Medial Branch Block
The spine's joints are called facet joints or zygapophyseal joints. Facet joints are found in the cervical (neck), thoracic (mid back), and lumbar (low back) spine. These joints allow the spine to flex, extend, and rotate. The medial branch nerve innervates (stimulates) the facet joint. As we age, or secondary to trauma (such as whiplash), the facet joints can be damaged and develop arthritis similar to other body joints.
Facet joint pain can be secondary to back pain and may radiate (travel) into the hips, buttocks, and posterior thighs. While arthritis is commonly detected by x-ray or MRI, the presence of arthritis/facet hypertrophy (increased joint size) does not always mean it is the cause of low back pain.
Diagnosis of Facet Joint Pain
The medial branch nerve innervates the facet joint and may cause nerve root irritation and pain. A medial branch nerve root block is performed to confirm that a facet joint is the source of your pain. While the nerve block is diagnostic, it may be therapeutic providing pain relief for a limited period of time, usually 4-6 hours.
Facet Medial Nerve Block Procedure
Before the nerve block, you may be given medication to relax you (based on physician preference). Most patients do not need anesthesia (twilight) because the needles are very small and the procedure is relatively quick.
The skin area is numbed using a local anesthetic. Using fluoroscopy (real-time x- ray), the physician guides the needle into the proper area of your spine. Once the needle is positioned near the median nerve and confirmed via imaging, a combination of anesthetics is injected into the medial region. The entire facet block procedure takes less than 10 minutes.
Upon completion of the procedure you may experience numbness into your normal pain distribution or area in which you have referred pain. This is not abnormal and should not last more than eight hours. Your physician or the physician’s staff will be in touch with you to document the efficacy of the procedure.
Be sure to have a follow up appointment with your referring physician within two weeks of your procedure to discuss therapy and treatment options.