What are the facet joints?
The facet joints are two small joints which exist at each level of the spine. In the lower spine (lumbar spine), these joints exist as vertical joints just away from the centre of the spine which interlock the lower vertebrae and upper vertebrae in a vertical fashion.
When the spine bends forwards (flexes) these facet joints open and when the spine bends backwards (extends) these facet joints close down and lock the movements of the spine.
Due to this anatomy, the facet joints tend to bear significant weight and take much of the strain on the spine when in positions that involve more extension of the lower spine. These include standing and walking.
The facet joints can give rise to pain for several reasons. The first is a whiplash style injury in which the lower spine is rapidly forced in to extension. This can inflame the facet joints which sometimes do not settle down without treatment.
Some individuals may have other structural problems in their lower spine which makes the spinal joints unstable. This can place a greater strain on the facet joints and can also lead to inflammation and pain.
The third reason is that these joints may suffer from age related changes (osteoarthritis).
Prior to a facet joint denervation your specialist will have requested appropriate imaging for your spine. This will normally include an MRI scan which shows the facet joints and specifically highlights any inflammation in the facet joints very well.
Under normal circumstances, if the facet joints are suspected to be the source of the pain a trial injection will be considered to assess whether this gives adequate pain relief prior to considering a facet joint denervation.
What does a facet joint denervation involve?
A facet joint denervation is performed by a specialist under xray guidance so they can see the exact structures they are targeting. Once the specialist has administered a local anaesthetic injection to numb the area they will insert a small, hollow tube towards the spine.
Through this hollow tube they are able to use a radiofrequency machine which heats the nerve supplying the facet joints. This heating effect essentially kills the nerve and thereby denervating it. You will be able to go home on the same day as the procedure and will be asked to carry on with normal daily activities once the procedure has been completed.