Facet joints are small joints at each segment of the spine that provide vertebral column stability during bodily movement. The facet joints can become painful due to arthritis of the spine, a back injury or mechanical stress to the back. A cervical (neck), thoracic (upper back) or lumbar (lower back) facet joint injection involves injecting a steroid medication, along with a local anesthetic which can anesthetize the facet joints and block the pain. The pain relief from a facet joint injection is intended to help a patient better tolerate a physical therapy routine to rehabilitate his or her injury or back condition.
Facet joint injections usually have two goals; to help diagnose the cause and location of pain and also to provide symptomatic pain relief:
- Diagnostic goals: By placing an anesthetic directly into the joint, the amount of immediate pain relief experienced by the patient will help confirm or deny the joint as a source of pain. If complete pain relief is achieved following the anesthetic injection, those joints are likely to be the source of pain.
- Pain relief goals: Along with the numbing medication, a facet joint injection also includes injecting steroid medications into the facet joints to reduce inflammation, which can often provide long term pain relief. The procedure may also be called a facet block, as its purpose is to block the pain.
Anatomy of the cervical, thoracic and lumbar facet joints
The facet joints are paired joints that exist along the entire length of the spinal column; one pair at each vertebral level (one joint on each side of the vertebrae). These joints have opposing surfaces of cartilage (cushioning tissue between the bones) and a surrounding capsule that is filled with synovial fluid, which reduces the friction between bones that rub together.
Cervical facet joints are located in the neck. Thoracic facet joints are in the upper back and lumbar facet joints are in the lower back. Depending on which joints are affected, pain can be located in different areas of the body:
- Cervical facet joints. Pain caused by cervical facet joints is usually felt in the head, neck, shoulder, and/or arm.
- Thoracic facet joints. Pain caused by thoracic facet joints is typically felt in the upper back, chest and/or arm (rarely).
- Lumbar facet joints. Pain cause by lumbar facet joints is typically felt in the lower back, hip, buttock, and/or leg.
Cervical, thoracic and lumbar facet joint injection procedure
As with many spinal injections, facet joint injections are best performed using fluoroscopy (live x-ray) for guidance to properly target and place the needle (and to help avoid nerve injury or other injury).
The injection procedure includes the following steps:
- An IV line will be started so that adequate relaxation medicine can be given, if needed.
- The patient lies face down on an x-ray table and the skin over the area to be treated is well cleaned.
- The physician numbs a small area of skin with an anesthetic (a numbing medicine). This may sting for a few seconds.
- The physician uses x-ray guidance (fluoroscopy) to direct a very small needle into the joint. Several drops of contrast dye are then injected to confirm that the medicine only goes into the joint.
- A small mixture of anesthetic (such as lidocaine) and anti-inflammatory medication (steroid) is then slowly injected into the joint.
The injection itself only takes a few minutes, but the entire procedure usually takes less than thirty minutes. After the procedure, the patient typically remains resting in the recovery room for twenty to thirty minutes, and then is asked to move the area of usual discomfort to try to provoke the usual pain. Patients may or may not obtain pain relief in the first few hours after the injection, depending upon whether or not the joints that were injected are the main source of the patient’s pain. On occasion, the patient may feel numb or experience a slightly weak or odd feeling in the area of the injection for a few hours after the procedure. Following the procedure, patients are advised to avoid driving and avoid doing any strenuous activities for a period of 12 to 24 hrs.
The patient should record the levels of pain relief during the next week in a pain diary. Tracking the level of pain is helpful to clearly inform the treating physician of the injection results and in planning future tests and/or treatment, as needed.
Following the procedure, patients are advised to avoid driving and avoid doing any strenuous activities for a period of 12 to 24 hrs. If sedation was used, the patient should not drive for 24 hours after the procedure. Patients may notice a slight increase in pain lasting for several days as the numbing medicine wears off and before the steroid medication starts to take effect. If the area is uncomfortable in the first two to three days after the injection, carefully applying ice or a cold pack to the general area of the injection site will typically provide pain relief.
If the facet joints that were treated are the source of the pain, the patient may begin to notice pain relief within two to five days after the injection. If no improvement occurs within ten days after the injection, then the physician will probably conclude that the patient is unlikely to gain any pain relief from additional injections and further diagnostic tests may be needed to accurately diagnose the patient’s pain.
Patients may continue to take their regular pain medicine after the procedure, with the exception of limiting pain medicine within the first four to six hours after the injection so that the diagnostic information obtained is accurate. Patients may be referred for physical therapy or manual therapy after the injection while the numbing medicine is effective and/or over the next several weeks while the steriod is working.
On the day after the procedure, patients may return to their regular activities. When the pain is improved, it is advisable to start regular exercise and activities in moderation. Even if the pain relief is significant, it is still important to increase activities gradually over one to two weeks to avoid recurrence of pain.
If the facet block procedure is effective in alleviating the patient's back pain, it is often considered reasonable for the procedure to be done up to three times per year. However, if the first facet joint injection does not relieve the patient’s pain then the injection should not be repeated.
Potential risks and complications
As with all invasive medical procedures, there are potential risks and complications associated with facet joint injections. However, in general the risk is low, and complications are rare. Potential risks and or complications that may occur from a facet joint injection include:
- Allergic reaction. Usually an allergy to x-ray contrast or steroid; rarely to local anesthetic.
- Bleeding. A rare complication, bleeding is more common for patients with underlying bleeding disorders.
- Infection. Minor infections occur in less than 1% to 2% of all injections. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
- Worsening of pain symptoms
- Discomfort at the point of the injection
- Nerve or spinal cord damage or paralysis. While very rare, damage can occur from direct trauma from the needle, or secondarily from infection, bleeding resulting in compression, or injection into an artery causing blockage.
In addition to risks from the injection, some patients will experience side effects from the steroid medication, such as:
- Transient flushing with a feeling of warmth (‘hot flashes’) for several days
- Fluid retention, weight gain, or increased appetite
- Elevated blood pressure
- Mood swings, irritability, anxiety, insomnia
- High blood sugar—diabetic patients should inform their primary care physicians about the injection prior to their appointment
Patients who are on a blood thinning medication (such as Coumadin®), or have an active infection, may not be able to have this procedure, and these situations should be discussed with the treating physician. Patients should also let their doctor know of any allergies they have to medications that may be used for the procedure.
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Injection Types
