What is an epidural spine injection?
It is an injection of a small amount of corticosteroid (a.k.a. “cortisone”) anti-inflammatory medication into the epidural space of your spine, usually in the neck or back, where the nerve roots exiting the spinal canal are located. Usually the injection includes 1-2 cc’s of steroid, mixed with 1-2 cc’s of saline or local anesthetic; though exact proportions and brands of medications may vary.
The injection has to be done under X-ray guidance, or “fluoroscopy,” in order to be sure the medication is placed in the right space. The use of contrast dye is also important to make sure the needle position is correct, and not inadvertently placed in a small blood vessel.
Injections may be directed straight into the back or neck, where the medication can flow across several nerve root levels at once, or it can be angled in from the side to target one specific nerve root level.
Are you a good candidate?
You need to have a thorough evaluation from a licensed physician, preferably the spine interventionalist (or injectionist) him or herself, before getting an injection. Those who respond best are usually in the acute “inflammatory” stage of their pain. Usually your symptoms will involve radiating pain down one or both arms, or one or both legs. You may have one or a combination of symptoms, involving abnormal or impaired sensation, pain, and in certain cases, extremity weakness. You must have an appropriate medical evaluation including a detailed history and physical examination, and often appropriate diagnostic imaging (i.e., spine MRI) before you are deemed a good candidate. The doctor should explain to you the possible risks, benefits, and alternative options, and give you realistic expectations for improvement.What to Expect
What to Expect
Before the Procedure:
You should be an appropriate candidate for an injection, which is a determination made in conjunction with your doctor. You should be told not to take certain medications; namely, anti-inflammorities or other blood-thinning medications that may increase the risk of bleeding, several days before the procedure. Ask your doctor which medications should not be taken, and for how long they should be held. You should make arrangements to have someone drive you home after the procedure.
During the Procedure:
First a nurse or other health professional will guide you into an examination room to take your vital signs (blood pressure and pulse), obtain your written consent, and read off a general safety check list. You will then be escorted to the fluoroscopic injection suite, where the X-ray tech, nurse or aide, and physician performing the procedure will be waiting. You will be helped onto the table with your head facing down in the prone position. The physician will prep the region with iodine and drape it in the usual sterile fashion. Once the anatomy of your spine is correctly visualized (throughout the procedure, the X-ray tech will be taking quick “snapshots” of your spine with low intensity X-rays from the C-arm encircling the table), you may feel a quick sharp prick and then burning, as the skin and superficial tissues are numbed with local anesthetic. Then you should feel pressure as the spinal needle is inserted, but usually the initial anesthetic injection is the most painful part. As the needle gets closer to your inflamed nerve root, you may experience sudden pain radiating down your leg according to your typical pattern of pain, but this is temporary. Then the physician will injection first contrast dye to check placement of the needle, and, if placement is correct, the medication itself will be injected. During the administration of the medication, you may again feel some pressure and pain radiating down the extremity in your typical pain referral pattern.
Most people tolerate the procedure very well, and it should take less than 15-20 minutes altogether if there are no outstanding anatomical issues for the injection to be technically more difficult. Everyone has a different anatomy, and everyone has a slightly different response to injections.
After the Procedure:
You may experience immediate relief from your symptoms, due to injection of the local anesthetic, but this usually wears off by the end of the day. The steroid medication may take 3-5 days or longer to reach full effect. The pain relief from a successful injection should last weeks to months, or potentially longer. Rarely will your pain be completely eliminated, but it should be more bearable. Some patients may require several injections to feel lasting relief.
You should have someone drive you home for your safety. You should immediately report any serious side effects, such as persistent numbness, weakness, or pain. Please refer to possible risks and side effects. Most everyone receiving an injection is fine to walk home, but extra precautions are usually taken. You should take it easy for the rest of the day. The following day, you should be able to resume all normal activities. You should follow up with the physician a few weeks after your injection to evaluate its success and your future management. Maintaining your fitness and core muscle strength, whether in a physical therapy program or on your own, is important for the longterm health of your spine.
Remember, injections do not correct the underlying problem causing your nerve root to be irritated, nor do they prevent progression of your disease or possible recurrences in the future. They do, however, relieve inflammation around that nerve – which is believed to be a major component of your pain. Studies have shown that these injections can help people get better faster – and hopefully prevent or break a cycle of chronic pain from occurring, which is very difficult to treat.
What are the potential risks and side effects?
With any procedure such as epidural injections, there is always a risk of: bleeding, infection, or nerve tissue damage. We try to minimize these risks by: 1. taking you off blood thinning medications, 2. using sterile technique to avoid infection, 3. using technical expertise and safety protocols for all injections, including X-ray guidance and contrast dye.
Tell your doctor if you have medical allergies, specifically to: contrast dye, local anesthetic (lidocaine, xylocaine, bupivicaine are often used), and steroid medication (Kenalog, Depo-Medrol, etc).
Is the radiation from injections potentially dangerous?
No. The amount of radiation you receive during an injection is miniscule, much less than the average radiation received from a single chest X-ray. You will see health workers wearing lead shields; this is for their protection only because they may work many consecutive hours in the fluoroscopy suite, and there are documented protocols for them to report how much radiation accumulates on their radiation badges over time (this is usually still well below the current safety guideline limits)