![[Product Image]](images/epiduralspread.jpg)
Fig. 1: Epidural spread of steroid medication.
What is Epidural Steroid Injection (ESI)?
Epidural Space is the space outside the covering
of the spinal cord called the dura. This space runs the entire
length of the spine. Nerves exit from the spinal cord and travel through the epidural space to
reach the neural foramen. Inflammation of these nerve
roots occur when they are pinched by bone spurs or ruptured disc. This may result
in radiating pain down the arm or leg.
An epidural is an
injection that delivers corticosteroids (cortisone) directly into the epidural
space. Sometimes a flushing solution (either lidocaine or normal saline) is also
used to help "flush out" inflammatory proteins from around the area
that may be the source of pain.
Steroids
(corticosteroids) have been shown to reduce inflammation by inhibiting the
production of substances that cause inflammation, the epidural injection can be
highly effective because it delivers the medication directly to the site of
inflammation.
Epidural
steroid injection in the neck region is called Cervical Epidural Steroid
Injection (CESI). In the lower back, it is called the Lumbar epidural Steroid
Injection (LESI). These are the common sites, but occasionally thoracic epidural steroid
injection (TESI) is performed for mid back pain.
When is an
epidural typically recommended ?
In general, epidural
injections are used to help provide pain relief to enable patients to progress
with their rehabilitation. Individuals who have less pain and feel more
comfortable are generally able to work on the active therapies—such as
stretching, strengthening/pain relief exercises and low impact aerobic
conditioning—that are critical in rehabilitating the lower back.
Several
common conditions—including lumbar disc herniation, degenerative disc disease,
and lumbar spinal stenosis—can cause severe acute or chronic low back and/or
leg pain. For these and other conditions that can cause chronic pain, an
epidural steroid injection may be an effective non-surgical treatment option.
How is the
injection performed ?
An epidural steroid
injection usually takes about 10 minutes. The patient lies flat on an
x-ray table on their abdomen. Prior to the injection, the skin is numbed with
lidocaine, which is similar to the novocaine that the dentist uses (a
"local" anesthetic).
Using fluoroscopy
(live x-ray) for guidance, the physician directs a needle toward the epidural
space. Fluoroscopy is considered important in guiding the needle into the
epidural space, as controlled studies have found that medication is misplaced in
13% to 34% of epidural injections that are done without fluoroscopy, called
" blind " injections. Experienced anesthesiologist often practice
blind injections, but their placement of needle can not be verified. Dr. Thiyaga
does not practice blind procedures. Images are recorded on x-ray paper and
available for inspection by the patient or third party for verification of
needle placement and administration of medication at the most appropriate site.
Since patients who fail epidural steroid injections under go open spine surgery,
we consider it is our duty to ensure that the spinal procedure is done in a verifiable
manner.
Once the needle is in
the exact position, the steroid solution is injected. Following the injection,
the patient is usually monitored for 15 to 20 minutes before being discharged to
go home.
Sedation is available
for patient anxiety and comfort. However, sedatives are rarely necessary, as the
procedure is usually not uncomfortable. If a sedative is used, the patient will
need to be monitored for a longer period following the injection.
Patients
are usually asked to rest on the day of the epidural steroid injection. Normal
activities (those that were done the week prior to the injection) may typically
be resumed the following day
What are the
benefits?
The benefits of the
epidural steroid injections include a reduction in pain, primarily in leg pain.
Patients seem to have a better response when the injections are coupled with an
organized therapeutic exercise program.
While the effects of
an epidural injection tend to be temporary—providing relief from pain for one
week up to one year—an epidural can be very beneficial for patients during an
episode of severe back pain. Importantly, it can provide sufficient pain relief
to allow the patient to progress with their rehabilitation program.
An
epidural is generally successful in relieving pain for approximately 50% of
patients. If a patient does not experience any pain relief from the first
injection, further injections will probably not be beneficial. However, if there
is some improvement in pain, one to two additional injections may be
recommended.
What are
the potential
risks and side effects ?
As with all invasive
medical procedures, there are potential risks associated with epidural
steroid injections. We encourage our patients to try non-invasive treatment
options prior to injections. Risks may include:
-
Infection. Minor infections occur in 1% to 2% of all injections. Severe
infections are rare, occurring in 0.1% to 0.01% of injections.
-
Bleeding. Bleeding is a rare complication and is more common for patients
with underlying bleeding disorders.
-
Nerve
damage. While extremely rare, nerve damage can occur from direct trauma
from the needle, or secondarily from infection or bleeding.
-
Dural puncture
("wet tap"). A dural
puncture occurs in 0.5% of injections. It may cause a post-dural puncture
headache (also called a spinal headache) that usually gets better within a
few days. Although rare, a blood patch may be necessary to alleviate the
headache.
How frequently can
epidural steroid injections be performed?
There is no definitive
research to dictate the frequency of epidural steroid injections for low back
pain and/or leg pain. In general, it is considered reasonable to perform up to
three injections per year.
Typically,
epidural injections are done in 3-4 week intervals. However, there is no general
consensus in the medical community as to whether or not a series of three
injections need always be performed. If one or two injections lessen the
patient’s low back and/or leg pain, we prefer to save the third
injection for any potential recurrences of back pain later in the twelve-month
period.
Is
there any difference between the first and the second ESI?
Yes,
in the lumbar region, every ESI is different in technique. The first ESI usually
targets the posterior epidural space, the technique is called interlaminar ESI.
The second ESI is called the transformational ESI which targets the lateral and
the anterior epidural space. Occasionally we also perform a caudal ESI,
especially if there is epidural scarring at the site of open surgery. In
the cervical region we usually perform the interlaminar ESI. Transforaminal ESI
is used very selectively.
What
is your success rate ?
Based
on experience, our success rate is about 30-50% with each injection. Best results
are seen in patients with radiating pain. Axial pain due to disc degeneration,
central spinal stenosis might not be relieved with ESI. Sometimes we
may have to do more than one procedure at multiple sites. Since the outcome
measures in pain management is difficult to determine, we do not audit success
rates. Chronic cigarette smokers, failed back surgical patients tend to do
poorly with ESIs.
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