Epidural Steroid Injections (Lumbar ESI)

Key facts

Who it is for

How an epidural steroid injection works

Spinal nerves leave the spinal canal through small openings on each side of the spine. When a disc bulges into that space or arthritis narrows it, the nerve root becomes inflamed and swollen, and that inflammation, more than pressure alone, produces the burning, shooting leg pain of sciatica. The epidural space is the thin fat-filled layer that surrounds the nerve roots inside the canal. Placing a small dose of corticosteroid there bathes the inflamed root directly, at a concentration no oral medication can match.

The steroid is a slow-acting anti-inflammatory. It does not shrink the disc or widen the canal. What it does is turn down the chemical irritation so the nerve can settle while the body reabsorbs disc material over the following weeks and months, a process that happens on its own in most disc herniations. That is why the injection works best for a recent flare of nerve pain and less well for years-old stenosis or for back pain without leg symptoms.

Every injection is done under fluoroscopy (live X-ray) with contrast dye. The contrast shows the physician that the medication is spreading along the target nerve and, just as important, that the needle is not in a blood vessel or in the fluid space around the spinal cord.

Interlaminar vs transforaminal: which approach and why

There are three ways into the lumbar epidural space. The choice depends on where your pain comes from, your anatomy and any prior surgery.

• Transforaminal (TFESI). The needle is guided to the opening where one specific nerve root exits, and medication is delivered to the front of the epidural space where the disc meets the nerve. This is the most targeted approach and the one we usually choose for one-sided sciatica from a disc herniation or foraminal narrowing at a single level. A transforaminal injection with a small volume of local anesthetic can also be used as a selective nerve root block to confirm which level is generating the pain.
• Interlaminar. The needle passes between the bony plates (laminae) at the back of the spine into the midline epidural space. Medication spreads across both sides and over one to two levels. This suits central spinal stenosis, symptoms in both legs, or multilevel disease. It carries a slightly higher chance of a dural puncture headache than the transforaminal route, and the medication is less concentrated at any single nerve.
• Caudal. The needle enters through the sacral hiatus at the very bottom of the spine. It is the safest route for a dural puncture and the usual choice after lumbar fusion or laminectomy, where scar or hardware blocks the other approaches, but it is the least targeted. See caudal steroid injection.

For neck and arm pain the approach is different and the safety rules are stricter; read cervical epidural steroid injection. We perform epidural injections at our Houston and Webster offices, and in Pearland when that office opens in November 2026.

What happens on procedure day

1. Check-in and review: we confirm your blood-thinner plan, glucose (if diabetic), allergies and any changes in symptoms, and you sign consent. Bring a driver if you chose sedation.
2. Positioning: you lie face down on the fluoroscopy table with a pillow under the abdomen. Your back is cleaned with antiseptic and draped. An IV is placed only if sedation is planned.
3. Numbing: the skin and deeper tissue over the target are numbed with lidocaine. Most people describe pressure rather than sharp pain from this point on.
4. Needle placement: using live X-ray, the physician guides a thin needle to the transforaminal or interlaminar target, then injects a small amount of contrast dye to confirm the spread pattern and rule out a blood vessel.
5. Injection: a mix of steroid (dexamethasone for transforaminal injections, or a longer-acting steroid for interlaminar) and a small dose of local anesthetic is injected slowly. You may feel a brief pressure or a reproduction of your usual leg pain that fades within seconds.
6. Recovery: you rest 15–30 minutes while we check your legs for strength and sensation, then go home. Total office time is usually 60–90 minutes.

After the procedure

Day 0. Take it easy. Your leg may feel numb, heavy or briefly weak for a few hours from the local anesthetic, so do not drive that day. You can eat normally, ice the injection site for 15 minutes at a time, and take your usual medications. Some people feel a temporary increase in back pain that evening.

Days 1–3. Return to work and light activity. A steroid flare (a sharp uptick in pain for 24–72 hours) happens in a small number of people and settles on its own. Facial flushing, trouble sleeping and a higher blood sugar are common for a few days. The steroid effect usually starts to build during this window.

Week 1–2. This is when most of the benefit arrives. Resume or start physical therapy and home exercise; the injection creates a window for rehab, not a replacement for it.

Judging the response. We ask you to rate the change at 2 weeks. If leg pain has dropped by half or more, we let the injection run its course and repeat only when pain returns. If there is little change at 2 weeks, a second injection with the same technique is unlikely to work and we look at the diagnosis instead.

Call us for a fever over 100.4 °F, a headache that is worse sitting up and better lying flat, new weakness in either leg, new bladder or bowel trouble, or redness and drainage at the site.

What the evidence shows

Epidural steroid injections are among the most studied procedures in pain medicine, and the honest summary is this: they reliably help radicular (nerve-root) leg pain in the short term, they help axial back pain very little, and they do not change whether someone eventually needs surgery.

• In a well-designed randomized trial of transforaminal injections for sciatica from a disc herniation (Ghahreman 2010), about half of patients had at least 50% relief one month after a steroid injection, compared with roughly one in five or fewer after local anesthetic or saline.
• The 2020 Cochrane review of epidural corticosteroids for lumbosacral radicular pain found a small short-term reduction in leg pain and disability compared with placebo; the authors judged the average effect modest, which matches what we see: some people get dramatic relief, others get little.
• For spinal stenosis, the LESS trial (New England Journal of Medicine, 2014) found that adding steroid to a lidocaine epidural gave minimal extra benefit at 6 weeks. Injections can still be worthwhile for stenosis flares, but expectations should be lower than for a disc herniation.
• The ASIPP 2021 epidural guidelines rate the evidence as Level I (strongest) for lumbar disc herniation and radiculitis with both interlaminar and transforaminal approaches, and weaker for axial pain and post-surgery pain.

Repeated steroid exposure has real costs: bone density loss, adrenal suppression and, in diabetics, glucose swings. That is why guidelines and most insurers limit steroid injections to roughly 3–4 per year, and why we only repeat an injection that clearly worked.

Alternatives and what comes next

Most sciatica improves within 6–12 weeks with or without an injection, so a short course of anti-inflammatories, a nerve-pain medication and guided exercise is a reasonable first step for milder symptoms. Read medication management for how we handle medications.

If an epidural injection helps and then wears off, a repeat injection is reasonable within the yearly limit. If leg pain persists beyond two well-placed injections, or weakness is progressing, we refer to a spine surgeon for a decompression discussion; a selective nerve root block can confirm the level first. If the pain turns out to be mainly in the back rather than the leg, medial branch blocks and radiofrequency ablation address facet joints, and SI joint injections address the sacroiliac joint. For pain that continues after spine surgery, see post-laminectomy syndrome and spinal cord stimulation.

Safety and preparation

• Blood thinners: tell us at scheduling if you take warfarin, apixaban, rivaroxaban, dabigatran, clopidogrel, prasugrel, ticagrelor, enoxaparin or daily aspirin. Epidural injections are considered higher bleeding-risk procedures, and most of these medications are paused for 1–7 days depending on the drug. We coordinate the hold with your prescribing physician or cardiologist; never stop a blood thinner on your own.
• Diabetes: the steroid can raise blood sugar for several days. Check your glucose more often for a week, keep taking your diabetes medication, and call if readings stay above 300. We may postpone the injection if your glucose is very high on the day.
• Infection or fever: we do not inject if you have a fever, an active infection anywhere (including urinary, dental or skin), or are on antibiotics for one. Reschedule when it has cleared.
• Allergies (contrast, steroid, local anesthetic): tell us about any reaction to iodine contrast dye, X-ray dye, cortisone, lidocaine or dental numbing. We can pre-medicate or use a different agent.
• Pregnancy: the procedure uses X-ray. Tell us if you are or could be pregnant; we will test or postpone.
• Sedation and driving: if you choose IV sedation, do not eat for 6 hours or drink for 2 hours beforehand, and bring an adult driver. Even without sedation, leg numbness after the injection makes driving unsafe that day, so plan for a ride.
• Recent steroids: a steroid injection anywhere in the body (joint, epidural, trigger point) within the past 2 weeks, or a course of oral prednisone, usually means we wait.
• Imaging: bring or have us request your MRI or CT report and images; we plan the level and approach from them.

Risks and side effects

Frequently asked questions

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