Diagnostic Facet Nerve Block (Medial Branch Nerve Block) What is a diagnostic facet nerve block? A diagnostic facet nerve block is used to determine if your back pain is being caused by the facet joints. Facet joints are the joints between the vertebra, which are present on both sides of the spine and provide flexibility to the spine. The joints are supplied by facet nerves (also called medial branch nerves). What are the goals of a diagnostic facet nerve block? The goals of a diagnostic facet nerve block are: To diagnose the cause of pain To determine the possibility of treatment with frequency ablation (rhizotomy) To reduce and possibly eliminate pain To increase function To possibly eliminate the need for surgery How will a diagnostic facet nerve block help my condition? The diagnostic facet nerve block is an injection of local anesthetic medication. If the block relieves the pain, the diagnosis of pain coming from the facet joints can be made. The degree and duration of pain relief will determine if radiofrequency ablation, also called rhizotomy (a procedure to deaden the nerves using heat), is an option. What happens during a facet nerve block? You will remain awake for the procedure. Once in the procedure suite: You will be positioned lying face down (face up for upper cervical). The area for the injection will be washed with an antiseptic solution and covered with sterile drapes. A local anesthetic may be used to numb the injection site. You will be asked to remain as still as possible. You may feel pressure while the medication is injected. How long is the procedure? The entire procedure lasts about 10 – 15 minutes. What happens after the procedure? You will be monitored for approximately 15 minutes, because the medication takes some time to act. A nurse will review discharge and follow-up instructions with you. You will need to carefully monitor the degree and duration of your pain relief. The day after your procedure, you may resume your normal daily activities.