Epidural Injections

What is an epidural injection?

An epidural injection is an injection into the epidural space, the space in the spinal canal just outside the sac that holds the spinal fluid. Sometimes this is done by directing a needle between the spinal lamina and is now frequently called a translaminar epidural. These can sometimes be done by an experienced physician, usually an anesthesiologist, without X-ray guidance, much like a labor epidural.

A transforaminal epidural injection is an injection of long acting steroid into the opening at the side of the spine where a nerve roots exits. This opening is known as a foramen. There is a small sleeve of the epidural space that extends out over the nerve root for a short distance. This epidural root sleeve is just outside the spinal canal. Sometimes these injections are referred to as selective nerve root blocks, especially when they are done with anesthetic drugs to diagnose affected levels rather than treat symptoms.

What is the purpose of an epidural injection?

The long acting steroid that is injected reduces the inflammation and swelling of spinal nerve roots and other tissues surrounding the spinal nerve root. The epidural injection may also somewhat reduce the swelling or inflammation of a torn, protruding or herniated disk. This may in turn reduce pain, tingling and numbness and other symptoms caused by such inflammation, irritation or swelling. Also, epidural injections can be used to identify a specific spinal nerve root level or levels that are the source of pain.

How long do epidural injections take?

The actual injections take five to ten minutes.

What is actually injected?
The injection may consist of a mixture of saline, local anesthetic and the long acting steroid medication. The amount of medication actually injected is very small, rarely more than one or two milliliters.

Will the injection hurt?

The injections involve inserting a needle through skin and deeper tissues. There is some pain involved. However, we often numb the skin and deeper tissues with a local anesthetic using a very thin needle before inserting the injection needle. Once numbed, placing the injection needle often feels like more of a strong pressure and pinching, often not as sharp pain.

How are epidural injections performed?

For X-ray guided epidural injections, it is done either with the patient on the side for most neck injections and with the patient on the stomach for back injections. Occasionally other positions are used to optimize the X-ray view. Some translaminar epidural injections are done in a seated position without X-ray guidance simialr to a labor epidural. The skin of the neck or back is cleaned with antiseptic solution and sometimes numbed with local anesthetic. Then the injection needle(s) is placed under X-ray guidance. Once in place, the injection is made and this will often feel like the normal pain that the patient feels in the distribution of that particular spinal nerve root. Finally, the needle(s) is removed and an adhesive bandage is applied.

What should I expect after the epidural injections?

Immediately after the injection, you may feel like your arm or leg is slightly heavy and may be numb, depending on where the injection was done and how much local anesthetic was used. Even so, despite the numbness, most patients can still actively move their arm or leg. This strange effect comes from the concentration of the local anesthetic and not from the amount of local anesthetic. Also, you may notice that your pain may be gone or quite less. This immediate effect is also due to the local anesthetic injected. This will last only for a few hours. Your pain may return and you may have some soreness or aching for a day or two. This is due to the mechanical process of needle insertion, as well as initial irritation from the medications injected. You should start noticing pain relief starting the third day or so.

What should I do after the epidural injections?

Patients are usually able to drive, although there may be sufficient numbness to make driving difficult, if not impossible for several hours. Thus, we generally advise all patients to have a ride home or backup plans in case one is needed. Most patients are advised to take it easy for a day or so after the procedure until the medication has a chance to work. However, most patients can perform any activity that they could perform before the procedure.

Can I go back to work the next day?

You should be able to go back to work the next day unless the procedure was extensive or complicated and involved a large number of levels. Usually you will feel some soreness or aching at the injection sites only.

How long does the effect of the medication last?

The immediate effect is usually from the local anesthetic injected. This wears off in a few hours. The steroid starts working in about 3 to 5 days and its effect can last for several days to several months.

How many epidural injections do I need to have?

If the first epidural injection or injections do not relieve your symptoms within two weeks, you most likely will be recommended to have a second injection or injections. Similarly, if the second time does not completely relieve your symptoms in about a week to two weeks, you may be recommended to undergo a third injection or injections. The physician will evaluate you to determine when the epidural injections are not going to be effective.

Can I have more than three epidural injections?

Yes. In general, the physician will try to continually evaluate the need for the next injection. Many patients do not need more than three injections in a six-month period. This is because the effect of the medication injected frequently lasts for six months or more. Giving more injections will increase the likelihood of side effects from the medications injected. There is no absolute rule as the the total number of injections. There may be insurance limitations on the number of injections covered.

Will the epidural injections help me?

It is sometimes difficult to predict if the injection will help you or not. Patients who have pain radiating from the spine down into the arms or legs respond better to the injections than the patients who have only pure neck or back pain. Similarly, the patients with a recent onset of pain may respond much better than patients with longstanding pain.

What are the risks and side effects?

Generally speaking, transforaminal injections are is safe. However, with any procedure there are risks, side effects and possibility of complications. The most common side effect is pain from the actual injection once the local anesthetic wears off and this pain is temporary. The other uncommon risk involve spinal puncture with headaches, infection, bleeding inside the epidural space, nerve damage and worsening of symptoms. Other uncommon risks are related to the side effects of the long acting steroid such as weight gain, increase in blood sugar in diabetics, water retention and suppression of body's own natural production of steroids.

Who should not have epidural injections?

If the patient is on a blood thinning medication like Coumadin (warfarin), has an active infection going on, or has poorly controlled diabetes or severe heart disease with angina, they should carefully discuss the risks and benefits of the injection with the physician.

Epidural Injections

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