Epidural steroid injection
One of the most commonly performed procedure in interventional pain
management. It involves the injection of steroid (usually combined with other
medication) close to the spinal cord into the epidural space. This procedure can
be performed in the neck (cervical epidural), upper (thoracic epidural) or lower
back (lumbar epidural). If the epidural space is accessed very low through the
sacral hiatus (close to the tailbone) the procedure is called caudal epidural
steroid injection. The procedure is closely related to the labor epidurals as
the medication goes into the same tissue plane close to the spine.
For an animation explaining epidural anesthesia and spinal anatomy click
here.
Here is a good picture of the epidural space (courtesy of UAMS Department of
Anatomy, for more pictures click
here). In this picture (4) shows the epidural space which has the dura mater
(3) separate it from the subarachnoid (or intrathecal) space (6). Other
structures: (1) intervertebral disc, (2) vertebral body, (5) spinal cord.
Indications
This procedure is performed for neck and back pain that is caused by
degenerative joint and disc disease. It is especially helpful for shooting pain
into the extremities which is often caused by prolapsed discs or narrowing of
the bony structures where the nerve roots exit the vertebral column (neuroforaminal
stenosis). Mechanical and chemical (from substances release by the ruptured
disc) irritation of the nerve root leads to inflammation and swelling. This
causes pain in the neck/back that can also shoot down the arm(s) or leg(s).
Steroids are very strong medication against inflammation.
The goal of the epidural steroid injection is to deposit long-acting steroid
preparations as close as possible to the area of inflammation/irritation
(precision targeting). To achieve the same concentration of steroids at the site
of pain would require a very large dose of steroids in pill form with all its
known side effects and complications.
Contraindications
Epidural injections should not be performed in patients with active
infections as there is a risk of introducing the infection close to the spine.
If you have a fever (elevated temperature), chills, a new cough, or any sign
or symptom of an infection, let your physician know so the procedure can be
rescheduled.
As the procedure involves and injection close to the spine it is also
contraindicated in patients who are on high doses of blood thinners. If blood
clotting is severely impaired due to hemophilia and other congenital bleeding
abnormalities or due to medication warfarin (brand name: Coumadin (R)),
clopidrogel (brand name Plavix (R)), ticlidipine (brand name Ticlid (R)) and
others there will be a high risk for a blood clot in the epidural space (hematoma)
which can lead to permanent neurological damage. If you have blood clotting
problems or are on medications (including over-the-counter medications and
supplemements) that impair clotting and increase bleeding, let your physicians
know about it. Easily bruised skin, excessive nose and gum bleeding could be
signs of impaired clotting.
Herbal supplements that are known to interfere with normal coagulation and could
lead to excessive bleeding -especially when taken in high doses- include garlic,
ginko biloba, ginseng and Vitamin E. Regular doses of aspirin and NSAIDs (NonSteroidal
Anti-Inflammatory Drugs) like iburofen (brand names Advil (R), Motrin (R) and
others), naprosyn (brand names Naproxen (R) and Aleve (R)) and others in the
same category have been shown to not increase the risk of bleeding during
epidural steroid injections.
Often iodine-based contrast will be used during the procedure to verify and
document the position of the needle and the flow of the medication. If you
ever had an allergic reaction to iodine, please let your physician know about
it. Depending on the exact allergy and reaction this could lead to a change
in the kind of contrast media used.
Procedure
Preparation
Most physicians will recommend for the patient not to have any food or fluids
after midnight to decrease the risk of nausea, vomiting and potentially
aspiration (getting stomach contents into the lungs which causes severe
pneumonia). In cases that are scheduled for the afternoon it may be acceptable
to have a light breakfast. Most places will ask for a responsible adult to be
the driver.
If you are diabetic, please let your physician know as you should not take your
full (regular) dose of insulin if you have an empty stomach. If you are not on
insulin but take pills for your diabetes, inform your physician about that as
some temporary dose adjustments could be appropriate.
All other medications should be taken at the usual time and dose.
Positioning:
Cervical epidurals can be performed in a sitting, lateral or prone (patient
lying on stomach) position. Our preference is the prone position.
Fluoroscopy:
We feel strongly that epidural steroid injections should be done under
fluoroscopy (live x-ray) to ensure that the medication is given in the correct
area.
During the procedure the skin will be numbed with a very small needle using
local anesthetic (lidocaine). The epidural needle will then be slowly advanced
until it is in the right position. Then contrast media (iodine) will be injected
under live fluoroscopy to confirm the position and evaluate the spread of
contrast. If the position is correct, the medication will be injected at this
time. The injected medication can be just steroids (usually diluted with some
sterile saline solution) or a combination of steroids with local anesthetics
(numbing medication). Some physicians may elect to add other medications as
indicated.
Duration of the procedure: usually 10 to 30 minutes depending on location and
anatomy.
Recovery
Epidural steroid injections are usually performed as outpatient procedures.
After the procedure the patient is usually observed for 15-30 minutes to ensure
that there were no untoward effects from the procedure. If there are no
problems, the patient is then allowed to be taken home by a responsible adult.
Patients are instructed not to do anything strenuous for the rest of the day and to
resume regular activities the next day.
Complications
Any time a needle penetrates the skin (injection) there is a risk for
bleeding and infection. To minimize these risks it is very important
to communicate with the physician if you have any ongoing infections or impaired
blood clotting.
There is always a risk of allergic reaction to medication which you may
not have received in the past.
As the procedure is done closely to the spine, there is also a risk of
nerve damage. Having an experienced physician do this procedure under
fluoroscopy will minimize but never eliminate this complication.
If the needle goes through the dura it will be in the spinal space and there is
a chance for a "spinal headache". You may be instructed to rest on your
back for a couple of days, drink plenty of fluids and caffeine. If your spinal
headache does not improve, you may be a candidate for an epidural blood patch.
There are also some side effects related to the steroids used. These range from
temporary high blood sugar values (important for diabetics) to mood changes and
acne.
Overall, epidural steroid injections are safe in the hands of experienced pain
physicians
Duration of Relief
Most patients will have 2-3 months of relief of some of their complaints. This
can range from no relief to near absolute relief with the duration being from
days to many months. Some patients may not get any relief with the first
injection but after one or two more done over the following days and weeks. Most
physicians will do these injections in cycles (series) where they will do one,
two or three epidural injections over a couple of days or weeks. The interval
between these cycles should be somewhere between two to tree months. More
frequent administration of steroids could lead to more serious side effects. | 
