MEDICAL POLICY

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APPENDIX
HISTORY

Interspinous Fixation (Fusion) Devices

Number 7.01.138

Effective Date November 20, 2014

Revision Date(s) 11/10/14; 11/11/13

Replaces N/A

Policy

Interspinous fixation (fusion) devices are considered investigational for any indication, including but not limited to use:

  • In combination with interbody fusion, or
  • Alone for decompression in patients with spinal stenosis.

Related Policies

7.01.107

Interspinous and Interlaminar Stabilization/Distraction Devices (Spacers)

7.01.130

Axial Lumbosacral Interbody Fusion

7.01.542

Lumbar Fusion

Policy Guidelines

Clinical input has identified potential exceptions where the devices might be considered medically necessary, such as patients with small pedicles where pedicle screws could not be safely placed.

Coding

CPT

22840

Posterior non-segmental instrumentation (e.g., Harrington rod technique, pedicle fixation across 1 interspace, atlantoaxial transarticular screw fixation, sublaminar wiring at C1, facet screw fixation) (List separately in addition to code for primary procedure)

22851

Application of intervertebral biomechanical device(s) (e.g., synthetic cage(s), methylmethacrylate) to vertebral defect or interspace (List separately in addition to code for primary procedure)

Description

Interspinous fixation (fusion) devices are being developed to aid in the stabilization of the spine. They are being evaluated as alternatives to pedicle screw and rod constructs in combination with interbody fusion. Interspinous fixation devices are also being evaluated for stand-alone use in patients with spinal stenosis.

Background

Contemporary models of interspinous fixation devices have evolved from spinous process wiring with bone blocks and early device designs (e.g., Wilson plate, Meurig-Williams system, Daab plate). The newer devices range from paired plates with teeth to U-shaped devices with wings that are attached to the spinous process. They are intended to be an alternative to pedicle screw and rod constructs to aid in the stabilization of the spine with interbody fusion. Interspinous fixation devices are placed under direct visualization, while screw and rod systems may be placed either under direct visualization or percutaneously. Use of an interspinous fixation device in combination with a unilateral pedicle screw system has also been proposed. Interspinous fixation devices are not intended for stand-alone use.

Interspinous fixation (fusion) devices contrast with interspinous distraction devices (spacers), which are used alone for decompression and are typically not fixed to the spinous process (see policy Related Policies). In addition, whereas interspinous distraction devices may use dynamic stabilization, interspinous fixation devices are rigid. However, the fixation devices might also be used to distract the spinous processes and decrease lordosis. Thus, the fixation devices might be used off-label without interbody fusion as decompression (distraction) devices in patients with spinal stenosis. If fixation devices are used alone as a spacer, there is a risk of spinous process fracture.

For use in combination with fusion, it is proposed that interspinous fixation systems are less invasive and present fewer risks than pedicle or facet screws. However, while biomechanical studies indicate that interspinous fixation devices may be similar to pedicle screw-rod constructs in limiting the range of flexion-extension, they may be less effective than bilateral pedicle screw-rod fixation for limiting axial rotation and lateral bending. (1) There is a potential for a negative impact on the interbody cage and bone graft due to focal kyphosis resulting from the interspinous device. There is also a potential for spinous process fracture. Given these uncertainties, studies are needed that compare health outcomes between interspinous fixation devices and pedicle screw-rod fixation.

Regulatory Status

The following interspinous fixation devices have received clearance to market by FDA. This may not be an exhaustive list.

  • Affix™ (NuVasive)
  • Aileron™ (Life Spine)
  • Aspen™ (Lanx, acquired by BioMet)
  • Axle™ (X-Spine)
  • BacFuse® (Pioneer Surgical)
  • BridgePoint™ (Alphatec)
  • coflex-F® (Paradigm Spine)
  • Inspan™ (Spine Frontier)
  • Interbridge Interspinous Posterior Fixation System (LDR Spine)
  • PrimaLOK™ (OsteoMed)
  • Octave™ (Life Spine)
  • Spire™ (Medtronic)
  • SP-Fix™ (Globus)
  • Zip Mis Interspinous Fusion System

Interspinous fixation devices are intended to be used as an adjunct to interbody fusion. For example, the indication for use of the coflex-F implant “is a posterior, non-pedicle supplemental fixation device intended for use with an interbody cage as an adjunct to fusion at a single level in the lumbar spine (L1-S1). It is intended for attachment to the spinous processes for the purpose of achieving stabilization to promote fusion in patients with degenerative disc disease – defined as back pain of discogenic origin with degeneration of the disc confirmed by history and radiographic studies – with up to Grade 1 spondylolisthesis.” Use of an interspinous fixation device for a stand-alone procedure would be considered off-label.

FDA Product code: PEK.

Scope

Medical policies are systematically developed guidelines that serve as a resource for Company staff when determining coverage for specific medical procedures, drugs or devices. Coverage for medical services is subject to the limits and conditions of the member benefit plan. Members and their providers should consult the member benefit booklet or contact a customer service representative to determine whether there are any benefit limitations applicable to this service or supply. This medical policy does not apply to Medicare Advantage.

Benefit Application

N/A

Rationale

This policy was created with a search of the literature through July 2012 and updated periodically using the MEDLINE database. The most recent update was performed though July 28, 2014.

Literature Review

Several studies were identified that evaluated the biomechanics of interspinous fixation devices, but no English language publications were found that evaluated clinical outcomes with use of these devices when used in combination with fusion.

Use of the Aspen interspinous fixation device as a stand-alone interspinous spacer was reported in a prospective series of 6 cases (an additional 32 patients received the X-stop interspinous distraction device, which is addressed in Related Policies). (2) The study population consisted of consecutive patients with a primary diagnosis of lumbar spinal stenosis with pain that was relieved by sitting or lumbar flexion. Of the 6 patients implanted with the Aspen device, 2 (33%) had spinous process fractures observable on computed tomography. Of the entire group of 38 patients, 55% of those with spondylolisthesis (n=20) had a fracture within 6 months of surgery. None of the 18 patients without spondylolisthesis experienced a fracture. In 2013, use of an interspinous fusion plate was reported in a series of 4 patients in conjunction with surgery for recurrent lumbar disc herniation.3

Ongoing and Unpublished Clinical Trials

A search of online site ClinicalTrials.gov in July 2014 found the following ongoing trials:

  • NCT01016314 is an industry-sponsored Phase IV multicenter randomized open-label comparison of the Aspen Spinous Process System versus pedicle screw fixation in patients undergoing lumbar fusion. The study has an estimated enrollment of 156 patients with completion expected December 2015.
  • NCT01019057 is an industry-sponsored study of interlaminar lumbar instrumented fusion (ILIF™) in 77 patients undergoing posterior decompression followed with an allograft spacer, spinous process fixation plate (Affix™), and a biologic. The study was completed in June 2014.

Clinical Input Received from Physician Specialty Societies and Academic Medical Centers

While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.

In response to requests, input was received from 3 physician specialty societies (2 reviewers) and 2 academic medical centers while this policy was under review in 2012. The input was mixed. Some cases where the devices might be medically necessary were noted, such as patients with small pedicles where pedicle screws could not be safely placed.

Summary

Interspinous fixation (fusion) devices are being developed to aid in the stabilization of the spine. They are being evaluated as alternatives to pedicle screw and rod constructs in combination with interbody fusion. Interspinous fixation devices are also being evaluated for stand-alone use in patients with spinal stenosis. There is a lack of evidence on the efficacy of interspinous fixation devices, both for use in combination with interbody fusion and for use as a stand-alone procedure. Randomized controlled trials are needed that evaluate health outcomes following use of interspinous fixation (fusion) devices in comparison with the established standard of pedicle screw-rod fixation. Clinical trials are also needed to evaluate these devices when used alone for decompression. Because of the lack of evidence and the lack of consensus from clinical vetting, interspinous fixation devices are considered investigational.

Practice Guidelines and Position Statements

The North American Spine Society (NASS) issued a coverage position on the use of interspinous devices with lumbar fusion.4 NASS recommends that interspinous fixation with fusion for stabilization is currently not indicated as an alternative to pedicle screw fixation with lumbar fusion procedures.

U.S. Preventive Services Task Force Recommendations

Use of interspinous fixation devices is not a preventive service.

Medicare National Coverage

There is no national coverage determination (NCD). In the absence of an NCD, coverage decisions are left to the discretion of local Medicare carriers.

References

  1. Wu JC, Mummaneni PV. Using lumbar interspinous anchor with transforaminal lumbar interbody fixation. World Neurosurg. May 2010; 73(5):471-472. PMID 20920928
  2. Kim DH, Shanti N, Tantorski ME, et al. Association between degenerative spondylolisthesis and spinous process fracture after interspinous process spacer surgery. Spine J. Jun 2012; 12(6):466-472. PMID 22622239
  3. Oppenheim JS, Mills J. Recurrent lumbar disc herniation treated with interspinous fusion and instrumentation: a case series. Surg Technol Int. Sep 2013;23:269-272. PMID 23686800
  4. North American Spine Society (NASS). NASS coverage policy recommendations: Interspinous fixation with fusion. https://www.spine.org/Documents/PolicyPractice/CoverageRecommendations/InterspinousFixationWithFusion.pdf. Accessed October, 2014.

Coding

Codes

Number

Description

CPT

22840

Posterior non-segmental instrumentation (e.g., Harrington rod technique, pedicle fixation across 1 interspace, atlantoaxial transarticular screw fixation, sublaminar wiring at C1, facet screw fixation)

 

22851

Application of intervertebral biomechanical device(s) (e.g., synthetic cage(s), methylmethacrylate) to vertebral defect or interspace

Appendix

N/A

History

Date

Reason

11/13/12

New policy. Policy created with literature search through July 2012; considered investigational.

01/29/13

Update Related Policies, add 7.01.130.

12/04/13

Replace policy. Policy updated with literature review through July 30, 2013; policy statement unchanged.

11/20/14

Annual Review. Policy updated with literature review through July 28, 2014.References 3-4 added; others renumbered/removed. Policy statement unchanged.


Disclaimer: This medical policy is a guide in evaluating the medical necessity of a particular service or treatment. The Company adopts policies after careful review of published peer-reviewed scientific literature, national guidelines and local standards of practice. Since medical technology is constantly changing, the Company reserves the right to review and update policies as appropriate. Member contracts differ in their benefits. Always consult the member benefit booklet or contact a member service representative to determine coverage for a specific medical service or supply. CPT codes, descriptions and materials are copyrighted by the American Medical Association (AMA).
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