Lumbar Radiculopathy Assessment

Original Editor - Matt Huey

Top Contributors - Jess Bell, Matt Huey and Wanda van Niekerk  

Introduction

Lumbar radiculopathy is usually caused by compression of a lumbar nerve root, resulting in symptoms which radiate down the legs. It causes at least one of the following: decreased strength in the associated myotome, altered sensation in the dermatome or decreased reflexes. While pain is not part of this definition, people with lumbar radiculopathy report various symptoms, including sharp, shooting pain, shocks, numbness or tingling, etc. These descriptions depend on the patient's interpretation of the symptoms.

Lumbar radiculopathy is "characterized by motor, reflex, and/or sensory changes, such as radicular pain, paresthesia, or numbness in the lower limb which may be provoked by spinal posture(s) and/or movement(s). While radiculopathy and radicular pain commonly occur together, radiculopathy can occur in the absence of pain and radicular pain can occur in the absence of radiculopathy."

Lumbar radiculopathy affects approximately 3-5% of the population, and it is the most common issue that spine surgeons evaluate. Patients may or may not experience back pain along with radiculopathy, but roughly 12-40% of people with back pain also experience radiculopathy symptoms.

Causes of Radiculopathy

The primary cause of lumbar radiculopathy is compression of the nerve root. It is commonly believed to be caused by a disc herniation or bulge pressing on the nerve, but there are a number of potential causes such as:

• degenerative conditions: spondylolisthesis, spinal stenosis, osteophytes
• trauma: fractures
• tumours
• infections
• venous congestion and vascular conditions: hemangioblastoma, arteriovenous malformations

Assessment for Radiculopathy

When patients present with radicular symptoms, it is essential to perform a thorough assessment to ensure appropriate management and to rule out red flags. If red flag symptoms are found, it is important to refer out. Red flags include:

• fever
• unexplained weight loss
• bowel or bladder dysfunction
• saddle anaesthesia
• gait ataxia
• history of malignancy

For more information on red flags, please see: An Introduction to Red Flags in Serious Pathology.

Body Chart

It is always important to fill in a body chart to determine where a patient does and does NOT have symptoms. This will give you a clearer picture of what is occurring.

• Make sure you palpate where the symptoms are and aren't, so you can establish the exact location of symptoms.
• Palpate spots that patients have not told you about to check for symptoms. A patient might not think some symptoms are as important, but if you palpate them, there is a better chance that they will tell you about symptoms that may be relevant.

Objective Examination

The assessment for patients with lumbar radiculopathy will typically include:

• myotome testing (manual muscle testing (MMT))
• other upper motor neurone testing, such as Hoffmann's sign, ankle clonus
• sensation testing
• deep tendon reflexes
• neurodynamics
• range of motion testing, repeated movements
• lumbar accessory mobility testing

There is research to suggest that physical tests have "poor diagnostic performance" when performed in isolation, but performance may improve when tests are used in combination. Please keep in mind that you can utilise these tests as a test and retest measure to show improvement.

Myotomes

Because nerve roots are affected in lumbar radiculopathies, patients may experience a loss of strength in their lower extremities. With manual muscle testing of the myotomes, the therapist can gain insight into the possible level of a lesion or compression of the nerve root.

To test myotomes:

• inform the patient about what you will be doing, such as "I want you to lift your leg up and hold it while I press down on it"
• have the patient move their lower extremity to the testing position
• ask them to hold while you place a gradually increasing downward force on their extremity
• instruct the patient to hold for 3 seconds (it can help to say Hold, Hold, Hold)
• record the patient's strength
• repeat on the opposite side

Table 1. Nerve root and associated movement

Nerve Root	Lower Extremity Movement
L2	Hip flexion
L3	Knee extension
L4	Ankle dorsiflexion
L5	Big toe extension
S1	Ankle plantarflexion
S2	Knee flexion

Remember that manual muscle testing can vary depending on the patient's and therapist's size and strength. It can be helpful to ask a patient if they felt as strong on each side after you have finished testing the myotome. A patient may test strong but tell you that one side did not feel as strong as the other.

The following video demonstrates both cervical and lumbar myotome testing. If you just want to view the lumbar myotomes, please watch from 7:22 minutes in the video.

Sensation

Patients may experience a change in sensation in their lower extremities with lumbar radiculopathy. Common complaints with lumbar radiculopathy are numbness, tingling, or prickling in the legs along a dermatomal pattern. Patients may also state they feel "weird" sensations in their lower extremities, such as tenderness, or that "it doesn't feel right."

Light touch can be assessed to determine if sensation is altered:

• have the patient in the supine or seated position
• inform them what you will be doing - i.e. "I will be brushing along your legs in certain areas; let me know if it feels the same on both sides"
• you can ask the patient to close their eyes or obscure their view so they are not biased to the testing
• use your fingertips or a cotton swab to apply a light touch to a dermatome
• test each side and compare if it feels the same
• to ensure consistency, use the same dermatomal map with each patient

Table 2. Lower extremity dermatomes

Dermatome	Area
L1	Greater trochanter
L2	Front of thigh to knee
L3	Anterior thigh and knee, medial lower leg
L4	Lateral thigh, medial leg, dorsum of foot, big toe
L5	Posterior and lateral thigh, lateral aspect of leg, dorsum of foot, medial half of bottom of foot, toes 1-3
S1	Posterior thigh

Deep Tendon Reflexes

While reflexes may or may not be altered with a lumbar radiculopathy, assessing deep tendon reflexes can be beneficial. If the nerve root is compromised, the patient may demonstrate diminished reflexes. For patients with a lumbar radiculopathy, you will usually test the patellar and Achilles reflexes. The testing is as follows:

• the patient can be either seated or lying down (prone and supine)
• palpate the tendon to ensure you are in the right place
• make sure the patient is relaxed
• using a reflex hammer, perform a brisk, firm strike to the tendon
• can repeat as necessary
• if a response is not found or the patient cannot relax, have the patient perform a Jendrassik manoeuvre, such as clenching their teeth or trying to pull their hands apart

Table 3. Lower limb reflexes

Reflex	Nerve Supply	Segmental Innervation	Area to test	Expected Response
Patellar	Femoral nerve	L2-L4	Patella tendon	Leg extension
Achilles	Tibial nerve	S1-2	Achilles tendon	Plantarflexion

Please watch the following video for a demonstration of reflex testing:

Neurodynamics

Neurodynamic testing assesses the sensitivity of the nerve and looks for a possible entrapment. The Straight Leg Raise Test (SLR) is one of the most commonly used tests, along with the Slump Test. The SLR and Slump tests assess the sciatic nerve (L4-S1). The Femoral Nerve Test can be used to assess the femoral nerve (L2-L4). A test is considered positive if it reproduces the patient's symptoms.

Straight Leg Raise Test

The patient is supine with both lower extremities extended. Starting with the non-painful side, the examiner passively raises the patient's leg while keeping the knee extended and the ankle in neutral. The examiner then repeats the test on the painful side. A positive response is the reproduction of symptoms between 30-70 degrees of flexion. Adding dorsiflexion at the end of the movement (Bragaad sign) can add further tension to the neural tissues.

The following video provides a demonstration of the Straight Leg Raise Test:

Slump Test

The patient is in a seated position. The patient is asked to bring their hands behind their back, round their spine (slouch) and bring their chin to their chest. Overpressure can be applied. The patient maximally extends their non-painful knee. They then dorsiflex their ankle. The symptom response is determined. The patient then comes out of cervical flexion, and any change in symptoms is noted. This sequence is then repeated on the painful side. This test can also be completed with both legs at the same time.

Please watch the following video if you would like to see a demonstration of the Slump Test:

Femoral Nerve Test

The patient is in prone with both lower extremities extended. The non-painful knee is passively flexed to end range. This movement is then repeated on the painful side. A positive response is the reproduction of the patient's symptoms. It is possible to add hip extension to further load the neural tissues. This test can also be performed in a side-lying position.

The following videos show how to perform the Femoral Nerve Test in a prone position and a side-lying position:

Repeated Movement

The use of repeated movement testing is a hallmark of Mechanical Diagnosis and Therapy (MDT or the McKenzie Method). The goal of repeated movement testing is to determine if a patient is able to centralise their radicular symptoms. There is evidence that utilising repeated movement testing can be useful in the assessment of patients with low back and leg pain. Repeated movement testing can be useful even if a patient is only experiencing symptoms in their lower extremity.

Several things must be considered when performing repeated movement:

• direction: clinicians often make the mistake of only performing repeated extensions
• loaded or unloaded: standing is considered a loaded position of the lumbar spine, whereas supine/prone are considered unloaded positions
• time and/or repetitions: another mistake that can be made is not giving enough time or the proper number of repetitions to exhaust a movement

Conclusion

Performing these tests can help clinicians diagnose lumbar radiculopathy and rule out serious pathologies and other causes of radicular symptoms not related to the spine. These measures can also be used to demonstrate improvements over time.