Modifications to the Straight Leg Raise test can be used to stress different peripheral nerves to a greater degree; these are referred to as SLR tests with a particular nerve bias.SLR test and its Modifications[17]

Also read : Upper Limb Tension Test

Background

The Straight Leg Raise (SLR) test is commonly used to identify disc pathology or nerve root irritation, as it mechanically stresses lumbosacral nerve roots. It also has specific importance in detectingdisc herniationand neural compression.^[1][2][3]It is also classified as a neurodynamic evaluation test as it can detect excessive nerve root tension^[4]or compression^[5]. This test is attributed to Dr. Charles Laseague, and referred to as Laseagues test. However, it is believed that Dr. Lazar Lazarevic was the first to establish this test^[6].

This test places tensile stresses on thesciatic nerveand of traction at the lumbosacral nerve roots primarily from L4 to S2. During the SLR, these nerve roots are pushed anteriorly and inferiorly, pulling the dura mater caudally, laterally and anteriorly. Tension in the sciatic nerve occurs sequentially as it pulls the sciatic foramen, then the sacrum and then the nerves that cross over the pedicles and finally the intervertebral foramen. Pain or tenderness is often localised in the vicinity of the greater sciatic notch.^[7][8][9]

Image: Overview of the sciatic nerve and its branches^[10]

Clinical Application

Most clinical practice guidelines suggest the SLR test as an assessment to identify radicular pain or radiculopathy^[11]. However, there is low level evidence that the SLR test can detect radiculopathy^[12]. The SLR test is more sensitive than specific, hence useful for ruling out lumbo-sacral radiculopathy^[13]. Adding structural differentiation (e.g., neck flexion, ankle dorsiflexion, hip adduction) improves the reliability of the SLR test to at least a moderate level, and is recommended in clinical practice^[11].

Technique

The classic straight leg raise is performed passively. Each leg is tested individually with the unaffected leg being tested first.^[2]When performing the SLR test, the patient is positioned in supine without a pillow under their head, the clinician stands at the tested side with their distal hand around the patient’s heel and proximal hand on patient’s distal thigh(anterior) to maintain knee extension. The clinician lifts the patient’s leg by the posterior ankle while keeping the knee in a fully extended position. The clinician continues to lift the patient’s leg slowly through flexing at the hip, until the patient’s symptoms are replicated, or they experience tightness in the back or posterior thigh.^[2][14]

When pain occurs, examiner ceases hip flexion and notes the ROM and the area of pain^[5]. The ROM for the affected leg can be compared to the unaffected leg and used as an outcome measure. It should however be noted that the inter-rater reliability for this is low^[11].

Interpretation & Reasoning

• A true positive SLR test should include^[5]:
  • Radicular leg pain (symptoms below the knee).
  • Pain occurs when hip is flexed at 30 and 60 or 70 degrees from horizontal. Neurological pain which is reproduced in the leg and lower back between 30-70 degrees of hip flexion is suggestive of lumbar disc herniation at the L4-S1 nerve roots^[15]
• Pain at greater than 70 degrees of hip flexion might indicate tightness of the hamstrings, gluteus maximus, or hip capsule, or pathology of the hip or sacroiliac joints^[5].
• If symptoms are primarily back pain, it is most likely the result of a disc herniation applying pressure on the anterior theca of the spinal cord, or the pathology causing the pressure is more central. “Back pain only” patients who have a disc prolapse have smaller, more central prolapses.^[2]
• If pain is primarily in the leg, it is more likely that the pathology causing the pressure on neurological tissue(s) is more lateral.^[2]
• Disc herniations or pathology causing pressure between the two extremes are more likely to cause pain in both areas.^[2]
• Nerve root irritation such as facet joint cysts or hypertrophy can also cause the SLR test to be positive^[6]. Other causes of a positive SLR test include intraspinal tumor and inflammatory radiculopathy^[16].

Sensitising Maneuvers

Sensitising maneuvers are performed to confirm neural tissue as the source of patient’s symptoms, by increasing load on neural tissue without changing load on non-neural tissue. After the elicitation of symptoms, the examiner can slowly and carefully lower the leg until the patient no longer feels pain or tightness. Next, either the patient is asked to bring his or her chin to the chest, or the examiner may passively dorsiflex the patient’s foot, or both actions may be done simultaneously; however, foot dorsiflexion is most commonly performed first. Both maneuvers are considered to be provocative or sensitising tests for neurological tissue.

Pain that increases with neck flexion or foot dorsiflexion or both indicates stretching of the dura mater of the spinal cord or a lesion within the spinal cord (e.g. disc herniation, tumor, or meningitis)^[2]

Pain that does not increase with neck flexion may indicate a lesion in the hamstring area (tight hamstrings) or in the lumbosacral or sacro-iliac joint.

• Inclusion of neck flexion in the SLR is documented asHyndman’s sign, Brudzinski’s Sign, Linder’s Sign, or the Soto-Hall test.
• Inclusion of ankle dorsiflexion in the SLR is documented asLasegue’s test or Bragard’s test.
• Inclusion of great toe extension in the SLR (instead of ankle dorsiflexion) is documented asSicard’s Test.

Modifications

Modifications to the Straight Leg Raise test can be used to stress different peripheral nerves to a greater degree; these are referred to as SLR tests with a particular nerve bias.

SLR test and its Modifications^[17]

SLR for hamstrings length assessments:

Subject is positioned in supine. Therapist grasps the ankle and lifts the leg straight up, using the other hand to stabilise the same side anterior superior iliac spine. If the leg cannot be raised beyond 80 degrees, the hamstrings are considered tight.

Evidence

1. A cross-sectional study by Boyd and Villa (2012)^[18]examined normal asymmetries between limbs in healthy, asymptomatic individuals during SLR testing and the relationship of various demographic characteristics. The authors concluded that overall range of motion during SLR was related to sex, weight, BMI and activity level, which is likely reflected in the high variability documented. We can be 95% confident that inter-limb differences during SLR neurodynamic testing fall below 11 degrees in 90% of the general population of healthy individuals. In addition, inter-limb differences were not affected by demographic factors and thus may be a more valuable comparison for test interpretation.
2. Rabin et al. has shown sensitivity of the SLR test to be .67^[19], while Deville et al. found the specificity to be .26^[20].
3. A systematic review of the clinical utility of SLR by Scaia V, Baxter D and Cook C (2012) investigated the diagnostic accuracy of a finding of pain during the straight leg raise test for lumbar disc herniation, lumbar radiculopathy, and/or sciatica. The authors concluded that variability in reference standard may partly explain the inconsistencies in the diagnostic accuracy findings. Further, pain that is not specific to lumbar radiculopathy, such as that associated with hamstring tightness, may also lead to false positives for the SLR; and may inflate the sensitivity of the test.
4. Diagnostic Test accuracy review (Cochrane Meta analysis)^[21]assessed the performance of tests performed during physical examination (alone or in combination) to identify radiculopathy due to lower lumbar disc herniation in patients with low-back pain and sciatica. The review included 16 cohort studies (median N = 126, range 71 to 2504) and three case control studies (38 to100 cases). Only one study was carried out in a primary care population.Most studies assessed the Straight Leg Raising (SLR) test. In surgical populations, characterized by a high prevalence of disc herniation (58% to 98%), the SLR showed high sensitivity (pooled estimate 0.92, 95% CI: 0.87 to 0.95) with widely varying specificity (0.10 to 1.00, pooled estimate 0.28, 95% CI: 0.18 to 0.40). Results of studies using imaging showed more heterogeneity and poorer sensitivity.The crossed SLR showed high specificity (pooled estimate 0.90, 95% CI: 0.85 to 0.94) with consistently low sensitivity (pooled estimate 0.28, 95% CI: 0.22 to 0.35).Combining positive test results increased the specificity of physical tests, but few studies presented data on test combinations.The authors of the meta analysis conclude that when used in isolation, current evidence indicates poor diagnostic performance of most physical tests used to identify lumbar disc herniation. However, most findings arise from surgical populations and may not apply to primary care or non-selected populations. Better performance may be obtained when tests are combined.

Case Study: Diagnosing Lumbar Disc Herniation Using the Straight Leg Raise Test

Patient Profile:

• Name: John
• Age: 35
• Occupation: Office worker
• Chief Complaint: Severe lower back pain with radiating pain down the back of the right leg
• Background:

John, a 35-year-old office worker, presents to a healthcare clinic with a chief complaint of severe lower back pain that has been radiating down the back of his right leg for the past week. The pain is accompanied by numbness and tingling sensations in the right leg, making it difficult for John to perform his daily activities. The pain started after he lifted a heavy object at work.

Assessment:

The healthcare provider performs a comprehensive physical examination to assess John’s condition. Upon inspection, no visible signs of trauma or inflammation are observed in the lower back region. Sensory testing reveals diminished sensation along the right L5 dermatome. Deep tendon reflexes and muscle strength are normal in both lower extremities.

Straight Leg Raise Test:

To further evaluate John’s symptoms, the healthcare provider decides to perform the Straight Leg Raise (SLR) test. With John lying flat on his back, the provider gently raises his right leg while keeping the knee extended. As the leg is elevated, John experiences severe pain that radiates down the back of his right leg. The pain intensifies at approximately 45 degrees of elevation, and he requests the provider to stop the test due to the discomfort.

Interpretation and Diagnosis:

Based on the findings of the SLR test, the healthcare provider suspects the presence of a lumbar disc herniation. The reproduction of leg pain during the SLR test suggests compression or irritation of the sciatic nerve or its root, commonly associated with disc herniation. The point at which pain occurs during leg elevation can provide valuable information about the level and location of the herniation.

Further Evaluation and Management:

To confirm the diagnosis, the healthcare provider orders additional imaging studies, such as an MRI or CT scan, to visualize the lumbar spine and identify the exact location and extent of the disc herniation. The results of the imaging studies will help guide the subsequent management plan, which may include a combination of conservative treatments such as pain medications, physical therapy, and activity modifications.

Follow-Up and Progress:

Over the next few weeks, John undergoes physical therapy sessions aimed at reducing pain, improving flexibility, and strengthening the muscles supporting the spine. The healthcare provider periodically reevaluates John’s progress by performing the SLR test during follow-up appointments. With each session, John reports a gradual decrease in leg pain during the SLR test and improvement in his ability to perform daily activities.

Conclusion:

In this case study, the Straight Leg Raise test played a crucial role in the diagnosis of a lumbar disc herniation in a patient presenting with lower back pain and radiating leg pain. The positive SLR test, characterized by the reproduction of leg pain during leg elevation, raised suspicion of sciatic nerve compression or irritation. The subsequent imaging studies and management plan were guided by the findings of the SLR test. Regular reevaluation using the SLR test helped monitor John’s progress and gauge the effectiveness of his treatment, allowing for tailored interventions and improved patient outcomes.

Example of SLR Test

The Straight Leg Raise (SLR) test is a valuable tool in assessing and diagnosing lumbar radiculopathy, a condition characterized by the compression or irritation of spinal nerve roots in the lumbar region. Here’s how the SLR test is used in evaluating lumbar radiculopathy:

1. Diagnostic Tool: The SLR test is commonly employed to help diagnose lumbar radiculopathy. During the test, the healthcare provider gently raises the patient’s leg with the knee extended while the patient is lying on their back. If the patient experiences pain that radiates down the leg, it suggests the involvement of the affected spinal nerve root. The specific angle at which the pain occurs can provide insights into the level and location of the radiculopathy.
2. Differentiating Radicular Pain: The SLR test helps distinguish between radicular pain (caused by nerve root compression or irritation) and non-specific lower back pain. Radicular pain typically increases during leg elevation due to mechanical stress on the affected nerve root. On the other hand, non-specific pain is less likely to be affected by leg positioning. Differentiating between these types of pain is crucial for accurate diagnosis and appropriate treatment planning.
3. Assessing Severity and Provoking Factors: The SLR test provides valuable information about the severity of lumbar radiculopathy. The degree of leg elevation required to elicit pain can indicate the extent of nerve root involvement. Additionally, the test can help identify specific movements or positions that exacerbate symptoms, providing insights into aggravating factors and guiding the development of a treatment plan.
4. Monitoring Treatment Progress: The SLR test is useful in monitoring the progress of treatment interventions for lumbar radiculopathy. By comparing the patient’s baseline SLR findings with subsequent assessments, healthcare professionals can determine the effectiveness of conservative treatments (e.g., physical therapy, medications, epidural injections) or surgical interventions. Improvements in pain thresholds or increased leg elevation angles during follow-up tests can indicate positive treatment outcomes.
5. Preoperative Assessment: The SLR test is often employed as part of the preoperative evaluation for patients considering surgery for lumbar radiculopathy. It helps confirm the presence and location of nerve root involvement, assisting surgeons in planning the surgical approach. The SLR test findings, along with other clinical and radiological data, help guide decision-making regarding the need for surgical intervention and the level of surgical decompression required.

By utilizing the Straight Leg Raise test in the evaluation of lumbar radiculopathy, healthcare professionals can gather valuable diagnostic information, differentiate between radicular and non-specific pain, assess severity, identify aggravating factors, monitor treatment progress, and guide surgical decision-making. This test plays a significant role in the comprehensive management of patients with lumbar radiculopathy, ensuring optimal care and improved patient outcomes.