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Pauza's IDET Study Print E-mail
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Pauza KJ et al. A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain. The Spine Journal 4 (2004): 27-35.

Study Design: Randomized, placebo-controlled, prospective trial.

Objectives: The procedure was promoted on the basis of observational studies and refereed papers and this study was an attempt to determine if the procedure was indeed effective.

Background Information: IDET was initially introduced by Saal et al in 1997 for the treatment of painful disogenic back pain. The procedure involves the percutaneous introduction of a catheter into the disc under fluoroscopy. The mechanism by which IDET helps discogenic disease is uncertain. The notion is that electrothermal treatment of the annulus denervates tissue or destroys nociceptors, thereby possibly decreasing pain, or that the collagen fibers of the annulus are reorganized during the heating process, causing an increase in annular stability.

Previous Studies: Prior studies and presentations have suggested success rates of approximately 60% to 70% in patients post-IDET. Most of these studies were observational studies.  A controlled trial, without randomization, found the success rates of IDET to vary from 23% to 60% depending on the criteria used.

Patient Sample: Patients were recruited by referral and the media. No inducements were provided to any patient in order to have them participate. Of 1,360 individuals who were prepared to submit to randomization, 260 were found potentially eligible after clinical examination and 64 became eligible after discography. All had discogenic low back pain lasting longer than 6 months, with no comorbidity. Thirty-seven were allocated to IDET and 27 to sham treatment. Both groups were satisfactorily matched for demographic and clinical features.

Methods:  IDET was performed using a standard protocol, in which the posterior annulus of the painful disc was heated to 90 C. Sham therapy consisted of introducing a needle onto the disc and exposing the patient to the same visual and auditory environment as for a real procedure. Thirty-two (85%) of the patients randomized to the IDET group and 24 (89%) of those assigned to the sham group complied fully with the protocol of the study.

Inclusion criteria:                                   
-          Men and women, 18 -65 years of age
-          Low back greater than leg pain for greater than 6 months duration
-          Failure to improve after at least 6 weeks of nonoperative care, including anti-inflammatory and analgesic medications and a physical therapy and/or home directed lumbar exercise program
-          Low back pain exacerbated by sitting or standing and relieved by lying down
-          A score of less than 20 on the Beck depression scale
-          No surgical interventions within the previous 3 months
-          Less than 20% disc height narrowing on lateral plain film radiographs

Exclusion criteria:
-          Previous lumbar spine surgery
-          Abnormal neurological exam other than ankle reflex changes
-          Radicular pain by history or examination
-          Structural deformities such as spondylolisthesis at the painful segment levels, vertebral canal stenosis or scoliosis
-          Intervertebral disc herniations greater than 4 mm or sequestered intervertebral disc herniations
-          Concomitant cervical or thoracic pain greater than 2/10 on a VAS
-          Uncontrolled or acute medical illness
-          Chronic severe conditions, such as rheumatoid arthritis
-          Ambulatory dysfunction
-          Pregnancy
-          Workman’s compensation, injury litigation, or disability remuneration
-          Allergy to contrast media or drugs to be used in the intended procedure
-          Unwillingness to consent to the study

Experimental Design:
-          64 Patients enrolled
-          37 Allocated to IDET
-          27 Allocated to sham therapy (consisted of needle into posterior annulus fibrosis, but instead of introducing electrode, the patient was exposed to a fluoroscopic monitor demonstrating passage of electrode and generator noises)

Outcome Measures:
-          VAS
-          SF-36
-          ODI
-          All of the above outcomes were assessed before treatment and 6 months after treatment by an evaluator blinded to which group the patient was in.

Statistical Analysis:
-          For continuous variables, group means, and standard deviations were determined and compared using t test
-          Fisher’s exact test and frequency distributions were used to summarize and compare categorical variables

Results:
-          Blinding was satisfactory (78% of IDET group believed they had active treatment and 74% of sham group thought the same).
-          Scores for General Health, Mental Health, Role Emotional, and Social functioning did not show a significant difference.
-          Both groups exhibited improvements in pain scores and on the ODI, but the IDET group was significantly greater than the sham group.
-          Both groups also improved with respect to Bodily Pain scores and Physical functioning, but there wasn’t a significant difference between the two groups.
-          Statistically significant differences in VAS pain scores for absolute and relative changes in favor of IDET.
-          While 40% of the patients achieved greater than 50% relief of pain, approximately 50% of patient did not improve at all.
-          The number need to treat, to achieve 75% relief of pain, was five.
-          When the outcomes were analyzed by further stratifying patients according to baseline measures, it showed that IDET was significantly more effective in patients with poor physical function and high disability (VAS≤7, SF-36<55, or ODI≥40).
-          Although not significant, 38% of people in the Sham group reported an improvement in pain greater than 20 points and 33% reported greater than 50% improvement.
-          If one outlier is censored, changes and mean scores at 6 months for VAS, Bodily Pain, and Physical Functioning, and Oswestry Disability Scale become significantly better.

Conclusions:
-          The Pauza study shows that nonspecific factors are a major determinant of the efficacy of IDET, but that its effects cannot be wholly attributed to placebo.
-          Potential candidates for IDET should be selected carefully as outlined previously and perhaps given greater consideration in patients with greater disability and poor physical function.
-          Future studies that include stricter inclusion criteria with regards to pain, physical functioning, and disability scores would be helpful.

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