An epidural steroid injection (ESI) is an injection of anti-inflammatory medicine — a steroid or corticosteroid — into the space around your spinal nerves known as the epidural space to treat pain caused by irritation and inflammation of spinal nerve roots. Healthcare providers use ESI injections as a chronic pain management tool. It can help relieve neck, arm, back and leg pain caused by inflamed spinal nerves due to certain conditions or injuries. Pain relief from an ESI may last for several days or months.
Other common names for an epidural steroid injection include:
. ESI injection.
. Spinal injection for back pain.
. Back pain injection.
. Steroid injection — epidural.
. Steroid injection — back.
Epidural steroid injections are not the same as epidural anesthesia or analgesia given for labor and childbirth or certain types of surgery. Those types of epidurals involve an injection of local anesthetic medication into the epidural space, which numbs certain regions of your body.
An epidural steroid injection (ESI) is used for chronic pain management. Your provider injects a steroid or corticosteroid medication into the epidural space around your spinal cord.
Your spinal cord is a very important bundle of nerves that runs from your brain to your lower back. Your spinal cord acts like a highway that connects the nerves located all over your body to your brain so that your brain can send signals and communicate with the rest of your body.
The epidural space surrounds your spinal cord like a sleeve and contains fat, the dural sac, spinal nerves, blood vessels and connective tissue. Your spine (backbone) is composed of a column of many small bones called vertebrae. These bones help protect your spinal cord from injury. Between the vertebral bones are disks that provide cushioning for your vertebrae and flexibility for you.
Sometimes, nerve roots that are attached to your spinal cord can become pinched or inflamed. This can happen, for example, if you have a herniated disk. The inflamed nerves can cause pain, and the pain may radiate down your arm, buttocks and/or legs depending on where the inflamed nerve is along your spine.
With an epidural steroid injection, the steroid coats the irritated nerve(s) that are causing your pain and works to reduce swelling and pressure on the nerves. The steroid allows the nerve(s) time to heal. Epidural steroid injections most often lead to temporary pain relief, but in some cases, people experience long-term or permanent pain relief. ESIs can also sometimes identify the painful nerve.
Healthcare providers use epidural steroid injections to manage chronic pain caused by spinal nerve root inflammation. Many conditions can irritate your spinal nerve roots. This kind of nerve irritation most commonly presents as low back (lumbar) pain that radiates down your buttocks or legs. It also commonly presents as neck (cervical) pain that radiates to your arms.
Epidural steroid injections may help alleviate pain caused by the following conditions:
. A herniated or bulging disk that pinches nerves, causing pain.
. Spinal stenosis (the narrowing of one or more spaces within your spine).
. Failed back surgery syndrome (This is a generalized term that describes the condition of people who have not had a successful result with back or spine surgery and still experience pain).
. Vertebral bone spurs (osteophytes).
. Scoliosis that causes nerve root irritation.
. Spondylolysis (spine degeneration).
. Other injuries to spinal nerves, vertebrae and surrounding tissues.
Epidural steroid injections are one of many treatments healthcare providers use to relieve certain causes of pain. Your provider may only recommend an ESI if your pain has not improved with physical therapy, medication or other nonsurgical therapies.
Epidural steroid injections may be classified by their location along your spine — cervical, thoracic or lumbar — and by the path of the needle to get to the epidural space — interlaminar, transforaminal or caudal.
There are three types of ESIs based on which section of your spine your provider injects the medication, including:
. Cervical (neck) ESI: For a cervical ESI, the needle entry site is slightly to the side of your spine in your neck (your cervical region). If you have pain in your neck that radiates down your arms from a herniated disk, bone spur or stenosis, your provider may recommend a cervical ESI.
. Thoracic (upper and middle back) ESI: For a thoracic ESI, the needle entry is slightly to the side of your spine in your upper or middle back. This area is known as the thoracic region. If you have pain in your upper or middle back from a thoracic disk herniation or thoracic spinal stenosis, your provider may recommend a thoracic ESI.
. Lumbar (low back) ESI: For a lumbar ESI, the needle entry site is slightly to the side of your spine in your low back (your lumbar region). If you have lower back and leg pain from a lumbar herniated disk, lumbar degenerative disk disease or lumbar spinal stenosis, your provider may recommend a lumbar ESI.
There are a few different ways to reach the epidural space surrounding your spinal nerves. The following types of epidural steroid injections explain the path the needle takes to get to the epidural space:
. Interlaminar (between the lamina) ESI: For an interlaminar ESI, the path of the needle is in between two laminae in your spine to get to the epidural space. A lamina is the flat plate of bone that’s part of each vertebra in your spine. The laminae in your spine form the outer wall of the spinal canal and protect your spinal cord.
. Transforaminal (across the foramen) ESI: For a transforaminal ESI, the path of the needle is through the foramina, which are openings through which nerve roots exit your spine.
. Caudal (via the sacrum) ESI: For a caudal ESI, the path of the needle is through the sacral hiatus, which is towards the bottom of your sacrum and just above your tailbone, to reach the lowest spinal nerves. Your sacrum is the triangular bone in your lower back that’s situated between your hip bones.
Epidural steroid injections are a common form of therapy for certain causes of chronic pain.
Side effects of ESIs include:
. You may experience a temporary increase in pain before the steroid medication starts working.
. You may have tenderness and/or bruising at the site of your injection.
. If your provider uses fluoroscopy for imaging guidance, there will be minimal low-level radiation exposure due to the X-rays. Fluoroscopy x- rays may be harmful to unborn babies. It’s essential to tell your healthcare provider if you’re pregnant or might be pregnant before you undergo the procedure.
. If you have diabetes, an epidural steroid injection will likely cause high blood sugar (hyperglycemia). This could last for hours or even days.
. If you have glaucoma, an ESI may temporarily increase your blood pressure and eye pressure.
The advantages of epidural steroid injections include:
. You’ll likely experience temporary pain relief. Some people experience long-term pain relief.
. You’ll likely have a better quality of life and an improved ability to do daily activities without the restrictions previously caused by pain.
. Epidural steroid injections may provide diagnostic information on the origin of your pain. This is often helpful in people who have more than one possible cause of pain.
. Epidural steroid injections may reduce the need for more invasive procedures for pain management.
Epidural steroid injections are usually safe, but there are risks of certain side effects and complications. Although rare, risks and complications that apply to ESI injections include:
. Having low blood pressure, which can make you feel lightheaded.
. Experiencing a severe headache caused by spinal fluid leakage. Less than 1% of people experience this side effect.
. Getting an infection from the epidural procedure, such as an epidural abscess, discitis, osteomyelitis or meningitis.
. Having a negative reaction to the medications, such as hot flashes or a rash.
. Experiencing bleeding if a blood vessel is accidentally damaged during the injection, which could cause a hematoma or a blood clot to form.
. Having damage to the nerves at the injection site.
. Temporarily losing the ability to regulate your bladder and bowels. You might need a catheter (a small tube) in your bladder to help you pee.
. Getting ESI injections too often or receiving higher doses of steroid medication may weaken the bones of your spine or nearby muscles. Because of this, most healthcare providers limit people to 2 to 3 ESIs per year.
While it’s very rare, complications from receiving an epidural steroid injection can have long-term consequences, including:
. Permanent neurologic deficit due to spinal cord or nerve root damage from the epidural injection.
. Chronic pain due to spinal cord or nerve root damage from the epidural injection.
. Permanent paralysis from a hematoma that occurs when there’s a buildup of blood between the dura mater and the spinal cord.
Before your ESI injection, it’s important to tell your healthcare provider if you are pregnant or might be pregnant. You also need to tell your provider which medications you are taking, including herbs, supplements and other non-prescription drugs.
Your healthcare provider will give you specific instructions about what you need to do to prepare for your ESI injection. Be sure to follow their instructions. Your provider may:
. Ask you not to eat or drink (fast) for a certain amount of time before your ESI injection.
. Adjust certain medications you’re taking, especially blood thinner medications.
. Have you undergone an MRI or CT scan of your back before your ESI injection to help determine the area that needs to be treated.
. Make sure you have someone with you to drive you home if you’re going to take a sedative for your ESI.
Epidural steroid injections are very technique-sensitive, so healthcare providers performing the injection must have significant specialized training. Healthcare providers who may perform ESIs include:
. Physiatrists (physical medicine and rehabilitation providers).
You will likely have your epidural steroid injection in a hospital or an outpatient clinic.
Depending on what’s causing your pain, your healthcare provider will inject the epidural somewhere along your spine. Here are the general steps of an epidural steroid injection procedure:
. You’ll change into a medical gown and lie on a comfortable table on your belly.
. Your healthcare provider will thoroughly clean the area of your back where they’ll insert the epidural to minimize the risk of infection.
. Your provider will inject local anesthesia with a small needle near the area where they’ll insert the epidural. This is so you won’t feel as much pain when they insert the epidural needle, which is larger than a standard shot needle. They may also give you medicine to relax, such as a sedative.
. Once the area is numb, your provider may use an imaging machine, such as fluoroscopy or X-ray, to help guide the epidural needle to exactly the right position. It’s important to be very still during this procedure.
. When the epidural needle is in the epidural space around your spinal cord, your provider may inject contrast material. The contrast material will make it easier for your provider to see the area they’re targeting on the screen of the imaging machine. This helps to make sure that the medication will reach the inflamed nerves they are targeting.
. Your provider will then slowly inject the medication, which is usually an anti-inflammatory medication, such as a steroid or corticosteroid. Some providers may inject a mixture of a corticosteroid and a local anesthetic.
. When your provider is done with the injection they’ll apply pressure to the site to prevent bleeding, clean the area again and apply a dressing to the site. You’ll move into a chair or bed to rest for a few minutes to an hour. This is so your provider can make sure you don’t have any reactions to the medication before you go home.
You’ll likely experience a minor pinch when your provider injects the local anesthetic to numb the area before your ESI injection.
You may not feel anything during the ESI injection, or you may feel the following:
. A burning sensation.
. Momentary pain.
If you have any discomfort during the injection, it usually disappears once the injection is finished.
If you feel intense, sharp pain during or after your ESI injection, tell your provider immediately.
After your injection, you may feel some discomfort where your healthcare provider inserted the needle. This is normal and should only last a few hours.
Your provider may tell you to take it easy and minimize your activity level for the rest of the day.
Your pain may become worse for two to three days after your ESI before it begins to improve. Epidural steroid injections start working within two to seven days, and the pain relief can last several days or longer.
Since there are many causes of chronic pain an ESI can potentially help treat and each person is different, there are different levels of results for ESIs. However, approximately 50% of people who get an ESI experience pain relief.
While evidence shows that epidural steroid injections are effective in providing pain relief, the length of time the pain relief lasts may vary. This is especially dependent on the underlying cause of the pain. The pain relief may last for weeks to months, but rarely up to a year.
You may receive more than one ESI over time, but most healthcare providers limit people to two to three ESIs per year. In the majority of cases, ESIs do not cure the cause of your pain. People who have chronic pain and receive ESIs often need other forms of therapy for sustained pain relief.
If you experience any of the following symptoms after you’ve returned home from your ESI injection, be sure to contact your healthcare provider or go to the nearest hospital as soon as possible:
. Experiencing a severe headache while you’re standing up or sitting that feels better after lying down. This could be a sign of a dural puncture.
. Having a fever, which could be a sign of an infection.
. Having a reduced or complete loss of bladder or bowel control.
. Feeling numbness and/or weakness in your legs, which could be a sign of nerve injury.