Epidural Steroid Injections


Epidural steroid injections (ESIs) are a common treatment option for many forms of low back pain and leg pain. They have been used for low back problems since 1952 and are still an integral part of the non-surgical management of sciatica and low back pain. The goal of the injection is pain relief; at times the injection alone is sufficient to provide relief, but commonly an epidural steroid injection is used in combination with a comprehensive rehabilitation program to provide additional benefit.

Most practitioners will agree that, while the effects of the injection tend to be temporary – providing relief from pain for one week up to one year – an epidural can be very beneficial for a patient during an acute episode of back and/or leg pain. Importantly, an injection can provide sufficient pain relief to allow a patient to progress with a rehabilitative stretching and exercise program. If the initial injection is effective for a patient, he or she may have up to three in a one-year period.

In addition to the low back (the lumbar region), epidural steroid injections are used to ease pain experienced in the neck (cervical) region and in the mid spine (thoracic) region. This article focuses on epidural injections in the low back area used to treat low back pain and radicular pain (also referred to as leg pain or sciatica).

Efficacy of Injections

Efficacy of Injections

Although many studies document the short-term benefits of epidural steroid injections, the data on long-term effectiveness are less convincing. Indeed, the effectiveness of lumbar epidural steroid injections continues to be a topic of debate. This is accentuated by the lack of properly performed studies.

For example, many studies do not include use of fluoroscopy or x-ray to verify proper placement of the medication despite the fact that fluoroscopic guidance is routinely used today. Additionally, many studies do not classify patients according to diagnosis and tend to ‘lump’ different types sources of pain together. These methodological flaws tend to make interpretation and application of study results difficult to impossible.

More studies are needed to properly define the role of epidural steroid injections in low back pain and in sciatica. Despite this, most studies report that more than 50% of patients find measurable pain relief with epidural steroid injections. They also underscore the need for patients to enlist the services of professionals with extensive experience administering injections, and who always use fluoroscopy to ensure accurate placement.

Potential Benefits of Injections

Potential Benefits of Injections

Epidural steroid injections deliver medication directly (or very near) the source of pain generation. In contrast, oral steroids and painkillers have a dispersed, less-focused impact and may have unacceptable side effects. Additionally, since the vast majority of pain stems from chemical inflammation, an epidural steroid injection can help control local inflammation while also “flushing out” inflammatory proteins and chemicals from the local area that may contribute to and exacerbate pain. This article provides an overview of epidural steroid injections.

An epidural steroid injection delivers steroids directly into the epidural space in the spine. Sometimes additional fluid (local anesthetic and/or a normal saline solution) is used to help ‘flush out’ inflammatory mediators from around the area that may be a source of pain.

The epidural space encircles the dural sac and is filled with fat and small blood vessels. The dural sac surrounds the spinal cord, nerve roots, and cerebrospinal fluid (the fluid that the nerve roots are bathed in).

Typically, a solution containing cortisone (steroid) with local anesthetic (lidocaine or bupivacaine), and/or saline is used.

  • A steroid, or cortisone, is usually injected as an anti-inflammatory agent. Inflammation is a common component of many low back conditions and reducing inflammation helps reduce pain. Triamcinolone acetonide, Dexamethasone, and Methylprednisolone acetate are commonly used steroids.
  • Lidocaine (also referred to as Xylocaine) is a fast-acting local anesthetic used for temporary pain relief. Bupivacaine, a longer lasting medication, may also be used. Although primarily used for pain relief, these local anesthetics also act as ‘flushing’ agents to dilute the chemical or immunologic agents that promote inflammation.
  • Saline is used to dilute the local anesthetic or as a ‘flushing’ agent to dilute the chemical or immunologic agents that promote inflammation.

Epidural Steroid Injections Control Inflammation

Epidural Steroid Injections Control Inflammation

Epidural injections are often used to treat radicular pain, also called sciatica, which is pain that radiates from the site of a pinched nerve in the low back to the area of the body aligned with that nerve, such as the back of the leg or into the foot. Inflammatory chemicals (e.g. substance P, PLA2, arachidonic acid, TNF-α, IL-1, and prostaglandin E2) and immunologic mediators can generate pain and are associated with common back problems such as lumbar disc herniation or facet joint arthritis. These conditions, as well as many others, provoke inflammation that in turn can cause significant nerve root irritation and swelling.

Steroids inhibit the inflammatory response caused by chemical and mechanical sources of pain. Steroids also work by reducing the activity of the immune system to react to inflammation associated with nerve or tissue damage. A typical immune response is the body generating white blood cells and chemicals to protect it against infection and foreign substances such as bacteria and viruses. Inhibiting the immune response with an epidural steroid injection can reduce the pain associated with inflammation.

Several common conditions that cause severe acute or chronic low back pain and/or leg pain (sciatica) from nerve irritation can be treated by steroid injections. These conditions include:

For these and many other conditions that can cause low back pain and/or leg pain (sciatica), an epidural steroid injection may be an effective non-surgical treatment option.

Who Should Avoid Epidural Steroid Injections

Who Should Avoid Epidural Steroid Injections

    Several conditions could preclude a patient from having an injection:

  • Local or systemic infection
  • Pregnancy (if fluoroscopy, a type of x-ray, is used)
  • Bleeding problems – patient taking blood thinners (Coumadin, etc), or patients with a bleeding problem (hemophilia, etc)

Epidural steroid injections should also not be performed on patients whose pain could be related to a spinal tumor. If suspected, an MRI scan should be done prior to the injection to rule out a tumor.

Injections may be done, but with caution, for patients with other potentially problematic conditions such as:

  • Allergies to the injected solution
  • Uncontrolled medical problems such as renal disease, congestive heart failure and diabetes because they may be complicated by the fluid retention that a small percentage of patients experience for a few days after the injections.

Use of high dose aspirin or other anti-platelet drugs (e.g. Ticlid, Plavix), all of which can cause bleeding from the procedure. These medications should be stopped prior to having an injection.

The epidural steroid injection procedure takes place in a surgery center, hospital, or a physician’s clinic. Many types of physicians can be qualified to perform an epidural steroid injection, including an anesthesiologist, radiologist, neurologist, physiatrist and surgeon.

Preparing to Receive an Epidural Steroid Injection

Preparing to Receive an Epidural Steroid Injection

Patients may be asked to change into a hospital gown, which allows for access to clean the injection area and to allow the physician to easily visualize the injection site. An epidural steroid injection usually takes between 15 and 30 minutes and follows a relatively standard protocol:

Additional Injections Info:

Radiofrequency Neurotomy

Injections for Pain Management

  • The patient lies flat on an x-ray table or with a small pillow under their stomach to slightly curve the back. If this position causes pain, the patient can be allowed to sit up or lie on their side in a slightly curled position.
  • The skin in the low back area is cleaned and then numbed with a local anesthetic similar to what a dentist uses.
  • Using fluoroscopy (live x-ray) for guidance, a needle is inserted into the skin and directed toward the epidural space. Fluoroscopy is considered important in guiding the needle into the epidural space, as controlled studies have found that medication is misplaced in many (> 30%) of epidural steroid injections that are done without fluoroscopy1.
  • Once the needle is in the proper position, contrast is injected to confirm the needle location. The epidural steroid solution is then injected. Although the steroid solution is injected slowly, most patients sense some pressure due to the amount of the solution used (which in lumber injections can range from 3mL to 10 mL, depending on the approach and steroid used). The pressure of the injection is not generally painful.
  • Following the injection, the patient is monitored for 15 to 20 minutes before being discharged home

Sedation is available for patient anxiety and comfort. However, sedatives are rarely necessary, as the epidural steroid injection procedure is usually not uncomfortable. If a sedative is used, some patient precautions should be taken, including not eating or drinking for several hours prior to the procedure and having a guardian available for discharge. A patient should contact his or her doctor for specific instructions.

Tenderness at the needle insertion site can occur for a few hours after the procedure and can be treated by applying an ice pack for 10 to 15 minutes once or twice an hour. In addition, patients are usually asked to rest for the remainder of the day on which they have the epidural steroid injection. Normal activities (those that were done the week prior to the epidural injection) may typically be resumed the following day. A temporary increase in the pain can occur for several days after the injection due to the pressure of the fluid injected or due to local chemical irritation.

In addition to understanding the general protocol and time involved in the procedure, patients should discuss with their clinician and physician whether pain medications (or certain other medications) can be taken on the day of the injection.

Number and Frequency of Epidural Steroid Injections vary

Number and Frequency of Epidural Steroid Injections vary

There is no definitive research to dictate how many epidural steroid injections should be administered or how frequently they should be given. In general, the consensus is to perform up to three epidural injections per year, which is about the frequency that many arthritis patients receive cortisone shots for shoulder and knee pain. Different strategies are used:

  • Some doctors will space the injections out evenly over a year.
  • Others take a different approach and administer two or three epidural steroid injections at 2-4 week intervals, if the first shot results in significant pain relief.

There is no general consensus in the medical community as to whether or not a series of three injections should be performed. If a patient does not experience any back pain or leg pain relief from the first epidural injection, further injections may not be beneficial.

Patients will find that the benefits of an epidural steroid injection include a reduction in pain, primarily in leg pain (also called sciatica or radicular pain). Patients seem to have a better response when the epidural steroid injections are coupled with an organized therapeutic exercise program.

Epidural Steroid Injection Success Rates

Epidural Steroid Injection Success Rates

While the effects of an epidural steroid injection tend to be temporary (lasting from a week to up to a year) an epidural steroid injection can deliver substantial benefits for many patients experiencing low back pain.

  • When proper placement is made using fluoroscopic guidance and radiographic confirmation through the use of contrast, > 50% of patients receive some pain relief as a result of lumbar epidural steroid injections.
  • Pain relief is more often felt for primary radicular (leg) pain and, less prominently, low back pain.
  • The pain relief and control brought on by injections can improve a patient’s mental health and quality of life, minimize the need for painkiller use, and potentially delay or avoid surgery.

Success rates can vary depending on the condition that patient has and the degree of radicular leg pain that accompanies it:

Recent research reports that lumbar epidural steroid injections are successful in patients with persistent sciatica from lumbar disc herniation, with more than 80% of the injected group with disc herniation experiencing relief (in contrast to 48% of the group that received a saline placebo injection)1.

Similarly, in a study focused on a group of patients with lumbar spinal stenosis and related sciatica symptoms, 75% of patients receiving injections had more than 50% of pain reduction one year following the injections. The majority also increased their walking duration and tolerance for standing2.

Nonetheless, there is still some skepticism about the efficacy of injections and the appropriateness of injections for most patients. As noted previously, much of the controversy is generated by studies that analyze injection outcomes where fluoroscopy and radiographic contrast were notused to ensure accurate placement of the steroid solution at the level of pathology, or do not confirm that the injection was in fact made directly into the epidural space, which would diminish its effectiveness considerably.

1See Lutz, GE, et al: Fluoroscopic transforaminal lumbar epidural steroidsL an outcome study. Arch. Phys Med Rehab, Nov. 1998, Vol 79(11), pp. 1362-6. Using analysis of prospective randomized study comparing transforaminal lumbar epidural injection with lumbar paraspinal trigger-point injection for treatment of patients with sciatica from herniated discs.

2See Botwin, KP et al. Fluoroscopically guided lumbar transforaminal epidural steroid injections in degenerative lumbar stenosis: an outcome study. Am J Phys Med Rehab Dec 2002, Vol 81(12), pp. 898-905.

There are several risks associated with epidural injections, and although they are all relatively rare it is worth discussing each with the professional who will be conducting the procedure to determine the incidence of prevalence in their practice.

Epidural Steroid Injections Potential Risks

Epidural Steroid Injections Potential Risks

As with all invasive medical procedures, there are potential risks associated with lumbar epidural steroid injections. In addition to temporary numbness of the bowels and bladder, the most common potential risks and complications include:

  • Infection. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
  • Dural puncture (“wet tap”). A dural puncture occurs in 0.5% of injections. It may cause a post-dural puncture headache (also called a spinal headache) that usually improves within a few days. Although infrequent, a blood patch may be necessary to alleviate the headache. A blood patch is a simple, quick procedure that involves obtaining a small amount of blood from a patient from an arm vein and immediately injecting it into the epidural space to allow it to clot around the spinal sac and stop the leak.
  • Bleeding. Bleeding is a rare complication and is more common for patients with underlying bleeding disorders.
  • Nerve damage. While extremely rare, nerve damage can occur from direct trauma from the needle, or from infection or bleeding.

Lumbar Epidural Steroid Injection Side Effects

Lumbar Epidural Steroid Injection Side Effects

In addition to risks from the injection, there are also potential side effects from the steroid medication itself. These tend to be rare and much less prevalent than the side effects from oral steroids. Nonetheless, reported side effects from epidural steroid injections include:

  • Localized increase in pain
  • Non-positional headaches resolving within 24 hours
  • Facial flushing
  • Anxiety
  • Sleeplessness
  • Fever the night of injection
  • High blood sugar
  • A transient decrease in immunity because of the suppressive effect of the steroid
  • Stomach ulcers
  • Severe arthritis of the hips (avascular necrosis)
  • Cataracts

An epidural injection delivers steroids into the epidural space around spinal nerve roots to relieve pain – back pain, leg pain, or other pain—caused by irritated spinal nerves. The steroid used in the epidural steroid injection reduces the inflammation of those nerves, which is often the source of the pain. It is important to note that an epidural steroid injection should not be considered a cure for back pain or leg pain: rather, the goal is to help patients get enough pain relief in order to be able to progress with their rehabilitation program.

An epidural steroid injection significantly reduces pain for approximately 50% of patients. It works by delivering steroids directly to the painful area to help decrease the inflammation that may be causing the pain. It is thought that there is also a flushing effect from the injection that helps remove or “flush out” inflammatory proteins from around the structures that may cause pain. In addition to relieving pain, the process of natural healing can occur more quickly once the inflammation is reduced.

Spinal nerves can become inflamed due to irritation from a damaged disc or from contact with a bone spur. Depending on which part of the spine the inflamed nerves are located in, pain and/or other symptoms (such as numbness, tingling) may be experienced in different areas of the body, as shown:

Nerve irritation in the cervical spine

  • Neck pain, or tingling, numbness
  • Shoulder pain, or tingling, numbness
  • Arm pain, or tingling, numbness

Nerve irritation in the thoracic spine

  • Upper back pain
  • Pain along the ribs to the chest wall
  • Pain in the abdomen (rarely)

Nerve irritation in the lumbar spine

  • Low back pain
  • Hip pain
  • Buttock pain
  • Leg pain, or numbness, tingling

Anatomy of the Spinal Nerves and Dura

Anatomy of the Spinal Nerves and Dura

There is a membrane called the dura covering the nerve roots in the spine. Around the dura is a sleeve-like space called the epidural space. Before nerves can travel from the spine into the arms, chest, and legs, they travel through the epidural space, and exit through small nerve holes. The medication from the epidural steroid injection is placed in the epidural space.

Epidural Steroid Injection Procedure

The injection procedure for an epidural includes the following steps:

  • An IV is started so that medicine can be given for relaxation if desired.
  • The patient lies face down on an x-ray table and the skin is well cleaned with an antiseptic.
  • The area where the epidural needle will be inserted is numbed with a local anesthetic.
  • Fluoroscopy (a guided X-ray procedure where the doctor can watch the placement and movement of the needle) will be used to direct a small needle into the epidural space. The patient will feel some pressure during this part. Fluoroscopy is important in this procedure to help ensure correct placement of the medications.
  • A contrast dye is injected to confirm that the medicine spreads to the affected nerve(s) in the epidural space.
  • A combination of numbing medicine (an anesthetic) and time released anti-inflammatory medicine (a steroid) is injected.

The procedure usually takes approximately 30 minutes, followed by about 45 minutes of recovery time at the clinic. On the day of the epidural steroid injection the patient should not drive. Rest is needed and strenuous activities must be avoided on the day of the epidural steroid injection.

Epidural Injection Results and Follow-up

Epidural Injection Results and Follow-up

Following the epidural injection, some partial numbness from the anesthetic may occur in the patient’s arms or legs. Any partial numbness usually subsides after a few hours. Any remaining pain needs to be reported to the physician, and ideally the patient should keep a “pain diary” to record the pain relief experienced over the next week. After the pain diary is returned to the treating physician, the physician should be kept informed of the results in order to plan future tests and/or treatment if needed.

There may be an increase in the patient’s pain that may last for up to several days. This may occur after the numbing medicine wears off but before the steroid has had a chance to work. Ice packs may help reduce the inflammation and will typically be more helpful than heat during this time. Improvements in pain will generally occur within 10 days after the epidural injection, and may be noticed as soon as one to five days after the injection.

Regular medicines may be taken after an epidural steroid injection. On the day following the procedure, the patient may return to his or her regular activities. When the pain has improved, regular exercise may be resumed in moderation. Even if improvement is significant, activities should be increased slowly over one to two weeks to avoid recurrence of pain.

As with any medical procedure, there are certain drawbacks and potential risks associated with an epidural steroid injection for back pain, leg pain or arm pain. One of the most important issues to consider is that the procedure only tends to significantly lessen the patient’s pain about half of the time.

Effectiveness of Epidural Injections

Effectiveness of Epidural Injections

Unfortunately, epidural steroid injections are not always effective—it is estimated that they help relieve the patient’s pain only about 50% of the time. In some cases the pain relief will be permanent. In others, the pain will be lessened enough to allow the patient to progress with rehabilitation and exercise, which helps the patient heal and find pain relief on a long-term basis.

If excellent pain relief is obtained from the first epidural injection, there will be no need to repeat it. If there is a partial benefit (greater than 30% relief from pain) the epidural injection can be repeated for possible additional benefit, or it may be necessary to conduct additional tests to more accurately determine what is causing the patient’s pain. Up to three epidural steroid injections may be performed within a one-year period, spaced at least two to four weeks apart. If the initial injection provides minimal benefit (less than 30% pain relief) the physician may either repeat the injection, or try a different type of injection or treatment.

Potential Risks and Complications

Potential Risks and Complications

As with all invasive medical procedures, there are potential risks associated with epidural steroid injections. However, in general the risk is low, and complications are rare. Potential risks include:

  • Infection. Minor infections occur in 1% to 2% of all injections. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
  • Bleeding. A rare complication, bleeding is more common for patients with underlying bleeding disorders.
  • Nerve damage. While extremely rare, nerve damage can occur from direct trauma from the needle, or secondarily from infection or bleeding.
  • Dural puncture (“wet tap”). A dural puncture occurs in 0.5% of injections. It may cause a post-dural puncture headache (also called a spinal headache) that usually gets better within a few days. Although rare, a blood patch may be necessary to alleviate the headache from a dural puncture.

For a lumbar epidural injection, paralysis is not a risk since there is no spinal cord in the region of the epidural steroid injection. In addition to risks from the injection, approximately 2% of patients will experience epidural side effects from the steroid medication, such as:

  • Transient flushing with a feeling of warmth (‘hot flashes’) for several days
  • Fluid retention, weight gain, or increased appetite
  • Elevated blood pressure
  • Mood swings, irritability, anxiety, insomnia
  • High blood sugar—diabetic patients should inform their primary care physicians about the injection prior to their appointment
  • Transient decrease in immunity
  • Cataracts—a rare result of excessive and/or prolonged steroid usage
  • Severe arthritis of the hips or shoulders (avascular necrosis)—a rare result of excessive and/or prolonged steroid usage

Lumbar epidural steroid injections should not be performed on patients who have a local or systemic bacterial infection, are pregnant (if fluoroscopy is used) or have bleeding problems. Epidural injections should also not be performed for patients whose pain is from a tumor or infection, and if suspected, an MRI scan should be done prior to the injection to rule out these conditions.

Injections may be done, but with extreme caution, for patients with allergies to the injected solution, uncontrolled medical problems (such as congestive heart failure and diabetes), and those who are taking aspirin or other antiplatelet drugs (e.g. Ticlid, Plavix).

Richard A. Staehler, MD. “Lumbar Epidural Steroid Injections for Low Back Pain and Sciatica.” Spine-Health.com. (2007): n. page. Web.