Overview of Facet Joint Injection
Facet joint injections are a common treatment for spine-related issues. Problems with the facet joints, which are small joints at each segment of the spine, can cause pain and discomfort. They can become painful due to different conditions like osteoarthritis, instability of the spine segments, injuries, pinched tissues, and swelling of the joint lining.
Those who have pain in their facet joints often have symptoms such as neck or back pain, which can worsen when they stretch their spine, bend sideways, or twist their body.
Pain that’s caused by an issue with the facet joints is usually concentrated around the spine, with only occasional spreading to the arms or legs. This is particularly true if the pain is in the neck or lower back. So, when possible facet joint pain is being diagnosed, patients are often asked whether their pain extends below their knees or beyond their elbows. If the answer is ‘yes’, then it’s less likely that the pain is caused by an issue with the facet joints. However, such symptoms are not specific and definitive for diagnosing facet joint disease. It’s also worth noting that even if you’re suffering from facet joint pain, your imaging tests (like X-rays or MRI scans) might still appear normal or just show signs of aging changes.
Diagnosing facet joint pain is often a process of ruling out other potential causes. That’s why facet joint injections are so valuable. They not only help to diagnose the cause of back or neck pain by seeing if these injections relieve the pain, but they can also provide a therapeutic benefit by reducing the pain.
Anatomy and Physiology of Facet Joint Injection
The facet joints are special joints found throughout the spine. Their size and shape differ depending on their location in the spine. Each joint is formed by two neighboring bony parts of the spine called vertebrae. One vertebra contributes an upwards-facing join, while the other contributes a downward-facing joint. Inside the joint there is a smooth cartilage surface, followed by a special fluid-filled sac (the “synovial membrane”), all covered by a firm outer layer. This joint space can hold about 1 to 2 ml of fluid.
These joints have multiple roles, such as controlling excessive motion, distributing weight along the spine, and preventing unwanted motion between successive vertebrae. Also, each facet joint is sensitive to information about movement and changes in position. It collects this information from the nerve at its level, as well as one level above.
Many people experiencing spinal pain might be feeling it because of a problem with these joints. It is estimated that they may account for up to 67% of neck pain, 48% of thoracic (middle back) pain, and 45% of lower back pain. The pain generally arises from injury or inflammation due to degenerative arthritis or bone wear and tear, excessive stretching or tearing of the joint covering, instability, and pinching of nerves due to bony growths.
Various factors have been connected with facet joint-related pain, such as damage to pain sensation fibers, nerves responsible for inflammation, and specific chemicals involved in the pain and inflammation process. Of all these, the most common cause of such pain is osteoarthritis or degeneration of joint due to age or wear and tear. Other causes include spondylolisthesis (slippage of one vertebra over another), rheumatoid arthritis (an immune system disorder), ankylosing spondylitis (a type of arthritis affecting the spine), and septic arthritis (inflammation of joint due to infection).
Why do People Need Facet Joint Injection
If your doctor suspects that your back or neck pain is due to issues with the facet joints (the small joints along your spine that help with movement), they may suggest injecting medicine into these joints as a form of treatment. Possibility that you need facet joint injections can increase when you have tenderness over the facet joint, pain when you extend your back, make twisting movements, or bend sideways, leg pain that doesn’t extend beyond your knee, constant low back pain, neck pain that doesn’t improve even after trying other treatments, back pain despite normal imaging results, neck pain after a whiplash injury, pain after a certain surgical procedure (known as laminectomy), a disruption of a small pouch in the joint (facet joint synovial cyst), alternative treatment for a spinal fracture (vertebral compression fracture), or a certain condition that can cause lower back pain (spondylolysis).
Before your doctor suggests these injections, they will usually ask you to try more conservative treatments first. For example, you may have tried a combination of different types of medications, physical therapy, and changes in behavior for at least 3 months before considering injections. The doctor may suggest facet joint injections when the pain is moderate to severe (rated more than 4 out of 10 on the pain scale) and when it’s affecting your ability to perform your daily activities or your quality of life.
A therapeutic facet joint injection, which is used for actual treatment rather than diagnosing the cause of pain, may be recommended if you have been confirmed to have pain from a facet joint and responded positively to a diagnostic injection previously, need additional pain management along with your current treatments, can’t manage pain with oral or systemic medications, experiencing pain after spinal fusion surgery, or have a defect in the structure connecting your vertebrae causing pain (spondylolytic defects).
When a Person Should Avoid Facet Joint Injection
There are only a few scenarios where the patient should possibly refrain from receiving this procedure, apart from if the patient simply does not want it. For instance, if the patient has either a whole body (systemic) infection or a local infection in the area where the injection will occur, it may not be safe to proceed. Similarly, if the patient has a condition that affects the blood’s ability to clot (known as coagulopathy) or a tendency to bleed excessively (referred to as a bleeding diathesis), especially around the neck region, the procedure may be risky.
If the patient has an allergy to the contrast agent (a dye used to highlight different parts of the body under imaging) or any of the medications being used, it may not be safe to proceed. Moreover, if the patient has a neurological condition (a disorder affecting the brain and nerves) that could be hidden by the effects of the procedure, it may not be appropriate. Finally, it’s generally not recommended to proceed with this procedure during pregnancy.
Equipment used for Facet Joint Injection
To get clear images of your body, we’ll use either a device called a C-arm fluoroscopy or a computed tomography (CT) scanning machine. Both of these devices are located in the imaging suite and helps your doctor see exactly what needs to be treated.
For the process, we’ll use a few types of needles. Firstly, an 18 gauge needle will be used to draw up the medication. Then, a smaller 25 gauge needle is used to numb the skin with a local anesthetic. This is the medication that will help numb the area and make the process more comfortable for you. For this, we’ll use something called 1% lidocaine.
Once the skin is numb, we’ll use a 22 to 25 gauge spinal needle to actually reach the facet joint, which is the part of the spine being treated. This needle is a bit bigger than the one used to numb your skin but you won’t feel this because of the anesthetic.
To ensure the needle is in the right spot, a contrast agent (in our case, 240 mg % iohexol) will be used. This is a type of dye that shows up on the imaging screen and allows the doctor to see everything clearly.
After that, a local anesthetic (we tend to use 0.5% bupivacaine) will be injected to numb the area being treated. This is a long-lasting anesthetic, but there are other options that can be used if necessary.
The final part of the treatment involves injecting a steroid (we usually use 40 mg % triamcinolone). This is also a long-acting medication, and it can help reduce inflammation and relieve pain. Like with the anesthetic, other types of steroids can be used if needed.
Who is needed to perform Facet Joint Injection?
Facet joint injections are normally done by doctors who are good at treating pain and helping with immobilisation, or those who specialize in looking at images of inside your body (interventional radiology). These doctors have also special training in helping patients recover their body movement and function (physical medicine and rehabilitation) and treating neck and back problems (spine intervention). They all work together to make sure you get the best care possible.
Preparing for Facet Joint Injection
Doctors must obtain a patient’s permission before performing a facet joint injection. This process involves explaining the advantages, potential hazards, and other possible treatments to the patient. It’s important to understand that pain relief from facet joint injections can differ greatly from person to person. Sometimes, multiple injections might be necessary as the pain relief can be short-lived.
This procedure is usually carried out in an outpatient clinic, meaning you’ll be able to go home the same day. Doctors generally don’t use sedatives because this can make it harder for them to understand your reaction to the pain, but if you’re feeling nervous, they may provide a gentle sedative. During the procedure, your vital signs such as heart rate and blood pressure will be monitored closely.
During the procedure, you’ll be lying on your stomach. Sometimes, a pillow might be placed under your belly to make it easier for the doctor to access the joint and to reduce curvature in your lower back. It’s important for your head and face to be well-supported for comfort and easier breathing. If the injection is to be given in your neck, you might lie on your side or at a slant. If you’re lying on your side, a headrest will be used to prevent straining your neck and your shoulders should be arranged in a downward posture.
How is Facet Joint Injection performed
The facet joint is a small joint between two vertebrae in your back. In treating conditions related to it, doctors use imaging techniques like fluoroscopy or CT scans to locate this joint. Fluoroscopy gives doctors real-time images and lets them view the joint from different angles with less radiation. A CT scan could help locate joints that are at steep angles.
Once the doctor identifies the facet joint, they will mark the skin above it, clean it, and cover the surrounding area to maintain sterility. Then, they apply a local anesthetic to numb the skin and underlying tissues.
Using the guiding image, the doctors insert a thin needle (either 3.5 inches or 5 inches, depending on the patient’s body weight) into the facet joint. This process also involves injecting a small amount of a contrast medium- something that can be picked up on the imaging scan. This medium helps to confirm correct needle placement within the joint by forming a visible streak between the surfaces of the joint.
Upon confirming accurate placement of the needle in the joint, a combination of a local anesthetic and steroids are injected. The injection amount should typically be between 1 to 1.5 milliliters. The local anesthetic provides immediate pain relief while the steroids work for a longer-lasting pain relief, reducing inflammation, suppressing the immune response, and blocking nerve transmission.
Commonly used steroids include methylprednisolone, dexamethasone, triamcinolone, and betamethasone. However, there’s a guideline to only use dexamethasone in the thoracic and cervical region to reduce the risk of artery blockage by particulates. Studies show substantial improvements in pain scores for patients with mild, moderate, and severe facet joint osteoarthritis, three months after steroid treatment.
Please note that this procedure only serves a therapeutic and not a diagnostic purpose for planning radiofrequency ablation – a treatment used for more prolonged pain relief. If such a treatment is desired, initial test blocks with local anesthetics should be administered at the level of the medial branches – the nerves supplying the facet joint. These test blocks must prove to provide more than 80% pain relief for the duration of the anesthetic used.
Possible Complications of Facet Joint Injection
In general, injections into the facet joints (small joints at each section of the spine that provide stability and guide motion) are low risk procedures. They’re not often associated with additional problems. However, although rare, there can be complications from the procedure.
Some potential complications include an infection of the joint (septic arthritis), a bruise or lump (hematoma), bleeding more than usual, nerve irritation, fainting reactions (vasovagal reactions), rupture of the joint capsule (the structure enclosing the joint), muscle abscess, a spinal fluid leak (dural puncture), damage to the main artery in the neck (vertebral artery), an injection into the spinal fluid space (intrathecal injection), an infection of the skin and underlying fat tissue covering the spine (epidural abscess), inflammation of the brain and spinal cord (meningitis), a collapsed lung (pneumothorax), and paralysis of the diaphragm causing difficulty in breathing (phrenic nerve palsy). These complications are reported occasionally in cervical injections – injections given in the neck region.
Due to these potential complications, injections into the facet joints in the neck are performed less often. A study also confirmed that serious problems from these injections were rare. They mostly occurred in patients above 60 years old, who had other health conditions that increased their risk of infections.
Common problems related to the injections, such as swelling and pain at the insertion point of the needle, typically resolve on their own and last only for a short time. Anesthetics used to numb the area usually don’t cause severe reactions. In some cases, steroid injections, used to decrease inflammation and pain, may cause local reactions that go away within two days.
What Else Should I Know About Facet Joint Injection?
Feeling pain from the facet joints, which are small joints at each segment of the spine that provide stability and guide motion, is quite common. However, diagnosing this condition can be difficult because the signs observed from a physical examination, medical history, and medical imaging might be vague and similar to other conditions causing pain. To better identify if the pain is coming from the facet joint, healthcare providers use a reliable method called diagnostic facet joint injections. Not only does this help point out the source of pain, but it can also ease the patient’s discomfort and provide insights for potential treatments or solutions in the future.