Introduction Spinal injections are not new – the use of spinal injections to treat low back pain was first documented in 1901, and in 1952 epidural steroid injections were first used to treat low back pain with associated sciatica (pain in the sciatic nerve due to lumbar disc herniation). Today, epidural steroid injections have become an integral part of non-surgical management of low back pain.
An epidural injection is typically used to alleviate chronic low back and/or leg pain. While the effects of the injection tend to be temporary - providing relief from pain for one week up to one year - an epidural can be very beneficial for patients during an episode of severe back pain. Importantly, it can provide sufficient pain relief to allow the patient to progress with their rehabilitation program.
An epidural is effective in significantly reducing pain for approximately 50% of patients. 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 proteins from around the structures that may cause pain.
How an epidural steroid injection works An epidural is an injection that delivers steroids directly into the epidural space in the spine. Sometimes a flushing solution (either lidocaine or normal saline) is also used to help "flush out" inflammatory proteins from around the area that may be the source of pain.
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).
Epidural steroid injections for inflammation There are often inflammatory factors and other substances that generate pain (e.g. substance P) that are associated with a 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 steroid injection can be highly effective because it delivers the medication directly to the site of inflammation.
Before the epidural steroid injection An epidural steroid injection usually takes between 15 and 30 minutes. The patient lies flat on an x-ray table on their abdomen. Prior to the epidural injection, the skin is numbed with lidocaine, which is similar to the novocaine that the dentist uses (a "local" anesthetic).
Only a Board Certified Interventional Pain Management Specialist should perform epidural steroid injections for chronic pain treatment. Using fluoroscopy (live x-ray) for guidance, the physician directs a needle toward the epidural space. Fluoroscopy is considered important in guiding the needle into the epidural space, as controlled studies have found that medication is misplaced in 13% to 34% of epidural steroid injections that are done without fluoroscopy.
During and after the epidural steroid injection Once the needle is in the exact position, the epidural steroid solution is injected. Following the injection, the patient is usually monitored for 15 to 20 minutes before being discharged to go home.
Sedation is available for patient anxiety and comfort. However, sedatives are rarely necessary, as the epidural steroid injection procedure is usually not uncomfortable. If a sedative is used, the patient will need to be monitored for a longer period following the injection.
Patients are usually asked to rest on the day of the epidural steroid injection. Normal activities (those that were done the week prior to the epidural injection) may typically be resumed the following day.