Bones of the spine articulate anteriorly by intervertebral discs and posteriorly by paired joints. These posterior paired joints commonly are termed facet joints, more formally termed zygapophyseal joints. Facet joints are true synovial joints with a joint space, hyaline cartilage surfaces, a synovial membrane, and a fibrous capsule. Two medial branches of the dorsal rami (nerves) innervate the facet joints. These nerves can be transmitters of Low back pain.

WHAT IS IT?
A block that is performed to confirm that a facet joint is the source of pain and decrease pain and inflammation in a facet joint or joints.

Typically, facet joint injections are performed as a part of a workup for back or neck pain. They include one (diagnostic) or two (diagnostic and confirmatory) injections. A Confirmatory facet injection is sometimes used to rule out the placebo effect and to further delineate the facet joint as the pain generator. These injections if helpful are then followed by a Radio Frequency Facet Neurotomy otherwise known as a Permanate facet injection of the medial branches of the dorsal rami.

The injection of local anesthetic and steroids into the facet joint is diagnostic and potentially therapeutic. When optimally performed, the injection is made directly into the joint space, though for generations anesthesiologists have been successful in injecting around the joint. Pain relief following a precise intra-articular injection confirms the facet joint as the source of pain. Although some physicians advocate the use of only local anesthetic, most practitioners inject steroids as well, attempting to provide longer pain relief. Long-term relief (6 mo) can be obtained in 30-50% of patients.

Patients referred for facet injections most often have degenerative disease of the facet joints. However, even if the facet joint appears radiologically normal, facet injections still may be of use, as radiologically occult synovitis can cause facet pain, particularly in younger patients. Postlaminectomy syndrome, or nonradicular pain occurring after laminectomy, is also an acceptable reason to perform facet injections.

Patients with lumbar facet pain (so-called facet syndrome) typically present with back, buttock, or hip pain. If the patient has only back pain, this pain may radiate into the buttocks or hips, and the pain is typically worse with extension. A useful test is to ask patients to push the pelvis forward while standing with their hands on their hips because this movement typically reproduces facet-mediated pain.

Radiculopathy, leg weakness, and leg numbness are not considered part of the facet syndrome and suggest nerve root compression, although this may be secondarily caused by facet hypertrophy.