An epidural steroid injection is a minimally invasive procedure that delivers steroids via a needle directly into the epidural space to help reduce inflammation. Inflammation is a common component of many low back conditions and reducing inflammation helps reduce pain.
Steroids inhibit pain by reducing the activity of the immune system to react to inflammation associated with nerve or tissue damage. A typical immune response is the body generating white blood cells and chemicals to protect it against infection and foreign substances such as bacteria and viruses.
An epidural, or spinal steroid injection delivers steroids directly into the epidural space in the spine. Sometimes additional fluid (local anesthetic and/or a normal saline solution) is used to help ‘flush out’ chemicals and substances from around the area that may be a source of inflammation or pain.
The epidural space encircles the dural sac and is filled with fat and small blood vessels. The dural sac surrounds the spinal cord, nerve roots, and cerebrospinal fluid (the fluid that the nerve roots are bathed in).
Typically, a solution containing cortisone (steroid) with local anesthetic (lidocaine or bupivacaine), and/or saline is used.
A steroid, or cortisone, is usually injected as an anti-inflammatory agent. Triamcinolone acetonide, Dexamethasone, and Methylprednisolone acetate are commonly used steroids.