In many cases of chronic back pain, spinal injections are used both to learn more about what is causing your pain and to treat your pain. Health care providers refer to these two separate uses of spinal injections as diagnostic and therapeutic. The injections can be a diagnostic tool because they give your doctor information that helps him or her make a diagnosis. For example, if an injection provides pain relief in the area that is injected, it is likely that this particular area is the source of the problem. Once the location of one or more sources of pain is discovered, your health care provider can perform other necessary tests to try to determine the actual problem and create the proper treatment plan. The injections are therapeutic in that they can provide temporary treatment and temporary relief from pain.
What Medications Are Injected and Why?
With most spinal injections, a local anesthetic (numbing medication) called lidocaine (also known as Xylocaine) is
injected into a specific area of the spine. Lidocaine is a fast-acting drug, but the effects wear off within about two hours. Therefore, this medication is used more as a diagnostic tool than a long-lasting pain reliever. Another type
of anesthetic, called Bupivacaine (also known as Marcaine), can also be used. This anesthetic takes longer to take effect, but it also wears off slower, giving the patient more relief from pain. A strong anti-inflammatory steroid
medication, cortisone, is also commonly injected along with one of the above anesthetics in order to reduce inflammation in the affected areas. Cortisone is long lasting and can be slow releasing in order to give the best possible benefits of pain relief. Cortisone may take several days to begin working to reduce inflammation following injection, but the effects can last for months. In some cases, a narcotic medication such as morphine or fentanyl may be mixed with the cortisone and the anesthetic to get better pain relief from the injection.
Epidural Steroid Injection (ESI)
An ESI is a common type of injection that is given to provide relief from low back pain and from certain types of neck pain. The "epidural space" is the space between the spinal sac (called the dura mater) and the inside of the bony
spinal canal. It runs the entire length of your spine. Once injected into this area, the medication moves freely up and down the spine to coat the nerve roots and the outside lining of the facet joints of the spine near the area of
injection. For example, if the injection is done in the lumbar spine, the medication will usually affect the entire lower portion of the spine.
Before the Procedure:
You will most likely be asked to come into the clinic or hospital a bit before the actual procedure to fill out paperwork and answer several questions to make sure you are ready to have the procedure. You may be asked to be "NPO". This means you should have nothing to eat or drink for at least eight hours before the procedure. The primary reason for this is to reduce the risk of vomiting food or liquids if you become nauseated or have a reaction to the medications. Nausea is unpleasant, but it can also cause serious complications if you aspirate food or liquid into your lungs while you are groggy. Not having anything in your stomach during any procedure is an extra precaution highly recommended by most health care providers.
You will probably be asked to undress and put on a hospital gown before the procedure. You will then be connected to a device to monitor your heart rate, blood pressure, oxygen saturation and pulse. You may have an intravenous line (IV) started. You may be asked to sit on a stretcher or lie on your side for the procedure. Your back will be prepared with an antiseptic. The skin where the injection will be performed will probably be injected with lidocaine first to numb the area.
The epidural needle is inserted into the back until the doctor feels sure it is in the epidural space. He or she will then place a small amount of lidocaine into the epidural space and wait to see if you feel warmth and numbness into your legs. If so, the needle is most likely in the correct position. The remainder of the medication is injected and the needle is withdrawn.
There are three different ways to perform an epidural injection:
Caudal Block - A caudal block is placed through the sacral gap (a space near the sacrum and below the lumbar spine), into the epidural space. This type of block usually affects the spinal nerves that are at the end of the spinal cord
near the sacrum. This collection of nerves is also called the cauda equina. One of the benefits of this type of injection is less chance of a "dural puncture" also called a "wet tap". As mentioned above, the dura covers the spinal cord.
It holds the spinal fluid and protects the cord and nerves from damage.
Translumbar - The most common way of performing an epidural is the translumbar approach. This type of injection is performed by placing a needle between two vertebrae from the back. The needle is inserted between the spinous processes of two vertebrae. You can actually feel the bumps that make up the spinous process by simply feeling along the back of your spine.
Transforaminal - This type of injection is a very selective injection around a specific nerve root. This type of epidural injection is used
most often for diagnostic purposes, and it is commonly used in the neck. The foramina are the small openings between your vertebrae through which the nerve roots exit the spinal canal and enter the body. By injecting medication only around a specific nerve root, the doctor can determine if this is the nerve root causing the problem.
Indications to use an epidural:
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.
Epidural injections are good for reducing radicular pain caused by nerve irritation from herniated discs and spinal stenosis. A herniated disc occurs when pressure to a disc's outer fibers (annulus) is so great that it rips, 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 basically a narrowing of the entire spinal canal, which places pressure on the nerves and spinal cord. The injections are also helpful when the main problem is arthritis of the facet joints in multiple areas. The medication coats the outside of the joints at multiple levels and is absorbed into the joint. This reduces the inflammation inside the joint.
Facet Joint Injections
Facet joint injections are used to localize and treat low back pain that is caused by problems of the facet joints. These joints are located on each side of the vertebrae; they join the vertebrae together and allow the spine to move with flexibility. The facet joint injections form a pain block that allows the doctor to confirm that it is a facet joint causing the pain. The medication used also decreases inflammation of the joint that occurs with arthritis and joint degeneration.
To insure that an injection is actually into the facet joint, "fluoroscopy" can be used to confirm that the needle is in the right position before the medication is injected. A fluoroscope uses X-rays to show a TV image, so the doctor can watch as the needle is placed into the joint. The fluoroscope can also magnify the image, increasing accuracy.
There are two types of facet joint injections:
Interarticular - This is injected directly into the joint to block the pain and reduce inflammation.
Nerve Blocks - These help determine whether the joint is indeed a source of pain by blocking the medial branch or nerves that connect with the joint.
Indications to use a facet joint injection - A facet joint injection is perhaps the best way to diagnose facet joint syndrome. Joints that may look abnormal on an X-ray may in fact be painless, and joints that look fine may indeed be the source of the pain - only the injection tells the true story. These injections may be used to treat low back pain and determine whether the facet joints are the true culprits. It is also a rather simple procedure with low risk.
At times, your doctor may need to determine whether the metal hardware that has been used during surgery could be contributing to your discomfort. A hardware injection is performed by injecting lidocaine alongside the spinal hardware that was placed in the spine during surgery. If the pain is removed temporarily by the injection, it may indicate that the hardware is contributing to your pain.
Indications to use a hardware injection - The injections are used to determine whether a specific piece of hardware is contributing to the pain and needs to be removed surgically.
Sacroiliac Joint Injections
Sacroiliac joint (SI joint) pain is easily confused with back pain from the spine. The SI joint is located between the sacrum and the hipbone. In some cases, injecting the SI joint with lidocaine may help your doctor determine whether it is the source of your pain or not. If the joint is injected and your pain does not go away, it is probably coming from somewhere else. If the pain goes away immediately, your doctor may also inject cortisone into the joint before removing the needle. The cortisone is added to treat the inflammation from SI joint arthritis that may be causing your pain. The injection usually gives temporary relief for several weeks or months.
Indications to use a sacroiliac joint injection - SI joint injections can be used to treat and to prove that the SI joint is the source of pain. This injection usually requires the use of fluoroscopic (radiologic) guidance or a CAT scan in order to make sure the needle is placed correctly in the joint. CAT scans are X-ray tests that produce X-ray "slices" taken of the spine, so each section can be examined separately.
Trigger Point Injection (TPI)
TPI's are intra-muscular (IM) injections of local anesthetic (like Novocain), and often an anti-inflammatory steroid, not muscle-building, into the muscle sites that are involved in your myofascial pain syndrome. Chronic muscular pain usually results from an injury to a muscle, such as from a sprain or strain. Pain can also develop gradually secondary to non-use of the muscle. When medications and time do not result in muscular pain relief, physical therapy often can improve your pain complaints. Sometimes, the muscular pain persists despite all conservative treatments. Then, TPI's may be tried to alleviate your pain. TPI's temporarily numb and relax the muscle sites involved in your pain complaints. This allows you to stretch these muscles more effectively than you would be able to otherwise, and also may increase blood flow through that muscle. Steroid is often used for only the first set of injections. It is thought that steroids may treat any inflammation present in these muscle sites.
The injections may never be able to alleviate all of the pain. It will be important for you to continue with home stretching exercises no matter how much relief you obtain. Obviously, if the first set of TPI's result in satisfactorily sustained relief, then there is no need to perform any more injections. If the first set of injections provide no relief, there is no point to repeat any further TPI's. If the first set of trigger point injections result in partial sustained relief, then a series of these injections may provide you with a greater degree of sustained relief as compared with only one set of injections..
You may be sitting or lying down for the procedure depending on where the injection sites are located. The area will be cleansed with an antiseptic. The doctor will then place the needle into the muscle site and inject a small amount of local anesthetic. A band-aid may be applied to the injection sites. You should immediately attend physical therapy or proceed with stretching exercises at home to get maximum benefit from the TPI's.
Stellate Ganglion Block (SGB)
A ganglion is a group of nerves. One part of the sympathetic nervous system chain is the stellate ganglion that is located in the neck. It controls blood flow to the head and arms, and is sometimes involved in pain transmission from those areas. A SGB involves the injection of a local anesthetic (like Novocain) around the stellate ganglion. A SGB may be performed if your facial or arm pain is thought to be sympathetically mediated. A SGB is both diagnostic as well as therapeutic, meaning that in addition to determining the cause of your pain, the block may treat the pain problem as well. Sympathetic pain results from the inappropriate activation of sympathetic nerves. This can result from any type of injury, large or very small, such as a paper cut. For whatever reason, these nerves can be activated and result in a chronic pain syndrome. This syndrome is referred to either as Complex Regional Pain Syndrome (CRPS I or II) which are also know as RSD (reflex sympathetic dystrophy) and Causalgia. Often, the skin becomes very sensitive, frequently changes color and temperature, and is associated with severe spontaneous pain at times. If left untreated, it can become somewhat permanent. Medications may not be effective. The appropriate treatment involves temporarily blocking these sympathetic nerves with local anesthetics either once, or multiple times if needed. It is not known why temporarily blocking these nerves re-sets the nerves back into their normal state, thus treating the pain syndrome.
An IV will be placed before the procedure. You will lie with your head tilted back. Your neck will be cleansed with an antiseptic. The doctor, by using his sensation of touch and pressure, will guide the needle to the correct area and then inject the local anesthetic. The procedure will take about 20 minutes. Your blood pressure and pulse will be monitored after the procedure for 15 minutes. You may experience the development of a "bloodshot" eye, nasal stuffiness, hoarse voice, difficulty swallowing, and the sensation of warmth, or tingling in your hand. These symptoms should disappear in 6 to 12 hours. A nurse will review your discharge instructions before you go home.
Differential Lower Extremity Injections
Various types of injections into certain areas of the lower extremities can help your doctor decide where the pain is most likely coming from. Pain that comes from problems with the back and the spinal nerves can mimic many other conditions. Sometimes it is impossible to tell if the pain you are experiencing is due to a back condition or from a problem in your hip, knee, or foot. To try to determine whether the joint is causing you pain or not, your doctor may suggest injecting medication, such as lidocaine, into the joint to numb the area. Once the medication is injected, if the pain goes immediately away, that joint is more likely the source of the pain than your back. Your doctor can then focus on finding the problem in the joint, rather than your back.
Some reasons not to use epidurals:
Technical Reasons: Your health care provider may suggest that an epidural injection not be considered if you have abnormalities of the
epidural space; it has been altered from a congenital (present at birth) abnormality or from 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 whole body (systemic) corticosteroid effect such as fluid retention or interference with glucose control. Therefore, an epidural might not be well suited for patients with diabetes or congestive heart failure.
With any surgery, there is a risk of complications. When surgery is done near the spine and spinal cord these complications (if they occur) can be very serious. Complications could involve subsequent pain and impairment and the need for additional surgery. You should discuss the complications associated with surgery with your doctor before surgery. The list of complications provided here is not intended to be a complete list of complications and is not a substitute for discussing the risks of surgery with your doctor. Only your doctor can evaluate your condition and inform you of the risks of any medical treatment he or she may recommend.
There are several risks involved with epidural injections to be aware of:
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, 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 he has a wet tap, he may perform a blood patch before he removes the epidural needle. A blood patch is a simple procedure where about three ounces of blood are drawn from an arm vein. The blood is then immediately injected into the epidural space with an epidural needle. The blood then clots around the spinal sac and stops the leak by
forming a "patch".
There is a small chance that the medication may be injected into one of the small blood vessels that run 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 low. Your doctor can discuss it with you in further detail.
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 in an epidural is going near the spine, an infection is much more serious if it occurs. The chance that an infection will occur is extremely small.
An epidural injection can result in a hematoma. A hematoma is simply a collection of blood due to an injury to a blood vessel. An epidural hematoma can be serious if it is big enough to cause enough pressure on the spinal nerves so that they quit working. This can cause problems with the bowels and bladder.
Because 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.
There is always a small risk of damage to the spinal nerves. The spinal cord is a bundle of millions of nerves that connects the brain with the rest of the body. If the epidural needle directly injures the spinal nerves, this can cause neurologic problems.
Unstable Medical Conditions
Injections are usually an elective procedure that is offered to patients without life-threatening conditions. A medically unstable patient should have their medical condition treated before any elective injections are given.
The following are basic warnings to consider before choosing to have a spinal injection:
If you are chronically taking a platelet-inhibiting drug, such as aspirin or NSAIDs (nonsteroidal anti-inflammatory drugs), you have an increased risk of bleeding and might not be a candidate for a spinal injection.
If you are hypersensitive or have certain allergies to medications, you may have a negative reaction to drugs used in the injection. Make sure you give your provider a list of your allergies.
If you have an accompanying medical illness, you should discuss the risks of spinal injections with your physician. For example, patients with diabetes mellitus might experience an increase in blood sugar after an injection with cortisone Patients with congestive heart failure, renal failure, hypertension, or a significant cardiac disease may have problems because of the effects of fluid retention several days after an injection.