| Epidural Steroid Injections |
Steroids are potent anti-inflammatory medications. The goal of an epidural steroid injection is
to place this medication near the area of injury or pathology within the spine. The steroid
medication reverses the effect of pain-producing inflammatory compounds produced by the
body, thereby easing pain and allowing for improved function. A local anesthetic is usually
injected with the steroid, which may provide immediate short-term pain relief.
By combining a local anesthetic and steroid, diagnostic information may be obtained in
addition to the provision of therapeutic relief. The most common use of epidural steroid
injection is for spinal nerve irritation, commonly referred to as radiculopathy or, in the lower
back, as sciatica. Epidural injections are also commonly used to treat intervertebral disc pain,
spinal arthritis, spinal fractures, post-surgical pain, tumor-related inflammation and
post-herpetic neuralgia. The injections can be performed on any level of the spine. Three
distinct techniques are commonly used and are described below: Interlaminar Epidural
Injections: In this technique, an x-ray (fluoroscopy) is used to guide a needle into the posterior
epidural space. The injectionist feels a change in resistance to determine the correct needle
depth and the correct needle position is confirmed by x-ray imaging of injected contrast
solution.
The major drawback of the interlaminar approach is the deposition of medication into the
posterior (back) area of the spinal canal, while most pathology is located in the anterior (front)
part of the canal. With large volumes, 5 to 10 ml of solution, the medication usually spreads to
both the front and the back of the canal. Therefore, with diffuse disease processes involving
several spinal levels or disease processes involving structures in the posterior spinal canal,
the interlaminar technique is a reasonable approach.
Transforaminal Epidural Injections: This technique represents a very precise, x-ray controlled
injection of a small volume of medication into the anterior epidural space and the exiting spinal
nerve sheath. It is a useful technique for precisely diagnosing the specific level of pain
generation, as well as treating pain of disc or spinal nerve origin. When making a diagnosis,
the suspected areas of pain generation are located on x-ray and a small needle is placed into
each neural foramen (the spinal opening through which the spinal nerve exits). Each needle is
then injected with a small amount of contrast and the appropriate spinal nerve and proximal
epidural space is observed on the x-ray monitor. The resulting contrast spread, called an
epidurogram, can give valuable information regarding the anatomy at the injected level.
Additionally, the patient may feel a paresthesia, or tingling sensation, in the area of the body
supplied by the injected spinal nerve. If this paresthesia is in the same location as the patient's
pain, it can be deduced that this spinal nerve is contributing to the patient's pain symptoms.
Furthermore, the injection of a small amount of local anesthetic should eliminate the pain for a
short time, further supporting the diagnosis. The injected steroid acts to decrease inflammation
at the specific area of injection, thereby providing analgesia and allowing for increased
function. Several studies have confirmed that transforaminal epidural steroid injections are
highly effective in treating radicular pain and can prevent surgery.
Caudal Epidural Injections: This is a technique that accesses the epidural space near the tail
bone. It is used for pathology in the lower spine, such as pain in the coccyx or tail bone, or to
atraumatically access the epidural space in the patient with low back pain and a history of
previous lumbar surgery. By entering below the area of previous surgery, scars and surgically
altered anatomy can be avoided. This is performed with X-ray guidance and contrast injection
to assure correct needle placement. Typically, relatively large volumes of medication are
injected into the caudal space, ten to fifteen ml, to assure that the medication reaches the
areas of pathology. Another advantage to the caudal approach is the tendency for the injected
medication to pass into the anterior epidural space, the area adjacent to the spinal nerves and
discs.
to place this medication near the area of injury or pathology within the spine. The steroid
medication reverses the effect of pain-producing inflammatory compounds produced by the
body, thereby easing pain and allowing for improved function. A local anesthetic is usually
injected with the steroid, which may provide immediate short-term pain relief.
By combining a local anesthetic and steroid, diagnostic information may be obtained in
addition to the provision of therapeutic relief. The most common use of epidural steroid
injection is for spinal nerve irritation, commonly referred to as radiculopathy or, in the lower
back, as sciatica. Epidural injections are also commonly used to treat intervertebral disc pain,
spinal arthritis, spinal fractures, post-surgical pain, tumor-related inflammation and
post-herpetic neuralgia. The injections can be performed on any level of the spine. Three
distinct techniques are commonly used and are described below: Interlaminar Epidural
Injections: In this technique, an x-ray (fluoroscopy) is used to guide a needle into the posterior
epidural space. The injectionist feels a change in resistance to determine the correct needle
depth and the correct needle position is confirmed by x-ray imaging of injected contrast
solution.
The major drawback of the interlaminar approach is the deposition of medication into the
posterior (back) area of the spinal canal, while most pathology is located in the anterior (front)
part of the canal. With large volumes, 5 to 10 ml of solution, the medication usually spreads to
both the front and the back of the canal. Therefore, with diffuse disease processes involving
several spinal levels or disease processes involving structures in the posterior spinal canal,
the interlaminar technique is a reasonable approach.
Transforaminal Epidural Injections: This technique represents a very precise, x-ray controlled
injection of a small volume of medication into the anterior epidural space and the exiting spinal
nerve sheath. It is a useful technique for precisely diagnosing the specific level of pain
generation, as well as treating pain of disc or spinal nerve origin. When making a diagnosis,
the suspected areas of pain generation are located on x-ray and a small needle is placed into
each neural foramen (the spinal opening through which the spinal nerve exits). Each needle is
then injected with a small amount of contrast and the appropriate spinal nerve and proximal
epidural space is observed on the x-ray monitor. The resulting contrast spread, called an
epidurogram, can give valuable information regarding the anatomy at the injected level.
Additionally, the patient may feel a paresthesia, or tingling sensation, in the area of the body
supplied by the injected spinal nerve. If this paresthesia is in the same location as the patient's
pain, it can be deduced that this spinal nerve is contributing to the patient's pain symptoms.
Furthermore, the injection of a small amount of local anesthetic should eliminate the pain for a
short time, further supporting the diagnosis. The injected steroid acts to decrease inflammation
at the specific area of injection, thereby providing analgesia and allowing for increased
function. Several studies have confirmed that transforaminal epidural steroid injections are
highly effective in treating radicular pain and can prevent surgery.
Caudal Epidural Injections: This is a technique that accesses the epidural space near the tail
bone. It is used for pathology in the lower spine, such as pain in the coccyx or tail bone, or to
atraumatically access the epidural space in the patient with low back pain and a history of
previous lumbar surgery. By entering below the area of previous surgery, scars and surgically
altered anatomy can be avoided. This is performed with X-ray guidance and contrast injection
to assure correct needle placement. Typically, relatively large volumes of medication are
injected into the caudal space, ten to fifteen ml, to assure that the medication reaches the
areas of pathology. Another advantage to the caudal approach is the tendency for the injected
medication to pass into the anterior epidural space, the area adjacent to the spinal nerves and
discs.
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