Epidural Steroid Injections
What Are Epidural Steroid Injections?
An epidural steroid injection is an injection of local anesthetic and steroid medication into the epidural space. The epidural space is located in the spine just outside the membrane that covers the spinal cord and nerve roots. This membrane is called the dural membrane. Nerves travel through the epidural space to the back and into the legs. Inflammation of these nerve roots may cause pain in these regions due to irritation from a damaged disc or from contact with the bony structures of the spine.
The goal of an epidural steroid injection is to provide pain relief by reducing the inflammation (swelling) of the nerve roots as they exit the spine. This is done by injecting an anti-inflammatory medicine into the epidural space. An epidural steroid injection will not correct the pre-existing medical problem (i.e., spinal stenosis, herniated or bulging disc, arthritis, etc.), but it may improve the level of pain.
Your back or neck is then cleansed with alcohol and an antiseptic solution. A sterile drape is placed, and your skin is anesthetized (numbed) with a local anesthetic. You may feel a temporary stinging or burning sensation at this time. Under Fluoroscopic guidance, a small needle is then advanced into the epidural space. Pressure is the usual sensation felt during this procedure. If pain is felt, more local anesthetic will be used.
Once in the epidural space, X-ray dye will be injected to confirm the correct location of the needle, and the steroid mixture will then be injected, completing the procedure. After the injection, your skin will be washed and a band aid will be applied.
It is not unusual for a patient to require more than one injection to receive long term benefit. The injections are done in a series of three about 3-4 weeks apart, if needed. If the pain significantly improves, no further injection is needed unless the pain begins to come back.
As with all invasive medical procedures, there are potential risks associated with lumbar epidural steroid injections. In addition to temporary numbness of the bowels and bladder, the most common potential risks and complications include:
- Infection. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
- Dural puncture (“wet tap”). A dural puncture occurs in 0.5% of injections. It may cause a post-dural puncture headache (also called a spinal headache) that usually improves within a few days. Although infrequent, a blood patch may be necessary to alleviate the headache. A blood patch is a simple, quick procedure that involves obtaining a small amount of blood from a patient from an arm vein and immediately injecting it into the epidural space to allow it to clot around the spinal sac and stop the leak.
- Bleeding. Bleeding is a rare complication and is more common for patients with underlying bleeding disorders.
- Nerve damage. While extremely rare, nerve damage can occur from direct trauma from the needle, or from infection or bleeding.