Facet Joint Neurotomies
WHAT IS A FACET JOINT NEUROTOMY?
- A facet joint neurotomy (FJN) (also called a rhizotomy) is a procedure used to treat chronic low back or neck pain.
- It involves placing needles near the nerves to the facet joint in the low back or neck, under x ray guidance,
- The nerves are either cauterized (heated), frozen or electrically-pulsed (pulsed radiofrequency) for a few minutes.
- This blocks pain signals coming from the painful facet joints.
- FJN is a common pain procedure which has been well studied.
WHAT IS FACET JOINT PAIN?
- The facet joints are small joints on the outside of the spine that act as stabilizers (see picture below).
- These joints can develop arthritis leading to back and neck pain.
- Painful facet joints are responsible for up to 30% back and neck pain, up to 60% of back in older persons.
- Facet pain is usually a dull and aching and can radiate into the buttocks and thighs (back pain), or shoulders and arms (neck pain).
- The pain tends to get worse with activity and lessen at night.
WHAT IS DONE BEFORE A FJN?
- A ‘test injection’ is often performed with local anaesthetic before the FJN.
- Either the facet nerve (medial branch) is blocked or a facet joint injection is performed.
- These procedures aim to numb the facet joint temporarily to see if it’s the source of the pain.
- These injections are done in an operating theatre with x-ray guidance and sedation.
- Sometimes these ‘test’ facet joint or nerve injections actually work as a pain treatment for weeks-to-months.
- These injections are simple, low risk procedures.
Sometimes, if you have a “good story” for facet pain or a previous good response to a facet joint injections, your doctor may go direct to a FJN without a test injection. The advantages of this include; having only one procedure instead of two, faster pain relief, and greater convenience. The disadvantage is that without a test injection, there is a small risk the FJN won’t work as expected, or of having a complication (see below).
HOW IS THE FJN PROCEDURE DONE?
You will need to be fasted on the day of the procedure due to the anaesthetic.
- A small intravenous drip will be inserted in your arm.
- The procedure is done in an operating theatre.
- You will be given medication to make you feel relaxed and sleepy, but not totally ‘knocked out.’
- You will lie on your front on an x-ray operating table.
- Local anaesthetic will be used to numb your back.
- Fine needles are inserted into your back and guided to the correct area using x-ray.
- The needles are either electrically pulsed, heated to 90 degrees to burn the nerve (see picture at bottom), or frozen with a special needle (like dry ice).
- The procedure takes 30-60 minutes, and you will go home the same day.
WHO IS NOT SUITABLE FOR THIS PROCEDURE?
- Patients who are on blood thinning medication (other than aspirin) will need to stop this (in consultation with their doctor) prior to the procedure.
- Patients who have pacemakers, defibrillators or other implanted medical devices may not be able to have this procedure as the electric current to heat the needles may interfere with them.
WHAT ARE THE BENEFITS OF THE PROCEDURE?
- Between 50 to 70% of patients will get a good response to a FJN.
- A good response is a 50% or greater reduction in pain lasting at least three months.
- Often patients have an improvement in function–they can walk more easily and do more of their normal activities.
- Some patients obtain complete relief of pain.
- Some people have multiple causes of back pain (e.g. pain coming from the discs) and a FJN will only help facet joint pain.
- It is important to know that it can take up to 4 weeks for pain relief from a FJN to ‘kick in’.
- The average duration of pain relief from a FRN is around one year.
- This can range from three months to over 2 years.
- The procedure can be safely repeated in the setting of a good result.
WHAT ARE THE RISKS OF THE PROCEDURE?
The common risks are:
- The procedure may not help in up to 30% of patients
- Some people experience a temporary increase in back or neck pain for days to weeks after the procedure-pain medications can be given to manage this.
- Very rarely there is a long-term increase in spinal pain.
- Bruising and tenderness around the injection site.
The rare risks are:
- Damage to nerves going to the legs, arms, bladder or bowel.
- This is a very rare complication (less than one in 10,000)
- It may result in a painful, numb or weak legs, weak bladder or bowel control-on rare occasions this can last a long time (weeks to months).
- Permanent nerve damage is possible (although even more rare).
- Damage to the spinal cord: This is extremely rare.
- Dangerous bleeding around spinal cord (very rare).
- Infection (very rare).
- Complications of the anaesthetic, such as breathing problems or pneumonia.
The Facet (medial) Nerve Branch
Where do the FJN needles go?
Needles are inserted through the skin to burn the small facet nerves