Medical Policy



Subject: Intervertebral Stabilization Devices
Document #: SURG.00075 Current Effective Date:    06/28/2017
Status: Reviewed Last Review Date:    05/04/2017

Description/Scope

This document addresses the use of flexible intervertebral stabilization devices as an adjunct to spinal fusion procedures to provide immobilization and stabilization of spinal segments. Such devices are designed to allow some degree of spinal flexibility following spinal fusion surgery.

Note: This document does NOT address the use of rigid spinal fixation devices or instrumentation.

Note: Please see the following for additional information regarding devices used for spinal surgery:

Position Statement

Investigational and Not Medically Necessary:

Use of intervertebral stabilization devices is considered investigational and not medically necessary for all indications.

Rationale

The use of dynamic stabilization devices has been proposed as an alternative to rigid stabilization devices. The goal of such devices is to allow some degree of spinal flexibility following spinal fusion procedures. There are currently several dynamic stabilization devices that have received United States (U.S.) Food and Drug Administration (FDA) 510(k) clearance, including the Dynesys® System (Zimmer Inc., Minneapolis MN), the BioFlex® (BioSpine Co., Ltd, Sungdong-gu, Seoul Korea), the DSSTM Dynamic Soft Stabilization System (Paradigm Spine, LLC, New York, NY) and the Isobar ™ Spinal System (Alphatec Spine, Inc. Carlsbad, CA).

Isobar Spinal System

Fu and colleagues (2014) conducted a study to evaluate the functional and radiological outcomes of dynamic stabilization in conjunction with spinal fusion. Prospective follow-up was conducted for 24 months on 36 participants who underwent posterior Isobar dynamic stabilization for single-level degenerative lumbar disc disease with instability (DLDI) and mild adjacent level degeneration. The authors assessed participant status with the collection of functional [visual analog scale (VAS) and Oswestry Disability Index (ODI)] and radiological data (resting, functional X-rays and MRI). At 24 months, functional outcomes demonstrated significant improvement in mean VAS score by 38.9 points (p<0.01) and ODI by 22.4 points (p<0.01). The disc height at the index and adjacent levels and intervertebral angle (IVA) at the index level showed a slight decreasing trend at each follow-up (p>0.05), while IVA at the adjacent level showed a slight increasing trend (p>0.05). Range of motion at the index level averaged 2.84° and remained unchanged at the adjacent level (p>0.05). With regard to adverse events, there were no reoperations, loosening of screws or infection reported. Two participants experienced a dural tear during the surgery and were given immediate repair. The authors concluded that individuals with single-level DLDI and mild adjacent level degeneration treated with Isobar semi-rigid stabilization demonstrated a significant improvement in functional scores 2 years postoperatively. However, disc degeneration at the adjacent and index levels appears to continue despite using semi-rigid dynamic stabilization. The authors stated that additional long-term follow-up is ongoing to provide more extensive information.

Dynesys Dynamic Stabilization Spinal System

Putzier (2005) looked at the effect of dynamic stabilization on the progression of vertebral segment degeneration after nucleotomy of the lumbar spine for symptomatic disc prolapse. A total of 84 participants were studied and dynamic stabilization with the Dynesys system was performed in 35 participants. Follow-up included MRI and subjective evaluation using Oswestry and VAS pain scores at 3 months and again at final follow-up (mean duration of follow-up of 34 months). Oswestry score and VAS improved significantly in both groups to the same degree at 3 months. At the end of follow-up, VAS pain scores worsened for the control group (p<0.05), but not for the group with dynamic stabilization. In the dynamically stabilized group, no progression of disc degeneration was seen at follow-up; while radiologic signs of segmental degeneration were seen in the participants not provided dynamic stabilization post nucleotomy. Although the authors concluded that the Dynesys system is useful to prevent progression of degenerative disc disease following nucleotomy, this study was non-randomized and the treatment group was retrospectively compared with participants treated only with nucleotomy before the availability of the Dynesys system.

Grob (2005) reported the results of a retrospective case series study of outcomes after implantation of the Dynesys Spinal System. A total of 50 consecutive individuals instrumented with Dynesys over the preceding 40 months were asked to complete a personal follow-up questionnaire. Thirty one individuals responded with at least 2 years of follow-up. Primary indication for surgery was degenerative disease (disc/stenosis) with "instability." In 68% of the individuals, more than one level was instrumented. Within the 2-year follow-up period, 19% required further surgical intervention. Back pain was reported improved (67%) and leg symptoms were improved (64%) or worsened (14%). Forty percent (40%) improved in their ability to do physical activities/sports while 27% worsened. Overall quality of life was 50% improved, 13% worsened. When asked how much the operation helped, 29% reported helped a lot and 35% reported didn't help at all. Pre-operative VAS pain intensity scores could not be compared with scores at follow-up due to methodological differences. Six of 31 participants either required reintervention in the 2-year follow-up period or were undergoing evaluation for re-operation in the near future. The investigators concluded that both back and leg pain are, on average, moderately high 2 years after instrumentation with the Dynesys system and that overall results were poorer than those for historic controls undergoing fusion for similar indications at their center. The investigators felt there is insufficient evidence to suggest that semi-rigid fixation of the lumbar spine results in better outcomes than lumbar fusion.

Schnake and colleagues (2006) reported on a small prospective case series study consisting of 26 participants (mean age 71 years) with lumbar spinal stenosis and degenerative spondylolisthesis. Participants underwent decompression and dynamic stabilization with the Dynesys system. The reported minimum follow-up was 2 years. The authors reported significant improvements in leg pain and mean walking distance. However, a significant number of participants (21%) reported continuing claudication. No significant progression of spondylolisthesis was detected, but an implant failure rate of 17% was reported. The authors concluded that results with the Dynesys device were comparable to clinical results seen with standard fusion techniques. They did acknowledge that the study is limited by a small number of participants, short follow-up, and lack of randomized controls.

Welch and colleagues (2007) published the results of the preliminary clinical outcomes using the Dynesys system as part of a multicenter randomized prospective U.S. Food and Drug Administration (FDA) investigational device exemption (IDE) clinical trial. The study included a total of 101 participants (53 women and 48 men) from six IDE sites who underwent dynamic stabilization with the Dynesys system. The inclusion criteria required the participants to have degenerative spondylolisthesis or retrolisthesis (Grade I), central or lateral spinal stenosis, and their physician's determination that the participant required decompression and instrumented fusion for one or two contiguous spinal levels between L-1 and S-1. The authors reported significant improvement in mean pain and function scores from the baseline to 12-month follow-up evaluation. The authors concluded that early clinical outcomes of treatment with the Dynesys system are promising; the value of this study is limited by the lack of randomized controls and only a 12 month follow-up which is inadequate to judge safety and long-term durable outcome of the Dynesys system.

Schaeren (2008) reported a 4-year follow-up study of 19 consecutive participants (mean age, 71 years) with symptomatic lumbar spinal stenosis and degenerative spondylolisthesis who underwent interlaminar decompression and stabilization with Dynesys. Participants were evaluated clinically and radiologically after a minimum follow-up of 4 years. Pain on VAS and walking distance improved significantly (p<0.001) at 2 years and remained unchanged at 4 years follow-up. Radiographically, spondylolisthesis did not progress and the motion segments remained stable, even in 3 participants who showed slight screw loosening at 2 and 4 year follow-up. One individual showed screw breakage with low back pain and motion at the instrumented level in flexion/extension views. At 4 years follow-up, 47% of the participants showed some degeneration at adjacent levels. This study showed that the degenerative disease is still progressive and degeneration at adjacent motion segments remains a problem.

In another study, Würgler-Hauri (2008) reported the outcomes, radiologic findings, and complications in 37 consecutive participants (mean age 58 years) with acquired lumbar stenosis, signs of segmental instability and degenerative disc disease. Lumbar and radicular pain was present in 33 participants (92%). The participants underwent lumbar microsurgical decompression and implantation of Dynesys. One participant was lost to follow-up. Clinical evaluation included visual analogue scale (leg and back), distribution and severity of pain (%), Prolo Functional and Economic Status, Stauffer Coventry Scale, self-evaluation and radiologic assessment preoperative and postoperative at 3 and 12 months. Leg and back pain (visual analogue scale) improved at 12 months from 8.4 ± 2.1 to 3.1 ± 1.4 and from 6.7 ± 2.8 to 4 ± 2.8, respectively. Overall pain severity improved due to reduction of radicular pain from 59.2% to 27.3% after microsurgical decompression. Lumbar pain deteriorated from 40.8% to 47.8%. Twenty seven percent of the self-evaluations and 29.7% (Stauffer Coventry Scale) of the participants described a fair or poor outcome. Complications included 4 broken and 2 misplaced screws from a total of 224 screws implanted, 2 loosened systems, and 1 cerebrospinal fistula. At 1 year, a total of 7 participants (19%) required surgical revision. The authors concluded that the biomechanical principles of Dynesys do not reflect advantages in outcome compared with none or other stabilization systems.

Kabir and colleagues (2010) performed a systematic review for clinical and biomechanical evidence for the efficacy of lumbar interspinous spacers (ISP) that included dynamic stabilization. The main outcome measure was clinical outcome assessment that was based upon participant questionnaire responses. Biomechanical analysis included the effects of ISP devices on the kinematics of the spine. Selected studies were subject to an analysis of their methodology. The authors concluded that lumbar ISPs may have a potential beneficial effect in a select group of individuals with lumbar degenerative disease. However, further good quality trials are needed to clearly outline the indications for their use.

Pham and colleagues (2016) conducted a review of the literature to explore complications associated with the Dynesys stabilization system. The researchers evaluated 21 studies which included a total of 1166 subjects with a mean age of 55.5 years and a mean follow-up period of 33.7 months. The data demonstrated a surgical-site infection rate of 4.3%, a pedicle screw loosening rate of 11.7%, a pedicle screw fracture rate of 1.6%, and an adjacent-segment disease (ASD) rate of 7.0%. Of studies reporting surgical revision rates, 11.3% of subjects required reoperation. Of subjects who developed ASD, 40.6% required a reoperation for treatment. The authors concluded that the Dynesys stabilization system has a similar complication rate compared with lumbar fusion studies and has a slightly lower incidence of ASD.

The Dynesys' FDA labeling indicates that the use of the device is "to provide stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of chronic instabilities or deformities of the thoracic, lumbar, and sacral spine." Indications include degenerative spondylolisthesis with objective neurologic impairment, kyphosis, and failed previous fusion (pseudoarthrosis). Although this device has been in clinical use for several years, there is insufficient evidence that the use of this device results in improved health outcomes compared to standard treatments. It is not possible to establish a health outcome benefit for this device due to insufficient data from prospective, randomized controlled clinical trials for the FDA approved indications.

The Dynesys Spinal System has also been proposed for immobilization and stabilization of spinal segments without a spinal fusion procedure and is part of a Phase III clinical trial. The FDA has not approved this application.

Regulatory Information

The currently available dynamic stabilization devices have all received clearance from the FDA through their 510(k) review process. This process does not involve or require extensive review of clinical trial data demonstrating the safety and efficacy of the device under review. In order to qualify for a 510(k) clearance, a manufacturer need only prove that their device is similar in function to a predicate device previously cleared or approved by the FDA. Thus, many devices cleared under this process have not yet been proven to be safe and effective based on the merits of data prospectively collected from clinical trials of the devices in question.

In October 2009, the FDA announced that post market surveillance studies are required from all manufacturers of dynamic stabilization systems to report the following:

In reviewing the clinical data gathered from the post market surveillance studies, the FDA will consider whether labeling changes or additional preclinical and clinical testing requirements are necessary.

Background/Overview

Spondylolisthesis is a condition in which a back bone (vertebra) slips forward on the vertebra below it. In adults, the most common cause is degenerative arthritis involving the fourth and fifth lumbar vertebrae. Other causes of spondylolisthesis include, but are not limited to, spinal fracture, and bone disease. Symptoms may include lower back pain and pain in the thighs and buttocks, stiffness, muscle tightness, and spinal tenderness. Neurologic damage (leg weakness or sensory changes) may result from pressure on nerve roots and may cause pain radiating down the legs.

Treatment varies depending on the severity of the spondylolisthesis. Most individuals require only strengthening and stretching exercises combined with activity modification (avoiding hyperextension of the back and contact sports). Some practitioners may also use a rigid brace.

For cases with severe pain not responding to therapy, if the slip is severe, or there are neurologic changes (loss of feeling in the legs, etc.), the slipping vertebra might be surgically fused to adjacent vertebrae to prevent further slippage and provide relief of symptoms.

Fusion procedures involve placement of a bone graft or equivalent substance into the joint space after removal of the intervertebral disc as well as attachment of a rigid metal frame to adjacent vertebral bodies. The frame is used to hold the joint in place while the joint space fuses over time. As a result of fusion surgery, there is a subsequent loss of mobility where the intervertebral joint once was. This loss of mobility has been associated with increased loading on adjacent joints and potential complications related to failure of those joints.

In an attempt to overcome the disadvantages of rigid instrumentation and improve the outcome of spinal fusion surgery, dynamic stabilization devices have been proposed as an alternative to the use of standard rigid frames. Like standard frame devices, these devices are fixed in place using pedicle screws which are attached to the vertebral bodies adjacent to the intervertebral space being fused. Unlike standard frames, these devices are designed using flexible materials which purport to stabilize the joint while still providing some measure of flexibility.

Coding

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.  

When services are Investigational and Not Medically Necessary:
When the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

CPT  
22899 Unlisted procedure, spine [when specified as insertion of a dynamic intervertebral pedicle-based stabilization device]
   
ICD-10 Procedure  
0RH00CZ-0RH04CZ Insertion of pedicle-based spinal stabilization device into occipital-cervical joint [by approach; includes codes 0RH00CZ, 0RH03CZ, 0RH04CZ]
0RH10CZ-0RH14CZ Insertion of pedicle-based spinal stabilization device into cervical vertebral joint [by approach; includes codes 0RH10CZ, 0RH13CZ, 0RH14CZ]
0RH40CZ-0RH44CZ Insertion of pedicle-based spinal stabilization device into cervicothoracic vertebral joint [by approach; includes codes 0RH40CZ, 0RH43CZ, 0RH44CZ]
0RH60CZ-0RH64CZ Insertion of pedicle-based spinal stabilization device into thoracic vertebral joint [by approach; includes codes 0RH60CZ, 0RH63CZ, 0RH64CZ]
0RHA0CZ-0RHA4CZ Insertion of pedicle-based spinal stabilization device into thoracolumbar vertebral joint [by approach; includes codes 0RHA0CZ, 0RHA3CZ, 0RHA4CZ]
0SH00CZ-0SH04CZ Insertion of pedicle-based spinal stabilization device into lumbar vertebral joint [by approach; includes codes 0SH00CZ, 0SH03CZ, 0SH04CZ]
0SH30CZ-0SH34CZ Insertion of pedicle-based spinal stabilization device into lumbosacral joint [by approach; includes codes 0SH30CZ, 0SH33CZ, 0SH34CZ]
   
ICD-10 Diagnosis  
  All diagnoses
   
References

Peer Reviewed Publications:

  1. Fu L, France A, Xie Y, et al. Functional and radiological outcomes of semi-rigid dynamic lumbar stabilization adjacent to single-level fusion after 2 years. Arch Orthop Trauma Surg. 2014; 134(5):605-610.
  2. Grob D, Benini A, Junge A, Mannion AF. Clinical experience with the Dynesys semirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years. Spine. 2005; 30(3):324-331.
  3. Kabir SM, Gupta SR, Casey AT. Lumbar interspinous spacers: a systematic review of clinical and biomechanical evidence. Spine (Phila Pa 1976). 2010; 35(25):E1499-1506.
  4. Maida G, Altruda C, Gatti M, et al. Two-year follow-up after microsurgical discectomy and dynamic percutaneous stabilization in degenerate and herniated lumbar disc: clinical and neuroradiological outcome. J Neurosurg Sci. 2014; 58(2):95-102.
  5. Pham M, Mehta V, Patel N, et.al. Complications associated with the Dynesys dynamic stabilization system: a comprehensive review of the literature. Neurosurg Focus. 2016: 40(1):E2.
  6. Putzier M, Schneider SV, Funk JF, et al. The surgical treatment of the lumbar disc prolapse: nucleotomy with additional transpedicular dynamic stabilization versus nucleotomy alone. Spine. 2005; 30(5):E109-114.
  7. Schaeren S, Broger I, Jeanneret B. Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization. Spine. 2008; 33(18):E636-642.
  8. Schnake KJ, Schaeren S, Jeanneret B. Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis. Spine. 2006; 31(4):442-449.
  9. Welch WC, Cheng BC, Awad TE, et al. Clinical outcomes of the Dynesys dynamic neutralization system: 1-year preliminary results. Neurosurg Focus. 2007 15; 22(1):E8.
  10. Würgler-Hauri CC, Kalbarczyk A, Wiesli M, et al. Dynamic neutralization of the lumbar spine after microsurgical decompression in acquired lumbar spinal stenosis and segmental instability. Spine. 2008; 33(3):E66-72.

Government Agency, Medical Society, and Other Authoritative Publications: 

  1. U.S. Food and Drug Administration News and Events. FDA Orders Postmarket Surveillance Studies on Certain Spinal Systems. FDA to request premarket clinical data for new versions of these devices. October 2009. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2009/ucm185312.htm. Accessed on March 14, 2017.
  2. U.S. Food and Drug Administration 510(k) Premarket Notification Database.
Websites for Additional Information
  1. National Library of Medicine. Medical Encyclopedia: Spondylolisthesis. Updated 03/09/2017. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/001260.htm. Accessed March 14, 2017.
Index

BioFlex System
DSS Dynamic Soft Stabilization System
Dynamic Stabilization
Dynesys Spinal System
Isobar Spinal System
Spondylolisthesis

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.

Document History
Status Date Action
Reviewed 05/04/2017 Medical Policy & Technology Assessment Committee (MPTAC) review. Updated Index, Rationale, References, and Websites sections.
Reviewed 05/05/2016 MPTAC review. Updated Description, Rationale and References sections. Removed ICD-9 codes from Coding section.
Reviewed 05/07/2015 MPTAC review. Updated Description, Rationale and References sections.
Reviewed 05/15/2014 MPTAC review. No change to the position statement. Updated Description, Rationale, Background/Overview and References sections.
Reviewed 05/09/2013 MPTAC review. Updated references.
Reviewed 05/10/2012 MPTAC review. Rationale and References updated.
Reviewed 05/19/2011 MPTAC review. Stabilmax NZ® Dynamic Spine Stabilization System removed from Rationale due to termination of the IDE trial. References updated.
Reviewed 05/13/2010 MPTAC review. Description, Rationale and References updated.
Revised 05/21/2009 MPTAC review. SATELLITE™ Spinal System information removed. Title and position statement revised. Rationale and references updated.
Reviewed 05/15/2008 MPTAC review. Updated review date, references and history sections.
  02/21/2008 The phrase "investigational/not medically necessary" was clarified to read "investigational and not medically necessary." This change was approved at the November 29, 2007 MPTAC meeting.
  10/01/2007 Updated Coding section with 10/01/2007 ICD-9 changes.
Revised 05/17/2007 MPTAC review. Changed title to "Intervertebral Stabilization Devices (Dynesys® Spinal System, SATELLITE™ Spinal System.)" SATELLITE™ Spinal System added as investigational/not medically necessary.
Reviewed 09/14/2006 MPTAC review. No change to position.
New 09/22/2005 MPTAC initial document development.