SPINE Volume 30, Number 21, pp 2369 –2377 ©2005, Lippincott Williams & Wilkins, Inc. A Randomized, Double-Blind, Controlled Trial Intradiscal Electrothermal Therapy Versus Placebo for the Treatment of Chronic Discogenic Low Back Pain Brian J. C. Freeman, FRCS (Tr & Orth), Robert D. Fraser, MD, FRACS, Christopher M. J. Cain, MD, FRACS, David J. Hall, FRACS, and David C. L. Chapple, MSc, FRCS (Tr & Orth) Study Design . A prospective, randomized, double- blind, placebo-con troll ed trial of intradiscal electr other- mal therapy (IDET) for the treatment of chronic discogenic low back pain (CDLBP). Objectives. To test the safety and efficacy of IDET com- pared with a sham treatment (placeb o). Summary of Backgr oun d Data. In Nor th America alone, more than 40,000 intradiscal catheters have been used to treat CDLBP. The evidence for efficacy of IDET is weak coming from retrospective and prospective cohort studies providing onl y Clas s II and Class III evid ence. There is one study published with Class I evidence. This demons trates stati stical ly signifi cant improv ements fol- lowing IDET; however, the clinical significance of these improvements is questionable. Methods. Patients with CDLBP who failed to improve following conservative therapy were considered for this study. Inclusion criteria included the presence of one- or two-level symptomatic disc degeneration with posterior or posterolateral anular tears as determined by provoca- tive compu ted tomog raphy (CT) disco graphy . Patien ts were excluded if there was greater than 50% loss of disc height or previo us spinal surgery. Fifty-seve n patien ts were randomized with a 2:1 ratio: 38 to IDET and 19 to sham procedur e (place bo). In all cases, the IDET catheter was positioned to cover at least 75% of the annular tear as defined by the CT discography. An independent techni- cian connecte d the cat heter to the generator and then either delivered electrothermal energy (active group) or did not (sham group). Surgeon, patient, and independent outcome assessor were all blinded to the treatment. All patien ts follo wed a stand ard postp roced ural rehabil ita- tion program. Independent statistical analysis was per- formed. Outcome Measures. Low Back Outcome Score (LBOS), Oswestry Disability Index (ODI), Short Form 36 question- naire (SF-36), Zung Depression Index (ZDI), and Modified Somat ic Perceptions Questionnaire (MSPQ) were mea- sured at baseline and 6 months. Successful outcome was defined as: no neurologic deficit, improvement in LBOS of great er then 7 points, and impro vement in SF-36 subset s (physical function and bodily pain) of greater than 1 stan- dard deviation. Results. Baseline demographic data, initial LBOS, ODI, SF-36, ZDI, and MSPQ were similar for both groups. No neurologic deficits occ urr ed. No subject in either arm showed improvement of greater than 7 points in LBOS or gre ater than 1 standa rd devi ati on in the specifi ed do- mains of the SF-36. Mean ODI was 41.42 at baseline and 39. 77 at 6 months for the IDET gro up, compared with 40.74 at baseline and 41.58 at 6 months for the placebo group. There was no significant change in ZDI or MSPQ scores for either group. Conclusions. The IDET procedure appeared safe with no permanent complica tions . No subject in either arm met criteria for successful outcome. Further detailed anal- yses showed no significant change in outcome measures in either group at 6 months. This study demonstrates no significant benefit from IDET over placebo. Key words: intradiscal electrothermal therapy, chronic discogenic low back pain, randomized double-blind con- trolled trial, clinical outcome. Spine 2005;30:2369–2377 Th e tr ea tmen t of ch ro ni c di scogen ic lo w ba ck pa in (C DL BP ) remains challenging for the spinal specialist. Failed conserva- tiv e tre atm ent tra dit ion all y has bee n fol low ed by spi nal fus ion . However, clinical outcome following spinal fusion remains variable with reported satisfactory clinical results varying be- tween 46 % an d 82 %. 1,2 Saa l and Saa l int roduce d an alt ernati ve met hod for the treatment of CDLBP usi ng controlle d the rma l ene rgy de- livered via an intradiscal catheter. 3 Early studies on in- tradiscal electrothermal therapy (IDET) were promising, offering patients an option other than chronic pain man- agement or spinal fusion. 4 There has been much written about the proposed mechanism of action of IDET. Targeted thermal energy has been shown to coagulate neural tissue 5 and shrink collagen fibrils. 6 It has been suggested that IDET may coa gul ate annula r noc ice pto rs and lea d to contra cti on of collagen, thereby addressing both the nociceptive and mechanical components of discogenic pain. 3 For these events to occur, tissue temperatures need to reach 45 C and 60 C, respectively, but doubt has been cast on the ability of both radiofrequency and thermal-resistive coil heating to achieve these temperatures. 7,8 Shah et al From the Spin al Unit, Dep artme nt of Orth opae dics and Trau ma, Roya l Adelaide Hospital, Adelaide, South Australia. Ackn owle dgme nt date : Augu st 18, 2004. First revisi on date : Dec embe r 11, 2004. Acceptance date: December 13, 2004. Supported in part by grants from Oratec Interventions, Menlo Park, CA; DePuy AcroMed, Raynham, MA; and Smith and Nephew Inc., Andover MA. The devi ce(s )/dru g(s) is/are FDA-app rovedor appro ved by corre spon d- ing national agency for this indication. Corporate/Industry funds were received in support of this work. Al- though one or more of the authors(s) has/have received or will receive benefits for personal or professional use from a commercial party re- lated directly or indirectly to the subject of this manuscript, benefits will be directed solely to a research fund, foundation, educational in- stitution, or other no nprofit organiza tion which th e author(s) has/hav e been associated. Address correspondence and reprint requests to Brian J. C. Freeman, FRCS (Tr & Orth), Centre for Spinal Studies and Surgery, University Hospital, Queens Medical Centre, Nottingham, NG7 2UH, United Kingdom; E-mail: brian.freeman@q mc.nhs.uk 2369
