The Safety of Epidural Steroid Injections: What You Need to Know
Practical Pain Management spoke with Steven H. Richeimer, MD, Chief, Division of Pain Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, to learn what people need to know before having an epidural steroid injection.
Q: What is an epidural steroid injection?
Dr. Richeimer: This procedure involves injection of corticosteroids into the epidural space around the spinal cord and nerves. It is most often used to treat spinal disorders of the low back (lumbar spine), and also may be used to treat disorders in the neck (cervical spine). Corticosteroids are believed to relieve low back pain by reducing inflammation.
Q: How effective are epidural steroid injections?
Dr. Richeimer: Studies are somewhat contradictory, showing different levels of response. Thus, we don’t have a clear understanding of how good this treatment is. Some people get relief for years with 1 to 3 injections. On the other hand, some people only get relief that lasts a few weeks.
In a classic patient with relatively new back pain radiating into the leg, a fairly good response in expected in approximately 70% of patients. In my opinion, there may be a less robust response in people with a more complex disorder, a longer duration of symptoms, surgery to the area, or more than one spinal diagnosis.
Q: Who is a good candidate for an epidural steroid injection?
Dr. Richeimer: Patients who respond best have low back pain with radiculopathy (nerve pain radiating down their leg) caused by a bulging or leaking disc, and have never had spine surgery in the area. Steroid injections also may be helpful for foraminal stenosis (narrowing of space through which nerves exit the spine, causing nerve compression), but it is currently unclear how people with this disorder will respond to the treatment. Central canal stenosis (narrowing of the space in the vertebrae through which the spinal cord passes) is a fairly weak indication for epidural steroids; however, that doesn’t mean that epidural steroids shouldn’t be considered at all if the only other alternative is surgery.
Epidural steroid injections may be used for neck pain (cervical spine) as well. There is a growing consensus that the transforaminal approach (injection into the opening at the side of the spine where nerve roots exit) in the cervical spine is too risky of approach and should be avoided. The interlaminar (injection into the back of the epidural space) or midline approach (injection is made into the center of the epidural space) is preferred.
Q: What are the potential risks of epidural steroids injections?
Dr. Richeimer: Side effects may include an increased blood sugar, anxiety, sleeping problems, water retention (bloating), facial flushing, infection, and suppression of the HPA axis (a system in your body that controls response to stress and regulates many body processes). Repeated use of epidural steroid injections may cause local osteoporosis (bone thinning) and weakening of the surrounding tissues that may cause further spinal degeneration over the years. Severe side effects are rare, but may include an allergic reaction, infection, nerve damage, and paralysis.
In 2012, an outbreak of fungal meningitis occurred in people who received contaminated corticosteroids produced at a compounding pharmacy (a pharmacy that makes the corticosteroid solution rather than using commercially available products). My preference is to use commercially available, preservative free dexamethasone for all of my epidural injections, but there are many doctors who do this differently.
I advise that multiple injections should be separated by at least a month or more and that no more 3 injections are given in a 6- to 12-month period.
Q: Are epidural steroid injections painful?
Dr. Richeimer: A local anesthetic is first injected into the area where the epidural injection will be placed, and often mild numbing/burning from the lidocaine is what people feel the most. The majority of people tolerate this procedure without the need for anesthesia beyond the local anesthesia and without out too much pain.
Q: What should you ask your doctor before receiving a steroid injection?
Dr. Richeimer: You should ask and understand what approach your doctor is going to be taking—is it a midline approach or is it transforaminal? It is advisable to ask your doctor why he/she is choosing a particular approach. If your doctor is using a transforaminal approach, I think it is reasonable to ask the doctor to use preservative-free dexamethasone rather than a particulate steroid.