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A Randomized, Double-Blind, Controlled Trial: Intradiscal Electrothermal Therapy Versus Placebo for the Treatment of Chronic Discogenic Low Back Pain

Freeman, Brian J. C., FRCS (Tr & Orth); Fraser, Robert D., MD, FRACS; Cain, Christopher M. J., MD, FRACS; Hall, David J., FRACS; Chapple, David C. L., MSc, FRCS (Tr & Orth)

doi: 10.1097/01.brs.0000186587.43373.f2
Randomized Trial

Study Design. A prospective, randomized, double-blind, placebo-controlled trial of intradiscal electrothermal therapy (IDET) for the treatment of chronic discogenic low back pain (CDLBP).

Objectives. To test the safety and efficacy of IDET compared with a sham treatment (placebo).

Summary of Background Data. In North 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 only Class II and Class III evidence. There is one study published with Class I evidence. This demonstrates statistically significant improvements following 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 provocative computed tomography (CT) discography. Patients were excluded if there was greater than 50% loss of disc height or previous spinal surgery. Fifty-seven patients were randomized with a 2:1 ratio: 38 to IDET and 19 to sham procedure (placebo). 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 technician connected the catheter 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 patients followed a standard postprocedural rehabilitation program. Independent statistical analysis was performed.

Outcome Measures. Low Back Outcome Score (LBOS), Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36), Zung Depression Index (ZDI), and Modified Somatic Perceptions Questionnaire (MSPQ) were measured at baseline and 6 months. Successful outcome was defined as: no neurologic deficit, improvement in LBOS of greater then 7 points, and improvement in SF-36 subsets (physical function and bodily pain) of greater than 1 standard deviation.

Results. Baseline demographic data, initial LBOS, ODI, SF-36, ZDI, and MSPQ were similar for both groups. No neurologic deficits occurred. No subject in either arm showed improvement of greater than 7 points in LBOS or greater than 1 standard deviation in the specified domains of the SF-36. Mean ODI was 41.42 at baseline and 39.77 at 6 months for the IDET group, 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 complications. No subject in either arm met criteria for successful outcome. Further detailed analyses showed no significant change in outcome measures in either group at 6 months. This study demonstrates no significant benefit from IDET over placebo.

Intradiscal electrothermal therapy (IDET) was compared with a sham treatment where the intradiscal catheter was appropriately positioned in the target disc, but no electrothermal energy was administered. Surgeon, patient, and outcome assessors were all blinded to the randomization. Independent statistical analysis failed to show clinically significant improvements in either the IDET group or the sham group. IDET is no more effective than placebo for the treatment of chronic discogenic low back pain.

From the Spinal Unit, Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, South Australia.

Acknowledgment date: August 18, 2004. First revision date: December 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 device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.

Corporate/Industry funds were received in support of this work. Although one or more of the authors(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript, benefits will be directed solely to a research fund, foundation, educational institution, or other nonprofit organization which the author(s) has/have 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:

© 2005 Lippincott Williams & Wilkins, Inc.