What is an Epidural?
An epidural steroid injection (ESI) is a minimally invasive procedure that can help relieve neck, arm, back and low back related leg pain caused by inflamed spinal nerves. An epidural steroid injection is typically ordered by your doctor to relieve pain caused by herniated discs, spinal stenosis (narrowing of spinal canal), spondylolysis (defect in connection between spinal vertebrae), spondylolisthesis (slippage of one vertebrae on top of another) herniated discs, degenerative disc disease or sciatica. Steroid medications are delivered to the spinal nerve roots through the epidural space, the area between the protective coverings of the spinal cord and the vertebrae.
Pain relief may last for several days, months or even years. The steroid medication utilized in an ESI is an extremely potent anti-inflammatory. The medication breaks the pain cycle at the level of the spinal cord or nerve roots, which may generate a much longer period of pain relief than the medication action itself. The length of pain relief is extremely variable, but tends to be shorter with more severe underlying degenerative changes.
The goal is to reduce pain so patients may resume normal activities and/or a physical therapy or exercise program. The number of epidural steroid injections a patient can have is limited by potential bone and soft tissue breakdown in the area of injection. Properly spacing treatment regimens helps to prevent or minimize problems.
Three types of Epidural Steroid Injections
There are three options for delivery of medication into the epidural space and your pain doctor will choose the technique that corresponds best to your pain pattern and pain history. All three should be performed under live x-ray (fluoroscopy) and may involve the use of a dye to visualize the proper placement or spread of the medication. Descriptions of the three types of ESI are below:
Interlaminar ESI. The most common type of epidural injection is delivered through the midline of the spinal area between 2 adjacent vertebrae. This is the most simple and easy to perform technique; however the technique relies upon proper spread of the medication from the site of injection to the area of pain. The spread of the medication takes place naturally and may spread over 2 or 3 adjacent vertebrae and both left and right sides of the spinal cord. Scar tissue from prior surgeries or injuries can prevent proper medication spread and effectiveness of this technique. A transforaminal or caudal approach may be indicated for these cases.
Transforaminal ESI. With a transforaminal ESI, often referred to as a ‘nerve block’, the needle is placed alongside the nerve as it exits the spine and medication is placed into the ‘nerve sleeve’. The medication then travels up the sleeve and into the epidural space from the side. This allows for a more concentrated delivery of steroid into one affected area. Transforaminal ESIs can also be modified slightly to allow for more specific coverage of a single nerve and can provide diagnostic benefit, in addition to improved pain and function. This technique is generally the most effective when the pain symptoms include radicular leg pain with or without back pain.
Caudal ESI. Caudal ESI’s utilize the small hole at the base of the spine called the sacral hiatus (a small boney opening just above the tailbone) to allow for needle and medication placement from the very bottom of the epidural space. When scar tissue is present in the epidural space a small instrument may be run from this opening up the epidural space to clear the way of scar tissue before introducing the medication. Once the medication is administered there should be spread of the medication over a several segments and both left and right sides of the spinal cord.
What Happens After the Epidural Injection?
The steroid will usually begin working within 1-3 days, but in some cases it can take up to a week to feel the benefits. Although uncommon, some patients will experience an increase in their usual pain for several days following the procedure. The steroids are generally very well tolerated, however, some patients may experience side effects, including a ‘steroid flush’ (flushing of the face and chest that can last several days and can be accompanied by a feeling of warmth or even a low grade increase in temperature), anxiety, trouble sleeping, changes in menstrual cycle, or temporary water retention. These side effects are usually mild and will often resolve within a few days. If you are diabetic, have an allergy to contrast dyes, or have other serious medical conditions, you should discuss these with your pain doctor prior to the injection.
Epidural steroid injections have been performed for many decades, and are generally considered very safe and effective treatment for back and leg pain or neck and arm pain. Serious complications are rare and when performed by a fellowship trained pain doctor using fluoroscopic guidance, the risk of experiencing a serious complication is further minimized.
Although not everyone obtains pain relief with ESIs, often the injections can provide you with improvement in pain and function that last several months or longer. If you get significant benefit, the injections can be safely repeated periodically to maintain the improvements. You should consult with your Novocur pain doctor to develop a comprehensive care plan that combines your ESI with physical therapy, chiropractic or other rehabilitation options to achieve the best long-term pain relief results.