INTRODUCTION
Pain specialists commonly use injections for both diagnosing and treating painful conditions. Facet joint injections are frequently employed to determine the cause of back pain. These injections serve primarily as diagnostic tools, helping doctors identify the source of the pain rather than providing long-term relief. By injecting an anesthetic medication into the facet joint, surrounding ligaments, and joint capsule, these injections temporarily numb the area and alleviate pain. If the injection successfully eliminates the pain for several hours, it strongly suggests that the facet joint is responsible for the discomfort. Once the underlying cause is determined, treatment options can be explored.
This guide aims to help you understand the following aspects of facet joint injections:
- Injection site
- Objectives of the procedure
- Preparation requirements
- Expected outcomes
- Potential complications
ANATOMY
Which parts of the body are involved?
To perform a facet joint injection, your doctor will insert a needle into the facet joint, positioning its tip inside the joint.
A facet joint is a small bony knob that extends from the vertebral body. When these knobs meet, they form a joint connecting two adjacent vertebrae. Articular cartilage covers the surface of the facet joints, providing a smooth, rubbery material that enables frictionless movement between the bone ends.
Each facet joint is surrounded by a joint capsule comprising ligaments and connective tissues that help maintain joint stability. The joint capsule forms a watertight sac containing the joint fluid. The facet joints facilitate forward and backward movement of the spine.
The lumbar and thoracic spine contain two facet joints between each pair of vertebrae, located on the back of the spinal column. In the cervical spine (neck), facet joints are positioned on each side of the vertebra.
Facet joints, like all joints, can degenerate or wear out over time, leading to conditions such as degenerative arthritis or osteoarthritis. When facet joints degenerate, they can cause back pain. Additionally, the pain may radiate into the buttock and back of the thigh.
RATIONALE
What is the purpose of the procedure?
Your doctor recommends a facet joint injection to determine if the facet joints are the source of your back pain. This injection is primarily diagnostic, providing temporary pain relief that may last only a few hours. Once your doctor confirms that the facet joints are causing your pain, they may suggest other procedures to provide longer-lasting pain reduction.
During a facet joint injection, the typical medications administered include a local anesthetic and cortisone. The anesthetic medication, such as lidocaine or bupivacaine, is similar to what is used for numbing during dental work or suturing lacerations. It induces temporary numbness that lasts one to six hours, depending on the specific anesthetic employed.
Cortisone, a potent anti-inflammatory medication, is also injected into the painful and inflamed joint. It reduces inflammation and swelling, consequently alleviating pain. If cortisone is combined with the injection, you may experience several weeks of pain relief. This relief can enable you to participate in physical therapy, strengthen your muscles, and resume normal movement. After the effects of cortisone wear off, the pain may not return.
PREPARATIONS
How should I prepare for the procedure?
To prepare for the procedure, your doctor may advise you to remain “NPO” (nothing by mouth) for a specific period beforehand. This means refraining from eating or drinking anything during that time. However, you may receive instructions to take your regular medications with a small amount of water. If you are uncertain about what to do, consult your doctor.
Several days before the injection, you might need to discontinue certainmedications that affect blood clotting to minimize the risk of excessive bleeding during and after the injection. These medications may include common Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) like aspirin, ibuprofen, naproxen, and other arthritis medications. If you are taking any blood-thinning medication, inform your doctor so they can assess whether it’s safe to temporarily discontinue or adjust the medication prior to the injection.
Arrange for transportation to and from the injection location, as you may need assistance. Wear loose-fitting clothing that is easy to remove and put back on. If possible, take a shower on the morning of the procedure using a bactericidal soap to reduce the risk of infection. Avoid wearing jewelry, scented oils, or lotions.
PROCEDURE
What happens during the procedure?
When you are ready for the injection, you will be brought to the procedure area, and an intravenous (IV) line will be started. The IV allows the healthcare team to administer any necessary medications during the procedure and ensures a rapid response in case of an allergic reaction to the injected medications. If you are experiencing pain or anxiety, you may receive sedation medication through the IV.
Fluoroscopic guidance is commonly used during injection procedures today. A fluoroscope is an x-ray machine that allows the doctor to visualize an x-ray image in real-time during the procedure. This enables the doctor to observe the needle’s placement as it is inserted, enhancing safety and accuracy. Once the needle is correctly positioned, a small amount of radiographic dye is injected to confirm the precise location. The medication is then injected into the same area. After the injection, the needle is removed.
You will be moved to the recovery area and remain there until the healthcare team ensures your stability and absence of any allergic reactions to the medications. The anesthetic may cause temporary numbness and weakness. You will be free to leave once these symptoms subside.
COMPLICATIONS
What are the potential risks?
Although complications during or after facet joint injections are uncommon, it’s important to be aware of possible risks. While this document does not provide an exhaustive list of all complications, it highlights some of the most common issues. Complications are rare, but understanding the warning signs is essential.
Allergic Reaction: Like any procedure involving medication injections, there is a risk of allergic reactions. The commonly used medications in facet joint injections include lidocaine, bupivacaine, radiographic dye, and cortisone. Allergic reactions can range from mild, such as developing hives or a rash, to life-threatening reactions that impair breathing. Most allergic reactions occur immediately in the procedure room, allowing for immediate intervention. They are usually treatable and do not cause permanent harm. If you have known allergies to any of these medications, inform your doctor.
Infection: Injection procedures carry a slight risk of infection, as the needle is inserted through the skin. Prior to the injection, the skin is cleansed with a disinfectant, and sterile technique is employed, ensuring that only sterile materials come into contact with the needle and the injection site. The healthcare provider may also use sterile gloves. Infections can occur beneath the skin, in muscles, or within the facet joint. Watch for signs of increasing redness, swelling, pain, and fever. Most infections require treatment with antibiotics, and in the case of an abscess, surgical drainage may be necessary. Antibiotics will be prescribed to treat the infection.
Nerve Damage: While facet joint injections are considered safe spinal procedures with minimal risk to the spinal nerves, there is a small possibility that the needle may accidentally contact a nerve, causing damage and increased pain. Nerve damage can result in numbness, weakness, and increased pain. Fortunately, nerves punctured bya needle typically recover without requiring additional surgical procedures.
Increased Pain: In some cases, injections may initially cause temporary increased pain. This could be due to muscle spasms around the injection site. However, once the medication takes effect, the injection may alleviate your pain as intended. Increased pain that persists for several days after the injection may indicate an infection, and you should promptly notify your healthcare provider.
While these potential complications exist, it’s important to note that facet joint injections are generally safe procedures with a low risk of complications. Your healthcare team will take all necessary precautions to minimize risks and ensure your well-being throughout the process.