An epidural steroid injection (ESI) is a minimally invasive procedure that can help relieve neck, arm, back, and leg pain caused by inflamed spinal nerves due to spinal stenosis or disc herniation. Medicines are delivered to the epidural space, which is a fat-filled area between the bone and the protective sac of the spinal nerves. Pain relief may last for several days or even years. The goal is to reduce pain so that you may resume normal activities and a physical therapy program.
What is an epidural steroid injection (ESI)?
A steroid injection includes both a corticosteroid (e.g., triamcinolone, methyl-prednisolone, dexamethasone) and an anesthetic numbing agent (e.g., lidocaine or bupivacaine). The drugs are delivered into the epidural space of the spine, which is the area between the bony vertebra and the protective dura sac surrounding the spinal nerves and cord
Corticosteroid injections can reduce inflammation and can be effective when delivered directly into the painful area. Unfortunately, the injection does not make a herniated disc smaller; it only works on the spinal nerves by flushing away the proteins that cause swelling. The pain relief can last from days to years, allowing your spinal condition to improve with physical therapy and an exercise program.
Who is a candidate?
Patients with pain in the neck, arm, low back, or leg (sciatica) may benefit from ESI. Specifically, those with the following conditions:
- Spinal stenosis: A narrowing of the spinal canal and nerve root canal can cause back and leg pain, especially when walking.
- Spondvlolisthesis: A weakness or fracture between the upper and lower facets of a vertebra. If the vertebra slips forward, it can compress the nerve roots causing pain.
- Hernitaed disc: The gel-like material within the disc can bulge or rupture through a weak area in the surrounding wall (annulus). Irritation, pain, and swelling occur when this material squeezes out and comes in contact with a spinal nerve.
- Degenerative disc: A breakdown or aging of the intervertebral disc causing a collapse of the disc space, tears in the annulus, and growth of bone spurs.
- Sciatica: Pain that courses along the sciatic nerve in the buttocks and down the legs. It is usually caused by compression of the 5th lumbar or 1st sacral spinal nerve.
Who performs the procedure?
Physicians who perform epidural steroid injections include physiatrists (PM&R), radiologists, anesthesiologists, neurologists, and surgeons.
What happens before treatment?
The doctor who will perform the procedure reviews your medical history and previous imaging studies to plan the best approach for the injections. Be prepared to ask any questions at this appointment.
Patients who take blood-thinning medication (Coumadin, Plavix, etc.) may need to stop taking it several days before the ESI. Discuss any medications with your doctors, including the one who prescribed the medication and the doctor who will perform the injection.
The procedure is usually performed in an outpatient center using x-ray fluoroscopy. Make arrangements to have someone drive you to and from the center on the day of the injection.
What happens after treatment?
Most patients can walk around immediately after the procedure. After being monitored for a short time, you usually can leave the center. Rarely temporary leg weakness or numbness can occur; therefore someone should drive you home.
Typically patients resume full activity the next day. Soreness around the injection site may be relieved by using ice and taking a mild analgesic (Tylenol).
You may want to record your levels of pain during the next couple of weeks in a diary. You may notice a slight increase in pain, numbness, or weakness as the numbing medicine wears off and before the corticosteroid starts to take effect.
Patients should schedule a follow-up appointment with the referring or treating physician after the procedure to document the efficacy and address any concerns the patient may have for future treatments and expectations.
What are the results?
Many patients experience some pain relief benefits from ESI [1,2]. For those who experience only mild pain relief, one to two more injections may be performed, usually in 1-4 week intervals, to achieve the full effect. Duration of pain relief varies, lasting for weeks or years. Injections are done in conjunction with a physical therapy and/or home exercise program to strengthen the back muscles and prevent future pain episodes.
What are the risks?
With few risks, ESI is considered an appropriate nonsurgical treatment for some patients. The potential risks associated with inserting the needle include spinal headache from a dural puncture, bleeding, infection, allergic reaction, and nerve damage/paralysis (rare).
Corticosteroid side effects may cause weight gain, water retention, flushing (hot flashes), mood swings or insomnia, and elevated blood sugar levels in people with diabetes. Any numbness or mild muscle weakness usually resolves within 8 hours in the affected arm or leg (similar to the facial numbness experienced after dental work). Patients who are being treated for chronic conditions (e.g., heart disease, diabetes, rheumatoid arthritis) or those who cannot temporarily discontinue anti-clotting medications should consult their personal physician for a risk assessment.