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Facet Block

The facet joint block is both a test and a form of treatment.

A local anaesthetic agent, such as Lidocaine or Novocain,  is injected into the facet joint or the small nerve branches that supply the facet joint.  This same type of local anaesthetic agent is used by a dentist to numb your jaw or by a doctor when suturing a wound.  The Lidocaine numbs the area around the facet joint.  If your pain goes away, the doctor can assume that the pathological facet joint is contributing to the problem.

  • Why is it done?

    • Like other joints in the body, facet joints can cause pain if they are irritated or inflamed.  The facet joint block is used in what is called a "therapeutic trial".  This means that when the test is done, it should relieve your symptoms if the problem is from the facet joint being treated.
    • Cortisone is sometimes used with the local anaesthetic to decrease inflammation in the joint and often gives relief for several weeks or months.  This however is not a permanent or long-term treatment.
  • What to expect?

    • If required, you will be given medication to help you relax..
    • You will be asked to lie face down on a fluoroscopy table.
    • A local anaesthetic agent is injected, to deaden the skin, in the area of the back where the test will be performed.
    • A long needle is inserted into the facet joint or next to the small nerve branches that supply the joint.
    • The Radiologist monitors the positioning of the needle with fluoroscopy.
    • The fluoroscope is a special X-ray TV that allows the doctor to see your spine and the needle as it is inserted.
    • Once the needle is in the facet joint or next to the nerve branch, a combination of local anaesthetic and cortisone is injected.
  • What are the limitations?

    • A facet joint block only shows how your symptoms react to the injection.
    • It does not involve taking any pictures, except to make sure the needle is placed in the right spot.
    • It does not give specific information about the nerves or discs.
  • What are the risks

    • This test has more risks associated with it than non-invasive tests.
    • A facet joint block requires a needle to be inserted into the back.
    • The risks are small but include infection of the joint and an allergic reaction to the medication that is injected.
    • Referring neurosurgeons or orthopaedic surgeons usually prefer to use non-invasive tests first, such as MRI and CT scans.
    • These tests, along with facet block if needed, help to clarify the diagnosis and in planning the best way to treat your back problem.

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