FACET JOINT INJECTIONS
Facet joint injections are used to diagnose and/or treat facet joint pain. Facet joint pain typically presents with low back pain with, or without referred pain into the leg. Facet joints can be damaged in accidents, such as motor vehicle accidents, and the changes does not necessarily show up on an x-ray, CT scan or MRI scanning.
WHEN ARE FJI USED?
Facet joint injections are used in two circumstances:
Acute phase of pain - pain does not settle quickly enough with the treatments such as exercise, medication and physical therapy. The injection typically includes cortisone.
Chronic presentations - where pain is not always present. If pain can't be reliably predicted to be present in the six hours after the injection, diagnostic nerve block is not relevant. If a facet joint injection leads to some prolonged improvement, it is likely that the facet joint is the source of pain.
INJECTION PROTOCOL
The main reason for the injection is to determine whether the pain is altered in the six hours following the injection, so a pain score should be taken over this period. You will be kept in recovery for a couple of hours until the doctor or nurse determines when it is safe to go home.
The pain scale rates pain from 0 to 10 on a linear chart called the Visual Analog Scale (VAS). Zero indicates no pain at all, at ten, a person can't think, move or function at all. Each person should know their VAS and apply it to each area of pain (eg. back and leg) in two separate columns on the chart.
As the aim of the block is to see if the pain level changes, it is essential that pain is present at the time of injection, therefore patients should not take any pain medications on the day of the injection. It's normal to feel anxious about the injection, However it is very safe and quick, and generally not too painful.Medial branch blocks are used for stubborn chronic pain if specific treatment to the facet joint is required. This treatment is known as radio-frequency neurotomy (RFN) or radio-frequency denervation. This involves applying heat lesions to the nerve and can lead to prolonged pain relief.
THE PROCEDURE
The injection itself consists of placing a needle through the skin under an x-ray machine. The thin needle, not much thicker than an acupuncture needle, is placed directly on to the bone. Other than local bruising and pain, the procedure does not have any side effects. In five percent of cases, pain and bruising can last for a few days. Generally, only one or two facet joint levels are investigated at a time to ensure the diagnosis is specific to a level in the lumbar spine.
POST - PROCEDURE
You should be driven home after the procedure. If good relief is obtained from the injection, it's assumed that the facet joint is the main cause of pain, and the radiofrequency neurotomy (RFN) procedure should benefit you.
If there is no relief after the first session, a second session may be conducted to investigate other levels. If there is still no relief, we conclude that the facet joint is not the source of pain.
MORE ON THE PAIN CYCLE
As previously mentioned, pain is rated from 0 to 10. Pre-injection pain should be rated in terms of your movements and how you feel doing the things that most aggravate the pain. Over the next six hours, this should be recorded again every thirty minutes, and eventually hourly. Pain in different areas should be described and rated differently. For example the injection may relieve back pain but not leg pain. This is important for doctors to know when making recommendations for further treatment.
MORE ON THE PAIN CHART
You should rate your pain between 0 and 10 before your injection, and after for 6 hours, firstly in 30 minute intervals and then hourly intervals. Ratings should be conducted in terms of movements and how you feel doing the things that most aggravate the pain.