By Jonathan Chu, MD
Interventional Pain Medicine
PM&R

When it comes to epidural steroid injections, my patients often have countless questions about the procedure—and often some apprehension as well.

It’s not surprising, given all of the conflicting information they’ve heard about the procedure from various sources.

They’ve read news articles that make the procedure sound risky and frightening.

They’ve known someone who had little relief with an epidural injection

They’ve known others who experienced complete and long-lasting relief after their injection.

As a physician specializing in interventional pain medicine, it’s a procedure that I’ve done thousands of times at various levels in the spine, from a variety of approaches, and so I want to take the time to fully explain everything you need to know about the procedure, from top to bottom.

What Conditions Do Epidural Injections Treat?

Contrary to what many people think, epidurals are not effective for every type of back and neck pain.

Based on evidence from various studies, there are a few common conditions that epidural injections are usually used for.

Overall, epidural injections are known to be most effective for treating something called radicular pain (or radiculopathy).

This is when painful inflammation, irritation, or swelling occurs around a nerve root that is exiting from the spine.

It can happen very commonly in the neck and lower back, and manifests as pain travelling down the arm or leg.

Many people will commonly refer to this as “sciatica” or “pinched nerve pain.”

The pinching of these nerves commonly occurs due to a herniated disc, which is when one of the flexible cartilage pads in-between the vertebral bones squeezes out and presses on the nerve root.

In other cases, it can also occur due to chronic arthritic degeneration of the spine, which over time, narrows the small holes in the spine where the nerves exit (known as foramen).

Additionally, epidural injections are also commonly used to treat discogenic pain. This is when an injured disc may not be pressing on a nerve root, but the disc itself is very painful due to the release of a variety of inflammatory chemicals.

Since radiculopathy and discogenic pain can occur in both the neck (cervical spine) and lower back (lumbar spine), epidural injections can be done in either area.

How Does Your Doctor Perform the Epidural Injection?

In the spine, the epidural space is the outermost area within the spinal canal. It is the space that surrounds the tough sac (dura) that wraps your spinal nerves and spinal cord.

During the procedure, your doctor will use X-ray guidance (also known as fluoroscopy) to help guide a thin needle into the proper location within the epidural space, and also avoid surrounding areas.

Once the needle enters the epidural space, your doctor will often inject a small volume of contrast dye to confirm placement.

Next, the medication is injected into the epidural space.

This medication usually consists of a corticosteroid mixed with either normal saline or a numbing medication.

This mixture spreads through the epidural space near the site of the injection and ideally should bathe the affected nerve roots, working to reduce the painful inflammation in the area.

What are the Different Types of Epidural Steroid Injections:

Medicine can be introduced into the epidural space in various ways.

There are advantages and disadvantages with each type of epidural injection, and your doctor will select the best method based on your history, imaging, and location of your pain.

Interlaminar Epidural Injection:

This is by far the most common type of epidural injection I perform in my practice, and is my favorite due to its versatility, ease, and good patient tolerance.

With the interlaminar approach, the needle will enter near the mid-line of your back.

Through a combination of the image guidance and a loss-of-resistance technique, the needle will be carefully guided into the epidural space. Contrast is then injected to confirm the needle placement by demonstrating flow in the epidural space. The medication is then delivered gently to the area.

The advantage of this approach is that it spreads the medicine very nicely and covers nerve roots on both sides of the spine.

The disadvantage is that this type injection does not concentrate the medication at a particular level. Furthermore, it is also not possible to perform in patients who have had prior spine surgeries that changed the anatomy in the usual path of the needle.

Transforaminal Injection:

This is another type of epidural injection that I do quite often in my practice and is commonly performed in pain centers across the country.

With this injection, after your skin is anesthetized, the needle will enter toward the side of the spine and be directed towards the opening (foramen) of the specific irritated nerve root.

Contrast is then injected to confirm the needle location before the steroid medication is administered.

The natural advantage of this type of epidural is that it allows the medication to be concentrated at the level of injury and irritation. Furthermore, it can also be performed safely in people who have had prior spine surgeries.

One disadvantage is that the medication does not spread as far as with the interlaminar injection, and can only treat one side at a time. Furthermore, this procedure is somewhat more technically challenging, and as such, carries a slightly higher risk.

Caudal Epidural Injection:

This type of epidural injection is quite different than the other two, but also is very effective.

With this type of epidural injection, once your skin is anesthetized, the needle enters the epidural space through an opening in your tailbone (known as the sacral hiatus).

Once the needle is in place, as with the other types of injections, a small amount of contrast is injected to confirm placement and flow in the epidural space

Next, a mixture of corticosteroid medication and either normal saline or numbing medication is injected into the area. A larger volume is often used for this injection to make sure the medicine can reach the lower levels of the spine and get to the problem areas. As such, you may temporarily experience more pressure in the low back after the procedure, though this usually subsides after 30 to 40 minutes.

Just like with the interlaminar injection, the medication will spread to both sides of your spine during a caudal epidural injection.

There a few distinct advantages to this type of epidural injection. First, it is easy to perform and carries a slightly lower risk than the others, since the injection is done further away from the spinal nerves. Second, it can also be easily performed in people who have had prior spine surgeries that would otherwise rule out an interlaminar approach.

The disadvantage of the procedure is that the medication needs to travel a further distance to reach the areas of inflammation, and often cannot adequately reach the upper levels of the lumbar spine.

How Well Do They Work?

My patients will often ask me what they can expect from their injection.

Everyone wants to know: “How well do these epidural injections actually work?”

The truth is that the amount and duration of pain relief really varies from person to person.

However, after performing so many and closely following the responses, I can say that overall they are very helpful in patients who have been properly selected.

Epidural injections have been used by physicians for decades, and in general they are definitely a very well-established treatment for radicular pain (pinched nerve pain).

Through the years many studies have looked at how well epidural injections work, and overall there is strong evidence that this procedure is very good for treating acute episodes of radicular pain (pinched nerve pain) in the short and medium term, providing good relief for about 3 months.

Of course, the therapeutic value of epidural injections for other types of pain is not nearly as well studied.

There has been some evidence that epidural injections can be helpful in people with:

Discogenic pain

Spinal stenosis

Pain after prior spinal surgeries

However, the research is limited, and these conditions do not seem to have as strong of a therapeutic response to epidurals as acute pinched nerve pain.

Lastly, it’s also important to note that epidural injections are thought to have much more limited benefit for patients with chronic low back pain.

That is, epidural injections tend to work much better for treating an episode of back pain that began only one or two months prior, versus pain that has been going for many years.

That being said, there are definitely exceptions to this. I’ve seen many patients with who suffered from very long-standing back pain get considerable relief from epidural injections. I’ve seen people with purely discogenic pain get substantial relief from epidural injections. Everyone has a unique spine and not everyone follows the textbook.

Do I Need Epidural Injections Forever?

Naturally, this leads to the next question that I commonly get:

“If they are only shown to provide pain relief for a few months at a time, does this mean I need to keep on getting shots forever?”

And to that, I would say that the answer is definitely…NO.

It is really important to understand that the epidural injection can be a great tool to help you feel better quickly—but it is only one component of your overall treatment plan and recovery process.

Steroid medications will eventually wear off, and the inflammation can potentially return.

To be the most effective, the epidural injection needs to be part of a multimodal treatment plan.

The goal of the epidural injection is to decrease the pain and inflammation coming from the painful area of the spine, so that you are able to MOVE again and properly progress through the rehabilitation process.

Often times, in the initial stages of a painful pinched nerve in the neck or low back, you’re just in too much pain to even get any benefit out of physical therapy.

Once all of that pain and inflammation is quelled with the epidural injection—it gives you a window of time to work with physical therapy properly and develop your home exercise program. It gives you the opportunity to rebuild your strength and flexibility so hopefully you can prevent another flare-up.

Sometimes pinched nerve pain can be very severe. There are many cases in which the inflammation is so intense that it can take more than one epidural injection to calm everything down. But overall, it’s important to keep in mind that the goal is definitely not to give you repeat injections endlessly—especially since steroid medications can have negative side effects if given in high doses repeatedly.

So in general, you can think of the epidural injection as an excellent tool that we can use to help you along your recovery, but it’s most effective when used in conjunction with physical therapy, home exercise, and other treatment modalities.

What Are the Possible Complications?

Fortunately, when epidural injections are performed with good technique, they are very safe overall, and complications are extremely rare.

Reading all of the possible complications online can be frightening—but it should reassuring to know that all of these potential risks occur in a very low percentage of cases.

By far the most common potential complication is the development of a spinal headache afterwards.

This occurs if the needle punctures the sac surrounding the nerves and there is some leakage of spinal fluid (CSF) after the procedure. More than 85 percent of the time, this will close up on its own over a few days and the headaches get better. In some cases your physician may do an epidural blood patch to help the hole close up faster.

If you happen to develop a spinal headache after the procedure, you should rest in a comfortable position on your back. Furthermore, you should make sure to hydrate, and can use over-the-counter pain medications as needed.

Even though headaches are the most common possible complication after this procedure, it is important to keep in mind that even these are quite rare. In fact, studies looking back over several hundreds of cases have reported the incidence to be somewhere between 0.25% and 0.33% of all epidural injections (far less than 1 percent!).

Of course, though epidural injections are considered very safe in general, there are other more serious complications that are possible. These include bleeding, infection, and nerve/spinal cord damage. These are exceedingly rare, but cases have been reported in the literature.

Furthermore, there are possible temporary side effects of the corticosteroid medications also, which includes: elevated blood sugars, elevated blood pressure, fluid retention, and suppression of the immune system.

It can be daunting and anxiety-inducing to read about all the different potential risks of the procedure. However, it’s definitely important to keep in mind that with the use of image guidance and sterile technique, your doctor will be taking absolutely every step possible to minimize these risks for you.

Conclusion

In closing, epidural injections are an established treatment for low back and neck pain, and are especially valuable for treating acute cases of pinched nerve pain (radicular pain).

Complications, such as spinal headache, are possible, but very rare.

Epidural injections usually provide a few months of relief at a time—and it is critical to use the period of pain relief to engage in both formal physical therapy and a dedicated home exercise program to rebuild your strength and prevent another flare-up.

Thank you so much for reading. I greatly commend you for taking the time and effort to educate yourself about your pain. As a physician I think it is of the utmost importance to take a proactive approach to your health, and I know that your dedication and positive efforts towards improving your pain will pay off over time.

Until Next Time,

Jonathan Chu, M.D.

References:

Ahmed SV, Jayawarna C, and Jude E. Post lumbar puncture headache: diagnosis and management. Postgrad Med J. 2006 Nov; 82(973): 713–716.

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Braddom RL, Chan L, Harrast MA, Kowalske KJ, Matthews DJ, Ragnarsson KT, and Stolp KA. Physical Medicine and Rehabilitation. 4th Edition. Philadelphia, PA: Saunders; 2011.

Furman MB, Lee TS, and Berkwits L. Atlas of Image-Guided Spinal Procedures. 1st Ed. Philadelphia, PA: Saunders, 2013.

Rathmell JP. Atlas of Image-Guided Intervention. 2nd Ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2012.