Epidural steroid injection is a technique for relieving pain from spinal stenosis and spinal disc herniation. Using a needle, relatively small amounts of corticosteroids together with a local anesthetic are injected into the epidural space around the spinal cord and spinal nerves. The anti-inflammatory effect of the corticosteroid is responsible for providing pain relief.
Modern techniques employ image guidance for accuracy. This allows the physician to visualize the location of the needle with respect to the anatomy prior to the injection. While traditional techniques without image guidance, also known as blind injections, can assure a degree of accuracy using anatomical landmarks, it has been shown in studies that image guidance provides much more reliable localization and accuracy in comparison.