Overview of Epidural Steroid Injections
Epidural steroid injections have been a trusted treatment for back pain caused by lumbar disc injuries since the 1950s. These injections are particularly useful for a specific type of nerve pain known as radicular pain. This is a type of pain that starts in the spine and travels down the area covered by one or more spinal nerves. Lumbar or cervical disc herniation, a condition where the soft inner part of the spinal disc bulges out of the tougher outer part, can lead to this condition by compressing the nerve root. Other conditions like spondylosis, ligamentum flavum hypertrophy, and spondylolisthesis can also cause this pain by compressing the spinal nerves.
Patients suffering from radicular pain in the lower back and sacral area (lumbosacral radiculopathy) often report that this pain affects their daily activities. Around a quarter of these patients experience severe pain that does not respond to medication. Out of these, approximately 14% require surgery to alleviate their pain.
However, in many cases, patients find relief from their pain through various non-surgical medical treatments and physical therapy. Here, epidural steroid injections play a significant role by reducing inflammation and relieving pain. The steroids are injected into the epidural space, which is the area surrounding the spinal cord. These injections help in managing pain effectively and could potentially prevent the need for medications or surgeries.
There are three main techniques to deliver these steroid injections: the transforaminal, interlaminar, and caudal approach. Doctors usually use x-ray imaging technology known as fluoroscopy, or less commonly computerized tomography (CT scan), to ensure the accurate placement of the needle during the procedure. Multiple studies have shown the effectiveness of these injections in reducing pain, especially in cases of lumbosacral radiculopathy. However, the long-term effectiveness of these injections in improving physical disability and reducing the need for surgery is yet to be consistently proven.
Similar injections in the neck area (cervical epidural steroid injections) have also been effective in providing temporary relief for radicular neck pain. However, there are limited studies that look at their long-term outcomes. Despite the potential benefits, like any medical procedure, these injections carry a small risk of complications that could be severe, although these are rare.
Anatomy and Physiology of Epidural Steroid Injections
The brain and spinal cord are protected by three layers called meninges. The pia mater is the innermost layer that closely touches the spinal cord. The middle layer is known as the arachnoid mater. The dura mater, which is the toughest and outermost layer, provides additional protection to the spinal cord. There’s a space between this layer and the actual spine, known as the epidural space. This space contains various structures like the dural sac, blood vessels, fat, and connective tissue, along with spinal nerves. The dura mater also plays a crucial role in the peripheral nervous system, which affects the nerves throughout your body.
The spinal cord itself is protected by the vertebral column, which is made up of 33 vertebrae—7 in the neck (cervical), 12 in the chest (thoracic), 5 in the lower back (lumbar), 5 in the pelvic region (sacral), and 4 at the very bottom of the spine (coccygeal). Between these vertebrae are 23 intervertebral discs that help with movement and provide cushioning. The spinal nerves exit the spine through openings called intervertebral foramina.
These openings are formed by the discs and the upper and lower parts of the vertebrae at the front, and parts of the vertebrae that form a joint at the back. The spinal nerves are formed within these openings by smaller nerve roots. Upon exiting the opening, each spinal nerve splits into two parts.
These openings also contain arteries, veins, and fat. The spinal nerves are supplied by radicular arteries. In the chest and lower back areas, these arteries come from the aorta (main artery from the heart) and the intercostal arteries (found between the ribs). These arteries then divide into three parts—one to the muscles around the spine, one that supplies the dura mater, and one that supplies the spinal nerve inside the opening. In the neck area, the arteries come from the ascending cervical, deep cervical, and vertebral arteries.
During some medical procedures, such as epidural steroid injections, it’s vital to carefully avoid these arteries. Special techniques for placing the needle and checks are used to ensure the needle doesn’t mistakenly enter a blood vessel. One significant artery to avoid is the Artery of Adamkiewicz, the largest radicular artery, providing blood to the lower part of the spinal cord. The location of this artery can vary, typically originating from T9 (in the thoracic spine) or as low as L5 (in the lumbar spine) It’s generally found to the left side in most people. The vertebral arteries, which run in front of nerve roots and joints in the neck area, also have variations in their anatomy.
Why do People Need Epidural Steroid Injections
Epidural steroid injections are used to manage pain that arises from inflammation or irritation of the nerves in your spine. One specific kind of pain treated in this way is radicular pain. This type of pain spreads along the path of the affected nerve. A variety of conditions can irritate your spinal nerve roots, and often leads to lower back pain which can spread down to the buttocks or legs, a condition popularly known as sciatica. The treatment can also help those with neck pain that spreads to their arms.
The most frequent reason for spinal nerve root irritation is a condition related to the spinal discs between your vertebrae. When a disc herniates or slips out of place, the central part of the disc presses against the outer layer, putting pressure on the nearby spinal nerve. This pressure can cause symptoms like pain, weakness, and numbness along the path of the affected nerve. Likewise, degenerative disc disease which is the gradual wearing away of these spinal discs can cause the collapse of the spaces between the vertebrae and squeeze the spinal nerve roots.
Epidural steroid injections can also be used when spinal nerve roots are irritated due to spinal stenosis. This is a condition where the spinal canal or the spaces through which nerves exit becomes narrow. This typically occurs due to arthritis in the vertebral joints or issues with the spinal discs.
Other conditions where these injections may be helpful include situations where there are nonspecific radiculitis, bone spurs in the vertebrae pressing against spinal nerves, thickening of the ligamentum flavum, post-surgery syndrome, cysts in facet or nerve roots causing radicular pain, neuralgia post-herpes or post-trauma, compression fractures causing radicular pain, spondylolysis, spondylolisthesis, and scoliosis that irritates nerve roots.
A thorough review of 70 studies on lumbar epidural steroid injections showed that their effectiveness was good for lumbar disc herniations, fair for spinal stenosis, and poor for failed back surgery syndrome. Another analysis showed good effectiveness of these injections for spinal stenosis and lumbar radiculopathy. Although these injections provide effective pain relief, the relief is generally short-term and additional therapy may be needed to achieve long-lasting pain relief.
When a Person Should Avoid Epidural Steroid Injections
There are certain situations where it’s not safe to give a patient an epidural steroid injection. These include:
– If the patient has a widespread infection in their body, or an infection at the spot where the injection would be given, this treatment isn’t safe.
– If the patient has a condition that makes them bleed easily or they’re taking strong medicine to stop their blood from clotting, then an epidural steroid injection could cause dangerous bleeding.
– If the patient is allergic or has a severe adverse reaction to the dye used in imaging, the anesthetic used for pain, or the corticosteroid medication used in the injection, then this treatment isn’t safe.
– If the patient has cancer in the area where the injection would be given, this treatment isn’t safe.
– If the patient does not want to get the injection, their wishes should be respected and they can’t have this treatment.
There are also certain situations where an epidural steroid injection might still be possible, but it comes with extra risks. These include:
– If the patient’s diabetes isn’t under control, steroid injections could cause blood sugar levels to rise, which can be very dangerous.
– If the patient has a condition called congestive heart failure where their heart doesn’t pump blood effectively, this treatment might not be safe.
– If the patient is pregnant, they’re usually advised not to get this treatment. This is because it involves a type of imaging called fluoroscopy, which uses X-rays and can be harmful to a developing baby.
Equipment used for Epidural Steroid Injections
An epidural steroid injection is a procedure where steroids are injected into your spine to lessen pain and inflammation. For this procedure, the following pieces of equipment and materials are needed:
– A special type of X-ray device called a Fluoroscopic c-arm
– Needles specifically designed for epidurals
– Local anesthetics like lidocaine or bupivacaine, to numb the area
– Various kinds of steroids, like methylprednisolone acetate, triamcinolone acetate, betamethasone acetate, betamethasone phosphate, or dexamethasone phosphate
– A syringe designed to tell when the needle enters the epidural space, known as a loss of resistance syringe
– Contrast solution, which is a special dye that helps your doctor see the area better
– Sterile gloves and drapes to help prevent infection
– Betadine, an antiseptic used to clean the affected area
An epidural steroid injection can be done with just a local anesthetic applied to the skin, or with the patient under intravenous sedation. The patient’s vital signs, such as their heartbeat and blood pressure, are constantly monitored throughout the procedure using devices like blood pressure cuffs, cardiac monitors, and pulse oximeters.
In the past, some doctors preferred using particulate steroids, meaning they could form small clumps, because they believed these stayed in the right spot in the body for longer periods of time. However, there is a safety concern with this type of steroids as these can form bigger particles that are larger in size compared to a red blood cell.
Dexamethasone betamethasone phosphate are examples of nonparticulate steroids. These types of steroids do not form clumps and are about 10 times smaller than a red blood cell. Studies have shown that these nonparticulate steroids do not cause neurological injury if accidentally injected into a blood vessel. Because of this, and the fact that no clear benefit has been shown for the use of particulate steroids, there is a growing preferance for using nonparticulate steroids in epidural steroid injections.
Who is needed to perform Epidural Steroid Injections?
The team for your procedure will have several members. First, there’s a doctor who was specially trained in giving epidural steroid injections. These shots help decrease back or leg pain. You will also have a nurse or an assistant present to help. Another team member will operate a special type of X-ray machine, known as a ‘fluoroscopic c-arm’, which allows the doctor to see the location in your body where the injection needs to be given. Finally, there’s a doctor who specializes in anesthesia, whose job is to carefully watch and care for you while the procedure is happening. It’s important to note that every person involved in the procedure is skilled in responding to any possible issues that could occur during the process.
Preparing for Epidural Steroid Injections
Before any medical procedure, the doctor will discuss its potential risks and benefits with the patient. If the patient agrees to proceed, they will need to sign a formal consent form. Once this is done, there is a quick pause to confirm the patient’s identity and the exact location for the procedure.
When it’s time to begin, the patient lies face-down on a special x-ray table. After identifying the exact spot for the injection, the doctor will mark it. Following this, the area around the mark is cleaned with a special solution called betadine to ensure full cleanliness and to prevent infection. Then, this cleaned area is covered with a hygienic, sterile drape to maintain sterility during the procedure.
How is Epidural Steroid Injections performed
Epidural steroid injections can be given in different areas of your spine, and there are different ways the needle can be inserted. These injections can be in the neck (cervical), mid-back (thoracic), or lower back (lumbar). The needle can go straight in (interlaminar), at an angle (transforaminal), or into the tailbone (caudal). Let me explain these three techniques:
In an Interlaminar Epidural Steroid Injection, you will lay on your stomach and the doctor finds the right spot between two backbones with a special X-ray machine (fluoroscope). After numbing the skin and tissues underneath with local anesthetics like lidocaine or bupivacaine, the doctor places a needle into the injection site. The needle goes through the skin, fat, muscles and a ligament. Then the doctor uses the fluoroscope again to make sure the needle is in the right place. She uses a small syringe filled with air or saltwater to know when the needle is in the right spot. Once the needle is in place, they inject a dye to see if it spreads correctly. When everything is confirmed to be correct, a steroid medication is then injected into the area to help reduce inflammation. After that, the needle is removed, and pressure is put on the place of the needle to prevent any bleeding.
In a Transforaminal Epidural Steroid Injection, again, you lay on your stomach. The doctor determines the right injection site, on the side of the vertebra, with the fluoroscope. After numbing the area with anesthetics, the needle is placed under the top vertebra, using the fluoroscope to guide the needle and prevent nerve damage. The correct position of the needle is confirmed by injecting a dye to view how it spreads. Then, the steroid medication is injected into the area to help with inflammation. The needle is then removed, and the injection site is compressed to prevent any bleeding.
In a Caudal Epidural Steroid Injection, you lay on your stomach, and the doctor identifies the injection site on your tailbone with fluoroscope. Then, similar to other procedures, the area is numbed, and the needle is guided into place. They then check the needle’s position with a dye injection, and inject the steroid medication once the needle’s position is confirmed. After injecting the medication, the needle is removed, and pressure is applied to the injection site to prevent bleeding.
These procedures are safe and effective ways to deliver medication to help manage pain and inflammation in your spine.
Possible Complications of Epidural Steroid Injections
Though uncommon, there can be few complications associated with medical procedures:
* Bleeding: Unusual loss of blood during or after the procedure.
* Infection: Invasion of harmful bacteria in your body post procedure.
* Allergic reaction: Undesired reactions of the body to certain substances involved in the procedure.
* Nerve injury: Damage to nerves that may happen during a procedure.
* Temporary numbness and tingling in your arms or legs: Loss of sensation or a prickly feeling in your arms or legs that will go away after sometime.
* Positional headache due to a puncture in the outer membrane of the spinal cord or brain: This type of headache worsens when you stand up and improves when you lie down.
* Epidural abscess: A pocket of pus that forms in the space outside the covering of the brain and spinal cord, which can be caused by an infection.
* Epidural hematoma: A condition where blood collects between the skull and the outer layer of the brain due to a ruptured blood vessel.
* Temporary back or leg pain: Discomfort or pain in your back or legs that only lasts for a short period.
* Side effects of steroids such as transient flushing or hot flashes, fluid retention, weight gain, increased blood sugar levels, and mood swings: These are potential reactions to the steroids used in some procedures.
* Adrenal suppression: A condition where your adrenal glands do not produce enough hormones, it can be side effect of taking certain medications.
* Spinal cord infarction: A stroke within the spinal cord, which can happen after an epidural steroid injection – a treatment for neck or back pain.
Also, there’s a rare complication called cerebral infarction which is a type of stroke that occurs when blood flow to part of the brain gets blocked, and this could occur after a specific type of injection with steroids into the neck area.
What Else Should I Know About Epidural Steroid Injections?
Epidural steroid injections are a way doctors treat neck or lower back pain that radiates to the limbs. Sometimes, these injections can prevent the need for surgery. There have been many studies on this method but they’ve had mixed results due to different methods of injection and broad criteria for patient selection. The reviews include a range of delivery routes, like transforaminal (through the side), interlaminar (between the layers), and caudal (near the tailbone), with many different reasons for use such as regular back pain, failed back surgery, and spinal narrowing.
More recent studies have shown that epidural steroid injections using the transforaminal and interlaminar methods can really help reduce pain for patients with low back pain that also have pain radiating to their limbs. But they haven’t shown to be useful for just regular back pain. In some cases, these injections can have long-term benefits, providing relief for up to 12 months and delaying the need for surgery. When we have pain radiating to the limbs due to a slipped disc, the medical evidence shows that the combination of local anesthetics with steroids provide good relief while only local anesthetics provide fair relief.
Theoretically, the transforaminal route is better because it delivers the medicine near the exiting spinal nerves and the sensitive neuron clusters. When comparing the transforaminal method with the interlaminar method, they’re found to be similarly effective at 6 months, but the transforaminal approach provides faster relief within 2 weeks. Other studies have shown that interlaminar injections for mainly regular back pain don’t have much effect other than short-term pain relief. Reviews investigating the dose of steroids in the injections found no link between the dose and the pain relief for chronic low back pain or pain radiating to the limbs.
Studies on using epidural steroid injections for neck pain have also had mixed methods and outcomes. The evidence supports more the use of the interlaminar method over the transforaminal method for neck injections. The injections have shown to lastingly relieve pain and improve disability measures over 12 to 24 months. However, many studies required multiple injections. Similar results were found between epidural steroid injections combined with local anesthetics and local anesthetics alone. The reasons for these injections included pain radiating to the limbs, slipped disc, neck spinal narrowing, and problems after neck surgery.
