An epidural steroid injection (ESI) delivers anti-inflammatory medication into the epidural space around a compressed or irritated spinal nerve to ease back, neck, and radiating arm or leg pain from conditions like sciatica and herniated discs.
OVERVIEW
What an epidural steroid injection is & how it works
An epidural steroid injection places a small, targeted dose of corticosteroid—usually combined with a local anesthetic—into the epidural space, the area just outside the protective covering of the spinal cord and nerve roots. When a disc herniation, bone spur, or narrowed canal presses on a nerve, that nerve can become inflamed and send pain, numbness, or tingling into the arm, leg, or buttock. The steroid works by reducing that inflammation, which can quiet the irritated nerve and help interrupt the pain cycle.
At Columbia Pain & Spine Institute in Gresham and Portland, Oregon, our dual board-certified, fellowship-trained Physical Medicine & Rehabilitation physicians most often use two access routes for this procedure:
- Interlaminar ESI: the needle is advanced between the bony plates (laminae) of adjacent vertebrae to reach the epidural space near the affected level, allowing medication to spread to the inflamed nerves at that level. This approach can be used in the cervical (neck), thoracic (mid-back), and lumbar (low back) spine.
- Caudal ESI: the needle enters through the sacral hiatus, a natural opening at the base of the spine, to deliver medication around the lower lumbar and sacral nerve roots. The caudal route is a versatile option, including for patients who have had prior lumbar surgery.
An ESI is primarily a therapeutic treatment aimed at relieving pain and inflammation. It is one of several approaches we offer—explore the full category of spinal & epidural injections to compare options.
Commonly treats
YOUR VISIT
What to expect during an ESI
An epidural steroid injection is a minimally invasive outpatient procedure performed under image guidance for accuracy. It may be done in our office setting or at the on-site Burnside Surgery Center in Gresham.
Before
Your physician reviews your history, exam, and imaging (such as an MRI) to confirm the level and side to target. You will receive instructions about your medications, including any blood thinners. The injection area is cleaned and a local anesthetic is used to numb the skin, so you stay comfortable. Most patients remain awake; light sedation is available when appropriate.
During
You typically lie face down on a procedure table. Using fluoroscopy (live X-ray), your physician guides a thin needle into the epidural space, often injecting a small amount of contrast dye to confirm correct placement before delivering the steroid and anesthetic. The injection itself takes only a few minutes, and the full visit is usually brief.
After & recovery
You will rest and be monitored for a short time, then go home the same day. Because an ESI is minimally invasive, many patients resume normal activities within a day or two; if you received sedation, please arrange for someone to drive you home. Mild soreness at the injection site is common and usually settles quickly. The local anesthetic may provide brief early relief, while the steroid typically takes several days to reach its full anti-inflammatory effect. Keeping a simple pain diary helps your physician gauge your response at follow-up. Because the injection can calm pain, it may open a valuable window to advance physical therapy and conditioning. See all of our pain management services.
RELATED PROCEDURES
Related & alternative options
Depending on your diagnosis and how you respond, your physician may recommend a more nerve-specific approach or a different target.
Transforaminal ESI
A more selective approach that delivers steroid alongside a single exiting nerve root through the foramen—useful when pain follows one specific nerve, and it can help confirm the level involved.
Medial branch block
When pain comes from arthritic facet joints rather than a compressed nerve, this diagnostic block helps identify the source and can guide longer-lasting treatment.
Radiofrequency ablation
If injections provide only short-term relief from facet-related pain, RFA may offer longer-lasting relief by interrupting the small nerves that carry those pain signals.
FAQ
Frequently asked questions
How long does relief from an epidural steroid injection last?
It varies from person to person. Some patients experience relief lasting weeks to months, while for others a single injection helps break the pain cycle. Because the steroid reduces inflammation gradually, meaningful relief often develops over several days rather than immediately.
How many injections will I need?
There is no fixed number. Your physician tailors the plan to your diagnosis and response; some patients do well with one injection, while others benefit from a planned series spaced over time. Steroid injections are generally spaced out and limited over the course of a year, and your physician will review what is appropriate for you.
Is an ESI a diagnostic or therapeutic procedure?
An epidural steroid injection is primarily therapeutic—its goal is to relieve pain and inflammation. A more selective transforaminal injection can carry added diagnostic value by targeting a single nerve root, helping confirm which nerve is responsible.