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Medial Branch Block Diagnostic Injection

A medial branch block involves the x-ray-guided injection of 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.

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Medial Branch Block Diagnostic Injection

A medial branch block involves the x-ray-guided injection of 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 the injection, you will have your pain and function briefly assessed, and then you will go home where you will continue to assess the outcome of the block over the next several hours.

What is a Z-Joint?

The Z-Joints, also called the facet joints, are in the back of the spine to prevent excessive twisting of the spine on the lower back, and excessive extension to the neck. Damage to the joints can occur due to trauma from automobile accidents, falls, arthritis, infection, reduced disc height, or in the lower back: repetitive lifting of heavy objects for many years.

Usually, the facet joints in the lower back carry 15% of the weight on the spine, but in some cases where the facet joint is narrow, the load carried may increase to 65%. The facets’ cartilage lining, overgrowth of the bone (bone spurs), joint tears in the thick fibrous capsule over the joints, or bleeding into the joints cause pain from facets that cannot be CT scan, MRI, or Bone scan.

The diagnosis is made by a local anesthetic or other substance onto the medial branch nerve (nerve by the facet joints). If your pain is relieved by 80% or more, then you may benefit from Radiofrequency Neurotomy. If the relief is less than 80% you may have other diseases that should be addressed with other therapies.

How is the procedure performed?

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, and 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.

Do the injections hurt?

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

Special instructions:

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. 

Medicines to be stopped in advance:

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

Risks:

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

After the procedure:

You will be in our clinic for about 20-30 minutes 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.

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.

Discharge instructions:

  • Activity: Resume normal activity today. 
  • Diet: Resume a normal diet. 
  • Medications: Resume normal medications unless otherwise instructed.
  • Dressing: You may have a small band-aid or band-aids 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 clinic 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 a fever of more than 102 degrees during the first few days after the injection or a severe increase in pain in the back, notify our office.

EMERGENCY CONTACT TELEPHONE NUMBER: 911

 

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