Surgery Section - Percutaneous Intradiscal Electrothermal Annuloplasty (IDET) and Percutaneous Intradiscal Radiofrequency Thermocoagulation

IMPORTANT REMINDER

Regence Medical Policies are developed to provide guidance for members and providers regarding coverage in accordance with contract terms. Benefit determinations are based in all cases on the applicable contract language. To the extent there may be any conflict between the Medical Policy and contract language, the contract language takes precedence.

PLEASE NOTE: Contracts exclude from coverage, among other things, services or procedures that are considered investigational or cosmetic. Providers may bill members for services or procedures that are considered investigational or cosmetic. Providers are encouraged to inform members before rendering such services that the members are likely to be financially responsible for the cost of these services.

DESCRIPTION

Intradiscal annuloplasty therapies use radiofrequency energy to thermally treat discogenic low back pain arising from annular tears and other forms of internal disc derangement. In contrast with disc nucleoplasty, which ablates disc material, thermal annuloplasty techniques are designed to decrease pain arising from the annulus and enhance its structural integrity. It has been proposed that heat-induced denaturation of collagen fibers in the annular lamellae may stabilize the disc and potentially seal annular fissures, and that pain reduction may occur through the thermal coagulation of nociceptors in the outer annulus.

The term electrothermal annuloplasty (IDET™) using the Oratec SpineCath System specifically describes a minimally invasive annuloplasty procedure used to treat low-back pain related to disc disease. In an initial step, the pathogenic disc is identified using pressure-based discography. A navigable catheter with an embedded thermal resistive coil is inserted posterolaterally into the disc annulus or nucleus. The catheter is then passed through the disc circuitously to return posteriorly. Using radiofrequency energy, electrothermal heat is then generated within the thermal resistive coil at a temperature of 90 degrees centigrade; the disc material is heated for up to 20 minutes. The procedure is not designed to coagulate, burn, or ablate tissue. The mechanism of action of pain relief is not precisely understood, but it is thought to be either shrinkage of the collagen fibers within the annulus or destruction of the adjacent nociceptive pain fibers.

Another procedure, referred to as percutaneous intradiscal radiofrequency thermocoagulation (PIRFT), uses direct application of radiofrequency energy.  The radiofrequency probe is placed into the center of the disc rather than around the annulus, and the device is activated for only 90 seconds at a temperature of 70 degrees centigrade.  The Radionics RF Disc Catheter System has been specifically designed for this purpose. The procedure is not designed to coagulate, burn, or ablate tissue.  Again, the mechanism of action of this procedure is not precisely understood, but is thought to be related to reducing the nocioceptive pain input from the free nerve ending in the outer anulus fibrosis.  Based on the destruction of nocioceptive pain fibers, the Radionics Disc Catheter System is similar in concept to IDET™. However, the method of delivering the thermal energy is distinctly different between these two.  The proposed advantages of indirect electrothermal delivery of radiofrequency energy (i.e., IDET™ procedure) compared to a radiofrequency needle (i.e., the Radionics device) is related to the fact that IDET™ provides electrothermal coagulation to a broader tissue segment and allows precise temperature control and temperature feedback.

A more recently developed annuloplasty procedure, referred to as intradiscal biacuplasty (Baylis Medical, Inc., Montreal, Canada), involves the use of two cooled radiofrequency electrodes placed on the posterolateral sides of the intervertebral annulus fibrosus. It is believed that by cooling the probes a larger area may be treated than could occur with a regular needle probe. The Baylis Pain Management Cooled Probe received marketing clearance through the U.S. Food and Drug Administration’s 510(k) process in 2005. It is intended for use “in conjunction with the Radio Frequency Generator to create radiofrequency lesions in nervous tissue.”

Note: This policy does not address DISC nucleoplasty™, a technique based on a device offered by ArthroCare. A bipolar radiofrequency device is used to provide Coblation® that is designed to provide tissue removal with minimal thermal damage to collateral tissue. DISC nucleoplasty is closer in concept to a laser discectomy, in that tissue is removed or ablated in an effort to provide decompression of a bulging disc. DISC nucleoplasty and laser discectomy are considered separately in Surgery Policy No. 131.

POLICY/CRITERIA

Percutaneous annuloplasty (e.g., intradiscal electrothermal annuloplasty, percutaneous intradiscal radiofrequency thermocoagulation, or intradiscal biacuplasty) is considered investigational as a treatment of chronic discogenic back pain.

SCIENTIFIC BACKGROUND

Intradiscal Electrothermal Annuloplasty (IDET™)

This policy is based in part on a 2000 TEC Assessment (2) which was updated in 2003. (3). Data published prior to the 2003 assessment consisted primarily of case series of patients.  However, since the 2003 TEC Assessment update, randomized controlled trials have been published. Pauza and colleagues published the results of a randomized study (4), which was the focus of the discussion in the 2003 TEC assessment.  This study is reviewed in detail below.  The study included 64 patients with low back pain of greater than six months duration who were randomized to receive either IDET™ or a sham procedure.  Visual analog scale (VAS) pain was reduced by an average of 2.4 cm in the IDET™ group compared with 1.1 cm in the sham group, a significant difference between groups (p=0.045).  The mean change in the Oswestry Disability Scale (ODS) was also significantly greater for IDET™ group compared with the sham group.  The improvement on the SF-36 Bodily Pain subscale was nearly significantly higher for the IDET™ group.  The authors stated that analyses were conducted  which excluded data from eight patients, five from the IDET™ group and three from the sham treatment group.  One patient died, one was lost to follow-up, one had unsatisfactory electrode placement, one had post-treatment bone fracture, and two had new injuries unrelated to low back pain and were excluded due to compensation claims or opioids.  While the analyses were consistent with the study question assessing the efficacy of IDET™ compared with sham treatment, intent-to-treat analysis, which includes all patients randomized, is the preferred method because it is less likely to introduce bias.  The Pauza study did not appear to use this method of analysis.

Besides failing to perform intent-to-treat analyses, there are additional concerns about statistical methods used by Pauza and colleagues. Potential confounding should be assessed and necessary adjustments should be made. The report noted that the analysis of SF-36 Role Physical scores adjusted for differences at baseline, but whether comparison used adjustment and the statistical techniques were not specified. The technique for comparing group scores on continuous variables was described only as a t-test, suggesting simple comparison of mean change at follow-up. More appropriate techniques for comparing changes between groups include analysis of covariance and repeated measure analysis of variance. It is also important to report an appropriate measure of effect with an index of the precision of estimation (i.e., the confidence interval). The comparison of means on the VAS for pain and the ODS for disability do not readily reveal how often patients achieve a clinically significant improvement. Minimally significant improvement in VAS has been estimated at 1.8 – 1.9 cm, and by this estimate, the mean change in VAS of 2.4 cm for IDET™ would be considered clinically significant. However, a small number of extreme values can influence this measure. The study also reported the percentage with a change in VAS of more than 2.0 cm, which is greater than the minimally clinically significant improvement of 1.8 – 1.9 cm. When the VAS is dichotomized in this way, a relative risk of 1.5 is observed with a 95% confidence interval of 0.82 – 2.74. Although these data suggest a higher relative probability of achieving a minimally clinically significant improvement for the IDET™ group, this estimation lacks precision and is not clinically significant.

It is interesting to note that, although the sham procedure consisted only of insertion of a needle into the patient's back, 38% of patients in the sham group reported improvement in pain of greater than 20 points, 33% reported greater than 50% improvement, and one patient reported complete relief of pain. These results illustrate the importance of placebo-controlled trials of pain therapies. In uncontrolled trials of pain therapies, what appear to be reasonable or promising outcomes may be the result of no more than "having a procedure."

In summary, the Pauza trial is a well-designed trial with respect to randomization, clear description of intervention, and use of valid and reliable outcomes measures. However, this single center trial does not permit conclusions about the relative effects of IDET™ and placebo. The study did not conduct an intent-to-treat analysis and it is unclear whether IDET™ achieves clinically and statistically significant improvements in measures of pain, disability, and quality of life.

In 2005, Freeman and colleagues reported the results of a double-blinded study in which 38 patients were randomized to IDET™ and 19 to sham treatment. (5) At the six month follow-up exam, IDET was found to be no more effective than sham treatment, and no subject in either group achieved a successful outcome. A more detailed secondary analysis, performed at the request of the manufacturer, showed no statistically significant or clinically significant important differences in the measured study outcomes for either treatment.

In another randomized study, comparison of 21 IDET and 21 radiofrequency procedures found significant improvements in a majority of IDET patients but not in matched radiofrequency-treated patients at one-year follow-up. (6)  The study did not have a placebo-control group. An industry funded meta-analysis and systematic review were published that support the use of IDET. (7,8) However, the quality of the studies included in these reviews was poor; 14 of 18 studies reviewed did not have appropriate controls.  An additional meta-analysis concluded that the available evidence was insufficient to support the safety and efficacy of this procedure. (9)

Percutaneous Intradiscal Radiofrequency Thermocoagulation

It is unknown whether percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) is safe and effective as a treatment of back pain.  The current clinical trial data is insufficient to permit conclusions about the long-term results of this procedure.  There is only one published randomized, controlled trial comparing active PIRFT with no intradiscal treatment. (10)  No difference in outcomes was found at eight weeks follow-up between the active PIRT group (n=13) and the group (n=15)  patients who underwent the same procedure but without use of radiofrequency current. The authors concluded that PIRFT is not effective for reducing chronic discogenic low back pain.  A meta-analysis concluded that the available evidence was insufficient to support the safety and efficacy of this procedure. (11)

Intradiscal Biacuplasty

It is unknown whether intradiscal biacuplasty provides long-term symptom reduction and restoration of function.  The published evidence consists of single case reports, a pilot study (12) recommending future randomized, controlled trials, and a meta-analysis (13) that concluded that there is minimal evidence on this technique.

Practice Guidelines

American Society of Interventional Pain Physicians (ASIPP) (14)

In 2007, practice guidelines from the ASIPP reported on the quality of the available evidence, but did not make an actual recommendation for or against use of IDET or PIRFT.  The guideline stated that there is moderate evidence for managing chronic discogenic low back pain. For radiofrequency posterior annuloplasty, the evidence was limited for short-term improvement, and indeterminate for long-term improvement in managing chronic discogenic low back pain. Reported complications included catheter breakage, nerve root injuries, post-IDET disc herniation, cauda equine syndrome, infection, epidural abscess, and spinal cord damage.  

National Institute for Health and Clinical Excellence (NICE) (15,16)

Guidance published in 2004 by NICE indicated that the current evidence on safety and efficacy of percutaneous intradiscal electrothermal therapy and percutaneous intradiscal radiofrequency thermocoagulation for lower back pain does not appear adequate to support use of these techniques.

REFERENCES

1. BlueCross and BlueShield Association Medical Policy Reference Manual, Policy No. 7.01.72
2. BlueCross and BlueShield Association Technology Evaluation Center TEC Assessment: Intradiscal Electrothermal Therapy for Chronic Low Back Pain 2000; Vol. 15 Tab 5
3. BlueCross and BlueShield Association Technology Evaluation Center TEC Assessment: Percutaneous Intradiscal Radiofrequency Thermocoagulation for Chronic Discogenic Low Back Pain 2003; Vol. 18 Tab 19
4. Pauza KJ, Howell S, Dreyfuss P et al. A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain. The Spine Journal 2004;4(1):27-35
5. Freeman BJC, Fraser RD, Cain CM et al. A randomized, double-blinded, controlled trial. Intradiscal electrothermal therapy versus placebo for the treatment of chronic discogenic low back pain. Spine 2005;30(21):2369-77
6. Kapural L, Hayek S, Malak O et al. Intradiscal thermal annuloplasty versus intradiscal radiofrequency ablation for the treatment of discogenic pain: a prospective matched trial. Pain Med 2005;6(6):425-31
7. Andersson GB, Mekhail NA, Block JE. Treatment of intractable discogenic low back pain. A systematic review of spinal fusion and intradiscal electrothermal therapy (IDET). Pain Physician 2006;9(3):237-48
8. Appleby D, Andersson G, Totta M. Meta-analysis of the efficacy and safety of intradiscal electrothermal therapy (IDET). Pain Med 2006;7(4):308-16
9. Urrutia G, Kovacs F, Nishishinya MB, et al. Percutaneous thermocoagulation intradiscal techniques for discogenic low back pain. Spine. 2007;32(10):1146-54
10. Barendse GA, van Den Berg SG, Kessels AH et al. Randomized controlled trial of percutaneous intradiscal radiofrequency thermocoagulation for chronic low back pain: lack of effect from a 90 second 70 C lesion. Spine 2001;26(3):287-92
11. Nezer D, Hermoni D. [Percutaneous discectomy and intradiscal radiofrequency thermocoagulation for low back pain: evaluation according to the best available evidence] Harefuah. 2007;146(10):747-50, 815
12. Kapural L, Ng A, Dalton J, et al. Intervertebral disc biacuplasty for the treatment of lumbar discogenic pain: results of a six-month follow-up. Pain Med. 2008;9(1):60-7
13. Helm S, Hayeck SM, Benyamin RM et al. Systematic review of the effectiveness of thermal annular procedures in treatment discogenic low back pain. Pain Physician 2009;12(1):207-32
14. Boswell MV, Trescot AM, Datta S et al; American Society of Interventional Pain Physicians. Interventional techniques: evidence-based practice guidelines in the management of chronic spinal pain. Pain Physician 2007;10(1):7-111
15. National Institute for Health and Clinical Excellence. Percutaneous intradiscal electrothermal therapy for lower back pain.  Available online at http://www.nice.org.uk/Guidance/IPG81. (Verified 4/2/09)
16. National Institute for Health and Clinical Excellence. Percutaneous intradiscal radiofrequency thermocoagulation for lower back pain. Available online at http://www.nice.org.uk/Guidance/IPG83 (Verified 4/2/09)

CROSS REFERENCES

Decompression of Intervertebral Discs Using Laser or Radiofrequency (DISC Nucleoplasty), Regence Medical Policy Manual, Surgery, Policy No. 131

Percutaneous Discectomy; Regence Medical Policy, Surgery, Policy No. 145

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