Epidural steroid injection (ESI) is a common procedure used to relieve pain in the spine caused by inflammation and pressure on the nerves. This injection is a minimally invasive procedure that involves injecting a corticosteroid medication into the epidural space, which surrounds the spinal cord and nerve roots which become irritated.
Please note that this procedure is very different than the epidural procedure that is used for women in labor during pregnancy. That type of epidural is referred to as a labor epidural.
ESIs are typically used to treat chronic pain conditions such as spinal stenosis (narrowing of the spinal canal), herniated discs which intrude into the space where the spinal nerves run through, and degenerative disc disease. In this article, we will discuss in detail what ESI is, how it works, and what to expect during the procedure.
1. Anatomy of the Spine and Epidural Space
To understand ESI, it is essential to understand the anatomy of the spine and the epidural space. The spine consists of 33 vertebrae that are separated by intervertebral discs. The spinal cord runs through a canal just behind the vertebrae and is surrounded by the epidural space, which is filled with fatty tissue and blood vessels.
2. What is an Epidural Steroid Injection?
An ESI is an injection of a steroid medication into the epidural space of the spine. Often the discs between the vertebrae start to degenerate and bulge into the epidural space causing compression of the spinal nerves. The nerves become inflamed due the pressure on them. The steroid medication reduces inflammation and relieves pressure on the nerve roots, thereby reducing pain.
3. How Does an Epidural Steroid Injection Work?
The steroid medication used in ESI is a synthetic version of cortisol, a hormone produced by the body’s adrenal glands. Cortisol is a potent anti-inflammatory medication that reduces inflammation by suppressing the immune system.
The steroid medication is injected into the epidural space, where it reduces inflammation and relieves pressure on the nerve roots. This reduces pain and improves mobility.
4. Procedure for Epidural Steroid Injection
The ESI procedure is usually performed as an outpatient procedure under local anesthesia. The procedure takes about 10-15 minutes and involves the following steps:
4.1 Preparation
Before the procedure, the patient is positioned on their stomach and the skin over the injection site is cleaned and sterilized. A local anesthetic is administered to numb the skin and deeper tissues.
4.2 Needle Insertion
Using live X-ray guidance (fluoroscopy), the physician inserts a needle into the epidural space. Confirmation of correct needle placement can be done by injecting a small amount of contrast dye and then taking an xray image. This should show spread of dye up and down the epidural space.
4.3 Injection
The steroid medication is injected into the epidural space through the needle.
4.4 Post-Injection Care
After the injection, the patient is monitored for a short period and is then allowed to go home. Patients may experience mild discomfort and numbness in the injected area. Ice may be applied to the injection site to reduce swelling.
It usually takes about 48 hours for corticosteroid medication’s effect to become noticeable.
5. Indications for epidural steroid injection
The following are typical diagnoses for having an epidural steroid injection:
- spinal stenosis
- sciatica
- brachial/cervical neuritis
- radiculopathy
- herniated discs
6. Risks and Complications of epidural steroid injections
ESI is generally considered safe, but as with any medical procedure, there are risks and complications. The most common side effects include temporary flushing, mild fever, and increased pain. In extremely rare cases, ESI can cause nerve damage, infection, or bleeding.
In 2022, we performed 4122 epidural steroid injections at our practice in southern California, University Pain Consultants, without any serious complications.
7. Benefits of Epidural Steroid Injection
ESI can be an effective treatment for relieving chronic pain caused by inflammation and pressure on the nerve roots. It is a minimally invasive procedure that may provide long-lasting pain relief without the need for surgery.
8. Take home message
ESI is a minimally invasive procedure that is used to relieve chronic pain caused by inflammation and pressure on the nerve roots. The procedure involves injecting a steroid medication into the epidural space of the spine, which reduces inflammation and relieves pressure on the nerve roots. ESI is generally considered safe and effective, but as with any medical procedure, there are risks and rare complications.
Related: The 5 most common pain injections
About the author: Rainier Guiang, MD is board certified in Pain Management and Anesthesiology and has been in academic and private practice since 1999.
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