What are facet joints?
The spine is made up of bones called vertebrae, which are separated by discs which allow the spine to bend. The facet joints link the vertebrae together, stabilising the spine and control movement as well as carrying some of the load. With age, they become more prone to injury and wear and tear, and are a common cause of lower back pain.
What are facet joint injections?
Facet joint injections can be used to both treat and diagnose back pain. To diagnose whether or not a facet joint is the cause of your back pain, local anaesthetic is injected into the joint. If the pain improves within a few hours or a couple of weeks, the facet joint is causing your back pain.
Why do I need them?
Facet joint injections are usually only done if you have had back pain for longer than six weeks and you have tried other treatments suggested by your doctor, such as painkillers or physiotherapy.
When will I feel pain relief?
It can take between 7 and 10 days to feel the full benefits but the effects can last anything from a few days to a month.
What does the procedure involve?
Facet joint injections are performed while you are awake, under a local anesthetic. The injection is usually performed while you are lying on your stomach on an X-ray table. ECG, blood pressure cuffs and blood-oxygen monitoring devices may be hooked up prior to the injection process.
A thin needle is passed through the skin of your back into the facet joint and a special dye may be inserted into the joint first. This will show on an X-ray whether or not the needle is in the correct place. The steroid and local anaesthetic mixture is then injected into the joint.
The treatment usually only takes a few minutes, and more than one joint can be injected during the same session. Facet joint injections can be uncomfortable because they are given in an area that may already be painful.
How do I prepare for the procedure?
On the day of the injection you should have no food or drink (including water) for at least four hours before the procedure. However, if you are an insulin dependent diabetic, inform your doctor; you may not need to change your normal eating habits prior to the procedure. If you need to take medication within four hours before the procedure, a sip of water may be allowed; however, you should check with your doctor prior to taking any medication before the injection.
You may be asked to remove most of your clothing for the procedure and wear a gown that opens in the back to allow access to your spine.
What happens after the injection?
Immediately following the procedure, you may feel a reduction or complete relief of your back pain. After a local anaesthetic it may take several hours before the feeling comes back into the treated facet joints. You should be able to walk immediately after the procedure, although some people have some tingling or numbness for a few hours.
Your doctor may ask you to perform a task that usually causes you pain to assess how much pain relief you have got from the procedure. Sedation temporarily affects your coordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards.
How effective are facet injections?
No medical study has definitively identified the facet joint as the cause of low back pain. Research has found that facet injections can give relief of lower back pain for longer than six months in 18-63% of patients who underwent the procedure. It has been recommended that facet injections are used as a method to allow the patient to be able to perform other forms of conservative treatment (such as physical exercise, yoga and stretching and bending), rather than using it as a stand-alone pain treatment.
If you do not get relief from your pain following the first therapeutic facet injections, further treatments by facet joint injection are not recommended. You will require further assessment by your specialist so that other forms of treatment can be considered.
Are there side effects?
You may feel more pain and tenderness in the area. In very rare cases the steroid injected into the facet joint may cause some side-effects, including fluid retention, weight gain, high blood pressure, mood swings and insomnia.