This is a procedure in which small nerves in the back or neck are treated by means of an electrically generated current that is passed down a thin needle that sits adjacent to the nerve. RFD is used when there is a high degree of suspicion that the facet joints are the cause of pain.
The small joints in the posterior part of the spinal column are often a source of debilitating and constant pain particularly when they become worn and inflamed. If spinal facet joint injection with local anaesthetic and steroid has provided good but temporary relief on at least two separate occasions then these joints can be de-sensitised on a semi-permanent basis.
Fine cannulae are guided (as a day case, under X-Ray control) onto the small branch of the main spinal nerve which supplies the pain sensation to the joint. For each joint at least two branches need to be located. For safety a small electrical signal tests how close the needle tip is to the relevant nerve and ensures that there is no risk of the needle tip being too close to the main nerve which governs motor control. Once these conditions have been satisfied a thermocouple electrode is placed through the cannula and a radiofrequency current is then produced via the lesion generator to heat the nerve to a temperature of 80-85 degrees for a period of 90 seconds.
Within the nerve that is heated are many small nerve fibres. The pain carrying fibres (A delta and C fibres) are among the smallest of them all and at about 80 degrees centigrade these are the fibres most affected. The fibres do recover, but slowly and the pain relief can last at least one year. The pain relief can allow for improved function of the back, and this may enhance the recovery of the back and diminish the need for a repeat procedure or other treatment.
RFD does not touch the nerves that supply the muscles in the leg or arm. These large nerves - the ventral rami - are not pain carrying nerves in the case of pain from the facet joints. Thus, RFD will not affect the leg or arm muscles.
The nerve supply at any level of the spinal cord includes the nerve supply to the disc and surrounding muscles and ligaments. If excess strain is applied to the area, these nerves will react by producing pain.
When the pain first developed it was a warning of fresh injury, and it was telling you to avoid particular activities and perhaps to rest. However, now that the pain has persisted beyond the time when it is useful, it can if possible be ignored. If the RFD produces pain relief, then you may be able to restore the function of the spine so that the pain never recurs.
The post procedure soreness is extremely variable, and in rare circumstances can last for up to 2 months. In general, however, it will ease in a few days. Even if pain is prominent after the RFD you should resume normal activities rapidly. In neck RFD's, a burning neuralgia can occur, and in rare circumstances this can last for up to six weeks.
The procedure is performed under x-ray control and is precise. The needles are a long way from the spinal cord, so this will not be damaged. Major blood vessels and nerves are also in front of the needle, and should not be damaged or effected. The following are possibilities:
Allergic reaction to the anaesthetic is possible. However, as the anaesthetic has already been used to diagnose the condition, and probably for dental and other procedures, the potential for this event is minimal. In addition, such effects are closely monitored by the anaesthetist, and treatment if necessary can be rapidly administered.
Bleeding and bruising are possible, but the effects are minimal and should pass within a week.
Infection could occur, but this possibility is minimised by the use of sterile techniques. The needles are all disposable, so you cannot catch hepatitis or HIV.
Post-procedure pain usually recovers in a few days, but can persist for up to eight weeks. In about 1% of lumbar RFD’s and 5% of cervical RFD’s, the pain can be severe and last up to about 10 weeks. Unfortunately, this type of pain can be difficult to control with codeine drugs, including morphine, and other approaches may be required, such as use of drugs that alter nerve conduction. Amitryptaline and Tegretol are two examples. Sometimes a repeat injection of anaesthetic and steroid can be used. This pain recovers.
Numbness can occur, particularly in RFD of the third occipital nerve. It usually resolves, but in isolated cases has continued.
An itch can also occur in the area around the RFD, and in 0.1% of cases it persists.
Loss of balance, in third occipital nerve RFD, can occur because this nerve carries information to the brain from the neck muscles.
To reduce post-procedure soreness a small dose of local anaesthetic and corticosteroid is then deposited at the site and the cannula is withdrawn. Since several small nerves have to be treated this way the procedure may take an hour or so but it does not require anything more than local anaesthesia and is not a painful experience to the patient.