Epidural Steroid Injections
What Are Epidural Steroid Injections?
Epidural steroid injections are injections 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.
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.