Currentblue cross blue shield - south dakotaPolicy N/A

Interlaminar Stabilization/Distraction Devices (Spacers) and Interspinous Fixation (Fusion) Devices

Policy governing coverage and evidentiary assessment of interlaminar stabilization/distraction (spacers), interspinous distraction devices, and interspinous fixation (fusion) devices for lumbar spinal stenosis and related indications for Wellmark (Blue Cross Blue Shield - South Dakota) members.

Policy Summary

Payerblue cross blue shield - south dakota

PolicyInterlaminar Stabilization/Distraction Devices (Spacers) and Interspinous Fixation (Fusion) Devices

Policy CodePolicy N/A

Change TypeAnnual review — no material changes

Effective DateJan 1, 2007

Next Review Date

Key ActionWhen seeking authorization, provide imaging confirmation, documentation of prior conservative therapy, baseline/outcome scores (eg, ODI), device intended, and plan for ≥2-year follow-up.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

investigationalDistraction devices stance

investigationalStabilization devices stance

investigationalFixation devices stance

200,000+U.S. affected (approx.)

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2 yearsMinimum follow-up

Coverage Criteria and Evidence Summary

Investigational / Not Covered

Distraction devices: Interspinous or interlaminar distraction devices are considered investigational for all indications, including as a stand‑alone procedure for treatment of spinal stenosis.

Evidence insufficient to determine improvement in net health outcomes.

Stabilization devices: Interspinous stabilization devices are considered investigational for all indications, including use following decompression surgery.

Evidence insufficient to determine improvement in net health outcomes.

Fixation devices: Interspinous fixation (fusion) devices are considered investigational for any indication, including use in combination with interbody fusion or alone for decompression in individuals with spinal stenosis.

See Regulatory Status for representative products.

Coverage for interspinous/interlaminar spacers — Covered when ALL of the following are met (per device labeling and clinical context)

Covered when ALL of the following are met (per device labeling and clinical context):

Population: Patient has lumbar spinal stenosis with functional impairment consistent with device indications; some devices allow up to Grade 1 spondylolisthesis as specified by labeling.see device-specific labeling

PICO population: spinal stenosis with no or Grade 1 spondylolisthesis.

Prior nonoperative care: Patient has undergone an adequate course of conservative (nonoperative) treatment unless medically unsuitable; many device labels require ≥6 months prior nonoperative therapy.>= 6 months when required by device labeling

Device labeling (eg, Superion, coflex) specifies prior nonoperative treatment durations.

Imaging confirmation: Radiographic imaging (x‑ray, MRI and/or CT) documents central canal, lateral recess, or foraminal narrowing and, where applicable, features such as thickened ligamentum flavum.

Coverage for interspinous fixation devices — Coverage for interspinous fixation devices (adjunct to fusion)

Coverage for interspinous fixation devices (adjunct to fusion):

Adjunct use: Interspinous fixation devices are covered only when used as an adjunct to interbody fusion per device indications; use as stand‑alone fixation is off‑label.use with interbody cage/fusion construct

Device labeling (eg, coflex‑IF) indicates adjunctive use with interbody fusion.

Indication match: Clinical indication and patient selection match device labeling (eg, degenerative disc disease or specified diagnoses with up to Grade 1 spondylolisthesis where indicated) and device is applied at appropriate spinal level(s).per labeling

Attach imaging and clinical documentation to demonstrate indication match.

Evidence synthesis — Evidence summary

Evidence summary nodes (do not represent an explicit policy approval or denial but capture criteria-relevant findings):

Systematic review findings: Pooled RCT data (Xin et al. 2023; N=852) showed shorter operative time for ISD but a significantly higher reoperation rate after ISD compared with decompression (OR 3.21; 95% CI 1.91–5.40); pain and ODI outcomes were not significantly different and ZCQ physical function favored decompression (mean difference −0.27).

Heterogeneity due to inclusion of X‑STOP and non‑FDA devices noted.

Pivotal randomized trials: Pivotal Superion vs X‑STOP trial met its 2‑year noninferiority endpoint but had high withdrawal for secondary intervention (28%); spinous process fractures were reported more often with Superion (16.4% vs 8.5%); long‑term reporting was incomplete.

Trial interpretation limited by withdrawals, comparator efficacy uncertainty, and incomplete long‑term reporting.

Observational/claims findings: Claims‑based observational analyses reported lower subsequent surgical intervention rates after some ISD procedures versus open surgery comparators, but these analyses lack clinical severity and patient‑reported outcome data and are subject to confounding.

Covered when ALL criteria met

Coverage may be considered when ALL of the following apply:

Indication: Severe or symptomatic lumbar spinal stenosis with functional impairment, with no spondylolisthesis greater than Grade 1 (unless device labeling specifies otherwise).

Population of interest per PICO and device labeling.

Prior therapy: Failure of an adequate course of conservative management prior to implantation (unless medically contraindicated); device labeling commonly specifies a trial of nonoperative care.

Conservative therapy requirement reflected in device labels and trial inclusion criteria.

Device use context: Interlaminar spacers are used as an adjunct to decompression; interspinous spacers may be used as standalone or with decompression depending on device labeling and supporting evidence.

Use must be consistent with FDA label and trial contexts.

Not supported or higher risk circumstances

Considered not supported or higher-risk when ANY of the following apply:

Higher reoperation risk: Use as a standalone alternative to decompression when randomized trials show increased reoperation rates (for example, higher reoperation with coflex in some trials) without clear improvement in validated pain or function outcomes.

FELIX and other trials reported higher reoperation rates with some implants.

Insufficient comparative data: When trial evidence lacks an appropriate decompression control or uses a comparator of uncertain net benefit, making interpretation of device benefit unclear.

Comparator uncertainty limits interpretation (eg, noninferiority trials vs fusion where fusion benefit is contested).

Incomplete or biased follow‑up reporting: When outcome reporting is based on a small fraction of the randomized cohort or has high withdrawal/censoring for secondary interventions, limiting reliability of reported success rates.

Superion trial follow‑up and reporting limitations exemplify this concern.

Evidence and coverage-relevant findings

Evidence summary and implications from randomized trials:

Coflex vs fusion (Davis et al): An open‑label noninferiority RCT compared decompression+coflex versus decompression+posterolateral fusion; noninferiority conclusions are limited by uncertainty about the comparator's net benefit and by fusion nonunion rates noted in trials.

Noninferiority framework depends on comparator assumptions; subgroup analyses reported but have limitations.

Coflex vs decompression alone (Schmidt et al): An RCT showed higher composite clinical success at 24 months for decompression+coflex versus decompression alone (58.4% vs 41.7%; p=0.017), largely driven by fewer postoperative injections in the coflex arm; individual outcome measures were not consistently different and open‑label design may introduce bias.

Inclusion of injections in composite endpoint and lack of blinding are sources of potential bias.

Safety considerations: Reported device harms include spinous process fractures (up to ~18% in some trials) and conversions to fusion in a subset of cases; operative time and blood loss may be lower with some implants but long‑term registry data are limited.

Medical necessity criteria for device placement

Covered when ALL of the following are met

Population: Patient has symptomatic lumbar spinal stenosis without spondylolisthesis greater than Grade 1 or without dynamic instability (unless device labeling specifies otherwise), and symptoms have not responded to conservative treatment.

Population definition aligned with trial selection criteria and device labeling.

Intervention: Interlaminar spacer is implanted as an adjunct to spinal decompression (eg, coflex) or interspinous fixation is used as intended with planned interbody fusion; device use must match the application evaluated in supporting studies.

Intervention must be consistent with device labeling and studied contexts.

Outcomes/Follow‑up: Expectation of documented baseline and postprocedure validated outcome measures (eg, ODI, VAS, ZCQ) and intent to follow for a minimum of 2 years to assess effectiveness and adverse events.>=2 years

Minimum follow‑up window recommended to judge treatment success.

Evidence synthesis (not prescriptive coverage criteria)

Evidence summary relevant to coverage decisions

RCT evidence for ISF with fusion: Two small RCTs (total N≈149) compared interspinous fixation plus interbody fusion versus pedicle screw constructs and reported similar short‑term fusion and functional outcomes but had methodological limitations and unclear long‑term safety.RCT size N=149 total

Larger, longer‑term RCTs are needed to confirm comparative safety and effectiveness.

Recent small RCTs vs decompression: A 2024 RCT (Baranidharan) randomized patients to decompression or an interspinous fixation device (Minuteman); numerical improvements favored decompression for pain and disability but interspinous fixation had lower blood loss and shorter operative time; study limitations preclude firm efficacy conclusions.N=43 or small sample

No definitive efficacy conclusions can be drawn from these small, limited trials.

Systematic review and case series:

Coverage rationale and clinical criteria

Coverage considerations and evidence summary for interspinous/interlaminar devices

Guideline‑aligned indications: Device use may be considered in carefully selected patients with symptomatic lumbar spinal stenosis (mild‑to‑moderate) and Grade ≤1 spondylolisthesis without dynamic instability when conservative therapy has failed, consistent with some society guidance and FDA summaries.

Guidelines vary in strength; device‑specific labeling should be followed.

Scenarios not indicated: Degenerative spondylolisthesis Grade ≥2, degenerative scoliosis/coronal instability, dynamic instability on flexion‑extension (>3 mm translation), iatrogenic instability, or use of interspinous fixation without open decortication/fusion are not supported.

NASS and other societies list these as non‑indications or contraindications.

Evidence quality summary: Randomized and comparative data are limited; some RCTs show benefit in composite endpoints for ILS (coflex) but have design limitations and concerns over long‑term durability and safety; robust RCTs are needed.

Heterogeneity across device classes (ILS vs ISP) limits generalizability.

Appropriate use of ILS (conceptual)

Coverage considerations and appropriate patient selection (conceptual — document discusses evidence and FDA labeling):

ILS appropriate candidate: Patient has symptomatic lumbar spinal stenosis with leg/buttock/groin pain (with or without back pain), experiences symptom relief in flexion, has at least moderate functional impairment (eg, ODI consistent with trial populations), and objective imaging demonstrates moderate‑to‑severe stenosis.ODI and imaging consistent with moderate‑to‑severe disease

ILS intended to be used with direct decompression; contraindicated for axial pain only (no leg/buttock/groin pain).

Comparative effectiveness

Comparative outcomes and selection trade-offs:

Comparative trade‑offs: Decompression plus ILS may have shorter recovery and lower index complication rates than decompression plus fusion; interspinous spacer‑alone procedures may have fewer immediate complications but higher reoperation rates compared with decompression alone or fusion. Device class (ILS vs ISP) and patient selection influence comparative outcomes.higher revision rates reported at mid‑term follow‑up

Clinicians must weigh shorter index morbidity against potential increased reoperation risk.

ILS patient selection

Provider comments regarding appropriate patient selection and evidence relevance for ILS:

ILS patient profile: Patient with moderate‑to‑severe lumbar spinal stenosis, significant functional impairment (eg, ODI ≥40 as in some trials), neurogenic claudication or leg/buttock/groin pain relieved by flexion, and MRI evidence of central/lateral/foraminal stenosis; not for patients with axial back pain only.ODI >=40

Reflects trial inclusion criteria and FDA labeling; supports selection for ILS.

Evidence assessment standards

Study design and outcome measurement considerations preferred by commentators:

Preferred primary endpoint: Use a composite clinical success endpoint combining multiple criteria (eg, ODI improvement ≥15 points, no significant adverse events, no subsequent interventions, and neurological maintenance/improvement) rather than isolated single outcomes to reduce confounding from subsequent interventions.ODI improvement >=15

Composite endpoints address survivorship bias and subsequent‑intervention confounding.

Interspinous and interlaminar distraction, stabilization, and fixation devices are categorized in this policy as investigational. The policy states these device classes lack sufficient evidence to demonstrate an improvement in net health outcomes and therefore are excluded from coverage for the indications reviewed, including use as a stand-alone treatment for lumbar spinal stenosis or as adjuncts to fusion when evidence is inadequate.

Representative regulatory and clinical summaries note that some individual products have FDA regulatory histories, but the policy-level conclusion remains that the available evidence is insufficient to support routine coverage of these device categories across the range of indications described.

Interspinous fixation devices are intended primarily as adjuncts to interbody fusion and, per device labeling and FDA summaries, are not intended for stand-alone use. The document identifies use of these fixation devices as a stand-alone procedure as off-label and notes that implantation in such circumstances may increase risks (for example, spinous process fracture) and is not consistent with device clearance.

Clinical trial evidence for interspinous fixation when used adjunctively with fusion is limited to small randomized trials and nonrandomized series; the policy highlights that stand-alone implantation of fixation devices lacks robust randomized evidence and therefore is not supported as standard practice.

Systematic reviews and pooled RCT data include a heterogeneous mix of devices (for example, X-STOP and other non–FDA-approved interspinous devices), contributing to statistical and clinical heterogeneity. The Xin et al. (2023) meta-analysis pooled eight RCTs with diverse devices and patient populations, limiting applicability of summary effects to any single, current FDA-cleared product.

Because trials and reviews often combine older devices and off-label uses with current device studies, direct translation of pooled results to a specific device or indication may be unreliable without stratified analysis by device and intended use.

The document notes several instances of off-label device use in the literature (for example, coflex used functionally as an interspinous spacer without direct decompression). Such off-label uses should be evaluated against the device's FDA labeling and the specific evidence supporting that labeled indication before inferring effectiveness or safety.

Commentators cautioned that mixing off-label study results with on-label ILS evidence confounds interpretation; reviewers should verify whether reported outcomes reflect the intended device use (ILS with decompression) or an off-label application.

Published evidence beyond pivotal trials is limited: several device manufacturers’ registries have incomplete public reporting, and many observational series or claims analyses lack patient-reported outcomes or long-term follow-up. The policy emphasizes that robust, published long-term data are sparse outside of the pivotal studies.

Claims-based analyses may provide supplementary signals (e.g., reoperation rates) but are constrained by absence of clinical severity metrics, validated outcome measures, and potential confounding, limiting their utility as proof of net clinical benefit.

Using an interlaminar device as a substitute for decompression-alone is not supported by robust evidence in populations without spondylolisthesis. The pivotal trials and subgroup analyses that informed some device approvals compared interlaminar stabilization plus decompression with decompression plus fusion rather than decompression alone, making it difficult to conclude that the implant can replace decompression-alone across broad populations.

Trial limitations, comparator uncertainty, and incomplete subgroup reporting reduce confidence in substituting an interlaminar implant for decompression-alone in routine practice.

The excerpt does not present an exhaustive list of explicit exclusions; however, it highlights evidence limitations and safety concerns (for example, reported spinous process fractures) that inform coverage decisions and may lead to denials in high-risk populations or where supportive documentation is absent.

Policy language and contextual regulatory summaries indicate that device-specific contraindications, inadequate follow-up documentation, or use outside labeled indications can influence coverage determinations even when an absolute procedural exclusion is not spelled out in the provided excerpt.

Several devices’ labeling and society guidance explicitly state that interspinous devices are not indicated for degenerative spondylolisthesis Grade 2+, degenerative scoliosis or coronal instability, or dynamic instability (for example, >3 mm translation on flexion-extension views). These scenarios are listed as contraindications in FDA summaries and professional society statements.

Device contraindications also commonly include severe osteoporosis, prior fusion or decompression at the index level, and morbid obesity (e.g., BMI > 40), which should be checked against the specific product labeling before implantation.

Clinical input captured in the document notes that some datasets and trial recruitment populations include patients with predominant back pain or substantial axial symptoms, which may not reflect the typical ILS candidate. Commentators emphasized that ILS is intended for patients with leg/buttock/groin pain relieved by flexion rather than axial pain–only presentations.

Synthesis of clinician feedback underscores the importance of matching trial populations (often with high baseline ODI scores) to real-world patient selection when interpreting applicability of evidence.

Per FDA labeling and the policy discussion, interlaminar stabilization (ILS) devices are contraindicated for patients with axial back pain only and without leg, buttock, or groin pain. The document emphasizes that ILS trials and device indications require symptom relief with flexion and presence of neurogenic claudication-type leg symptoms.

Commentators reiterate that patients with isolated axial pain are not appropriate candidates for ILS and that such use would be inconsistent with approved labeling.

The policy cautions against conflating evidence from interspinous process (ISP) spacers used as stand-alone implants and interlaminar stabilization (ILS) devices used with decompression. ISP and ILS devices are biomechanically distinct, intended for different patient populations, and their trial outcomes are not interchangeable.

Stand-alone ISP device studies—especially when devices are used off-label or outside their intended mechanism—should not be treated as direct evidence for ILS performance or indications.

A commenter summarized clinical practice by stating they do not use interspinous devices due to significant limitations compared with standard surgical approaches. Contributing concerns included higher long-term reoperation rates and uncertainty about net health benefit despite some short-term perioperative advantages.

This practical viewpoint from clinical stakeholders reinforces caution in adopting these devices broadly outside well-defined, evidence-supported indications.

Restating the policy's central determination: interspinous/interlaminar distraction and stabilization devices, as well as interspinous fixation devices, are considered investigational within the scope of this policy because current evidence does not establish a net health benefit for the indications reviewed.

Consequently, these device categories are excluded from coverage for the indications described unless and until higher-quality evidence or labeling changes justify a different coverage posture.

Use of interspinous fixation devices off‑label as stand‑alone implants to substitute for decompression or fusion is considered unsupported by the evidence presented. Small randomized trials and case series do not provide sufficient comparative data to justify routine stand-alone fixation in place of established surgical options.

The policy therefore treats stand-alone interspinous fixation for decompression or fusion substitution as not medically supported absent robust trial evidence demonstrating net benefit.

Claims-based analyses cited in the literature are limited by lack of clinical detail (severity, prior therapies, patient-reported outcomes) and potential coding or selection biases. The policy highlights that use of ISDs inferred solely from claims data without supporting clinical documentation is a concern for assessing medical necessity.

Therefore, claims-only evidence that does not include validated outcome measures or imaging and clinical context should be interpreted cautiously when assessing coverage.

Section summaries and pooled trial data indicate higher reoperation or revision rates after interspinous spacer implantation compared with decompression, with no consistent advantage on validated pain and function outcomes. Meta-analytic findings (for example, Xin et al. 2023) reported significantly higher odds of reoperation after ISD versus decompression without clear differences in VAS or ODI.

These findings have influenced the policy's cautious stance and its emphasis on requiring rigorous outcome documentation where devices are considered.

Interpretation of noninferiority trial results is limited by uncertainty regarding the comparator's effectiveness. The policy notes that the Coflex pivotal noninferiority trial used decompression plus fusion as the comparator; subsequent trials questioned whether fusion provided a net benefit over decompression alone, complicating interpretation of noninferiority conclusions.

Because the comparator's net benefit is uncertain, noninferiority against that comparator does not unambiguously establish clinical equivalence or superiority in real-world practice.

Given uncertainties in long-term comparative effectiveness and safety for several device types, the policy advises avoiding routine addition of interlaminar stabilization or interspinous fixation in cases where the net benefit is unproven. Device use should align with labeling and high-quality evidence demonstrating improved outcomes compared with established treatments.

Where evidence is uncertain, preference should be given to treatment approaches with clearer net benefit until more definitive trial data are available.

The provided excerpts do not include an explicit, standalone statement declaring interspinous fixation devices to be definitively 'not medically necessary' for all uses; rather, the document emphasizes that evidence is insufficient to support routine use and that many such devices are considered investigational.

Policy language couples investigational classification with recommendations for careful documentation and alignment with device labeling when device use is considered.

Evidence does not support the use of interspinous fixation as a stand-alone replacement for decompression or fusion. Small RCTs and case series report limited or inconsistent benefits compared with decompression, and methodological limitations preclude confidence in stand-alone application for routine practice.

Until larger, well-controlled trials demonstrate net health benefit for stand‑alone use, such applications should be considered unproven.

Within the provided excerpt there are no procedural entries explicitly labeled as 'not medically necessary' beyond the broader investigational classification. The policy relies on investigational determinations and evidence limitations to guide coverage decisions rather than listing specific procedural exclusions in the excerpt.

Operational claims and coding guidance are provided (CPT and HCPCS codes) to support reporting and prior‑authorization workflows where applicable.

The document re-emphasizes that evidence for interspinous process spacers (ISP) and interlaminar stabilization (ILS) are distinct; conflating ISP and ILS findings risks misapplication of evidence. Stand-alone ISP implantation should not be justified by ILS trial results, and vice versa.

Clinicians and reviewers are cautioned to treat ISP and ILS as separate device classes with different indications, mechanisms, and supporting evidence bases when assessing medical necessity or coverage.

The policy underscores that patients with axial pain only (no leg, buttock, or groin pain) are not appropriate candidates for interlaminar stabilization (ILS) devices. This contraindication is explicitly noted in FDA labeling and reiterated in the clinical commentary included in the document.

ILS indications require symptoms consistent with neurogenic claudication or radicular-type leg symptoms and demonstrable imaging correlates; isolated axial low back pain falls outside intended device use.

A commenter restated that they do not use interspinous devices in their practice due to perceived limitations compared with standard surgical approaches, including concerns about higher rates of subsequent surgery despite short-term perioperative advantages.

This clinician perspective aligns with the cautious interpretation of the evidence and the investigational classification articulated in the policy.

Coding and Product Identifiers

See Codes tablemixed

No codes listed

FDA Premarket Approval / Product codemixed

FDA product code NQO

Interspinous/interlaminar stabilization/distraction devices (PMA examples: X-STOP, Coflex, Superion)

FDA Clearance / Product codemixed

FDA product code PEK

Interspinous fixation devices (clearance)

Procedure/Study identifiers referencedmixed

No codes listed

Procedure CPT CodesCPT

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 an interspinous process distraction or fixation device].

HCPCS Implant CodesHCPCS

C1821

Interspinous process distraction device (implantable).

Spondylolisthesis grade threshold

Spondylolisthesis thresholdGenerally allowed up to Grade 1 for some devices; Grade 2 or greater is a contraindication per device labeling (eg, coflex, Superion) and society guidance.

Device labeling examplescoflex contraindicated for Grade II or greater spondylolisthesis; Superion labeling cites degenerative spondylolisthesis greater than grade 1 as instability precluding implantation.

Society guidanceASPN and NASS indicate use limited to patients with ≤ Grade 1 spondylolisthesis in appropriate contexts; devices not indicated for Grade 2+ spondylolisthesis.

BMI

BMI contraindication

Authorization, Documentation, and Operational Considerations

Prior Authorization

Prior authorization

Prior authorization: Not applicable per this document; however, procedures involving interspinous/interlaminar devices may be denied because these devices are considered investigational for many indications.

Prior approval: Not applicable (policy header).
Investigational stance: Distraction, stabilization, and fixation devices considered investigational for many indications; standalone spacers often not covered.

Prior Authorization

Prior authorization recommended

Expected when placing FDA‑approved interspinous/interlaminar spacers or interspinous fixation devices in indications consistent with device labeling and payer rules; documentation should accompany requests.

PA is commonly requested for placement of FDA‑approved devices (eg, Superion, Coflex) when used per label.
Interspinous fixation devices (many cleared; intended as adjuncts to fusion) may also prompt PA.

Background and Definitions

Interspinous spacer (interspinous distraction device)

DefinitionSmall implant placed between vertebral spinous processes that is opened/expanded to distract the neural foramina and decompress nerves; limits extension to relieve neurogenic claudication.

Typical useInserted between spinous processes through a small incision; may preserve supraspinous ligament depending on design and does not necessarily require decompression at time of insertion.

Alternate phrasingAlso described as an interspinous distraction device or spacer that maintains flexion at the treated interspace to indirectly decompress neural elements.

Interlaminar spacer (interlaminar stabilization device)

DefinitionImplant placed midline between adjacent lamina and spinous processes to provide dynamic stabilization, typically used following decompression or as an alternative to decompression in some devices (eg, coflex).

Policy Summary

Payerblue cross blue shield - south dakota

PolicyInterlaminar Stabilization/Distraction Devices (Spacers) and Interspinous Fixation (Fusion) Devices

Policy CodePolicy N/A

Change TypeAnnual review — no material changes

Effective DateJan 1, 2007

Next Review Date

Key ActionWhen seeking authorization, provide imaging confirmation, documentation of prior conservative therapy, baseline/outcome scores (eg, ODI), device intended, and plan for ≥2-year follow-up.

SourceLink

On This Page

imaging consistent with symptomatic stenosis

FDA indications reference imaging confirmation.

Symptom behavior: Symptoms include leg/buttock/groin pain, numbness, or cramping relieved by flexion and associated with impaired function.symptom relief with flexion

Device indications reference relief in flexion as part of the clinical picture.

Device‑specific contraindications absent: No device‑specific contraindications are present (examples: prior fusion or decompressive laminectomy at index level, severe osteoporosis, morbid obesity BMI>40, degenerative scoliosis beyond device limits, cauda equina syndrome, allergy to device materials).contraindications absent

Refer to the specific device labeling for full contraindication lists.

Claims analyses cannot substitute for controlled clinical outcome data.

Outcomes documentation:

Availability of baseline and follow‑up validated outcome measures (eg, Oswestry Disability Index, ZCQ, VAS) and intent to follow outcomes for a minimum of 2 years to assess effectiveness and adverse events.

Policy emphasizes a 2‑year minimum follow‑up window.

Long‑term safety and durability data are incomplete.

Systematic reviews and nonrandomized studies report decreased operative time and blood loss with interspinous fixation compared with pedicle screw constructs but overall evidence quality is limited.

multiple small studies

Evidence level insufficient to support broad coverage expansion without more rigorous data.

Morbid obesity defined as BMI > 40 is listed as a contraindication for several devices (eg, Superion, coflex).

Device labeling noteFDA labeling for distraction/stabilization devices explicitly lists BMI >40 as a contraindication for implantation.

Coverage implicationPresence of BMI >40 may trigger denial per device contraindications and policy denial triggers.

Osteoporosis

Osteoporosis thresholdSevere osteoporosis (T-score ≤ -2.5) is listed as a contraindication to implantation in FDA labeling.

Device examplesSuperion and coflex labeling cite severe osteoporosis or compromised vertebral bodies as contraindications.

Clinical riskSevere osteoporosis increases risk of spinous process fracture and may prompt denial per policy.

Follow-up window and ODI change

Minimum follow-up windowMinimum 2-year follow-up window to judge treatment success is required for outcome assessment and may be requested in authorization/review.

ODI improvement thresholdA 15-point improvement on the Oswestry Disability Index is used as a meaningful function improvement (trial composite endpoint).

ODI minimal detectable changeODI Minimum Detectable Change at 90% confidence is 10 percentage points (used for interpreting change).

Minimum follow-up window

Minimum outcome window>= 2 years minimum follow-up to assess treatment success and adverse events (policy expectation).

PurposeTwo-year window cited as minimal timeframe to evaluate durability, reoperations, and composite endpoints.

Documentation implicationFailure to document ≥2-year outcomes may trigger coverage or medical necessity questions.

ODI thresholds

Trial inclusion ODIDavis IDE trial required minimum ODI ≥40 for inclusion; Davis baseline average ODI ≈61.

Other trial baselinesSchmidt trial baseline average ODI ≈53; Forsth and Ghogawala reported averages ~42 and 37 respectively, reflecting lower baseline severity in some comparator trials.

Clinical interpretationODI ≥40 commonly used in trials to define moderate-to-severe disability and candidate selection for ILS/ILS-related studies.

Verify member benefits and submit clinical documentation for review.

Prior Authorization

Prior authorization for standalone spacer placement

Indicate when the planned procedure is standalone spacer placement for lumbar stenosis (no concurrent decompression) so reviewers can apply the appropriate investigational/coverage stance and evidence expectations.

State explicitly if the spacer is being placed as a standalone treatment versus with decompression.
If standalone, note that evidence and claims analyses have limitations and spacers as standalone therapy are often considered investigational.
Include rationale if patient is not a candidate for decompression (eg, medical comorbidity).

Documentation Required

Prior authorization: clinical indication and baseline measures

Require documentation of diagnosis, conservative therapy history, device details, and baseline validated outcome measures to support medical necessity reviews.

Diagnosis: imaging-confirmed lumbar spinal stenosis (MRI/CT/X‑ray) and statement on presence/grade of spondylolisthesis.
Prior conservative management: describe modalities tried (PT, medications, epidural injections) and duration—typically ≥6–12 weeks, often ≥6 months for some device labels.
Device information: device name, model, intended level(s), and planned use (standalone vs adjunctive).
Baseline measures: Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), visual analog scale (VAS) for back/leg pain.

Prior Authorization

Prior authorization for interspinous fixation

When requesting authorization for interspinous fixation (fusion) devices, document failure of conservative therapy, intended use with interbody fusion if applicable, and comparator rationale; these devices are generally intended as adjuncts to fusion per FDA labeling.

Document conservative therapy failure (eg, ≥6 months where applicable) and current symptoms.
If device is intended as adjunct to interbody fusion, state planned fusion technique and how the implant will be used to promote fusion.
If proposing fixation without fusion, note that interspinous fixation without open decortication/fusion lacks supporting literature and is frequently considered investigational.
Include operative plan, levels, and whether pedicle-screw fixation comparator is being avoided and why.

Billing Rule

Procedure and implant codes (may require PA)

Report provider services and implants using the appropriate CPT/HCPCS codes; some codes may trigger prior authorization or affect claims processing.

Relevant CPT codes: 22867, 22868 (with open decompression); 22869, 22870 (without open decompression); 22899 (unlisted spine procedure) when applicable.
HCPCS implant code: C1821 (interspinous process distraction device, implantable).
Note: use of 22899 or incorrect coding may prompt payment/processing review; include implant model and manufacturer on claims and medical records.

Prior Authorization

Prior authorization for ILS

For interlaminar stabilization (ILS) requests, demonstrate the patient population matches device indications (eg, symptomatic stenosis with leg/buttock/groin pain, relief in flexion) and document prior conservative therapy and imaging findings.

Show symptoms consistent with FDA label: relief in flexion from leg/buttock/groin pain; ILS is contraindicated for axial pain only.
Confirm radiographic evidence of moderate-to-severe lumbar stenosis and absence of gross instability.
Document at least 6 months (device label) or 12 weeks (ISASS guidance) of nonoperative treatment as applicable.
Specify whether ILS is being placed with decompression (ILS) or alone (different evidence and coverage implications).

Note

Prior authorization — none stated

Some comments and sections note no explicit prior authorization requirements for certain implants; nevertheless, reviewers may request records due to investigational status or limited evidence.

Policy header lists prior approval as Not applicable, but investigational designations for devices can still lead to denial or record requests.
Even without a formal PA program, plans may request clinical records to substantiate medical necessity given evidence limitations.
Facilities/ASC setting suitability may be noted but does not replace required clinical justification.

Denial Risk

Denial triggers from device labeling and intended use

Implantation in patients who meet device contraindications (per FDA labeling or society guidance) or outside labeled indications can trigger denials.

Examples of denial triggers: use in patients with Grade ≥2 spondylolisthesis, degenerative scoliosis beyond Cobb thresholds, dynamic instability on flexion-extension views, axial pain only, prior fusion at index level, severe osteoporosis, morbid obesity (BMI>40).
Allergies to titanium or device materials, active infection, or anatomic conditions making implantation unstable are contraindications.
Ensure preauthorization/medical records explicitly address these contraindications if present or absent.

Denial Risk

Claims data limitations may prompt denial or request for clinical records

Claims-based analyses lack clinical detail and patient-reported outcomes; reviewers may request medical records, imaging, and validated outcome measures to resolve ambiguities.

Claims data cannot capture symptom severity, imaging-confirmed stenosis grade, ODI/ZCQ scores, or reasons for loss to follow-up.
Claims analyses may have coding errors or baseline differences that confound interpretation; include clinical context to support conclusions about need for reoperation.
If claims are used to justify prior authorization decisions, be prepared to supply chart notes, imaging, and outcomes data.

Denial Risk

Potential bias from trial design

Open-label trial designs, exclusion of blinded adjudication, and protocol decisions (eg, inclusion of epidural injections in composite endpoints) can introduce bias that affects interpretation of effectiveness and may influence coverage decisions.

Trials without independent blinded adjudication or preset criteria for subsequent interventions are at risk of assessment bias.
Composite endpoints driven by differences in use of less-invasive rescue therapies (eg, epidural injections) may overstate net benefit.
Reviewers may require sensitivity analyses, longer follow-up, or higher‑quality comparative data to mitigate bias concerns.

Denial Risk

Evidence limitations may trigger coverage denial or additional review

Evidence limitations — including small trials, short follow-up, methodological weaknesses, and inconsistent comparators — may lead to coverage denial or request for additional review.

Key limitations: noninferiority trials using uncertain comparators, missing data handling, small sample sizes, and high variability in outcomes.
Safety concerns (eg, spinous process fracture) and unclear long‑term comparative benefit may prompt denials or case-by-case medical necessity reviews.
Provide long-term outcomes (≥2 years), ODI/ZCQ results, and documentation of adverse events to support coverage requests.

Denial Risk

Contraindicated scenarios per NASS

Society guidance (NASS, ISASS) lists contraindicated scenarios and specific coverage criteria that should be addressed in authorization requests; failure to meet these criteria may prompt denial.

ISASS criteria: radiographic confirmation of at least moderate stenosis, absence of gross instability, and ≥12 weeks nonoperative therapy for ILS adjunctive use.
NASS contraindications: Grade ≥2 degenerative spondylolisthesis, degenerative scoliosis beyond Cobb thresholds, dynamic instability (>3 mm translation), axial pain only, prior fusion at adjacent segment, and others.
Align submitted clinical documentation with these society criteria when applicable.

Note

None explicit in this section of the doc

This section contains multiple informational and operational notes rather than an exhaustive PA checklist; incorporate the above documentation and coding guidance when seeking authorization or responding to record requests.

Clinical context, operative details, and validated outcomes are central to medical necessity determinations.
Where no explicit PA is required, medical records requests and claims reviews may still be used to adjudicate investigational/coverage questions.
Providers should supply complete operative notes, device identifiers, baseline and follow‑up PROs, and rationale when deviating from typical comparators (eg, decompression vs fusion).

Provides stabilization by contacting the lamina and surrounding spinous processes; aims to restrict extension while allowing motion.

Usage noteInterlaminar spacers are often implanted after decompression to provide adjunct stabilization per device labeling.

Interspinous fixation device

DefinitionDevice intended to provide fixation between spinous processes and used as a supplemental fixation adjunct to interbody fusion (not intended for stand-alone use per labeling).

Design featuresRanges from paired plates with teeth to U-shaped constructs that attach to spinous processes; may limit flexion/extension but be less effective for rotation/lateral bending than pedicle screw constructs.

Stand‑alone useUse of interspinous fixation as a stand-alone procedure is considered off-label and evidence for stand-alone efficacy is insufficient.

Interspinous spacer (alternate phrasing)

Alternate phrasingAn implant inserted between spinous processes acting as a spacer to distract neural foramina and limit extension, decompressing nerves and preserving or reestablishing flexion at the index level.

Surgical approachCan be inserted through a small incision (4–8 cm) without laminectomy in some designs; other designs may require resection of interspinous ligament.

Clinical goalIntended to reduce neurogenic claudication and leg/buttock/groin pain by indirect decompression.

Interlaminar spacer (alternate phrasing)

Alternate phrasingDevice placed midline between lamina and spinous processes (interlaminar U-shaped implant) providing dynamic stabilization, often implanted after decompression to augment stability.

Examplescoflex described as a U-shaped titanium alloy interlaminar device implanted after decompression for 1–2 levels (L1–L5) in patients meeting labeling criteria.

Intended effectRestricts extension, distracts laminar space, and aims to indirectly enlarge the neural foramen and decompress the cauda equina.

Interspinous fixation device (alternate phrasing)

Alternate phrasingAn implant (eg, plates, U-shaped constructs) attaching to spinous processes to provide posterior fixation, intended as a supplemental fixation device used with interbody fusion constructs.

BiomechanicsMay limit flexion/extension comparably to pedicle screw constructs but can be less effective for axial rotation and lateral bending; potential for focal kyphosis affecting interbody grafts.

Safety noteUse carries risk of spinous process fracture; comparative safety versus pedicle screws remains uncertain in existing RCTs.

Population

Population descriptionPatients with lumbar spinal stenosis without spondylolisthesis or with Grade 1 spondylolisthesis are the relevant target population for spacer devices per the policy and trials.

Severity contextDevice candidates typically have moderate-to-severe functional impairment and symptoms relieved by flexion (neurogenic claudication).

Exclusion notePatients with Grade ≥2 spondylolisthesis, dynamic instability, or predominant axial back pain alone are generally not appropriate candidates.

Intervention

Intervention descriptionStandalone placement of an interspinous or interlaminar spacer device (ISD) between spinous processes to provide distraction/stabilization and indirect decompression for lumbar spinal stenosis.

Device contextInterlaminar spacers are often used adjunctively with direct decompression, whereas interspinous spacers may be implanted standalone per FDA labeling for some devices.

Outcome intentIntended to reduce leg/buttock/groin pain and improve function by limiting extension and enlarging foraminal/canal dimensions.

Zurich Claudication Questionnaire (ZCQ)

DefinitionZurich Claudication Questionnaire (ZCQ) is a disease-specific instrument with three subscales: symptom severity (1–5), physical function (1–4), and patient satisfaction (1–4), used to evaluate function and walking capacity in lumbar spinal stenosis.

Physical function subscaleThe 5-item Physical Function Scale assesses walking distance and activities of daily living related to walking and is frequently used in surgical outcome studies.

Scoring noteSubscales may be used separately to evaluate symptom severity, physical function, and satisfaction.

Oswestry Disability Index (ODI)

DefinitionOswestry Disability Index (ODI) is a 0–50 self‑administered questionnaire quantifying disability from low back pain; a 15‑point improvement is used as a meaningful clinical improvement and the Minimal Detectable Change at 90% confidence is 10 percentage points.

Interpretation bandsODI bands categorize disability from minimal (0–20%) to bed‑bound (80–100%), aiding clinical interpretation of severity and candidacy for interventions.

Trial useODI change (≥15 points) is commonly included in composite clinical success endpoints in pivotal trials (eg, Davis IDE).

Interlaminar spacer (additional)

Additional definitionInterlaminar spacer (eg, Coflex) is a U‑shaped implant placed between laminae and around spinous processes, typically implanted after decompression to provide stabilization and potentially improve back pain.

Indication detailCoflex is indicated for 1–2 level lumbar stenosis after decompression in patients with at least moderate functional impairment and relief in flexion; contraindications include prior fusion at index level, Grade II+ spondylolisthesis, severe osteoporosis, and BMI >40.

Mechanism noteContacts lamina for fixation and aims to maintain foraminal height while allowing some motion.

Interspinous spacer (ISD) (additional)

ISD additional phrasingInterspinous spacer (ISD) is an implant placed between spinous processes to limit extension, distract the neural foramina, and relieve neurogenic claudication; may be implanted standalone without decompression depending on device.

Insertion approachesSome ISDs are inserted through a small posterior incision without laminectomy, preserving supraspinous ligament; others require resection and fixation around spinous processes.

Intended effectsAims to reduce nerve root compression and improve walking capacity and function by maintaining flexion at the treated segment.

Composite clinical success (CCS)

Composite clinical success (CCS)A trial endpoint defined as meeting multiple criteria including ≥15‑point ODI improvement, no secondary surgical intervention or lumbar epidural injection, neurologic maintenance/improvement, and absence of device‑ or procedure‑related severe adverse events.

PurposeCCS combines efficacy and safety outcomes to avoid survivorship bias and to ensure durability of primary treatment effect in RCTs.

Use in trialsUsed as the primary or composite endpoint in pivotal IDE and RCTs (eg, Davis study) for interlaminar devices.

Interlaminar spacer (Coflex example)

Coflex exampleCoflex is a U‑shaped interlaminar stabilization implant indicated for 1–2 level lumbar stenosis implanted after decompression in patients with moderate impairment who experience relief in flexion.

Labeling specificsCoflex labeling requires prior decompression at the treated levels and lists contraindications such as prior fusion at index level, Grade II+ spondylolisthesis, osteoporosis, and BMI >40.

Evidence noteCoflex has RCT evidence including 5‑year follow‑up in the pivotal noninferiority trial discussed in the policy.

Interspinous fixation device (ISF/ISPF) (alternate)

ISF/ISPF alternateInterspinous fixation devices (ISF/ISPF) are implants intended to provide posterior supplemental fixation in conjunction with interbody fusion (eg, Coflex‑IF); indications specify adjunct use with an interbody cage to promote fusion.

Regulatory codeFDA product code PEK corresponds to interspinous fixation devices cleared for adjunctive use with fusion constructs.

Off‑label cautionStand‑alone use of ISF/ISPF without open decortication or interbody fusion is off‑label and not supported by robust evidence.

Interspinous fixation device (ISF/ISPF) (additional)

Additional ISF detailsInterspinous fixation devices range from plates to U‑shaped constructs attaching to spinous processes and are evaluated as alternatives to pedicle screw constructs when used with interbody fusion; RCTs are small and long‑term safety remains uncertain.

Potential benefits/risksProposed benefits include less invasiveness and lower index operative morbidity; risks include spinous process fracture and uncertain comparative fusion quality.

Evidence gapRandomized trials with longer follow‑up are needed to establish net health benefit compared with pedicle screw fixation.

BSF radiographic fusion criteria

BSF radiographic fusion criteriaBrantigan, Steffee, Fraser (BSF) radiographic criteria categorize fusion status: BSF‑1 pseudoarthrosis, BSF‑2 locked pseudoarthrosis with bone growth into cage, BSF‑3 fusion with bony bridges in at least half the fusion area.

Use in trialsBSF criteria used to interpret radiographic fusion outcomes in RCTs comparing interspinous fixation adjuncts to pedicle screw constructs.

RelevanceRadiographic fusion assessments inform comparative safety and durability in fusion‑adjunct device studies.

Interspinous spacer (additional phrasing)

Additional phrasingInterspinous spacer described as an implant placed between spinous processes providing indirect decompression for mild‑to‑moderate lumbar spinal stenosis and limiting extension to relieve symptoms.

Population specificsGenerally indicated for patients without dynamic instability and with Grade ≤1 spondylolisthesis per guideline statements.

Mechanistic noteBiomechanically distinct from interlaminar devices; often intended as stand‑alone implants without direct decompression.

Interspinous fixation (with fusion)

Interspinous fixation with fusionInterspinous fixation used with interbody fusion functions as adjunct posterior fixation to promote fusion and is described in labeling as an adjunct to interbody cages rather than a stand‑alone fusion method.

NASS guidanceNASS notes fixation without open decortication and fusion is not supported; interspinous fixation may be considered only in the context of robust fusion technique.

Clinical cautionUse of ISF without appropriate fusion technique may increase risk of failure and spinous process complications.

Interlaminar/interspinous process stabilization/distraction device and related CPT codes

Definition and codingInterlaminar/interspinous process stabilization/distraction device: implantable device placed between spinous processes to provide stabilization or indirect decompression; reported with CPT codes 22867–22870 and HCPCS C1821 for the implant.

Procedure variantsCodes distinguish insertion with open decompression (22867/22868) versus without open decompression (22869/22870) and an unlisted spine code (22899) may be used when unspecified.

Billing implicationAppropriate coding is required for claims reporting and may affect prior authorization and adjudication.

Interlaminar stabilization (ILS)

DefinitionInterlaminar stabilization (ILS) refers to devices implanted in conjunction with direct surgical decompression (eg, Coflex) that contact the lamina for fixation and are intended to stabilize the segment without fusion.

Intended populationILS is intended for patients with stenosis who experience relief in flexion and have leg/buttock/groin pain with moderate‑to‑severe impairment, not for axial pain only.

Evidence noteILS has stronger long‑term evidence (eg, 5‑year follow‑up for Coflex) compared with ISP devices when used per labeling.

Interspinous process (ISP) spacer

DefinitionInterspinous process (ISP) spacer is a device placed between spinous processes primarily contacting the spinous processes and often used as a stand‑alone implant without direct decompression.

BiomechanicsISP devices are biomechanically distinct from ILS devices and intended for different patient severity profiles; historic ISP outcomes have been less favorable in some studies.

Labeling distinctionFDA IDEs for ISP devices typically evaluate stand‑alone implantation without direct decompression; combining ISP and ILS evidence is discouraged.

Interlaminar Stabilization (ILS) (alternate)

Alternate ILS definitionInterlaminar Stabilization (ILS) devices are implanted with direct decompression and contact lamina for fixation; they are intended to provide stabilization without fusion in select stenosis patients.

Clinical labelingFDA labeling for ILS specifies patient relief in flexion and at least moderate impairment in function; contraindicated for axial pain only.

Example deviceCoflex is an example of an ILS device used after decompression for 1–2 levels in patients meeting inclusion criteria.

Interspinous Process (ISP) device (alternate)

Alternate ISP deviceInterspinous Process (ISP) device: implant placed between spinous processes primarily contacting spinous processes and often used without direct decompression; intended for indirect decompression in mild‑to‑moderate stenosis.

Clinical cautionHistoric ISP use has been associated with higher reoperation rates in some meta‑analyses compared with decompression alone.

Distinction from ILSISP devices should not be conflated with ILS devices due to differing mechanisms, intended use, and evidence bases.

Composite clinical success (trial endpoint)

Trial endpoint (CCS)Composite clinical success as a trial endpoint requires ODI improvement ≥15 points, no significant adverse events, no subsequent interventions (including epidural injections), and neurological maintenance/improvement.

RationaleCCS reduces survivorship bias and accounts for subsequent interventions when classifying long‑term success in RCTs.

ApplicabilityUsed in pivotal device trials (eg, Davis IDE) to assess net benefit across multiple dimensions.

Recurrence of pain after primary surgery

Recurrence definitionRecurrence of pain after primary surgery denotes failure of initial surgical treatment and may indicate need for subsequent intervention; trials count subsequent interventions in composite endpoints.

Implication for outcomesPatients receiving subsequent interventions (eg, epidural injections or reoperations) are classified as failures in composite clinical success measures.

Authorization relevanceDocumentation of recurrence and subsequent treatments is important for medical‑necessity adjudication and outcome assessment.

ILS / interspinous device (short)

Short definitionILS / interspinous device: implantable stabilization or distraction devices placed between spinous processes; term used to refer broadly to interlaminar stabilization and interspinous spacers in policy context.

Distinction reminderPolicy emphasizes distinction between ILS (used with decompression, contacts lamina) and ISP (stand‑alone spacer contacting spinous processes) due to differing indications and evidence.

Coding and documentationDevice type (ILS vs ISP) and intended use (with/without decompression) should be specified in documentation for coverage review.