FAQ’s on Epidural Steroid Injection
What is an epidural steroid injection?
An epidural injection is an outpatient procedure performed by a pain management doctor to relieve pain emanating from a pinched nerve(s). When a nerve root gets compressed, it can spark up an inflammatory reaction. This may send pain shooting down the path of that nerve root, which is called sciatica in the leg and radiculopathy in the arm.
An epidural steroid injection bathes the area of compression with soothing anti-inflammatory medicine to relieve the shooting pain. These injections have been performed for over 60 years, largely due to the fact that overall, they work very well in helping patients obtain relief, avoid surgery, and reduce the amount of pain medication necessary.
What conditions benefit from an epidural injection?
Epidural injections are meant mostly to relieve extremity pain, not back or neck pain. However, there is one condition where neck or back pain may be relieved. Here are the conditions that benefit:
- Spinal Stenosis – occurs in the neck or lumbar spine. When arthritis leads to bony or soft tissue overgrowth, it can pinch spinal nerves as they try to exit from the spinal canal.
- Cervical or Lumbar Disc Herniation – when a “slipped disc” occurs in either area, a piece of disc may compress on a nerve root. An epidural injection may relieve the resulting arm or leg pain.
- Degenerative Disc Disease – in the neck or low back, degeneration of a disc may lead to a tear in the outer portion and resulting back or neck pain. It may also lead to what is known as “chemical radiculitis” where nearby nerve roots are inflamed. In this situation, a large disc herniation may not be seen at all on an MRI, yet a person may have severe arm or leg pain along with back or neck pain. An epidural injection may help tremendously in these situations, which is why an epidural may help at times with back or neck pain.
Epidural steroid injections are performed as an outpatient in either a procedure room or surgery center. IV sedation is not mandatory, the patient may simply need numbing medicine under the skin and through the soft tissues down to the spinal area. Or a patient may receive an oral Valium 30 minutes prior to the procedure for anti-anxiety.
The individual is placed prone on an x-ray friendly table. Modern pain management doctors use image guidance for these procedures, either with a real time form of x-ray known as fluoroscopy, or ultrasound. Studies in the past have shown that without image guidance, up to 40% of epidural injections for pain management miss the mark.
There are currently three different types of performing epidural injections:
1) Interlaminar injections – for these injections, the pain doctor will insert the needle between the bones of the back of the spine, known as the lamina. As the needle goes through the soft tissue between the bones, the doctor uses a “loss of resistance” technique to enter the epidural space. Once reached, contrast medicine is injected to ensure satisfactory placement. At that point, numbing medicine and steroid is placed.
2) Transforaminal epidural steroid injection (TESI) – this is the newest type of epidural injection, which involves placing the steroid medication as close as possible to the pinched nerve root. The foramen is the exit opening for the nerve root which is where the pinching usually occurs, so that is where the needle is placed. For the low back, it’s extremely popular and works well. For the cervical spine, TESI has a higher risk profile and is not used very often.
[two_thirds]Caudal Injection – This injection involves placing the numbing and steroid medicine from the lowest portion of the spine through an area called the sacral hiatus. This type of epidural injection allows the medicine to cover a broader area and treat nerve root compression of several nerve roots. For instance, spinal stenosis often involves several nerve roots being pinched. So a caudal injection may be able to provide relief by traveling and covering each area.
It is unknown how much steroid is “too much steroid” with these injections. There have been guidelines published, none of which are based on actual research data. Currently it is routine for steroid injections to be performed a few times a year if necessary.
What are the outcomes?
Overall, the outcomes from the various types of epidural injections is outstanding. The average for a good to excellent result is 75% to 90% in multiple research studies (Manchikanti et al, Pain Physician, 2012;15;E199-E245). It may be necessary for a series of injections to be placed, with 3 injections placed a couple weeks apart. The series may be repeated every few months as necessary.
Caudal epidural injections have been shown to relieve bilateral radicular pain (sciatica) nicely in those with spinal stenosis. Over 50% pain reduction was achieved in 65% of patients (Botwin et al, Pain Physician, 2007;10;547-558).
Epidural steroid injections (ESIs) have been endorsed by the North American Spine Society and the Agency for Healthcare Research and Quality of the Department of Health and Human Services for treating radicular pain from lumbar spine problems.
There are studies that have not been favorable of ESI. However, quite a few of these studies did not use image guidance such as fluoroscopy. Up to 40% of epidural steroid injections miss the mark if this is not used.
Usually, epidural steroid injections are used for arm or leg pain due to pinched nerves in conjunction with additional treatment options. These may include physical therapy, chiropractic manipulations, spinal decompression therapy, acupuncture, pain medication management and TENS units.
What are the risks?
Thankfully, the risks associated with epidural steroid injections are small. They are real, though, and may include infection, bleeding, nerve injury or allergic reaction to the medication used.
In addition, patients may have a transient reaction to the steroid medication used, which may include facial flushing, weight gain, water retention, or high blood sugars. This usually resolves within days.