The facet joints are small joints that limit the amount of twisting and bending in the back. They can be affected by arthritis and strained by unaccustomed or heavy exercise. They are sometimes a cause of back pain.
Injection of the lumbar facet joints, in the lower back, can help to find out if these joints are contributing to your back pain, and treat the pain. Without other treatment, the pain will sometimes return. It is often necessary to treat more than one joint. Sometimes the injections may need to be repeated. We often arrange for other treatment after the injection to help the joints work in a more normal way.
The injections
When the injection is performed, you will need to lie on your stomach for about 20 minutes
A small needle is put into a vein on your hand or forearm so that we can give medicines rapidly should they be needed. An X-ray machine is used to take pictures of the injection. If there is any possibility of pregnancy, then we cannot perform the injection. The site of the injection is cleaned with cold antiseptic. A small injection of local anaesthetic (lidocaine), which stings for a few seconds, is used to numb the skin over the facet joints in the back.
A fine needle is placed onto the joint, which can be uncomfortable if the joint is tender. The needle is checked by injecting a small amount of iodine-containing dye (iopamidol) that shows up in the X-rays. The treatment is then injected.
Local anaesthetic.(bupivacaine) in the injection will reduce the pain within a few minutes, and will work for several hours. There may be some warmth, a little discomfort, weakness, a feeling of heaviness and sometimes a feeling of numbness that includes the leg and lasts for a few hours at most.
A steroid is often included in the injection to prolong the effects: the steroid is chosen to remain around the joint, and has little effect on the rest of the body. It takes more than a day to have an effect, and the pain may return as the local anaesthetic wears off before the steroid begins to work.
Because of the effects of the injection, you should not travel home alone, and someone should stay with you on the day of the injection.
Problems
There is a small possibility that facet joint injections may cause faintness or a fall in blood pressure. The injection cannot be given to patients who are sensitive or allergic to the drugs used. We put a dressing over the injection, and you should tell us if you are allergic to plasters, tapes or dressings. It is too dangerous to perform the injection on patients with clotting problems, or are taking anticoagulants. It is also too dangerous to perform the injection when there is an infection of the skin of the back, or septicaemia.
