ZIGOAPOPHYSEAL JOINT INJECTIONS
WHAT ARE ZIGOAPOPHYSEAL OR “Z” JOINTS?
Zigoapophyseal joints, also known as facet joints, are the small joints located on the back of the vertebrae that enable flexion, extension, rotation, and lateral movement of the spine but prevent excessive forward displacement of one vertebra over the one below. These joints have a layer of cartilage and a joint capsule filled with synovial liquid, which acts as a lubricant, reducing the friction between the two bone surfaces when the spine moves, and nourishes the cartilage.
Zigoapophyseal joints, also known as facet joints
WHY WOULD A ZIGOAPOPHYSEAL JOINT INJECTION BE NECESSARY?
A zigoapophyseal joint injection may be carried out either to determine the source of pain (diagnosis) or to treat the abnormality that has been detected (treatment).
If you suffer from low back pain (LBP) for more than 6 weeks and conservative treatments have proven ineffective, your spine will be studied by performing a CT scan or an MRI. These tests may reveal facet joint anomalies which could be causing the pain, but even if they don’t facet joints may still be the cause of the pain. Thus, to determine whether facet joints are causing LBP or not, an anaesthetic block of the facet joint involved in the pain may be performed. If the injection of small about of anaesthetic (“anaesthetic block”) or anti-inflammatory medication reduces, or eliminates, the LBP, then the facet joint may be causing the pain. This is how facet joint injections are used for diagnosis.
Once it has been confirmed that the facet joints are the source of pain, treatment is applied by performing a percutaneous facet joint denervation. This procedure is carried out on an outpatient basis, under local anaesthesia and sedation, and leaves no cuts since needles are used.
HOW ARE FACET JOINT INJECTIONS CARRIED OUT?
An iodated solution will be used to sterilise the area where the injection is to be performed. This area is usually found in the low back, but facet joints in the dorsal or cervical region may also receive injections.
X-rays will show the anatomy of the bones in the affected region. Once the facet joints that cause the pain are identified, local anaesthesia and anti-inflammatory agents (usually corticosteroids) will be injected. This process is then repeated on all affected facet joints. This means that, though an actual injection only takes a few minutes, the whole procedure will take about 30 minutes.
After the procedure it is recommended not to take anti-inflammatory agents for 3 days so that the results of the injection can be assessed. If you are to undergo a facet joint injection, check with the surgeon which medication you can and can’t carry on taking
In addition, to avoid problems during the procedure, the patient must have no food or drink (including water) for at least 6 hours before the operation. If you suffer from diabetes, let us know. If you need to take medication within a few hours before the procedure, a sip of water may be allowed.
For the procedure you will be asked to remove most of your clothing. A gown will be provided to you, and it will have an opening in the back to allow access to your spine.
WHAT WILL HAPPEN AFTER THE INJECTION?
Usually, after the procedure the patient will feel their pain relieved, sometimes already a few minutes after the injection. If you have had a facet joint injection, after the operation you will be able to walk and go home, but you must not drive vehicles, for the anaesthetic medication may produce dizziness. You should get another person to accompany you and take you home.
Some patients experience leg weakness, numbness or tingling a few hours after the injection and will stop feeling these effects when the anaesthetic effect stops, but this is rare.
Once home, you may treat the injection site with ice to reduce the pain. If it hurts a lot, get in touch with the surgeon to check if you can take a light analgesic.
Injected local anaesthetic lasts 8 to 12 hours. The anti-inflammatory effect lasts 1 to 3 weeks. Past this period of time, the pain may return.
After the first day, you should return to your usual daily activities so that the response to the injection can be assessed. In the majority of cases, it is possible to go back to work the day following the injection.
WHO SHOULD NOT RECEIVE FACET JOINT INJECTIONS?
This procedure is not recommended for patients who are prone to excessive bleeding, or are taking aspirin or anticoagulant medication, such as Coumadin, Warfarin or heparin. Any medication must be withdrawn before the procedure to avoid problems, so let us know if you are taking medication. If your LBP has been diagnosed as a result of an infection or tumour, other forms of treatment will be required.
POSSIBLE SIDE EFFECTS
Any surgical procedure may have side effects. The most common side effects of facet joint injections are inflammation, infection, hematoma or pain at the site of injection and allergic reactions to local anaesthetics. Anti-inflammatory agents don’t usually cause any problems, excepting a rise in blood glucose levels in diabetic patients, which might thus need more anti-diabetic medication for a few days.