You will probably be asked to arrive early to fill out paperwork and
answer some questions. Your doctor will want to verify that you are
ready for the procedure.
You may be asked to come in "NPO". This means you should not have
anything to eat or drink for at least six hours before the procedure.
This reduces the risk of vomiting food or liquids if you should become
nauseated or have a reaction to the medications. Nausea is unpleasant,
but it can also cause serious complications if you accidentally inhale
(aspirate) food or liquid into your lungs while you are groggy. Not
having anything in your stomach during this procedure is an extra
precaution highly recommended by most health care providers.
You will probably be asked to change into a hospital gown. You will
then be connected to a device that monitors your heart rate (pulse) and
blood pressure. An intravenous (IV) line may be started in your arm.
You may be asked to sit on a stretcher or lie on your side for the
procedure. The area of the back will be prepared with an antiseptic.
Lidocaine may be injected to numb the skin around area where the
epidural will be performed.
Epidural injections are used to treat radicular pain caused by nerve irritation. This type of pain is usually caused by herniated discs
or spinal stenosis. A herniated disc occurs when pressure or
degeneration produces a tear in the disc's outer ring (the annulus),
and the nucleus ruptures out of its normal space. If it rips near the
spinal canal, the bulging disc can push out of its space and into the
spinal canal, placing inappropriate pressure on the spinal cord and
nerve roots. Spinal stenosis is a narrowing of the spinal canal that
can cause pressure on the spinal cord and spinal nerves.
Epidural injections are also helpful when the main problem is
arthritis of the facet joints in multiple areas of the spine. The
medication coats the outside of the problem joints and absorbs into the
joints. This type of injection reduces the inflammation in the joint.
The injection is sometimes aimed at the small nerves that supply the
joints.
It may be necessary to have several epidural injections in a series
over a period of a few weeks. This is because the relief from the
epidural injection usually decreases with time. It is not uncommon to
have three lumbar epidural injections, each about ten days apart.
Your doctor may suggest that an epidural injection not be considered
if you have abnormalities of the epidural space. Either it has been
altered from a congenital (present at birth) abnormality, or from a
previous surgery that has left scarring.
Infection
Injecting steroids, such as cortisone, anywhere in the body allows
for absorption of the medication into the bloodstream and can lower the
body's ability to fight infections. Cortisone should not be used if
there is any type of serious infection in the body.
Steroid Related
Absorption of the medication may also cause a systemic (whole body)
corticosteroid effect such as fluid retention or interference with
glucose control. An epidural might not be appropriate for patients with
diabetes or congestive heart failure.
There are risks associated with epidural injections. This is not
intended to be a complete list, but these are some of the most common.
- dural puncture
- intravascular injection
- infection
- bleeding
- bladder dysfunction
- neurologic complications
Dural Puncture
A dural puncture, or "wet tap," is perhaps the most common
complication from an ESI. This complication only occurs in 0.1 to 5
percent of all injections. The result of a dural puncture is usually a
spinal headache and nausea. A spinal headache occurs when the puncture
in the spinal sac fails to seal itself off. This allows the spinal
fluid to continue to leak out and lowers the spinal fluid pressure in
the brain. When sitting or standing, the headache and nausea are much
worse because the spinal fluid pressure is lower at the top (near your
head) than at the bottom of the spine. The headache usually goes away
when you lie down with your feet higher than your head.
To treat a spinal headache, a "blood patch" is usually recommended.
If the doctor realizes immediately during the procedure that there is a
wet tap, he may perform a blood patch before he removes the epidural
needle. A blood patch is a simple procedure. About three ounces of
blood are drawn from an arm vein and immediately injected into the
epidural space with the epidural needle. The blood clots around the
spinal sac and stops the leak by forming a "patch."
Intravascular Injection
There is a slight chance that the medication may be injected into
one of the tiny blood vessels that runs through the epidural space
instead of the epidural space itself. This can cause seizures, cardiac
arrest, and even death if too much of the medication goes directly into
the blood steam. The chance of this happening is very small. Your
doctor can discuss it with you in further detail.
Infection
Epidural injections are done under sterile conditions very similar
to surgery. Still, anytime a needle is inserted into the body there is
a small chance of infection. Since the needle must be placed near the
spine during an epidural, an infection is much more serious if it
occurs. The chance that an infection will occur is extremely small.
Bleeding
An epidural injection can result in a hematoma. A hematoma is simply
a collection of blood caused by an injury to a blood vessel. An
epidural hematoma can be serious if it is big enough to put sufficient
pressure on the spinal nerves so that they quit working. This can cause
problems with the bowels and bladder.
Bladder Dysfunction
The epidural injection actually paralyzes the nerves to the bowel
and bladder for a short period. You may not have control over your
bladder for one to two hours following the procedure.
Neurological Complications
There is always a small risk of damage to the spinal nerves. The
spinal cord is a bundle of millions of nerves connecting the brain with
the rest of the body. If the epidural needle directly injures the
spinal nerves, it may result in injury to the nerves.
