Radiofrequency neurotomy (RFN), also known as radiofrequency ablation, is a well-established interventional procedure used to treat chronic pain arising from joints that has not responded to conservative treatments, such as medications and physical therapy. Common indications for RFN include the following:
Facet Joint Pain - Neck pain arising from the cervical facet joints of the spine and/or back pain arising from the lumbar facet joints. Causes include injury to the spine, arthritis, degenerative disc disease or other degenerative spine disorders, such as spondylolisthesis.
Sacroiliac Joint Pain - Pain arising from the joints connecting the sacrum of the spine to the pelvis/hips. The pain is experienced in the low back/buttocks/thigh(s) and may radiate further down the leg(s).
Occipital Neuralgia and Cervicogenic Headaches - Headaches arising from the occipital nerves or the cervical spine. Causes include trauma (such as whiplash injury), arthritis, nerve entrapment, infection, tumors or other lesions.
Other painful conditions treated with RFN include shoulder pain (from the suprascapular nerve) and complex regional pain syndrome.
The aim of RFN is to interrupt pain signalling to the brain and eliminate the pain by lesioning the pain generating nerves. This is achieved by delivering alternating electrical current to the nerve via an electrode that is encased within a needle and inserted parallel to the nerve. The dense electrical current generates heat (above 60°C) at the tip of the needle which is applied to the nerve to create lesions.
For pain arising from the lumbar or cervical spine, the medial branch nerves are targeted. These nerves exit the facet joints and transmit pain from the facet joints to the brain. For pain arising from the sacroiliac joint, the lateral branch nerves are targeted.
Pulsed radiofrequency neurotomy (pRFN) is a modified version of traditional RFN. Heat is applied to the pain generating nerve(s) at a lower temperature (below 42°C) for short periods. Rather than causing nerve destruction, the nerve is modulated such that nerve activity is altered. This method only affects the pain generating “C” nerve fibers.
Before RFN is performed, a diagnostic nerve block will be conducted in order to confirm that the suspected facet/joint/nerve is the source of the pain, and that the pain will be blocked by targeting this area. This is a simple procedure in which an anaesthetic is injected into the site of the pain generating nerves. If significant short term pain relief is achieved, the result is positive and RFN is performed.
The RFN procedure is performed in a day surgery setting under light sedation. Once in the procedure room, the patient is assisted into position on the procedure table and a special earthing pad is placed on the back of the leg. An anaesthetist will provide partial sedation. The procedure is performed under fluoroscopic x-ray guidance to ensure accuracy of needle placement adjacent to the target nerve. Once correct placement has been established, nerve testing (sensory and sometimes motor stimulation) will take place, to confirm this placement. The patient will be asked to let the doctor know when they feel a tingling sensation, after which the RFN procedure will commence. Each radiofrequency lesion takes 90 seconds and at least 2 lesions are done at each level. During the procedure, the patient may experience some faint aching or muscle contraction, which is entirely normal.
The results of the RFN procedure are highly individualised and depends on the condition, though most patients will experience pain relief for many months and will regain a significant degree of functionality. In some cases, pain relief may last up to 2 years post-procedure. Nerves will eventually regenerate, upon which the pain may return and the procedure may be repeated.