Epidural Steroid Injections are a non-surgical treatment typically used to alleviate chronic low back and/or leg pain. While the effects from the injection tend to be temporary, providing relief from pain for one week to one year, an epidural can be very beneficial for patients during an episode of severe back pain. One important use is to provide sufficient pain relief to allow the patient to start (or progress in) a rehabilitation program.
An epidural injection significantly reduces pain for approximately 50% of the patients that receive one. It works by delivering steroids directly to the painful area to help decrease the inflammation that may be causing the pain. It is thought that there is also a flushing effect from the injection that helps remove or “flush out” inflammatory problems from around the structures that may cause pain.
As a disc degenerates, the inner core of the disc can extrude – or herniate – back into the spinal canal. The herniated disc material can irritate the nerve (A), which can cause pain to radiate down the path of the nerve – from the lower back through the buttocks and into the leg or even into the foot.
An epidural is an injection that delivers steroids directly into the epidural space. The epidural space is the space between the dura mater (a membrane) and the vertebral wall and is filled with fat and small blood vessels. It is located just outside the dural sac. The dural sac surrounds the nerve roots and cerebrospinal fluid (the fluid that the nerve roots are bathed in).
There are often inflammatory factors and other substances that generate pain (e.g. substance P) that are associated with lumbar disc herniation and this inflammation can cause significant nerve root irritation and swelling.
Steroids (corticosteroids) have been shown to reduce inflammation by inhibiting the production of substances that cause inflammation; the epidural injection can be highly effective because it delivers the medication directly to the site of inflammation.
In general, epidural steroid injections are used to help provide pain relief to enable patients to progress with their rehabilitation. Individuals who have less pain and feel more comfortable are generally able to work on the active therapies—such as stretching, strengthening and pain relief exercises and low impact aerobic conditioning—that are critical in rehabilitating the lower back.
Several common conditions—including lumbar disc herniation, degenerative disc disease, and lumbar spinal stenosis—can cause severe acute or chronic low back and/or leg pain. For these and other conditions that can cause chronic pain, an epidural steroid injection may be an effective non-surgical treatment option.
The benefits of the epidural steroid injections at a pain clinic include a reduction in pain, primarily in leg pain. If a patient does not experience any pain relief from the first injection, further injections will probably not be beneficial. However, if there is some improvement in pain, one to two additional injections may be recommended.