A facet by definition is a small smooth surface on the bone. In the spinal column, they are found on either side of the vertebral column, and are part of the many joints that help to provide spinal stability while allowing some degree of functional motion. To understand the structure and function of a facet joint, one needs to understand the structure of the remaining elements that compose the spine.
The spine is composed of dynamic interplay of multiple bones and joints. The bones are individually known as vertebra, and vertebra essentially stack on top of one another to form a column of vertebra, known simply as the vertebral column. Each vertebra is connected to one another by a set of joints, or connections between bones that allow for additional movement. This is an important concept to understand. If the spine were composed of one long bone, then mammals would lack the three dimensional freedom to explore their environment. Fortunately, the spine has not evolved this way. The interplay between each vertebra allows for more freedom to explore our universe.
Each vertebra is made of two major structures. The front portion is a thick, square shape piece of bone known as the vertebral body. A bridge of bone then branches off the back of the vertebral body to form a ring like structure known collectively as the “posterior elements.” This ring provides additional stability to the spine, while providing a protective shield of bone around the spinal cord and spinal nerves.
A facet joint then serves to connect each vertebra. The disc is a soft donut shaped piece of connective tissue that connects the vertebral bodies, provides cushion and support during spine loading, and allows for a certain degree of range of motion between the vertebral bodies. The facet joints connect the posterior ring of bones that branch off the vertebral body. As mentioned, two facets exist between each vertebra, one on the right and one on the left.
Facet joints exist in all portions of the spine (cervical, thoracic, and lumbar). Each facet joint is built similar to most other joints in the body. The facets are lined with a thin layer of cartilage, surround by a capsule of connective tissue, and contain a small amount of joint fluid to keep the joint lubricated. Just like other joints in the body, facet joints can become irritated due to a variety of reasons. These include aging, injury, and mechanical overload. Facet joint injections can, therefore, be useful to diagnosis and treat painful conditions affecting the facet joint.
What is a Facet Joint Injection?
A facet joint injection or block is a minimally invasive procedure used by your pain management physician to diagnosis and treat facet joint pain. Your physician can inject an anesthetic into the joint itself. If the patient experiences pain relief, one can conclude that the facet joint was indeed causing a portion of the patient’s pain. On occasion, longer term pain relief can be obtained with the addition of cortisone to the injection. Even still, facet joint injections are known to only be a reliable way to diagnosis facet pain. To treat facet mediated pain for longer durations (6-18 months), a procedure known as a facet radio-frequency denervation (rhizotomy) can be utilized. This is another minimally invasive procedure which involves using a small needle to cauterize the nerve endings supplying the joint.
What Happens During a Facet Joint Injection?
Facet joint injections are performed under fluoroscopy (x-ray guidance) with the patient lying on his/her stomach. The injection can be performed with simple local anesthesia (numbing the skin) or with intravenous sedation. The treatment involves the injection of an anesthetic and a steroid medication into the facet joint. Some physicians choose to block the nerves supplying the facet joint instead of the facet joint itself. This technique is known as a medial branch block. The injection usually takes 5-10 mins, followed by a brief recovery before being discharged home. Procedures are usually performed in an outpatient setting such as an office or outpatient surgery center.
If the facet joint is the main cause of the patient’s pain, he/she may experience immediate pain relief as a result of the anesthetic. Typically the injection will last approximately 6 hours if bupivicaine is used. It is important to report whether or not immediate pain relief was obtained to your physician. The patient’s pain can then return as the anesthetic wears off, before the steroid takes effect (usually within 3-5 days). As noted, steroid alone is often not good enough to give long lasting relief from facet mediated pain. If these injections do tend to isolated the facet as a prominent pain generator, your physician may recommend a radio-frequency denervation.
Who is a Candidate for a Face Joint Injection?
Candidates for facet joint injections typically have tried conservative therapy such as rest, physical therapy, chiropractic care and anti-inflammatory medication. Facet joint pain can present with multiple symptoms. The pain can isolate to the low back or radiate to the buttock, lateral hip, and posterior thigh. This pain is often worsen with standing, walking, extending, but can occasionally present with bending/flexion.
What to Expect Following a Facet Joint Injection?
Patients are encouraged to remain active immediately after the injection (first several hours). Remember, the goal of the injection is to see if the anesthetic (numbing medication) injected into the joint turns the pain off. This cannot be done if the patient goes home and rests or “takes it easy.” We suggest continuing normal activity like you did the day before the injection. You may feel discomfort at the injection site. It is important to differentiate this discomfort from you normal pain. It is not uncommon to have increased pain after the numbing medication wears off. This can be treated with ice, Tylenol, or other over the counter anti-inflammatories. As noted, if the steroid is going to improve your pain, it may take 3-5 days. Your physician will want you to come back into the office for a follow up to determine the effect of the injection.
Results of the Facet Joint Injections?
Some patients will receive relief with the facet joint injections. If the patient only has minimum relief or no improvement at all, then further diagnostic testing and/or other treatments may be prescribed.
What are the Risks of a Facet Joint Injection?
Facet injections are very safe procedures when done in a strict sterile environment with an experienced clinician. Still, as with any injection, there exist a risk for allergic reaction (mild to severe), side effect to steroids (including but not limited to headache, elevated blood pressure, anxiety, elevated blood sugar, hot flashes, rash), infection, bleeding, or even a reaction to sedating medication if intravenous sedation is chosen. Being that the needle is in close vicinity to the spinal canal and nerves, one must consider the risk for nerve or spinal cord injury. Again, these latter complications are extremely rare.