Facet joint injection
What is an image guided facet joint corticosteroid injection?
The spine is made up of bones called vertebrae. At the front of the spine is solid bone, and at the back there is a bony canal, or channel. The solid bone is separated from the next bone by a disc. One vertebra is connected to the next vertebra at the back in the bony canal by pairs of facet joints on the right and left sides of the spine (see diagram). These joints allow forward and backward bending, as well as side-to-side rotation. The joints also prevent one vertebra from slipping over the other.
An image guided facet joint corticosteroid injection involves a radiologist (specialist doctor) a computed tomography (CT) scanner to guide the injection of a thin needle containing corticosteroid (or ‘steroid’) into one of these facet joints. The injections are designed to decrease inflammation in the facet joint and will often reduce pain.
Why would my doctor refer me to have this procedure?
Arthritis of the facet joint or strain of the joint from bending and twisting may lead to back pain in the area of the arthritic facet joint, muscle spasm and dull pain in the buttock, hip, groin or upper leg. Clinical examination may suggest that the facet joint is the cause or one cause of the pain symptoms.
An injection of corticosteroid into the facet joint may alleviate the pain by reducing inflammation of the joint. If the pain is suspected to come from a particular joint, but it is not certain which one (especially in older people who may have arthritis at a number of spinal levels), blocking the joint with anaesthetic confirms or rules out that particular joint as the cause. This can help planning for future surgery. If surgery is a consideration, facet joint corticosteroid injection may be used to relieve the pain before the surgery and can sometimes allow surgery to be delayed or avoided
How do I prepare for an image guided facet joint corticosteroid injection?
Because you will be lying on your stomach during the procedure and will be uncomfortable if your stomach is too full, it is advisable to limit food intake to a light meal only, up to 2 hours before the procedure.
You should wear comfortable clothes that are easy to remove and leave jewellery at home. Please note that some of the disinfectant agents used during these procedures may stain light-coloured clothing. A blood test may be required to check your blood clotting on the day of the procedure.
Continue with pain medication and other medications as usual.
What happens during an Image guided facet joint corticosteroid injection?
You may be asked to change into a hospital gown, depending on the area of the joint to be injected. You will be helped onto a CT scanner table on a thin plastic mattress. For CT guided injections, you will be placed on your stomach for lower back injections, you will be placed on your stomach for neck joint injections.
The area of the skin is cleaned with an antiseptic solution, and local anaesthetic injected into the skin and deeper tissues. This is usually the most uncomfortable part, with a sharp pin prick followed by stinging. You will be awake and only the area where the facet joint injection is being carried out will be numb. Through this numb skin, a thin needle is guided into the joint and a combination of long acting local anaesthetic and corticosteroid is injected. This may produce a dull ache for a few seconds.
How long does an image guided facet joint corticosteroid injection take?
The procedure itself usually takes approximately 15 -30 minutes.
Are there any after effects of an image guided facet joint corticosteroid injection?
The area around the joint is expanded during the injection. This may irritate the joint further and the symptoms may be aggravated for a day or so before the steroid starts having its effect. Occasionally, numbness or weakness lasting a few hours will occur in the arm or leg on the same side as the injection.
What are the benefits of an image guided facet joint corticosteroid injection?
Relief of pain from facet joint injection in a patient with pain of undetermined cause is a strong indicator of facet joint related pain. This aids in management in organising appropriate physiotherapy and posture correction therapy. Acute facet pain is very rapidly relieved and this relief may be long term, with approximately 80% of patients experiencing relief for 3 months or more. Chronic facet joint related pain may be relieved for weeks to months. Identifying that a facet joint injection has provided relief from pain is a necessary first step for patients who are potential candidates for radiofrequency facet joint nerve blocks.
What are the risks of an image guided facet joint corticosteroid injection?
This is a very safe procedure and lower risk than both image guided epidural corticosteroid steroid injection and image guided nerve root corticosteroid injection.
Allergy to the local anaesthetic may produce itching and hives or, rarely, a more severe allergic reaction, as with an allergy to any medication.
Reaction to the corticosteroid is relatively common, and produces redness and flushing of the face and body, usually starting a few hours or the day after the procedure and lasting a few days, the so called ‘cortisone flare’.
Allergy to corticosteroid ranging from a mild rash to anaphylaxis (breathing problems and low blood pressure) is very rare, occurring in fewer than 1 in 250,000 patients.
A numb arm(s) or leg(s) may result if the anaesthetic mixed with the steroid leaks into the adjacent epidural space. This lasts an hour or so in most people and is also uncommon.
Bleeding into the joint and joint infection are the more serious complications. These complications are extremely rare, as the procedures are always carried out under sterile conditions. If you experience any of the following symptoms within the first 2 weeks after your injection, you should seek urgent medical advice:
- Fevers or night sweats
- Worsening pain beyond 5–7 days after your
- Persistent or new weakness or numbness in your arm(s) and/or legs (if your injection was in the neck)
- Persistent or new weakness or numbness in your leg(s) (if your injection was in the lower back)
- Loss of control of bladder or bowel function
Bleeding into the joint is very uncommon, and usually requires no active treatment and can be managed with pain medication and follow up with your local doctor. Joint infection is also extremely rare, but is potentially very serious. It usually requires treatment with antibiotics. In very severe cases, an operation may be needed to remove the infected tissue, as well as a stay in hospital for antibiotics given intravenously (directly into a vein).
How do I get my results?
Your doctor will receive a written report on your test as soon as is practicable.
It is very important that you discuss the results with the doctor whom referred you so that they can explain what the results mean for you.
This information is credited to Inside Radiology, Royal Australian and New Zealand College of Radiology (RANZCR).
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