Medical Policy: 07.01.35 

Original Effective Date: January 2007 

Reviewed: October 2020 

Revised: October 2020 



This policy contains information which is clinical in nature. The policy is not medical advice. The information in this policy is used by Wellmark to make determinations whether medical treatment is covered under the terms of a Wellmark member's health benefit plan. Physicians and other health care providers are responsible for medical advice and treatment. If you have specific health care needs, you should consult an appropriate health care professional. If you would like to request an accessible version of this document, please contact customer service at 800-524-9242.


Benefit Application:

Benefit determinations are based on the applicable contract language in effect at the time the services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary based on contract, and individual member benefits must be verified. Wellmark determines medical necessity only if the benefit exists and no contract exclusions are applicable. This medical policy may not apply to FEP. Benefits are determined by the Federal Employee Program.


This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.



Interspinous Distraction Devices (Interspinous Decompression Devices)

Interspinous implants are intended to restrict painful motion while otherwise enabling normal motion. The devices, also known as spacers, distract the spinous processes and restrict extension. Theoretically, this enlarges the neural foramen in patients with spinal stenosis and neurogenic claudication. The spacer is inserted between the spinous processes through a small incision. The supraspinous ligament is maintained and assists in holding the implant in place.


In November 2005, the X-STOP® Interspinous Process Decompression System was approved by the Food and Drug Administration (FDA) for treatment of patients aged 50 or older suffering from neurogenic intermittent claudication secondary to a confirmed diagnosis of lumbar spinal stenosis. It is approved for those who have had a regimen of at least six months of non-operative treatment and who have relief of their pain when in flexion. The device is approved for implantation at one or two lumbar levels in patients whose condition warrants surgery at no more than two levels. The X-STOP® PEEK IPD® System, a modified version of the original X-STOP system, received FDA approval in 2006. Medtronic has discontinued the distribution of the X-Stop system.


The Superion InterSpinous Spacer was FDA approved in 2015 and is an H-shaped implant composed of titanium alloy. Unlike X-Stop, the Superion is delivered percutaneously as a single-piece through a cannula after dilators have opened the interspinous space. The implant has superior and inferior cam lobes that rotate during deployment, so as to capture the superior and inferior spinous processes.


The coflex® Interlaminar Technology implant (Paradigm Spine) was approved by the FDA in 2012 (P110008). It is a single-piece U-shaped titanium alloy dynamic stabilization device with pairs of wings that surround the superior and inferior spinous processes. The coflex® is indicated for use in 1- or 2-level lumbar stenosis from L1-L5 in skeletally mature patients with at least moderate impairment in function, who experience relief in flexion from their symptoms of leg/buttocks/groin pain, with or without back pain, and who have undergone at least 6 months of non-operative treatment. The coflex® is intended to be implanted midline between adjacent lamina of 1 or 2 contiguous lumbar motion segments. Interlaminar stabilization is performed after decompression of stenosis at the affected level(s). The Coflex® device is not to be used accompanying a fusion at the treatment level.


The North American Spine Society

(2011 revised clinical guideline) concluded that “there is insufficient evidence at this time to make a recommendation for or against the placement of an interspinous process spacing device in patients with lumbar spinal stenosis” (Grade of Recommendation I - Insufficient Evidence).


Current evidence is insufficient to permit conclusions about whether any beneficial effect from interspinous process distraction or interlaminar stabilization spacers provides a significant advantage over surgical decompression, which is the current standard of care for surgical treatment of lumbar spinal stenosis. In addition, the complication rates and reoperation rates for these spacers compared with those of decompression surgery is unknown.


Interspinous Fixation Devices

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 withinterbody fusion. Interspinous fixation devices are also being evaluated for stand-alone use in patients with spinal stenosis.


The pedicle is a small area of bone that is the first to extend out from both sides of the back of the vertebral body and joins with broad flat plates of bone (laminae) to form a hollow archway that protects the spinal cord. One type of fixation involves pedicle screws that are inserted as anchors for rods that provide fixation. Another type of fixation is the interbody cage placed in the disc space. Both of these fixation devices support fusion when used with bone graft material.


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. 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. 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.


The following interspinous fixation devices have received clearance to market by the U.S. Food and Drug Administration (FDA):

  • Affix™ (NuVasive)
  • Aileron™ (Life Spine)
  • Aspen™ (Lanx, acquird by BioMet)
  • Axle™ (X-Spine)
  • BacFuse® (Pioneer Surgical)
  • BridgePoint™ (Alphatec)
  • CD Horizen Spire
  • coflex-IF® (Paradigm Spine)
  • Inspan™ (Spine Frontier
  • Interbridge Interspinous Posterior Fixation System (LDR Spine
  • Minuteman™ (Spinal Simplicity)
  • PrimaLOK™ (OsteoMed)
  • Octave™ (Life Spine)
  • Spire™ (Medtronic)
  • SP-Fix™ (Globus)
  • Superion Interspinous Spacer (ISS Veriflex)
  • Zip Mis Interspinous Fusion System


The North American Spine Society

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


The North American Spine Society (NASS; 2018) published specific coverage policy recommendations on the lumbar interspinous device without fusion and with decompression., NASS recommended that: "Stabilization with an interspinous device without fusion in conjunction with laminectomy may be indicated as an alternative to lumbar fusion for degenerative lumbar stenosis with or without low-grade spondylolisthesis (less than or equal to 3 mm of anterolisthesis on a lateral radiograph) with qualifying criteria when appropriate:

  1. Significant mechanical back pain is present (in addition to those symptoms associated with neural compression) that is felt unlikely to improve with decompression alone. Documentation should indicate that this type of back pain is present at rest and/or with movement while standing and does not have characteristics consistent with neurogenic claudication.
  2. A lumbar fusion is indicated post-decompression for a diagnosis of lumbar stenosis with a Grade 1 degenerative spondylolisthesis as recommended in the NASS Coverage Recommendations for Lumbar Fusion.
  3. A lumbar laminectomy is indicated as recommended in the NASS Coverage Recommendations for Lumbar Laminectomy.
  4. Previous lumbar fusion has not been performed at an adjacent segment.
  5. Previous decompression has been performed at the intended operative segment.


Interspinous devices are NOT indicated in cases that do not fall within the above parameters. In particular, they are not indicated in the following scenarios and conditions:

  1. Degenerative spondylolisthesis of Grade 2 or higher.
  2. Degenerative scoliosis or other signs of coronal instability.
  3. Dynamic instability as detected on flexion-extension views demonstrating at least 3 mm of change in translation.
  4. Iatrogenic instability or destabilization of the motion segment.
  5. A fusion is otherwise not indicated for a Grade 1 degenerative spondylolisthesis and stenosis as per the NASS Coverage Recommendations for Lumbar Fusion.
  6. A laminectomy for spinal stenosis is otherwise not indicated as per the NASS Coverage Recommendations for Lumbar Laminectomy."


Prior Approval:

Not applicable



Interspinous Distraction Devices

Interspinous distraction devices (including but not limited to Coflex® Interlaminar Technology Implant/Coflex Intralaminar Stabalization Devices, X-STOP® Interspinous Process Decompression (IPD®) System Vertiflex interspinous decompresseion spacer/Superion InterSpinous Spacer) are considered investigational.


There is insufficient evidence in the peer-reviewed medical literature to demonstrate the long-term safety and efficacy of interspinous distraction devices and the durability of the devices. The impact of this technology on net health outcome is not known. There is a need for longer-term outcome data on symptom relief, the need for repeat procedures, and implant survival.


Interspinous Fixation Devices

Interspinous fixation devices (including but not limited to: Affix™, Axle™, BacFuse®, Coflex-F®, Inspan™, Screwless Fusion Devise, Spire™, Lanx® SFS, TOPS™ (Total Posterior – element System) Spinal System) 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 and or spondylolisthesis


These procedures allow for a period of relief before the canal has to be opened and can delay the day when a more invasive operation is needed. It does not prevent the procedures from being needed later. It is the longer term performance which remains the principle unanswered question. 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. There is a need for longer term (>2 years) outcome data on the durability of symptom relief, the need for repeat procedures, and implant survival.


Procedure Codes and Billing Guidelines:

To report provider services, use appropriate CPT* codes, Modifiers, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or diagnosis codes.

  • C1821 Interspinous process distraction device (implantable)
  • 22859 Insertion of intervertebral biomechanical device(s) (eg, synthetic cage, mesh, methylmethacrylate) to intervertebral disc space or vertebral body defect without interbody arthrodesis, each contiguous defect (List separately in addition to code for primary procedure)
  • 22867 Insertion of interlaminar/interspinous process stabilization/distraction device, without fusion, including image guidance when performed, with open decompression, lumbar; single level
  • 22868 Insertion of interlaminar/interspinous process stabilization/distraction device, without fusion, including image guidance when performed, with open decompression, lumbar; second level (List separately in addition to code for primary procedure)
  • 22869 Insertion of interlaminar/interspinous process stabilization/distraction device, without open decompression or fusion, including image guidance when performed, lumbar; single level
  • 22870 Insertion of interlaminar/interspinous process stabilization/distraction device, without open decompression or fusion, including image guidance when performed, lumbar; second level (List separately in addition to code for primary procedure)
  • 22899 Unlisted procedure, spine [when specified as insertion of a non-pedicle interspinous process fixation device]


Selected References:

  • Zucherman JR, Hsu KY, Hartjen CA et al. A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermittent claudication: two-year follow-up results. Spine. 2005;30(12):1351-8.
  • Talwar V, Lindsey DP, Fredrick A et al. Insertion loads of the X STOP interspinous process distraction system designed to treat neurogenic intermittent claudication. Eur Spine J. 2005 May 31.
  • Sengupta DK. Dynamic stabilization devices in the treatment of lower back pain. Orthop Clin North Am. 2004 Jan; 35(1):43-56.
  • Lee J, Hida K, Seki T et al. An interspinous process distractor (X STOP) for lumbar spinal stenosis in elderly patients: preliminary experiences in 10 consecutive cases. J Spinal Disord Tech. 2004 Feb; 17(1):72-7.
  • Richards JC, Majumdar S, Lindsey DP et al. The treatment mechanism os an interspinous process implant for lumbar neurogenic intermittent claudication. Spine. 2005;30(7): 744-49.
  • Kondrashov DG, Hannibal M, Hsu KY et al. Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: a 4-year follow-up study. J Spinal Disord Tech. 2006 Jul;19(5):323-7.
  • AndersonPA, Tribus CB, Kitchel SH. Treatment of neurogenic claudication by interspinous decompression: application of the X STOP device in patients with lumbar degenerative spondylolisthesis. J Neurosurg Spine. 2006 Jun;4(6):463-71.
  • National Institute for Health and Clinical Excellence (NICE). Interventional procedure overview of interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine. London, UK: NICE; 2005 Nov.
  • North American Spine Society Evidence-based clinical guidelines for multidisciplinary spine care: Diagnosis and treatment of degenerative lumbar spinal stenosis. January 2007
  • Verhoof OJ, Bron JL, Wapstra FH, van Royen BJ. High failure rate of the interspinous distraction device (X-STOP) for the treatment of lumbar spinal stenosis caused by degenerative spondylolisthesis. Eur Spine J, 2008 Feb;17(2):188-92.
  • ECRI. Interspinous Process Decompression to Treat Spinal Stenosis. Plymouth Meeting (PA): ECRI Health Technology Information Service 2007 August 14. (ECRI Hotline Response)
  • ECRI Institute. Interspinous process decompression to treat spinal stenosis. Plymouth Meeting (PA): ECRI Health Technology Information Service 2009 Oct. 7. 11 p. [ECRI hotline response].
  • ECRI Institute. Interspinous process decompression to treat spinal stenosis. Plymouth Meeting (PA): ECRI Health Technology Information Service 2011 Mar 17 p. 11 [ECRI hotline response].
  • North American Spine Society (NASS). Diagnosis and treatment of degenerative lumbar spinal stenosis. Burr Ridge, IL: North American Spine Society (NASS); December 2011.
  • Kim DH, Tantorski M, Shaw J, et al. Occult spinous process fractures associated with interspinous process spacers. Spine (Phila Pa 1976). 2011;36(16):E1080-E1085.
  • Davis R, Auerbach D, et al. Can low grade spondylolisthesis be effectively treated by either coflex interlaminar stabilization or laminectomy and posterior spinal fusion? J Neurosurg: Spine May 31, 2013.]
  • North American Spine Society. Interspinous device without fusion 2014.
  • Sclafani JA, Liang K, Ohnmeiss DD, Gordon C. Clinical outcomes of a polyaxial interspinous fusion system. Int J Spine Surg. 2014; 8. Kim DH, Shanti N, Tantorski ME, et al. Association between degenerative spondylolisthesis and spinous process fracture after interspinous process spacer surgery. Spine J. 2012a; 12(6):466-472.
  • North American Spine Society (NASS). NASS Coverage Policy Recommendations. Interspinous fixation with fusion May 2014.
  • Roberto Gazzeri, Marcelo Galarza, and Alex Alfieri, “Controversies about Interspinous Process Devices in the Treatment of Degenerative Lumbar Spine Diseases: Past, Present, and Future,” BioMed Research International, vol. 2014, Article ID 975052, 15 pages, 2014. doi:10.1155/2014/975052
  • Vokshoor A, Khurana S, Wilson D, et al. Clinical and radiographic outcomes after spinous process fixation and posterior fusion in an elderly cohort. Surg Technol Int. Nov 2014; 25:271-276. PMID 25433267
  • Patel VV, Nunley PD, Whang PG, et al. Superion((R)) InterSpinous Spacer for treatment of moderate degenerative lumbar spinal stenosis: durable three-year results of a randomized controlled trial. J Pain Res. 2015;8:657-662. PMID 26491369.
  • Roder C, Baumgartner B, Berlemann U, et al. Superior outcomes of decompression with an interlaminar dynamic device versus decompression alone in patients with lumbar spinal stenosis and back pain: a cross registry study. Eur Spine J. Oct 2015;24(10):2228-2235. PMID 26187621.
  • Musacchio MJ, Lauryssen C, Davis RJ, et al. Evaluation of decompression and interlaminar stabilization compared with decompression and fusion for the treatment of lumbar spinal stenosis: 5-year follow-up of a prospective, randomized, controlled trial. Int J Spine Surg. 2016;10:6. PMID 26913226
  • Yuan et al. Evaluation of Coflex interspinous stabilization following decompression compared with decompression and posterior lumbar interbody fusion for the treatment of lumbar degenerative disease: A minimum 5-year follow-up study. Journal of Clinical Neuroscience 2017:35 24-29.
  • Forsth P, Olafsson G, Carlsson T, et al. A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med. Apr 14 2016;374(15):1413-1423. PMID 27074066
  • Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. Apr 14 2016;374(15):1424-1434. PMID 27074067
  • Phan, K., Rao, P. J., Ball, J. R., & Mobbs, R. J. (2016). Interspinous process spacers versus traditional decompression for lumbar spinal stenosis: systematic review and meta-analysis. Journal of Spine Surgery, 2 (1), 31-40.
  • Bae HW, Davis RJ, Lauryssen C, Leary S, Maislin G, Musacchio MJ., Jr Three-year follow-up of the prospective, randomized, controlled trial of coflex interlaminar stabilization vs instrumented fusion in patients with lumbar stenosis. Neurosurgery. 2016;79(2):169–181. doi: 10.1227/NEU.0000000000001237.
  • U.S. Food and Drug Administration. Superion InterSpinous Spacer. 2015.
  • Machado GC, Ferreira PH, Yoo RI, Harris IA, Pinheiro MB, Koes BW, et al. Surgical options for lumbar spinal stenosis. Cochrane Database Syst Rev. 2016 Nov 1;11:CD012421. 
  • Schmidt S, Franke J, Rauschmann M, Adelt D, Bonsanto MM, Sola S. Prospective, randomized, multicenter study with 2-year follow-up to compare the performance of decompression with and without interlaminar stabilization. Journal of neurosurgery Spine. 2018:1-10.
  • North American Spine Society. NASS Coverage Policy Recommendations: Lumbar interspinous device without fusion & with decompression. Burr Ridge, IL: NASS; 2018. 
  • Nunley, PP, Patel, VV, Orndorff, DD, Lavelle, WW, Block, JJ, Geisler, FF. Interspinous Process Decompression Improves Quality of Life in Patients with Lumbar Spinal Stenosis. Minim Invasive Surg, 2018 Jul 31;2018:1035954. PMID 30057811.
  • Inose H, Kato T, Yuasa M, et al. Comparison of decompression, decompression plus fusion, and decompression plus stabilization for degenerative spondylolisthesis: a prospective, randomized study. Clin Spine Surg. Aug 2018;31(7):E347-E352. PMID 29877872.
  • Dijkerman ML, Overdevest GM, Moojen WA, et al. Decompression with or without concomitant fusion in lumbar stenosis due to degenerative spondylolisthesis: a systematic review. Eur Spine J. Jul 2018;27(7):1629-1643. PMID 29404693.
  • North American Spine Society (NASS). NASS coverage policy recommendations: Interspinous fixation with fusion (Draft for comment only). 2019;


Policy History:

  • October 2020 - Interim Review, Policy Revised
  • February 2020 - Annual Review, Policy Renewed
  • February 2019 - Annual Review, Policy Revised
  • February 2018 - Annual Review, Policy Renewed
  • February 2017 - Annual Review, Policy Revised
  • February 2016 - Annual Review, Policy Revised
  • March 2015 - Annual Review, Policy Renewed
  • April 2014  - Annual Review, Policy Renewed
  • May 2013  - Annual Review, Policy Renewed
  • May 2012  - Annual Review, Policy Renewed
  • June 2011  - Annual Review, Policy Renewed

Wellmark medical policies address the complex issue of technology assessment of new and emerging treatments, devices, drugs, etc.   They are developed to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. Wellmark medical policies contain only a partial, general description of plan or program benefits and do not constitute a contract. Wellmark does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Wellmark or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. Our medical policies may be updated and therefore are subject to change without notice.


*CPT® is a registered trademark of the American Medical Association.