Facet Joint Injections
What are they?
Facet joints, also known as Zygapophysial joints, are located on the back (posterior) of the spine on each side of the vertebrae where it overlaps the neighboring vertebrae. The facet joints provide stability and give the spine the ability to bend and twist. They are made up of the two surfaces of the adjacent vertebrae, which are separated by a thin layer of cartilage. The joint is surrounded by a sac-like capsule and is filled with synovial fluid (a lubricating liquid that reduces the friction between the two bone surfaces when the spine moves and also nourishes the cartilage.)
Why do I have facet Joint pain ?
Disc space narrowing causes a marked increase in pressure in the facet joints. An association between disc degeneration and facet joint osteoarthrosis has been well documented in the medical literature. The onset of facet joint osteoarthrosis leads to hypervascularity and increased intraosseous pressure which is the source of pain. Occassionally there may be sudden episodes of worse back pain caused by acute injury (ie twisting, lifting etc) of the already inflamed facet joints.
The core spine muscles normally help to stabilise the spine and prevent undue movement and stress on the facet joints. The natural response of these muscles is to go into spasm to protect theinflamed facet joints from movement and prevent further pain during acute episodes. However, by going into spasm, there is eventual fatigue leading to more generalised back pain. This leads to weakening of these muscles and further damage to facet joints.
Most back pain will improve within a few weeks by itself, or with conservative treatments such as rest, antiinflammatory medications, physical therapy and exercise. If you suffer from back pain for more than six weeks and conservative treatments have not helped, or if your pain has increased you may require an magnetic resonance imaging (MRI) or computerized tomography (CT) scan to look at the structures of the spine. A persistent problem (such as inflammation, irritation, swelling or arthritis) in the facet joint may cause low back pain. If these diagnostic tests or careful clinical exxamination reveal an abnormality in a facet joint, it may be the source of the pain.
Why Get A Facet Joint Injection?
There are basically two reasons for having a facet joint injection: for diagnosis (to determine the source of pain) or for therapy (to treat an abnormality that has been detected.)
To determine if a facet joint is truly the source of back pain, an injection (sometimes called a “block”) may be prescribed. If an injection of a small amount of anesthesia into the facet joint reduces or removes the pain, your doctor is assured that the facet joint is the source of the pain. This is a diagnostic use of the facet injection.
Once a facet joint is pinpointed as a source of pain, therapeutic injections of anesthesia and antiinflammatory medications may give pain relief for longer periods of time. Often the injections are only a method of helping relieve pain while allowing an exercise program to work. It is vital to pursue an exercise program concentrating on core stability and posture training after facet joint injections in order to improve the strength in the core stabilising muscles and prevent return of facet joint pain.
How Are The Injections Performed?
Facet joint injections are performed while you are awake, under a local anesthetic, and able to communicate. Sometimes we may also administer drugs to make you more comfortable during the procedure. 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.
During the procedure, you probably will undergo a fluoroscopic X-ray that allows the doctor to place the needle in the correct facet joint. The doctor or an assistant will clean and sterilize the area of the back directly over the affected joint. You will hav ea local anesthetic to numb the skin over the injection site. Before the injection of the actual medication into the joint capsule, a contrast (dye) may be injected that will show up on the X-ray to ensure proper location for injecting the medications.
Once the proper site has been determined, the doctor will inject the anaesthetic (often lidocaine or bupivicaine) and the anti-inflammatory (usually a corticosteroid.) You may be asked whether you are experiencing pain relief or not, to make sure the injection is in the right place and determine if additional injections are needed. This process may then be repeated depending on the number of affected facet joints. Although the actual injection takes only a few minutes, the overall procedure usually takes approximately 30 to 60 minutes.
Are There Special Preparations?
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 health care provider; 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 health care provider 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. Your doctor may ask you to perform a task that would normally cause pain to assess the level of pain relief. You will be able to walk immediately after the procedure, although some patients may experience leg weakness, numbness or tingling for a few hours after the injection. Because your reaction times may be affected by the medications, driving is not recommended immediately following the injection. You probably should have someone who is able to drive you home following the procedure.
Once home, you can treat any pain you may have at the injection site with ice or a pain medication prescribed by your health care provider. It is generally recommended that you take it easy and not exert yourself for the first day. After the anesthetic component of the injection wears off, your back pain may return. It may take seven to ten days for the steroid component of the injection to relieve the pain. After the first day, you can usually return to your daily activities as your pain will allow; however, you should check with doctor or physiotherapist to get his or her recommendations on specific activities that will be allowed. In most cases, you can return to work the day following the injection.
How Effective Are Facet Injections?
The effectiveness of facet injections for the treatment of low back pain is controversial. 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 be 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.
f you do not get relief from your pain following the first therapeutic facet injections, further treatments by facet joint injection are not recommended. You require further assessment by your specialist so that other forms of treatment can be considered.
Who Should Not Receive Facet injections?
You should not undergo facet injections for the treatment of low back pain if your pain has not been present for at least four weeks and if other forms of conservative treatment have not been tried. If you are prone to excessive bleeding or are taking an anticoagulant medication (such as coumadin or heparin), this procedure is done under care and guidance by your specialist. It is usually recommended that aspirin and clopidrogel are stopped for at least one week before injections; you should notify your health care provider if you are taking these medications. If your back pain has been diagnosed as a result of an infection or malignancy, it is also recommended that other forms of pain relief be used.
Are There Side Effects?
There is a possibility of side effects with just about any medical procedure and you should always discuss that possibility with your physician before undergoing any treatment. Possible side effects from facet injections include pain at the injection site, bleeding, infection or a worsening of the pain symptoms. Side effects of the steroid medications used may include fluid retention, weight gain, elevated blood pressure, mood swings and insomnia but these are quite rare because the corticosteroid dose used is relatively low.