Sciatica
Sciatica is a sharp or burning pain that travels down the back of the leg. It follows the path of the sciatic nerve, which runs from the lower back through the buttock and down each leg. In most cases, sciatica affects only one side of the body.
Sciatica usually develops when a herniated disc in the lower back presses on one of the nerve roots that form the sciatic nerve. This can cause inflammation, pain, numbness and weakness in the leg and foot. Nearly 85% of sciatica cases are linked to a problem with a lumbar disc (1).
Most cases of sciatica improve with conservative care, but more severe cases can seriously affect daily function. Growing leg weakness may need a surgical evaluation. If you notice numbness in your groin or inner thighs, or new trouble controlling your bladder or bowels, seek emergency care right away.
How Common Is Sciatica?
Estimates vary widely, but some studies suggest that as many as 43% of people will have sciatica at some point in their lives (27). Sciatica is more common in people who live with chronic back pain.
Low back pain is the leading cause of years lived with disability worldwide (7), and one of the most common reasons people seek care for muscle and joint pain (8). About 60% of people who visit a primary care provider for low back pain also report pain that travels into the leg (9).
What Causes Sciatica?
The sciatic nerve is about as thick as your thumb, making it the largest nerve in the body. It is formed from nerve roots that leave the lower spine, specifically the fourth and fifth lumbar roots and the first two sacral roots. These roots join to form the sciatic nerve, which exits the pelvis, runs beneath the buttock muscles and travels down the back of the thigh. Near the knee, it divides into the tibial and common peroneal nerves. Together, these nerves control the muscles of the back of the thigh and all the muscles of the lower leg and foot (1).
Sciatica is most often caused by an injury to an intervertebral disc. Discs sit between the bones of the spine and act as shock absorbers. Each disc has a tough, fibrous outer layer and a gel-like center. Discs can be injured, and they also wear down with age. When the outer layer tears, the inner material can bulge out and irritate or press on nearby nerve roots. Pressure on a nerve root is called radiculopathy, so sciatica is also known as lumbosacral radiculopathy.
In most cases, sciatica comes from a herniated disc in the lower back, where disc material pushes through the outer layer and presses on a nerve root (12). Less common causes include degenerative spine conditions such as spondylolisthesis, spinal stenosis and foraminal stenosis. Rarely, tumors can cause similar symptoms, which is one reason a careful evaluation matters. Research suggests that sciatica pain comes not only from pressure on the nerve root, but from a combination of pressure, inflammation and immune activity (10).
Inflammatory chemicals called cytokines appear to play a key role in both disc degeneration and the pain of a herniated disc. Activated immune cells release these chemicals, which signal the brain about tissue damage. The brain and spinal cord can then increase their own production of inflammatory signals. Inflammation from the injured disc can irritate nearby nerve roots, leading to pain and changes in how those nerves function (12).
What Are the Symptoms of Sciatica?
The most common symptom of sciatica is sharp, shooting or burning pain that travels from the buttock down the back of the thigh, and sometimes into the foot. The pain can range from a dull ache to severe and disabling. Some people also develop weakness in the affected leg. In more advanced cases, this can include foot drop, which is difficulty lifting the front of the foot (26).
What Are the Risk Factors for Sciatica?
Factors that raise the risk of developing sciatica include age, with the highest risk between 45 and 64, greater height, smoking and mental stress (11).
Work-related risk factors include strenuous physical activity, such as frequent lifting, especially while bending and twisting, and driving, including exposure to whole-body vibration (11).
How Does Sciatica Affect the Brain?
Studies show that the size of a herniated disc does not closely match how much sciatic pain a person feels. Because the brain is what ultimately interprets pain, researchers have studied how the brain changes in people with ongoing pain. Research suggests that chronic pain is not just a signal from the injured area. Over time, the parts of the nervous system that process pain can become more sensitive and more efficient at producing pain, which can make it harder to turn off once it has built up.
This process is called central sensitization. It is a form of nervous system adaptation that can play a major role in chronic pain. Once it develops, the increased sensitivity can last for a long time, even after the original injury has healed (6).
Imaging studies have found differences in brain structure in people with chronic low back pain and disc herniation compared with healthy people. These include changes in gray matter volume in several areas involved in pain processing, movement and emotion, such as parts of the prefrontal cortex, the anterior cingulate cortex, the caudate nucleus and the cerebellum (13).
Other studies have found changes in the default mode network in people with chronic low back pain and sciatica (14). The default mode network is a widely connected system in the brain that plays important roles in thinking and emotional regulation at rest (15). Chronic low back pain has also been associated with lower gray matter density in the cerebellum and with signs of greater brain aging on imaging (16). Researchers are still working to understand what these changes mean and how they relate to recovery.
How Is Sciatica Usually Treated?
Sciatica is usually treated conservatively at first, with chiropractic care, physical therapy, massage and acupuncture. Anti-inflammatory and pain medications are also commonly used, and imaging such as x-rays or an MRI may be ordered. If a disc herniation is found and symptoms don’t improve, options may include steroid or nerve block injections, and in some cases surgery, such as a discectomy.
How the NeuroRescue Program Can Help
We take a thorough and conservative approach to sciatica, and we work alongside your other providers, including any doctor managing your medications. Please don’t change any medication without talking with your prescriber.
Spinal manipulation and exercise. We generally begin by improving how your spine moves and functions, using spinal manipulation and exercise. Research supports combining spinal manipulation with a home exercise program for back-related leg pain (2). Research has also begun to look at how spinal manipulation affects the brain. One study found changes in default mode network activity after spinal manipulation in people with chronic low back pain and sciatica (17).
Lumbar traction. When appropriate, your program may include lumbar traction, which is designed to reduce pressure on nerve roots from bulging or herniated discs. Some studies have found improvements in back and leg symptoms with traction therapy (4, 5).
Light therapy. We often use photobiomodulation, including low-level and high-intensity laser and LED therapy. Research suggests that laser therapy may support nerve and muscle repair (18, 19) and may help reduce chronic low back pain, especially when combined with spinal manipulation (20).
Electrical stimulation. Your program may include forms of electrical stimulation, applied through the skin, that have been studied for reducing low back pain and sciatica (21).
Transcranial magnetic stimulation. TMS has been studied for reducing pain, as well as the depression and sleep problems that can come with chronic low back pain and sciatica (22). At our clinic, TMS is provided by our psychiatric mental health nurse practitioner, who will evaluate whether it’s appropriate for you.
Nutritional support. When appropriate, we may recommend polyphenols and related supplements to help address inflammation (23).
Balance and eye movement exercises. Your program may also include vestibular rehabilitation to address the subtle balance problems seen in some people with lumbar instability (24), and eye movement exercises to address the eye position and posture control differences found in some people with low back pain (25).
Every nervous system is different, so every NeuroRescue Program is different too. Your plan is based on your test results and the specific factors of your case.
How the NeuroRescue Program Works
Your NeuroRescue Program begins with your Discovery Day. We start with a detailed history of your condition and your life on a timeline. This helps us understand the factors that may have contributed to where you are now, and identify related conditions that may be making it harder to move forward.
Because sciatica and back pain can be affected by how your brain processes pain and controls posture, we also evaluate your central nervous system. We measure how your visual, vestibular and balance systems are working through computerized analysis of your eye movements, inner ear reflexes and balance under different conditions.
Our testing includes videonystagmography and saccadometry to measure several types of eye movements, the video head impulse test to measure inner ear reflexes, and CAPS computerized posturography to assess your balance under different sensory conditions. We also use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and your perception of vertical in a virtual reality environment.
We combine this with a thorough physical and neurological exam of your sensory, motor, autonomic and cognitive systems. We also review any relevant lab work, imaging and prior testing, and integrate it with our findings.
Together, this helps us understand which parts of your nervous system are working well, which are struggling, and how quickly they tire. We use that information to design your personal NeuroRescue Program, aimed at improving function, endurance and comfort in the systems that need support. Our testing also helps us decide when to push and when to let you rest.
Our goal is to help you move more freely, reduce your pain and get back to more of the activities you enjoy.
Your Next Step
Living with sciatica can be exhausting, but there is real hope for relief. Many people improve with conservative care. To find out if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.
It’s never too late to take the next step.
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