An epidural steroid injection is a procedure which decreases the irritation of the nerve root that is caused by tissues next to the nerve pressing against it, mostly by an inflamed intervertebral disc, or disc contents, directly touching the spinal nerve.
It is mostly used in situations of radicular pain, which is a radiating pain that is transmitted away from the spine by an irritated spinal nerve in the low back (lumbar radiculopathy) down the leg and nerve compression in the neck (cervical spine), referred to as cervical radiculopathy.
The procedure is quick and simple. The spinal cord rests in the spinal canal and the nerve roots branch out from it at each level of a spinal vertebra. It is protected by cerebrospinal fluid which is held in place by a membrane with several layers. The epidural space is outside of this tough membrane.
During the procedure, with help of a fluoroscope (a viewing instrument using X-rays) to visualize the local anatomy, a needle and syringe are used to enter the epidural space and deposit small amounts of long-lasting steroids around the inflamed spinal nerve.
The effect of epidural steroid injections is temporary and pain relief may last for several days or even years; the goal is to reduce pain so that patient may resume normal activities and a physical therapy program.
Epidural steroid injections have advantages with oral steroids and painkillers, because when the patient takes them by mouth they disperse, have less-focused impact and may have unacceptable side effects.