To the Editor: Bogduk, in his recent clinical update on management of chronic low back pain, stated that “zygapophysial joint pain can be relieved by radiofrequency neurotomy (E2, E3), and techniques are emerging for treating sacroiliac joint pain and internal disc disruption (E2, E3, E4)”.1 (E2, E3 and E4 refer to the levels of evidence: E2 evidence is obtained from at least one properly designed randomised controlled trial; E3 from pseudorandomised controlled trials or comparative studies; and E4 from case series, either post-test or pre-test and post-test.)

I have two concerns about this statement. Both involve the fact that at least three systematic reviews (E1 level of evidence) have now been published on treatment of lumbar zygapophysial joint-mediated low back pain with radiofrequency procedures.2-4 Together, these three reviews cast considerable doubt on Bogduk’s claim about the role of radiofrequency neurotomy.

My first concern is that the earliest of those systematic reviews,2 which came to a very different conclusion from that of Bogduk, was published in 2001, well before he submitted his clinical update to the Journal on 16 July 2003. Yet, he does not mention that review, even though he was obviously aware of it, as evidenced by his letter to the journal Regional Anesthesia and Pain Medicine expressing concern with the methods underpinning the review.5 Even if Bogduk disagrees with the conclusions of that review, justification for excluding it from the evidence base of his recent clinical update seems warranted.

Secondly, two more recent systematic reviews3,4 have come to conclusions very different from those of Bogduk on the role of radiofrequency neurotomy in treatment of lumbar zygapophysial joint pain.

The first of those two reviews, from the Cochrane Collaboration Back Review Group, concludes: “There is . . . conflicting evidence for its [radiofrequency denervation] effectiveness for lumbar zygapophysial joint pain. There is limited evidence suggesting that intradiscal radiofrequency may not be effective in relieving discogenic low back pain. Further high-quality randomized controlled trials are needed, with larger patient samples and data on long-term effects, for which current evidence is inconclusive.”3

The second review concludes: “Current studies fail to give more than sparse evidence to support the use of interventional techniques [zygapophysial injections and radiofrequency denervation] in the treatment of lumbar zygapophysial joint-mediated low back pain. This review emphasizes the need for larger, prospective, randomized controlled trials with uniform inclusion and exclusion criteria, standardized treatment, uniform outcome measures and an adequate duration of follow-up period so that definitive recommendations for the treatment of lumbar zygapophysial joint-mediated pain can be made.”4

In summary, authors who knowingly exclude important relevant evidence from clinical updates should at a minimum justify the exclusion of that evidence. Given the collective weight of recent relevant systematic reviews, considerable doubt now exists about the role of radiofrequency procedures in the treatment of lumbar zygapophysial joint pain.

In reply: Although systematic reviews have identified three studies of lumbar radiofrequency neurotomy, they do not take into account technical errors in the procedure. Neither the study of Gallagher et al1 nor that of Leclaire et al2 used techniques that could coagulate the target nerves accurately, consistently, and thoroughly.3 Therefore, these studies are not a measure of the efficacy of the procedure when performed correctly and have no place in a systematic review. Nor are systematic reviews permitted to include complementary, observational studies like that of Dreyfuss et al.4 Yet, this study sets the benchmark for what outcomes can be achieved, if and when correct techniques are used.

The “conflicting” evidence reported by systematic reviews arises because inaccurate surgical techniques are used. When studies using inaccurate techniques are eliminated, there is no conflict. The literature reduces to one controlled study5 and one complementary study.4 These were the studies that I cited in the clinical update on chronic low back pain.6 In the face of that literature, the conclusion that I proffered, and which Wenban has quoted, is valid. Zygapophysial joint pain can be relieved by radiofrequency neurotomy. Perhaps the extra words that are required are provided that correct techniques are used.