Epidural Steroid Injection Overview

An epidural steroid injection (ESI) is a common method for treating conditions associated with herniated disc4inflammation of the low back. With certain spine and back disorders, there is associated leg and arm pain.

This occurs when the spinal nerves become inflamed due to narrowing of the canal where the nerves pass down and out the spine. Certain conditions cause narrowing of the spinal passages, which results in nerve compression. These conditions include herniated discs, thickening of ligaments, bone spurs, joint cysts, and spondylolisthesis (abnormal alignment of vertebrae).

How does the epidural steroid injection work?

A steroid medication has a very potent anti-inflammatory action, which allows it to decrease pain and improve function. The steroid is placed in the epidural space, which is a fat-filled sleeve surrounding the spinal sac.

The epidural space provides cushioning for the spinal cord and nerves. While the steroidal agent cannot alter the underlying condition, it can break the cycle of inflammation and pain, which allows the patient to tolerate the symptoms related to the spine disorder.

How is the ESI performed?

The three methods of the epidural steroid injection procedure are the interlaminar, caudal, and transforaminal approaches. These approaches are all done using fluoroscopic (x-ray) guidance.

Before the medication is injected, a contrast dye is instilled to confirm that the needle is positioned in the right place. Most doctors add a local anesthetic to provide temporary pain relief.


  • Interlaminar ESI – This involves placement of the needles into the back portion of the epidural space, to deliver the steroid over a wider area. The medication spreads to both sides of the spinal canal and over many spinal segments.

    Lumbar Transforaminal Injection

    Lumbar Transforaminal Injection


  • Caudal ESI – The needles are placed at the sacral hiatus, which is a small boney opening right above the coccyx (tailbone) and at the very bottom of the epidural space. The steroid will spread over several spinal segments, as well as both sides of the spinal canal.


  • Transforaminal ESI – Also called a “nerve block,” this involves the needle being placed along the nerve as it exits the spine. The steroid medication is placed into the nerve sleeve and then travels up the sleep to the epidural space. This method allows for the concentrated steroid to enter just one segment and one side, allowing for more specific coverage of a single nerve. In addition to relieving pain and improving function, this approach is often used as a diagnostic procedure.


How long will I stay at the office or hospital?

All three ESI procedures are done on an outpatient basis. This means the patient can return to his/her pre-injection level of activities the next day. Because some patients receive sedation for the procedure, a driver will be necessary.

What can I expect after the epidural steroid injection?

pain relief3The steroid medication starts to work within 1 to 3 days, but for some patients, it can take up to a week for maximum benefits. A few patients report an increase in their usual pain for 24 to 48 hours following the procedure.

While the steroids are usually well-tolerated, some people experience side effects, such as the “steroid flush” (flushing and a feeling of warmth of the chest and face that persists for several days). Other side effects include trouble sleeping, anxiety, and temporary water retention.

How well do ESIs work?

The epidural steroid injection is a safe and effective procedure for the treatment of pain associated with spinal conditions. The injection can be safely repeated periodically to maintain benefits. Overall, ESIs are well-tolerated when used as an adjunctive therapy along with medications and physical therapy.

According to numerous research studies, patients who have had symptoms for less than three months have a usual response rate of 90%, whereas patients who have had symptoms much longer have success rates of between 70 and 80%.

Patient response to ESI is related to the underlying conditions, and in general, pain related to disc herniation responds better than radicular pain from spinal stenosis.



Kim D, Brown J. Efficacy and safety of lumbar epidural dexamethasone versus methylprednisolone in the treatment of lumbar radiculopathy: a comparison of soluble versus particulate steroids. Clin J Pain. Jul-Aug 2011;27(6):518-22

McLain RF, Kapural L, Mekhail NA. Epidural steroid therapy for back and leg pain: mechanism of action and efficacy. Spine J. 2005;5:191-201