Treatment for Chronic Neck and Back Pain: Epidural Steroid Injections
What Are Epidural Steroid Injections?
What happens after you have been treated with physical therapy, medications, activity modification, chiropractic treatment and acupuncture? Some would think that the only reasonable treatment for their spinal condition would be surgery. However, epidural steroid injections are a less invasive and commonly effective treatment. They can be performed on an outpatient basis in a surgery center without the need for general anesthesia in most cases. This type of injection is typically administered by a pain management physician after conservative treatments, such as medications and therapy, have been tried and failed to provide benefit. This article provides information about these injections, including indications for use, expected outcomes, and potential risks.
Indications for Epidural Steroid Injections
Epidurals are indicated in the treatment of radiculopathy. Radiculopathy is a condition that is characterized by pain, numbness, tingling, or a pins and needles sensation that extends from the spine into the extremity in a focal distribution. A person can have radiculopathy that comes from the cervical spine, thoracic spine, or the lumbar spine.
To further discuss the pathology that causes radiculopathy, it is important to understand the anatomy of the spine. As you read through this section, you can reference the above picture for further understanding.
Anatomy of the Spine
In the spine, there are vertebral bones that are separated by intervertebral discs. There are 7 vertebrae (vertebral bones) in the cervical spine, 12 in the thoracic spine, and 5 in the lumbar spine. The intervertebral disc acts as a cushion between each level. These discs have a firm outer layer called the annulus, a jelly-like substance inside, and an inner core called the nucleus fibrosus. The vertebrae (vertebral bones) form a column through which the spinal cord passes. The vertebral column is in place to protect the spinal cord from injury. The spinal cord is a large bundle of nerves that extends from the brain and innervates our entire body. As the spinal cord extends down the spine, branches of nerves come off it and travel to our muscles, organs, skin, bones, etc. If you picture a tree's roots extending out in multiple directions underground, this is similar to what our nerves do as they come off the spinal cord. The brain would be the top portion of the tree and the spinal cord and nerves are the roots of the tree.
Nerves Branch From the Spinal Cord to Other Parts of the Body
The nerves extend off the spinal cord at all of the vertebral levels of the spine. The spot where the nerves come off the spinal cord is referred to as a nerve root. Each vertebral bone has a foraminal space on the right and left side through which the nerve root passes. The foraminal space is like a short tunnel that allows the nerve root to pass through it. When there is any pathology of the spine at any of these levels, it can cause the nerve root to be compressed or irritated. The intervertebral disc between the vertebral levels can degenerate as we get older. This causes the disc to lose some of its height. The disc can also bulge or protrude if there is an injury or trauma to the area. When the disc bulges, degenerates, or protrudes out, this can cause the foraminal space to become smaller. When the foraminal space is smaller, the nerve root that travels through it may become impinged or compressed. When this happens, you would experience radiculopathy, or pain, in the arms or legs dependent upon the level that is affected.
How Nerves Are Organized
The nerve roots are named based on the location that they exit the spine. For example, a nerve root that comes off the spinal cord between the fourth cervical vertebra and the fifth cervical vertebra is called the C5 nerve root. This nerve then travels to a specific location down the arms.
Each nerve root has a specific location that they innervate. Dermatomes are areas on the skin that are innervated by a specific nerve root. The L5 nerve root innervates the lateral (or outside) portion of your legs and extends down into the top of the foot and to the 2nd, 3rd, and 4th toes. This area is referred to as the L5 dermatome.
There are also myotomes, which are a specific group of muscles that are innervated by a nerve root. The L5 nerve root innervates the extensor hallucis longus muscle in the ankle/foot and the extensor muscles of the foot. This is referred to as the L5 myotome.
If you have a problem at the L5-S1 level of the spine affecting the exiting nerve root L5, you would expect to have numbness on the outside of your leg down into the top of your foot and you could also have a weakness with extension of the foot. This would cause a "foot drop," meaning that you cannot pick up your foot to take a step and instead the foot drags when walking.
Who Would Need an Epidural Steroid Injection?
Patients who have an intervertebral disc pathology that is affecting the exiting nerve roots at a spinal level would develop these signs and symptoms of radiculopathy. Physicians and practitioners would first need to localize the findings with imaging, such as an x-ray, MRI, or CT scan. Once a pathological level is located, neurological testing can be done to determine if there is evidence of radiculopathy that comes from that level. Patients who have clear imaging evidence of pathology that correlates with a specific dermatomal/myotomal pattern of radiculopathy would be candidates for an epidural, which is typically administered before surgery is considered because they can help establish the level as being the cause of pain and because, in some cases, they can provide long-term relief of pain without the need for immediate surgery.
The Epidural Steroid Injection Procedure
At the time of the injections, a doctor may use either local anesthesia to numb the area or general anesthesia, depending on the location of the pathology and some other factors. The whole procedure can take about 20 to 30 minutes only and you would be observed for a few hours after the injection and then discharged to home.
An injection of steroids and lidocaine (or similar anesthetic agent) is applied to the specific level where pathology exists in the foraminal space or epidural area. The injection is performed using fluoroscopy, an imaging procedure that can be taken live during the injection to ensure proper placement.
Once the injection is applied to the correct area, the expectation is that the anesthetic agent will provide immediate relief of symptoms for the first day to several days, depending on what specific agent is used. The steroids that are injected are expected to decrease inflammation in the area, relieve pressure on the nerve roots, and provide longer-term relief of symptoms. A successful injection will provide 50% or greater relief of symptoms in the arms or legs, for a duration of at least 2-3 months. During that time period, some people will have little to no symptoms and can be more active and take fewer pain medications.
Outcome of Epidural Injections
The intent of these injections is not usually to resolve the condition, as they are typically only able to provide a short-term benefit of 3-6 months. However, these injections can be repeated up to 3-4 times per year provided that the initial injection results in significant pain relief, functional improvement, and medication reduction. Some physicians administer a series of 2-3 injections in rapid succession of 1 per week in hopes of resolving the inflammation in the area permanently. However, complete resolution of pain is not likely with this type of treatment. Evidence-based research shows that this type of injection is only capable of providing short-term relief of pain for up to 6 weeks or up to 6 months in some cases.
Risks of Epidural Injections
There are risks associated with repeated injections, however. Repeated injections of steroid could cause scar tissue to develop in the region and could also lead to atrophy in the muscles surrounding the injection. Additionally, there is a risk for elevated blood glucose with steroid injections, especially in patients who already have a diagnosis of diabetes. Other less common risks include injury to the nerve due to contact with the needle, dural puncture (a puncture of the dural sac surrounding the spinal cord), nerve damage, and infection.
In conclusion, epidural injections are indicated in the treatment of patients who have radiculopathy due to pathology in the spine. These injections are only indicated after conservative treatment fails, including medications and therapy. Before injections are administered, diagnostic testing is necessary to identify a specific pathological level and to determine if it correlates with radicular symptoms and findings. In most cases, relief from epidural steroid injections lasts for up to 3-6 weeks. However, some patients can have complete resolution of pain after a series of injections. These injections are also helpful for diagnostic purposes to determine if the pain is coming from that specific level of the spine dependent upon if pain relief is experienced. There are some risks with this type of injection, but usually risks are minor or minimal. If there is no relief with this type of injection, surgery may be necessary dependent upon the degree of radiculopathy and its impact on your overall functional level.
Have you ever had an epidural steroid injection?
If you have had an epidural steroid injection in the past, what type of response did you have?
© 2012 Kortney Tholen