A lumbar injection is a procedure where medication is delivered directly into or near structures in the lower spine to relieve pain or pinpoint its source. Most commonly, this means a combination of a steroid (to reduce inflammation) and a local anesthetic (to numb pain) placed precisely near an irritated nerve or joint. The procedure typically takes 15 to 30 minutes, and most people resume normal activities within 24 hours.
Types of Lumbar Injections
Not all lumbar injections target the same structure. The type you receive depends on where your pain originates and whether the goal is treatment, diagnosis, or both.
Epidural injections are the most common type. The medication is placed into the epidural space, a narrow area just outside the membrane that surrounds the spinal cord. These are primarily used when a nerve is compressed or inflamed, such as from a herniated disc causing sciatica. The steroid calms inflammation around the nerve, and the anesthetic provides more immediate relief.
Facet joint injections target the small joints that connect each vertebra along the back of your spine. These joints can become painful from arthritis or injury. Medication is injected directly into the joint or around the tiny nerves that carry pain signals away from it.
Medial branch blocks are purely diagnostic. Small amounts of anesthetic are placed on the nerves that supply a specific facet joint. If your pain disappears, the doctor has confirmed which joint is causing the problem. This information can guide the next step in treatment, including a procedure that disrupts those pain-signaling nerves for longer-lasting relief.
How Lumbar Injections Reduce Pain
The steroid component works the same way your body’s own cortisol does, just in a much more concentrated dose delivered right where it’s needed. It blocks the chemical chain reaction that produces inflammation. Specifically, it prevents cells from releasing the compounds that trigger swelling, redness, and pain signaling. The result is less fluid pressing on the nerve, less irritation, and less pain.
Steroids also quiet the nerve fibers responsible for transmitting pain. This is separate from the anesthetic effect. While the local anesthetic wears off within hours, the anti-inflammatory action of the steroid builds over several days and can last weeks to months.
What Happens During the Procedure
You’ll lie face down on a procedure table. The doctor identifies the correct spot on your lower back using live imaging, either X-ray (fluoroscopy) or CT guidance. This is not optional or decorative. Real-time imaging lets the doctor see exactly where the needle tip is relative to your spinal cord, nerves, and surrounding structures.
After cleaning the skin and numbing it with a local anesthetic, the doctor advances a thin needle toward the target. For epidural injections, the needle passes through the muscles of the lower back and through a tough ligament called the ligamentum flavum. The doctor confirms entry into the epidural space using a technique called “loss of resistance,” where the syringe plunger suddenly moves freely as the needle passes through the ligament into the open space beyond it.
A small amount of contrast dye is then injected so it shows up on the imaging screen. This confirms the needle is in the right location and not inside the spinal fluid or a blood vessel. If you have a contrast allergy, air or an alternative agent can be used instead. Once placement is confirmed, the steroid and anesthetic mixture is injected, and the needle is removed. No stitches are needed.
How Well They Work
For sciatica caused by a herniated disc, epidural steroid injections provide meaningful short-term relief (within three months) and moderate relief out to six months. A 2024 meta-analysis in Frontiers in Neurology found that across multiple studies, 60% to 86% of patients experienced more than 50% pain reduction. Long-term effects beyond six months, however, are limited.
One earlier study found that the relief from epidural steroid injections for sciatica could last up to 12 months and produced outcomes comparable to surgery for the same condition. This makes the injection a reasonable option to try before considering a surgical approach, particularly since the recovery is dramatically simpler.
Facet joint injections and medial branch blocks are harder to evaluate for “success” because their primary value is often diagnostic. When a medial branch block eliminates 80% to 100% of your pain, that’s a positive result not because it’s a lasting treatment, but because it confirms the pain source and opens the door to a longer-lasting nerve procedure.
Recovery and Activity Restrictions
Recovery is quick. Cleveland Clinic’s post-procedure guidelines advise resuming normal activities 24 hours after the injection. On the day of the procedure, you should not operate heavy machinery, power tools, or drive. For the first 48 hours, avoid lifting anything over 20 pounds without help.
Gentle stretching is not just allowed but recommended afterward. It helps the medication spread and absorb into the surrounding tissue. The anesthetic portion of the injection may give you near-immediate relief that fades within hours. Don’t be discouraged. The steroid typically takes three to seven days to reach its full effect. Some people notice the best results after two weeks.
Side Effects and Risks
The most common side effects are mild: temporary soreness at the injection site, a brief increase in pain, facial flushing from the steroid, and occasionally a slight rise in blood sugar that lasts a few days (relevant if you have diabetes). These resolve on their own.
Serious complications are rare but real. The FDA has issued a safety communication warning that epidural corticosteroid injections can, in rare cases, cause loss of vision, stroke, paralysis, seizures, nerve injury, and spinal cord damage. Many of these events occurred within minutes to 48 hours of the injection, and some patients did not recover. The risk is low enough that millions of these procedures are performed safely each year, but it is not zero.
Who Should Avoid Lumbar Injections
Blood-thinning medications are the biggest concern. If you take warfarin, clopidogrel, aspirin, ibuprofen, or any other anticoagulant or antiplatelet drug, your doctor needs to know before scheduling the procedure. Inserting a needle near the spinal column while your blood’s clotting ability is reduced raises the risk of dangerous bleeding and potential nerve compression.
Certain health conditions also increase bleeding risk, including uncontrolled high blood pressure, recent surgery or trauma, and some cancers. Active infections near the injection site or throughout the body are also reasons to postpone. Your doctor will typically ask you to stop specific blood thinners days before the procedure, with the exact timeline depending on which medication you take.
Diagnostic vs. Therapeutic Injections
One detail that surprises many patients: lumbar injections aren’t always about treatment. Sometimes the entire point is to figure out where your pain is coming from. If you’ve had back pain for more than six months without a clear explanation on imaging, your doctor may recommend diagnostic injections to narrow down the source.
For this to work reliably, the process often requires two separate injections on different days using anesthetics that wear off at different rates. If your pain disappears for the expected duration with both injections, that’s strong confirmation the targeted structure is the culprit. A single injection can produce false positives, so the two-injection approach is considered the most reliable standard. This diagnostic clarity can be the difference between an effective treatment plan and months of guesswork.