A randomised double blind placebo controlled trial of radiofrequency neurotomy for the treatment of lumbar zygapophysial joint pain

In most patients with chronic low back pain, the cause of their pain is unknown. As well, there are very few proven treatments for chronic low back pain, and none of the commonly used treatments are known to relieve pain completely. However, in a small proportion of patients, the source of pain can be traced to one or more small joints in the lumbar spine, called the zygapophysial joints – or “Z” joints for short. Pain from these joints can be relieved by sealing the small nerves that supply the joints. This is done using a probe inserted, under X-ray control, onto each of the nerves. The probe delivers a tiny heat-lesion that seals the nerve. In full, this procedure is called percutaneous lumbar medial branch radiofrequency neurotomy. In short, it is known as radiofrequency, or RF neurotomy. Lumbar RF neurotomy is not an experimental procedure. It has been used in Medicine for nearly 30 years. In Australia, it is recognized in having a Medicare item number. Doctors who use this procedure to treat their patients believe that it works. However, some commentators have questioned if the results of the operation are genuine. They believe that patients report relief because of non-specific effects of the procedure – such as the ceremony of having an operation, or because patients want it to work. They argue that it is not necessary actually to coagulate the nerves in order to achieve a beneficial effect. This argument arises because there has been no rigorous scientific studies of the procedure in the form of controlled trials. In a controlled trial, a computer indicates whether patients should undergo the real treatment or a sham treatment. A sham treatment is one which is just like the real treatment but differs in one critical respect. In the present study, the difference is that in the sham procedure not actually coagulated. If an operation works in such a study, the results obtained from the real treatment emerge as better than those obtained from the sham treatment. The difference in results indicates how powerful the real treatment is. However, if there is no difference in the results, any apparent effectiveness of the treatment is attributed to non-specific influences. Some controlled trials for lumbar RF neurotomy have been conducted, but in each instance the operators used techniques that have been shown to fail to coagulate the target nerves accurately. In the one study in which correct techniques were used, the investigators found that some 80% of patients obtained at least 60% relief of their pain, and 60% of patients obtained at least 80% relief, lasting for at least 12 months after treatment. But these results have been disregarded because the study was not controlled: it provided the real treatment but had no patients who underwent sham treatment. Because of the lack of convincing scientific evidence that lumbar RF neurotomy actually works, some insurance carriers have undertaken to deny this form of treatment to their clients. This has occurred both in the United States and in Australia. In response to the conflict between those doctors who believe that lumbar RF neurotomy works and those who believe it does not, the International Spine Intervention Society has provided funding for study of the procedure, to be conducted in which will look at recruiting 30 patient volunteers.