Epidural Injection for Low Back and Leg Pain

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Nearly everyone experiences an episode of low back pain at one time or another during his or her lifetime. Often low back pain results from nerve compression. Typically, the patient's complaint includes a low backache or sharp pain traveling down one or both legs. A spinal epidural injection, a non-surgical treatment option, may be recommended by the doctor.
Working man experiencing back and leg painThis construction worker's face and body position demonstrates he may have been caught off guard by sudden low backache or sharp pain traveling downward possibly into one or both of his legs.Photo Source: 123RF.com.

Causes of Nerve Compression

Common causes of pinched nerves include disc protrusions into the nerve space (eg, herniated or bulging disc), arthritic facet joints with resultant narrowing of the spinal canal, and bone spurs. Less often, scar tissue that has formed from a previous surgery can cause nerve impingement and pain.

Nerves exit the spinal cord through the epidural space. Often, this space is utilized to deliver medicine in close proximity to the spinal nerves. The most effective medications include local anesthetics (drugs that numb or deaden pain) and anti-inflammatory steroids, which help reduce swelling and inflammation that can lead to pinched nerves.
extradural and intradural space The location of key spinal structures, such as the facet joints and nerve structures, can broaden your understanding of your diagnosis and how a spinal epidural injection works. Photo Source: Shutterstock.com.

Classic Epidural Injection

The epidural space in the spine is accessed during the  injection procedure. First, a sterile solution is applied to the skin area over the injection's target site. Next the site is numbed with a small injection of a local anesthetic. A special type of needle is used to identify the epidural space.

Epidural Injection Needle Guidance

A technique utilizing fluoroscopy (real time x-ray) is used to guide the needle. During fluoroscopy, the physician can watch the needle as it moves through tissues to its destination on a nearby monitor. Fluoroscopy makes it possible to place the medicine close to the exact lesion location (pinched nerve). In addition, modifications, such as a flexible guided catheter can be maneuvered into the proper position to deliver medication. Other modifications include injecting into the foramen, the spinal windows where the nerves exit.
fluoroscopy procedural image  A fluoroscopic image taken during a spinal procedure shows the needle/catheter to the right of the lumbar spine, the low back. Photo Source: SpineUniverse.com.

SpineUniverse News/Research Comment:
2 Epidural Steroid Injection Studies You Need to Know About

Epidural steroid injections are not a new spinal therapy, but researchers are continuing to learn more about them. We describe findings from 2 current studies below, which may help you set clear and realistic expectations if you decide to pursue this treatment.

Study questions injections’ ability to stave off spine surgery.

The first study, published in 2014, explored one of the top benefits of epidural steroid injections: the ability to delay or even prevent the need for spine surgery. The results of the study showed that steroid injections may prevent or delay surgery, but only up to a year.

Being able to avoid surgery for up to a year is still a significant benefit, but the injections’ ability to delay surgery may be more limited than once thought.

“The main finding in this study is that there may be a weak surgery-sparing effect for ESI [epidural steroid injection] in the short term but not the long term,” the authors wrote.

Corticosteroids may not offer additional benefits over anesthetic alone.

The second study, published in 2015, examined the effectiveness of epidural steroid injections on people experiencing lumbar spinal stenosis. Specifically, they wanted to know whether an injection containing a corticosteroid (an anti-inflammatory) plus anesthetic relieved symptoms better than an injection containing only an anesthetic.

The authors found that the injections containing both a corticosteroid and an anesthetic did not provide significant benefit over the anesthetic-only injections. In other words, the results do not show that corticosteroids relieve spinal stenosis symptoms better than an anesthetic alone.

“…results suggested that there was little to no benefit 6 weeks later from adding corticosteroids to lidocaine in epidural injections for the treatment of lumbar spinal stenosis symptoms,” said author Judith Turner, PhD, Professor of Psychiatry and Behavioral Sciences and Rehabilitation Medicine at the University of Washington, Seattle, WA.

While these 2 studies question the overall effectiveness of epidural steroid injections, that doesn’t mean injections aren’t worthwhile spine treatments. Other current research shows that epidural steroid injections safely relieve pain and improve function. The mixed evidence underscores the need for open and honest dialogue between you and your doctor before starting any treatment. By setting the right expectations beforehand, you’re more likely to experience success after.

Commentary by: Leonardo Kapural, MD, PhD

Epidural injection procedures for management of low back and leg pain have significantly evolved over the last decade. The main purpose of such injections is to deliver medication as close as possible to the area of pathology, thereby avoiding the effects of orally administered steroids. It seems likely that the outcomes and potential complications may differ from one technical approach to another.

One should also bear in mind that different technical approaches (like interspinal or transforaminal) may be needed for various spinal causes of back and leg pain. The main rationale for performing these minimally invasive procedures is their favorable risk/benefit ratio.

Updated on: 02/26/19
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