The z-joints, also called the facet joints, are located in the back of the spine and prevent excessive twisting of the spine in the low back, and excessive extension in the neck. Damage to the joints can occur due to trauma (automobile accidents, falls), arthritis, infection, reduced disc height, or in the low back: repetitive lifting of heavy objects for many years. Usually the facet joints in the low back carry about 15% of the weight on the spine, but in cases where the disc is very narrow, the weight load may increase to 65%. The facets can have damage to the cartilage lining, overgrowth of bone (bone spurs), fractures through the joint, tears in the thick fibrous capsule over the joints, or can have bruising or bleeding into the joints. Pain from the facets cannot be diagnosed by x-ray, CT scan, MRI, or Bone scan. The diagnosis is made by precision injection of a local anesthetic or other substance onto the medial branch nerve (nerve to the facet joints). If your pain is relieved 80% or more by this injection you may benefit from Radiofrequency Neurotomy, for longer term pain relief. If the relief is less than this amount, you may have other significant spine disease that should be addressed with other therapies.

What is a Medial Branch Block?

A medial branch block involves the x-ray guided injection of a medication onto the nerve to the z-joint. You will be placed face down on a soft table for the low back medial branch block and face down or on your side for the neck (cervical) medial branch blocks. After skin preparation, a small amount of local anesthesia is injected into the skin. IV sedation is usually not given as this is a diagnostic test whose outcome depends on your ability to perceive pain relief. A thin needle is guided onto the medial branch nerve and a small amount of iodinated x-ray dye is injected to assure proper placement, then a medication will be injected and the needle is removed. Usually 2-3 injections are required at the time of the procedure. After the injection, you will have your pain and function briefly assessed, then you will go home where you will continue to assess the outcome of the block over the next several hours. The time period for which relief is perceived and the degree of relief (pain scale or other) is important information that is used to direct further therapy.

Answers to frequently asked questions

Does the injection hurt?

Usually the actual injections do not hurt significantly because only a thin needle is used and is not inserted into the joint.

Yes, it is possible to repeat the injection two or three times if there is significant relief of pain or other desired symptom relief from the first injection. A series of these blocks is a reasonable choice to desensitize the nervous system, but if more than 3 blocks are used in a 3 month time period, other alternatives need to be considered.

If sedation is not scheduled, you may eat and drink on the day of the procedure. However if sedation is scheduled, then you should have nothing to eat or drink after midnight on day of the procedure except to take your regular medications. Do NOT take any of the medicines listed below on the day of the procedure or for the time period before as listed.

Stop Plavix 7 days before the procedure Stop coumadin and warfarin 5 days before the Procedure. Stop Ticlid (ticlopidine) 14 days before the procedure.

Bleeding, infection, abscess, nerve injury, spinal injury are all very rare.

You will be in our Center for about 20-30minutes after the procedure and will have your pain and function assessed at that time. You should not have any leg weakness or significant numbness at the time of discharge.

  • Activity: Resume normal activity today.
  • Diet: Resume normal diet
  • Medications: Resume normal medications unless otherwise instructed
  • Dressing: You may have a small bandaid or bandaids placed over the injection site. This can be removed the next day
  • Discomfort at the Injection Site: If there is discomfort at the injection site, apply ice wrapped in a washcloth for short periods of time (20 minutes per hour) during the first 24 hours, then apply low to medium heat
  • IV Site: If you had an IV site, there may be soreness and bruising around the site that will go away in a few days. A warm moist cloth placed over the area for half-hour periods several times a day will sometimes help. Increased tenderness or red streaking around the area of the IV site or increasing swelling of the hand requires attention. Our Center needs to be notified if this occurs
  • Side Effects: Possible side effects of local anesthetics used include numbness of the leg or arms. Let us know if this occurs. If you experience new onset severe generalized weakness during the first week after the injection, call our office. If you develop fever of more than 102 degrees during the first few days after the injection or severe increase in pain in the back, notify our office.
  • Return to Normal Activities: You may experience some numbness in the skin over the back during the first several hours. Relief from the diagnostic injection may last up to 12 hours or longer.

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