Facet joints are small joints at each segment of the spine that provide stability and help guide motion. The facet joints can become painful due to arthritis of the spine, a back injury, or mechanical stress to the back.
A cervical, thoracic or lumbar facet joint injection involves injecting a small amount of local anesthetic (numbing agent) and/or steroid medication, 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 pain relief:
- Diagnostic goals: By placing numbing medicine into the facet joint, the amount of immediate pain relief experienced by the patient will help determine if the facet joint is a source of pain. If complete pain relief is achieved while the facet joint is numb, it means that joint is likely a source of pain.
- Pain relief goals: Along with the numbing medication, a facet joint injection also includes injecting time-release steroid (cortisone) into the facet joint to reduce inflammation, which can sometimes provide longer-term pain relief.
The injection procedure may also be called a facet block, as its purpose is to block the pain.
Facet Joint Anatomy
The facet joints are paired joints in the back and neck, 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 on the back or side of 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 (in the neck) is usually felt in the head, neck, shoulder, and/or arm.
- Thoracic facet joints. Pain caused by thoracic facet joints (in the upper spine) is typically felt in the upper back, chest, and/or arm (rarely).
- Lumbar facet joints. Pain cause by lumbar facet joints (in the lower spine) is typically felt in the lower back, hip, buttock, and/or leg.