The epidural space lies outside the spinal cord between the vertebrae and the dura mater (a tough membrane which encloses the spinal cord and the cerebrospinal fluid). Via the epidural, the spinal nerves to the entire body can be accessed and treated with medications. The space is filled with loose fatty tissue and small blood vessels.
An epidural steroid injection delivers steroid medication into the epidural space around the spinal nerve roots. It works by decreasing the inflammation in the area thus reducing discomfort and pain in the back, and/or the legs. The duration of the action of the local anesthetic is usually only a few hours and the steroid may take a day to two to start working. You may get your pain back in the window of the local anesthetic wearing off and the delayed onset of action of the long acting steroids.
Steroid and lidocaine anesthetic are injected under fluoroscopy x-ray with you under conscious sedation in the neck area.