What Is an Epidural Steroid Injection?
An epidural steroid injection (ESI) is a minimally invasive procedure in which a corticosteroid (anti-inflammatory medication), often combined with a local anesthetic, is injected into the epidural space — the area surrounding the spinal cord and nerve roots. The goal is to reduce inflammation around irritated or compressed nerves, which can significantly decrease pain and improve mobility.
ESIs are one of the most commonly performed interventional pain procedures and are used for a range of spinal conditions.
When Are Epidural Steroid Injections Used?
Your doctor may recommend an ESI if you have pain radiating from the spine into your arms or legs — commonly called radiculopathy or "pinched nerve" pain. Conditions frequently treated with ESIs include:
- Herniated disc: When a disc bulges and presses on a spinal nerve.
- Spinal stenosis: Narrowing of the spinal canal that compresses nerves.
- Degenerative disc disease: Wear-and-tear changes in the discs causing nerve irritation.
- Sciatica: Pain radiating down the leg along the sciatic nerve path.
- Spondylolisthesis: One vertebra slipping forward over another, irritating nerve roots.
Types of Epidural Steroid Injections
There are three main approaches, depending on the location of your pain and the anatomy involved:
- Interlaminar ESI: The needle is inserted between two vertebrae from the back, depositing medication near the affected nerve roots. This is the most traditional approach.
- Transforaminal ESI (selective nerve root block): The needle is directed through the opening where a specific nerve exits the spine. This is more targeted and often preferred for one-sided radicular pain.
- Caudal ESI: The injection is given through the sacral hiatus at the base of the spine — useful for lower lumbar and sacral nerve issues.
What Happens During the Procedure?
Epidural steroid injections are typically performed in an outpatient or ambulatory surgery setting and take about 15–30 minutes. Here's what to expect:
- You'll be positioned on a procedure table — usually lying face down.
- The skin will be cleaned and a local anesthetic applied to numb the area.
- Using live X-ray guidance (fluoroscopy) or ultrasound, your doctor carefully guides a needle to the exact target location.
- A contrast dye is often injected first to confirm correct needle placement.
- The steroid and anesthetic mixture is then injected.
- You'll rest briefly in a recovery area before being discharged.
Most patients can return home the same day and resume light activities within 24 hours.
What Results Can You Expect?
Responses to ESIs vary. Some people experience significant relief within days; others notice gradual improvement over 1–2 weeks. The local anesthetic may provide brief relief immediately after the procedure before wearing off, with the steroid's anti-inflammatory effects taking hold over the following days.
Relief can last from a few weeks to several months. ESIs are generally not a permanent cure — they are most effective when used as part of a broader treatment plan that includes physical therapy and rehabilitation.
Typically, physicians recommend no more than three injections per year in a given spinal region to minimize the cumulative effects of steroids.
Risks and Side Effects
ESIs are generally considered safe when performed by an experienced specialist under imaging guidance. Potential risks include:
- Temporary increased pain or soreness at the injection site
- Headache (more common with inadvertent dural puncture)
- Temporary blood sugar elevation (important for people with diabetes)
- Rare risk of infection, bleeding, or nerve injury
- Flushing, facial redness, or mild insomnia in the days after the injection
Discuss your full medical history, including any blood thinners or allergies, with your pain specialist before the procedure.