Facet Joint or Zygapophysial Joint Pain
The facet joints are articulations or connections between the vertebral bodies of the spine. They are found in the cervical, thoracic and lumbar levels. Disease of these joints can be responsible for neck pain, headache and low back pain. Each vertebral level contains 1) a vertebral body (bone), 2) an intervertebral disc or cushion between the bones and 3) a facet joint which are small joints that stabilize the spine.
The facet joints not only provide stabilization for the spine, they limit spinal rotation and flexion/extension. The upper portion of each joint is paired with the lower portion of the joint at the next highest level in the spine. These joints are synovial joints and have cartilage, a capsule and synovial membrane. They vary in their size, shape, and orientation in the spine. Each joint is innervated by the medial branch from the primary dorsal ramus of the spinal nerve at each level as well as from the level above.
Facet joints undergo wear and tear just like any other joint in the body. Their cartilage can tear or become thin and disappear. There can be bony overgrowth and spurs at the joints. This is referred to as facet joint disease. Facet joint or zygapophysial joint disease can cause chronic neck pain, headache and chronic low back pain. It can mimic other disorders such as bulging discs or herniated discs. The pain may radiate down the leg and mimic sciatica. Most people with facet joint disease will have tenderness overlying the joints. There may be more pain leaning backwards than forwards. In the back, the pain may radiate down the leg like sciatica, but rarely goes past the knee. In the neck, facet disease may radiate to the shoulders or upper arms. Rarely, it may radiate down the arm like a herniated disc.
The diagnosis of low back pain or neck pain due to facet disease is not easy. X-ray films may be useful to examine bony changes in the joints. A CT scan may be more useful and also provide information about other structures such as the disc, vertebral body and surrounding structures.
There are many options for treatment of low back pain and neck pain due to facet disease. Conservative measures are tried first. They may include exercise, physical therapy, heat, ice, TENS, and ultrasound. Modification of daily activities may be necessary. Non-steroidal anti-inflammatory medications may decrease the level of pain.
When conservative therapy is not successful, then facet joint injections or a block of the nerves innervating the joint (medial branch block) may help. These injections are done by an interventional pain management physician, usually an anesthesiologist. The procedures are done on an outpatient basis and usually take just a few hours from start to finish. A positive response to the injection (decrease in pain) may indicate that the facet joints are a source of the pain. More than one injection may be necessary to eliminate a majority of pain. If the injections provide relief and then the pain returns, the nerves may be destroyed using radiofrequency ablation. The decision to undergo injections or radiofrequency ablation is made by the interventional pain management doctor, using the data obtained from the history, physical exam and radiologic evidence. A consultation with the patient will occur prior to any intervention and include a discussion of expectations, nature of procedure and risks.