My doctor wants me to have diagnostic facet blocks for my back pain. How will this help?
Given the large number of people who have had or have back pain in their lifetime, it is a surprise that only 15 percent of the time back pain could be specifically diagnosed in the past. This meant that the great majority of back pain was termed non-specific. This also meant that treatments were not targeted to specific parts of the spine.

Facet joints, discs, ligaments, nerve roots, and muscles can all be a source of back pain. Some can be eliminated as a source of pain given a patient’s symptoms, physical examination, or imaging such as X-ray or MRI.

More recently, doctors, with the help of injections that numb certain parts of the spine, can make a specific diagnosis in up to 85 percent of patients.

Studies have shown that facet joints, the small joints in the spine may be the source of neck, mid-back (thoracic), and low back pain 25 to 40 percent of the time.

Determining this requires using an injection with a numbing agent such as lidocaine. The lidocaine is used to block the nerve to the targeted facet joint(s). A positive diagnosis can be made if pain is markedly decreased (some doctors require 80 percent improvement) and ability to move or function while the joint(s) is numb is improved.

Most doctors require repeating the injection(s) to ensure a proper diagnosis. Up to half of patients with a positive response initially will have a negative response when the injection(s) is repeated.