Epidural Steroid Injection

• What is an epidural steroid injection?
• How is an epidural steroid injection performed?
• When are epidural steroid injections used?

spinal nerve irritation that is caused by tissues next to the nerve pressing against it. The beginning of the nerve (nerve root) is most often irritated by an inflamed intervertebral disc, or disc contents, directly touching the spinal nerve.

[Drawing of a disc herniation compressing the spinal nerve root]

An epidural steroid injection involves bathing an inflamed nerve root in steroids (potent anti-inflammation medicine) in order to decrease the irritation of the nerve root that is causing pain.

spinal cord rests in the spinal canal. The nerve roots branch out from the spinal cord at each level of a spinal vertebra (the bony building blocks of the spine). The cord is protected by cerebrospinal fluid (CSF), which serves as a shock absorber for the cord. The CSF is held in place by a membrane with several layers, one of which is called the dura, from the Greek for tough (think of "durable"). The Greek word "epi" means "outside of." So, the epidural space is outside of this tough membrane. During an epidural steroid injection, a needle and syringe are used to enter the epidural space and deposit small amounts of long-lasting steroids around the inflamed spinal nerve. A fluoroscope (a viewing instrument using X-rays) is used to visualize the local anatomy during the injection. The epidural steroid injection specifically targets the inflamed area and treats it with a maximal amount of steroids, thereby minimizing exposure of the rest of the body to the steroids.

[Epidural steroid injection with injection needle visible in the epidural space using a fluoroscope)

radicular pain, which is a radiating pain that is transmitted away from the spine by an irritated spinal nerve. Irritation of a spinal nerve in the low back (lumbar radiculopathy) causes pain that goes down the leg. Epidural injections are also used to treat nerve compression in the neck (cervical spine), referred to as cervical radiculopathy.