At times, it becomes quite difficult for the doctor to decide what is causing the pain in your low back or legs, or your neck or arms. Often through history, examination, and review of your X-rays, MRI or CT scan, a pain generator can be determined. If your pain persists despite efforts at physical therapy, rehabilitation, and medication, then a decision must be made on how to proceed. If you are unable to tolerate the pain and it remains persistent and/or severe, then nerve blocks may pinpoint a pain generator. Once a pain generator has been identified, decisions can be made regarding how best to treat it. Diagnostic blocks are tests meant to decrease your pain temporarily and to define it more precisely.
Pain which is mostly in the back or neck with a less specific vague aching in the legs or arms may be coming from one or more of the little guiding joints in the lumbar or cervical area of the spine. These joints are called FACET JOINTS. Just as a joint in your finger, shoulder, or elbow can give you discomfort, so can facet joints in your back or neck. This is “mechanical low back pain” or “mechanical neck pain” and has certain characteristics, which can be identified from your history and physical. In addition, the X-rays, MRI or CT scan might suggest some “wear and tear” or arthritis in these joints.
Initial treatment is usually physical therapy (instructions in exercise, posture, and body mechanics) and, if needed, weight loss. If there is little else that can be done, if the pain becomes unbearable, surgery may be indicated. However, it is possible to block the nerve going to each of these joints to see if the pain can be reduced. If a significant decrease is obtained through the temporary block, there is the possibility a longer lasting block of the nerve, using a radiofrequency probe, could lessen the overall discomfort.
The test is done by your physician in the surgery suite, using fluoroscopy (a visual X-ray process). Fluoroscopy is used to guide the placement of the needle used to inject a local anesthetic at the appropriate area. You are awake throughout the procedure. After the injection site is prepared with an antiseptic solution. A small needle is inserted to place anesthetic near each of the facet joints to block the medial branch nerve. During the injection there may be some pressure or pain in the back.
Make arrangements to have a responsible adult accompany and drive you home. This is for your safety and the safety of others.