CurrentAetnaPolicy 0772

Axial Lumbar Interbody Fusion (AxiaLIF)

Defines Aetna's coverage stance for axial lumbar interbody fusion (AxiaLIF), a percutaneous presacral approach to L5-S1 fusion; affects providers requesting coverage for this procedure under Aetna plans.

Policy Summary

PayerAetna

PolicyAxial Lumbar Interbody Fusion (AxiaLIF)

Policy CodePolicy 0772

Change TypeNo material change noted

Effective DateN/A

Next Review DateN/A

Key ActionExpect prior authorization review for AxiaLIF; provide clinical and imaging documentation and consider alternative fusion techniques given investigational status and potential denial risk.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

94%radiographic fusion (2 yr)

87.8–97%fusion range

12.9%pooled complication rate

14.4%reoperation rate

71.9% / 80.8% / 33.3%select study fusion rates

Coverage Determination

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inv-01: Not medically necessary / Experimental

Aetna coverage determination for AxiaLIF

Experimental/Investigational Determination: Axial lumbar interbody fusion (AxiaLIF) is considered experimental and investigational by Aetna because of insufficient evidence and the effectiveness of this approach has not been established.

This is a policy-level stance; no clinical-criteria approvals are specified in this document excerpt.

inv-02: General candidate criteria (as used in published series)

Covered when ALL of the following are met (as reported in series):

Clinical symptoms: Symptomatic degenerative disc disease or disc pathology at L5–S1 or L4–S1 causing back and/or leg pain refractory to non-surgical treatmentrefractory to non-surgical treatment

Reflects inclusion criteria used in reported series (e.g., Zeilstra et al, Tobler et al, Melgar et al).

Imaging and planned fusion levels: Imaging-confirmed pathology at the operative levels with planned interbody fusion at L5–S1 (single-level) or L4–S1 (two-level) as appropriate for the patientlevels specified (L5–S1 or L4–S1)

Fusion assessment in series was performed with CT and flexion/extension radiographs.

Adjunct fixation: Planned use of supplemental posterior fixation (e.g., pedicle screw constructs) is documenteddocumented fixation plan

Several series report supplemental posterior instrumentation and note its potential effect on fusion rates and outcomes.

Aetna considers axial lumbar interbody fusion (AxiaLIF), a percutaneous pre‑sacral access route to the L5–S1 vertebral bodies, experimental and investigational due to insufficient evidence and because the effectiveness of this approach has not been established.

Concerns in the literature include inadequate long‑term anterior column support and construct subsidence with loss of segmental lordosis noted in a retrospective series; subsidence was associated with reduced clinical improvement and lower fusion rates, and several constructs required revision surgery. Systematic review data also reported higher complication rates in deformity cohorts and in prospectively collected series.

Comparative and pooled analyses indicate a notable complication profile and measurable rates of pseudarthrosis and reoperation with AxiaLIF: a systematic review found an overall complication rate of 12.9%, a pseudarthrosis rate of 6.9%, and 14.4% of patients requiring additional surgery. In comparative series of ALIF versus AxiaLIF, higher rates of pseudarthrosis, major complications, and revision surgery were reported in the AxiaLIF groups.

Because prospective and comparative evidence is limited and suggests higher complication and revision rates than reported in retrospective series, AxiaLIF is considered experimental and investigational and therefore excluded from coverage by Aetna due to insufficient evidence of effectiveness.

The use of AxiaLIF as a routinely preferred technique over established approaches such as ALIF or TLIF is not established. Reported fusion rates for axial interbody fusion are variable (pooled range approximately 79.0%–97.0% with a pooled value reported at ~90.5%), whereas pooled fusion rates for TLIF and ALIF were higher in some analyses (99.2% and 97.2%, respectively). Limited prospective data and technique‑dependent variability mean superiority of AxiaLIF has not been demonstrated.

Overall, the evidence is mixed: retrospective series report relatively high fusion rates and some symptomatic improvement, but prospective data and independent analyses raise concerns about higher complication and revision rates, construct subsidence, and lower fusion in certain series, limiting conclusions about long‑term effectiveness and safety.

Provider Requirements and Prior Authorization

Prior Authorization

Prior Authorization Expected

Prior authorization expectation — AxiaLIF is considered experimental and investigational by Aetna due to insufficient evidence of effectiveness. Prior authorization requests for AxiaLIF are expected to be reviewed and may be denied as not medically necessary consistent with this policy.

Aetna classifies AxiaLIF as experimental/investigational
Prior authorization requests may be subject to denial

Prior Authorization

Prior Authorization May Be Appropriate

Prior authorization for AxiaLIF — Given variable fusion and complication rates across studies and limited prospective data, prior authorization may be appropriate to confirm medical necessity and that alternative standard fusion techniques and conservative measures have been considered or attempted.

Document rationale for choosing AxiaLIF over ALIF/TLIF/TLIF with bilateral pedicle screws
Provide details of prior conservative therapy and prior surgeries

Note

Administrative Prior Authorization Note

Prior authorization note — Check plan-specific prior authorization procedures and timelines; administrative policy dates and review history are provided in the policy header.

Refer to plan prior authorization portal for submission details
Policy effective and next review dates available in header

Denial Risk

Experimental/Investigational — Denial Risk

Experimental/Investigational — denial risk: AxiaLIF is considered experimental and investigational by Aetna. Claims and prior authorization requests for AxiaLIF are at risk for denial as not medically necessary.

Denial risk for procedures coded as AxiaLIF when submitted without supporting evidence of medical necessity

Note

Evidence Quality Concerns

Evidence-quality risk — The evidence base is dominated by retrospective case series; prospective data are limited and indicate higher complication and revision rates in some series. Studies with conflicts of interest report lower complication rates. Payers may require stronger prospective evidence to support coverage.

Limited prospective data show higher complication/revision rates
Many published reports are retrospective and some have conflicts of interest

Denial Risk

Safety and Outcomes Concerns

Safety and outcomes concerns — Comparative and systematic reviews report higher rates of pseudarthrosis, major complications, and revision surgeries with AxiaLIF versus ALIF in some analyses; deformity and prospective studies show higher complication and revision rates. Reported complications include graft subsidence, loss of lordosis, adjacent-segment disease, and re-operations.

Higher pseudarthrosis, major complication, and revision rates reported in some comparative studies
Reported complications: graft subsidence, loss of lordosis, adjacent-segment disease, need for reoperation

Documentation Required

Device Indications and Documentation

Device indications/documentation — The AxiaLIF system received FDA 510(k) clearance. Per the 510(k) documentation, it is indicated for anterior supplemental fixation at L5–S1 in conjunction with legally marketed facet and pedicle screw systems for indications such as pseudoarthrosis, unsuccessful previous fusion, spinal stenosis, grade 1–2 spondylolisthesis, and degenerative disc disease. It is not indicated for severe scoliosis, severe spondylolisthesis (grades 3–4), tumor, or trauma.

FDA 510(k) clearance: indicated for anterior supplemental fixation at L5–S1 with adjunct posterior instrumentation
Not intended for severe scoliosis, severe spondylolisthesis (grades 3–4), tumor, or trauma

Documentation Required

Required Clinical and Imaging Documentation

Required clinical and imaging documentation — Prior authorization submissions should include clinical indication, levels to be treated, prior conservative therapies, prior spine surgeries, objective outcome measures, and imaging documentation of fusion status. Post-operative reporting should include measures such as VAS and ODI and radiographic fusion assessment (CT or flexion/extension radiographs).

Clinical indication and levels treated (e.g., L5–S1, L4–S1)
Documentation of failed conservative treatment
Prior spine surgery history
Objective outcome measures: VAS, ODI
Radiographic fusion assessment: CT or flexion/extension radiographs

Documentation Required

Terminology

AxiaLIF — AxiaLIF system

TermAxiaLIF system

DescriptionA minimally invasive system (TranS1, Inc.) that uses a small para-coccygeal incision to create a pre‑sacral corridor for access to the anterior lumbosacral body and insertion of bone graft and an anterior fixation rod at the L5–S1 interspace.

Regulatory statusCleared for marketing by FDA 510(k); device includes instruments for creating a pre‑sacral axial track and an anterior fixation rod.

Intended use (per FDA 510[k])Indicated for patients requiring fusion to treat pseudoarthrosis, unsuccessful prior fusion, spinal stenosis, spondylolisthesis (grade 1–2), or degenerative disc disease at L5–S1; limited to anterior supplemental fixation at L5–S1 in conjunction with legally marked facet and pedicle screw systems.

Contraindications / limitationsNot intended for severe scoliosis, severe spondylolisthesis (grades 3–4), tumor, or trauma; use limited to L5–S1 anterior supplemental fixation with appropriate posterior instrumentation.

pre-sacral approach — Pre-sacral (presacral) percutaneous transaxial approach

TermPre‑sacral (presacral) approach

DescriptionA percutaneous transaxial approach that accesses the lumbosacral junction via a para‑coccygeal incision and a created pre‑sacral corridor to reach the L5–S1 interspace without direct anterior exposure.

Key featuresMinimally invasive, accesses the anterior surface of the sacrum percutaneously, seeks to minimize risk to adjacent vital structures and avoid annular disruption.

Clinical contextUsed as an alternative to traditional anterior or posterior interbody fusion techniques to insert bone graft and anterior fixation via a small axial track to L5–S1.

AxiaLIF — A percutaneous retro-rectal, pre-sacral corridor technique

TermAxiaLIF (technique)

DescriptionA percutaneous retro‑rectal, pre‑sacral corridor technique that places an axial rod through the body of S1 (and L5 for 2‑level procedures) to achieve interbody fusion at L5–S1 and L4–S1.

Approach specificsAccess via a pre‑sacral retro‑rectal track created transaxially through S1 (and L5 for two‑level constructs) to introduce bone graft and an anterior fixation rod.

Adjunct requirementsTypically used with supplemental posterior fixation (e.g., pedicle screws) per reported series and device labeling to achieve stability and improve fusion rates.

Subsidence

TermSubsidence

DefinitionSinking of the graft or implant into the vertebral endplates leading to loss of segmental lordosis and potential clinical failure.

Clinical impactMay abolish correction of segmental lordosis, reduce lordosis degrees post‑operatively, predict failure to improve pain scores, and can necessitate revision surgery.

Adjacent‑segment disease (ASD)

TermAdjacent‑segment disease (ASD)

DefinitionRadiographic and clinically significant disease at a level adjacent to a previous fusion that requires surgical intervention.

Reported incidence (2‑level AxiaLIF cohort)13.4% of 149 patients developed ASD; disease‑free survival 95.3% at 2 years and 89.1% at 5 years.

Risk factors notedAdjacent laminectomy and greater loss of lordosis were associated with higher risk of developing ASD.

OpenPayer

Axial Lumbar Interbody Fusion (AxiaLIF)

Coverage Determination

Billing and Codes

Provider Requirements and Prior Authorization

Clinical Background

Terminology