Anesthesiology | Interventional Pain Medicine
Assistant Professor — University of Toronto
Interventional Pain Physician — Afiya Spine & Pain Institute
Staff Anesthesiologist — Scarborough Health Network
An epidural steroid injection is a procedure used to place anti-inflammatory medication near irritated spinal nerves.
The epidural space is the area around the spinal nerves inside the spine. When a nerve is irritated or compressed, it can cause pain that travels from the spine into the leg, buttock, hip, shoulder, or arm, depending on the level involved.
The steroid medication is intended to reduce inflammation around the irritated nerve. In simple terms, it does not remove a disc bulge, arthritis, or narrowing in the spine. It tries to calm the irritated nerve so that pain signals traveling toward the brain are reduced.
Epidural steroid injections can be performed in different ways, including transforaminal, interlaminar, or caudal approaches. These are variations of the same general procedure. The best approach depends on your symptoms, examination, imaging, and the nerve level being targeted.
This procedure is most commonly done for pain caused by irritation or inflammation of a spinal nerve. This is often called radicular pain or sciatica when it affects the leg.
Spinal nerve irritation may cause sharp, burning, electric, or shooting pain. Some people also feel numbness, tingling, heaviness, or weakness in the affected arm or leg.
Common reasons for considering an epidural steroid injection include a disc herniation, spinal stenosis, foraminal narrowing, or inflammation around a nerve root.
The goal is to reduce nerve-related pain, improve function, and make it easier to participate in physiotherapy, walking, strengthening, exercise, or other rehabilitation strategies.
A recent MRI is almost always needed before proceeding with an epidural steroid injection. The MRI helps confirm the likely pain source, choose the safest approach, and identify the correct level to treat.
You usually do not need to fast for this procedure unless you are specifically told otherwise.
The injection is quick, but the full visit includes check-in, assessment, preparation, and recovery.
Most patients should expect the full appointment to take approximately 60 to 90 minutes, although this can vary depending on clinic flow that day.
A transforaminal epidural injection places medication near a specific nerve as it exits the spine. An interlaminar epidural injection places medication into the epidural space from the back of the spine. A caudal epidural injection places medication into the epidural space through an opening near the tailbone.
These are different routes to deliver medication to the same general epidural region. The approach is chosen based on the location of the suspected nerve irritation and what is safest and most appropriate for your anatomy.
Most patients describe:
Local anesthetic is used to reduce discomfort. The procedure is usually brief.
You may walk and do normal light activity after the procedure. Avoid unusually strenuous activity for the rest of the day.
Do not drive until any numbness, weakness, heaviness, or altered sensation has fully resolved. If you feel lightheaded or weak after the procedure, do not drive.
Unlike diagnostic nerve blocks, an epidural steroid injection is not judged only by the first few hours afterward. The steroid effect can take time to develop.
Some patients notice improvement within a few days. For others, improvement may take 1 to 2 weeks.
It is common to have temporary soreness or a pain flare before the benefit becomes clear.
The amount and duration of relief varies from person to person. Some patients have substantial relief, some have partial relief, and some do not improve.
The next step depends on how much relief you have after the injection and how long that relief lasts.
If your nerve pain improves significantly, we may continue to monitor your response and focus on rehabilitation, activity progression, strengthening, or other conservative measures.
If your pain does not improve, or only partially improves, we would usually reassess. This may mean reviewing the MRI again, considering a different epidural approach, targeting a different level, considering a different procedure, or discussing whether another specialist opinion is needed.
For some patients with persistent nerve-related pain, dorsal root ganglion pulsed radiofrequency neuromodulation may be considered as a later step. This is a different procedure aimed at modulating the irritated nerve signal rather than placing steroid into the epidural space.
When symptoms suggest more than one pain source, an epidural steroid injection may sometimes be performed at the same appointment as lateral branch blocks, medial branch blocks, sacral radiofrequency ablation, or lumbar radiofrequency ablation. This is considered only when there is nerve-related or radicular pain as well as a separate pain pattern that may be appropriate for one of those procedures.
Some patients have more than one source of pain. An epidural steroid injection may help nerve-related pain, but it may not explain or treat all of your symptoms.
Keep the injection site dry for 24 hours. Remove bandages after 24 hours.
If you develop a pain flare, this usually improves with time. Ice packs and over-the-counter pain relievers may help if you are allowed to use them. Avoid unusually strenuous activity for the rest of the day.
Epidural steroid injections are commonly performed procedures, but they are deeper spinal injections and have different risks than superficial nerve blocks.
The most common issues are temporary soreness, bruising, lightheadedness, temporary increase in pain, or temporary steroid side effects such as flushing, insomnia, mood change, or elevated blood sugar.
Uncommon risks include bleeding, infection, allergic reaction, medication entering a blood vessel, temporary numbness or weakness, or a dural puncture. A dural puncture can cause a spinal headache that is usually worse when sitting or standing and better when lying down.
Serious complications such as epidural hematoma, deep infection, nerve injury, spinal cord injury, stroke, paralysis, or loss of vision are very rare, but have been reported after epidural steroid injections.
Seek medical attention if you develop fever greater than 38.5°C, worsening redness or swelling at the injection site, drainage from the injection site, new or worsening weakness, new numbness that does not settle, loss of bladder or bowel control, severe headache after the procedure, or severe worsening pain that does not settle.
The procedure itself, including the clinic visit and use of X-ray guidance, is covered by OHIP.
OHIP does not cover the cost of medications used or prescribed, such as local anesthetic, steroid medication, contrast dye, or other medications. These costs may be covered by private insurance.
The medication cost is usually in the range of $25 to $100, depending on the extensiveness of the procedure, but this may vary.
Unless you are told otherwise, you may usually take your regular medications. Blood thinners require separate review.
It is very important that you tell us if you take blood thinners or antiplatelet medications. These medications often need to be held before an epidural steroid injection to reduce the risk of bleeding around the spine. Do not stop them on your own. We will give you specific instructions based on the medication and your medical history.
Tell us before the procedure if you have ever had an allergy or serious reaction to contrast dye, local anesthetic, steroid medication, or antiseptic skin-cleaning solution.
Tell us if you have diabetes, an active infection, are taking antibiotics, are pregnant or may be pregnant, or have had a recent major change in your health.
Afiya Spine & Pain Institute
301 - 15 Wellesley St W, Toronto, ON M4Y 1G1
Phone: 416-413-7999 | E-Fax: 416-641-4520
For questions or concerns after your procedure, contact the clinic.