Surgery Section - Artificial Intervertebral Disc

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Artificial intervertebral disks are synthetic replacements for damaged intervertebral discs in the cervical or lumbar regions of the spine.

The artificial cervical disc currently marketed in the U.S. is the PRESTIGE® Cervical Disc System (Medtronics).

Artificial cervical discs that are currently under investigation in the U.S. include Medtronics’ Bryan disc (polycarbonate, polyurethane core between porous coated titanium shells), Medtronic’s Prestige-STLP, SpineCore’s Cervicore (metal on metal), Synthes Spine’s ProDisc®-C (cobalt-chrome metal end plates and polyethylene core), and Cervitech’s PCM (polyethylene-on-metal).

Artificial lumber discs that are currently marketed in the U.S. include the Charité® (DePuy Spine, Inc.) and the ProDisc®-L (Synthes Spine).

Artificial lumber discs that are currently under investigation in the U.S. include the FlexiCore and Maverick devices.

Policy/Criteria

Total disc replacement with artificial intervertebral discs is considered investigational.

Position Summary

Preliminary data from short-term randomized, controlled clinical trials of total disc replacement with artificial intervertebral discs (TDR) for the treatment of neck or back pain is encouraging. The long-term safety and effectiveness have not been established. (2-7)

• The conditions for FDA approval of artificial intervertebral discs included ongoing follow-up data on the subjects in the randomized trials for the lumbar discs through five years and for the cervical disc through and at three, five and seven years. In addition, the sponsor of the cervical disc will conduct a five year enhanced surveillance study of adverse events in a broader patient population.  This data is not yet available. (8-10)
• At least five years are recommended to assess the long-term effects of spinal surgery on overall health outcomes. (11-13) The long-term device performance, durability, revisability, complication rate and effect on adjacent vertebral levels remain unknown.
• There are no long-term data from well-designed randomized controlled clinical trials on the health outcomes with any FDA approved artificial intervertebral discs.
• There are no evidence-based clinical practice guidelines from U.S. professional associations that recommend TDR as a surgical option for the treatment of degenerative disc disease (DDD).
• There is one guidance document from the National Institute for Clinical Excellence (NICE), a European professional association, that has determined that TDR is a surgical option. (14,15) This guideline is based on data from lower forms of evidence including case series studies and professional opinion.  This guidance specifically notes that patients should be informed that the long-term effectiveness is uncertain.

Effectiveness

It is uncertain whether TDR provides long-term pain reduction and restoration of function.

There are two randomized, controlled studies comparing the FDA approved cervical artificial intervertebral discs (PRESTIGE®) to fusion (14,15), and two randomized, controlled studies comparing FDA approved lumbar artificial intervertebral discs (Charité and ProDisc-L) to fusion. (4-7) These studies, summarized below, do not permit conclusions regarding long-term health outcomes because the duration of these studies was limited to two years.

There are no randomized studies comparing lumbar or cervical TDR to conservative, non-surgical interventions.  The magnitude of potential benefits is unknown.

Other clinical studies are limited to unreliable observational case series that do not allow conclusions about the long-term effectiveness and durability of TDR.

Cervical disc

The published randomized trials of TDR in the cervical spine do not permit conclusions regarding long-term health outcomes and adverse effects.

The extensive information in international published literature for artificial intervertebral discs is encouraging. However, there are only two randomized, controlled trials comparing the effects of the FDA approved artificial cervical disc(PRESTIGE) with spinal fusion on neck pain, arm pain, and neurological status. The first study was a small pilot study with 24-month follow-up of 55 patients. The results of this study supported further research. (16) The second study was the pivotal study on which FDA approval was based. (17)  This short-term study suggests PRESTIGE may be similarly effective to fusion; however, the study has significant design and analysis flaws that limit interpretation of the data.  These include the following:

• Study duration is limited to two years
• Unclear, inconsistent and incomplete study endpoints

The primary endpoint of this trial was the patient’s “overall success” calculated using: Neck Disability Index (NDI) scores; ill-defined neurological status scores; and the absence of implant or related surgical adverse events or “second surgery classified as a failure”.  The criteria by which a second surgery is classified as a success or failure are not defined.  Details were not provided on how the neurological status was measured and evaluated.

Other components of pain and function (i.e., SF-36 scores, neck and arm pain scale scores) were evaluated separately but were not included in determining overall success.  There was no statistically significant difference in the SF-36 and neck and arm pain scale scores at six month and 24 month follow-up.

Revisability was not studied in this trial. Patients receiving TDR may outlive the device.

• Potential Bias

Since patients may be biased in favor of new technology (13), patient masking or blinding when possible is essential to elimination this potential bias.  In this study patients were not blinded to the surgery performed even though the surgical approach and postoperative care were similar for both groups.

A statistically significant proportion of patients (4%) withdrew from the study prior to surgery due to dissatisfaction with the treatment group to which they were randomized.

• Population studied may not be reflective of typical surgical candidates for DDD.

The AAOS guidance for the design of clinical trial of artificial intervertebral discs recommends six months of conservative therapy before the patient is considered a surgical candidate.

The investigators note that “most patients reported a minimum six week history of neck and arm pain that was recalcitrant to nonoperative treatments”.

Lumbar Disc

The published randomized trials of TDR in the lumbar spine do not permit conclusions regarding long-term health outcomes.

The extensive information in international published literature for artificial intervertebral discs is encouraging. However, there are only two randomized, controlled trials comparing the effects of FDA approved artificial lumbar discs (i.e., Prodisc-L, Charite) with spinal fusion on low back pain, leg pain and neurological status.

• Study duration is limited to two years
• No intent-to-treat analysis was provided in the ProDisc study.

Eleven percent of fusion patients and 7.5% of ProDisc patients were excluded from the results, presumably due to missing data.

• The ProDisc-L study used a controversial version of the Oswestry Disability Index (ODI) which could make scores invalid.

Safety

The durability and replacement rate of TDR are unknown.

Placement of an artificial intervertebral disc may limit surgical options if revision is needed due to complications or device failure. (18-20)

The long-term safety and complication rate for TDR are unknown compared to other therapies. (21-23)

• It is unknown whether TDR increases the rate of degenerative disc disease in neighboring discs compared to other therapies.
• It is unknown whether TDR increases the rate of degeneration in the facet joints at the level of the implant compared to other therapies.
• Vertebral body and pedicle fractures have been reported with some artificial disc designs.
• Wear debris from the polyethylene component of the prosthesis has been found in surrounding tissue.
• Retrograde ejaculation has been reported following TDR in some men.

The rate of failure of the TDR device itself is unknown compared with other therapies. (24-28) Reported causes for device failure include but are not limited to the following:

• Allergic reaction to implant materials
• Excessive wear, bending or breakage of any component of the artificial disc device
• Loosening, migration or dislodging of the artificial disc device
• Collapse of the artificial disc device into the bone (subsidence)
• Fusion (heterotopic ossification) or loss of motion at the level of the implant
• Errors in positioning or prosthesis size (e.g., under sizing)

Metallic devices release metallic ions into the body.  The long-term effect of these ions in the body is unknown.

References

1. BlueCross and BlueShield Association Medical Policy Reference Manual, Policy No. 7.01.87 and Policy No. 7.01.108
2. TEC Assessment: Artificial Lumbar Disc Replacement, 2007; BlueCross and BlueShield Association Technology Evaluation Center. Vol. 22, No. 2
3. TEC Assessment: Artificial Intervertebral Disc Arthroplasty for Treatment of Degenerative Disc Disease of the Cervical Spine, 2007; BlueCross and BlueShield Association Technology Evaluation Center Vol. 22, No. 12
4. Geisler FH, Blumenthal SL, Guyer RD et al. Neurological complications of lumbar artificial disc replacement and comparison of clinical results with those related to lumbar arthrodesis in the literature: results of a multicenter, prospective, randomized investigational device exemption study of Charité intervertebral disc. J Neurosurg Spine 2004;1(2):143-54
5. Blumenthal S, McAfee PC, Guyer RD, et al: A prospective, randomized, multi-center Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: Part I. Evaluation of clinical outcomes. Spine 2005;30(14):1565-75
6. McAfee PC, Cunningham B, Holsapple G, et al. A prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: part II: evaluation of radiographic outcomes and correlation of surgical technique accuracy with clinical outcomes. Spine. 2005;30(14):1576-83; discussion E388-90
7. Zigler J, Delamartar R, Spivak JM, et al. Results of the prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of the ProDisc-L total disc replacement versus circumferential fusion for the treatment of 1-level degenerative disc disease. Spine 2007;32(11):1155-62; discussion 1163
8. U.S. Food and Drug Administration. PRESTIGE® Summary of Safety and Effectiveness Data.  Accessible at http://www.fda.gov/cdrh/pdf6/P060018b.pdf (Verified 5/28/08)
9. U.S. Food and Drug Administration. Charite® Summary of Safety and Effectiveness Data.  Accessible at http://www.fda.gov/cdrh/pdf4/P040006b.pdf (Verified 5/28/08)
10. U.S. Food and Drug Administration. ProDisc®-L Summary of Safety and Effectiveness Data.  Accessible at http://www.fda.gov/cdrh/pdf5/P050010b.pdf (Verified 5/28/08)
11. Proposed guidance document for pre-clinical and clinical trial design for cervical and lumbar disc replacement systems. American Academy of Orthopaedic Surgeons. Available online at http://www.fda.gov/ohrms/dockets/dockets/05d0113/05d-0113-gdl0001-01-vol1.pdf (Verified 5/29/08)
12. Peng-Fei S, Yu-Hua J. Cervical disc prosthesis replacement and interbody fusion - a comparative study. Int Orthop 2008;32(1):103-6
13. Benzel EC. Cervical disc arthroplasty compared with allograft fusion. J Neurosurg Spine 2007;6:197
14. National Institute for Health and Clinical Excellence (NICE) Practice Guideline: Prosthetic intervertebral disc replacement in the cervical spine. http://www.nice.org.uk/nicemedia/pdf/ip/IPG143guidance.pdf (Verified 5/28/08)
15. National Institute for Health and Clinical Excellence (NICE) Practice Guideline: Prosthetic intervertebral disc replacement. http://www.nice.org.uk/guidance/index.jsp?action=download&o=30929 (Verified 5/28/08)
16. Porchet F, Metcalf NH. Clinical outcomes with the Prestige II cervical disc: preliminary results from a prospective randomized clinical trial. Neurosurg Focus. 2004;17(3):E6
17. Mummaneni PV, Burkus JK, Haid RW, et al. Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial. J Neurosurg Spine. 2007;6(3):198-209
18. McAfee, PC, Geisler FH, Saiedy SS, et al. Revisability of the CHARITE artificial disc replacement: analysis of 688 patients enrolled in the U.S. IDE study of the CHARITE Artificial Disc. Spine 2006;31(11):1217-26
19. Wagner WH, Regan JJ, Leary SP, et al. Access strategies for revision or explantation of the Charité lumbar artificial disc replacement. J Vasc Surg 2006;44(6):1266-72
20. Punt IM, Visser VM, van Rhijn LW, et al. Complications and reoperations of the SB Charité lumbar disc prosthesis: experience in 75 patients. Spine 2008;17(1):36-43
21. Freeman BJ, Davenport J. Total disc replacement in the lumbar spine: a systematic review of the literature. Eur Spine J.2006;15 Suppl 3:S439-47
22. Mathew P, Blackman M, Redla S, et al. Bilateral Pedicle Fractures Following Anterior Dislocation of the Polyethylene Inlay of a ProDisc® Artificial Disc Replacement; A Case Report of an Unusual Complication. Spine 2005;30(11) 30:E311–E314
23. de Kleuver M, Oner FC, Jacobs WC.  Total disc replacement for chronic low back pain: Background and a systematic review of the literature. Eur Spine J 2003;12(2):108-116
24. van Ooij A, Oner FC, Verbout AJ. Complications of artificial disc replacement: a report of 27 patients with the SB Charité disc. J Spinal Disord Tech 2003;16(4):369-83
25. van Ooij A, Kurtz SM, Stessels F, et al. Polyethylene wear debris and long-term clinical failure of the Charité disc prosthesis: a study of 4 patients. Spine 2007;32(2):223-9
26. Tortolani PJ, Cunningham BW, Eng M, et al. Prevalence of heterotopic ossification following total disc replacement. A prospective, randomized study of two hundred and seventy-six patients. J Bone Joint Surg Am  2007;89(1):82-8
27. Mehran C, Suchomel P, Grochulla F, et al. Heterotopic ossification in total cervical artificial disc replacement. Spine 2006;31(24):2802-6
28. Leary SP, Regan JJ, Lanman TH, et al. Revision and explantation strategies involving the CHARITE lumbar artificial disc replacement. Spine. 2007;32(9):1001-11

Cross References

1. Lumbar Spine Surgery, Regence Medical Policy Manual, Surgery, Policy No. 101
2. Surgery for Degenerative Diseases of the Cervical Spine Surgery, Regence Medical Policy Manual,  Surgery, Policy No. 103

Surgery Section Table of Contents