Curr Rev Musculoskelet Med (2009) 2:15–24 A subsequent study by Leclaire et al. [127] involved 70 patients, all of whom had experienced what investigators termed ‘‘signiﬁcant’’ improvement in low back pain for at least 24 h after a single diagnostic facet joint injection of both lidocaine 2% and triamcinolone. The patients were randomized into control and treatment groups, who received identical procedures with the exception that the control group did not experience lesioning with heated probes. There was no signiﬁcant difference in any of the outcome measures at 12 weeks, which included functional disability according to the Roland-Morris or Oswestry scales, or pain according to the VAS scores. Although this was one of the larger studies examining radiofrequency denervation, it is also important to note that in this study, only one diagnostic block was performed and there was no set deﬁnition of what was accepted as a successful diag- nostic block. Only ‘‘signiﬁcant pain relief’’ was described. Furthermore, the description of the radiofrequency tech- nique is incomplete and it is unclear whether the probe was positioned parallel or perpendicular to the medial branch. A more recent study by van Wijk [107] represents the largest randomized double blind study examining the efﬁ- cacy of radiofrequency ablation to date. Eighty-one patients were randomized to radiofrequency ablation or a sham procedure after facet joint pain was conﬁrmed with a two level intra-articular facet joint block. There was no difference in the combined primary outcome (VAS, anal- gesic intake, and physical activity) measure at 3 months. VAS scores improved in both the treatment and control groups but there was no statistically signiﬁcant difference between groups. In this study, the authors used a 50% improvement in pain for determining a successful diag- nostic facet joint block. However, although the authors recognize that uncontrolled diagnostic blocks may have false-positive effects with a low predictive value, con- trolled diagnostic blocks were not performed. Dreyfuss et al. [106] examined the efﬁcacy of lumbar medial branch neurotomy with a thorough and compre- hensive protocol, including stringent inclusion and exclusion criteria. Facet joint pain was subsequently con- ﬁrmed with both diagnostic and conﬁrmatory blocks of the medial branches utilizing an 80% or greater pain relief criteria for inclusion. Care was taken to ensure that the radiofrequency electrode was positioned parallel to the medial branch. Unique to this study is that 6 weeks after neurotomy, patients underwent an electromyogram to determine the presence or absence of denervation poten- tials. Eighty-seven percent of patients obtained at least 60% relief of pain and 60% of patients obtained at least 90% relief of pain at 12 months. Although technically sound, this study was limited by its lack of a control group. Although the study examined cervical facet joint pain rather than lumbar facet joint pain, it is important to consider 21 the study by Lord et al. [108] who presented one of the most rigorous protocols to date. This randomized, double-blind controlled trial included patients who had cervical pain after motor vehicle crashes that had undergone successful diag- nostic controlled blocks. In order to proceed to radio- frequency ablation, facet joint pain had to be conﬁrmed with not two but three diagnostic blocks of the medial branches employing 2% lidocaine, 0.5% bupivacaine, or saline under strict double blind conditions. The study patient was accepted for radiofrequency lesioning of the medial branches only if they experienced 100% pain relief with the local anesthetic block and no relief when normal saline had been injected. The median time for return of at least 50% of preoperative pain level was found to be 263 days in the active-treatment group and 8 days in the control group (P = 0.04). Conclusions Despite some of the pitfalls associated with facet joint blocks, they have been shown to be valid, safe, and reliable as a diagnostic tool [128]. Medial branch denervation has shown some promise for the sustained control of lumbar facet joint-mediated pain, but at this time, there is insuf- ﬁcient evidence that it is a wholly efﬁcacious treatment option. This may be simply because we do not have enough highly-powered randomized controlled studies to support its use. Developing a universal algorithm for evaluating facet joint-mediated pain and standard procedural tech- niques may facilitate the performance of larger outcome studies. Implementing guidelines for the comprehensive reporting of both patient selection and the various aspects of radiofrequency techniques as outlined by Geurts et al. [129] will in turn, allow us to form more powerful evi- dence-based conclusions. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. Cypress BK. Characteristics of physician visits for back symptoms: a national perspective. Am J Public Health. 1991;12: 141–56. 2. U.S. Department of Health and Human Services. Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2002. Vital Health and Statistics Series 10, No. 222. 3. Von Korff M. Studying the natural history of back pain. Spine. 1994;19:2041S–6S. 4. Katz JN. Lumbar disc disorders and low back pain: socioeco- nomic factors and consequences. J Bone Joint Surg Am. 2006; 88(Suppl 2):21–4.