CurrentAmbetter NevadaPolicy CP.MP.203

Diaphragmatic/Phrenic Nerve Stimulation

Medical necessity criteria and coding guidance for diaphragmatic/phrenic nerve stimulation (diaphragm pacing) for members of Centene-affiliated health plans, including device-specific indications and limits.

Policy Summary

PayerAmbetter Nevada

PolicyDiaphragmatic/Phrenic Nerve Stimulation

Policy CodePolicy CP.MP.203

Change TypeClarifiedCoding additionsBackground revisions

Effective Date

Next Review Date

Key ActionObtain prior authorization and document device-specific medical necessity including imaging evidence of diaphragm movement (fluoroscopy or ultrasound) and required age/ventilator-independence thresholds.

SourceLink

POLICY UPDATE CHANGES

Criteria updated to allow diaphragm movement demonstration by other radiographic techniques such as ultrasound in addition to fluoroscopy.

Spirit Diaphragm Pacing Transmitter and additional HCPCS codes (L8685-L8688) were added to criteria and coding tables.

Background updated to include full FDA approval information for NeuRx RA/4 and the Avery Spirit transmitter; Remedé System section added.

3Distinct device systems discussed

Age limitsAge thresholds noted

CPT & HCPCSCodes referenced

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

inv-01: Initial coverage criteria — Mark IV and Spirit

Covered when ALL of the following are met for Mark IV or Spirit systems:

Mark IV/Spirit coverage: Stimulation is used as an alternative to mechanical ventilation for severe, chronic respiratory failure due to either (1) upper cervical spinal cord injury at or above the C3 vertebral level, OR (2) central alveolar hypoventilation disorder; diaphragm movement with stimulation is visible under fluoroscopy; intact and sufficient function in the phrenic nerve, lungs, and diaphragm; stimulation of the diaphragm (directly or via the phrenic nerve) results in sufficient muscle activity to accommodate independent breathing without ventilator support; and the individual has normal chest anatomy, a normal level of consciousness, and the ability to participate in and complete the required training and rehabilitation.

inv-02: NeuRx RA/4 coverage criteria

Covered when ALL of the following are met for NeuRx RA/4 (per HDE/approval):

NeuRx ALS HDE coverage: Stimulation is used as an alternative to mechanical ventilation for individuals with amyotrophic lateral sclerosis (ALS); age 21 years or older; experiencing chronic hypoventilation but not progressed to forced vital capacity (FVC) less than 45% predicted; diaphragm movement with stimulation is visible under fluoroscopy or by other radiographic techniques such as ultrasound; and intact and sufficient function in the phrenic nerve, lungs, and diaphragm.

NeuRx spinal cord injury coverage: For upper cervical spinal cord injury (at or above the C3 vertebral level): age 18 years or older; diaphragm movement with stimulation is visible under fluoroscopy or by other radiographic techniques such as ultrasound; stimulation allows the individual to breathe without the assistance of a mechanical ventilator for at least four continuous hours a day; and intact and sufficient function in the phrenic nerve, lungs, and diaphragm.

inv-03: Unproven or insufficient evidence indications

Not covered / insufficient evidence:

Other conditions: There is insufficient evidence to support the safety and efficacy of diaphragmatic/phrenic nerve stimulation for indications other than those specified in this policy, including but not limited to central sleep apnea (for which the Remedé System has FDA approval but evidence is considered insufficient).

Diaphragmatic/phrenic nerve stimulation devices (including the Mark IV and Spirit systems) are intended only for the specific indications listed in this policy. Use for other diagnoses or symptoms not explicitly covered should be considered off‑label or outside the scope of this policy and will be evaluated against the medical necessity criteria described herein. Documentation must demonstrate the applicable covered indication and that the device-specific criteria (for example, demonstrable diaphragm movement with stimulation and intact phrenic nerve/lung/diaphragm function) are met prior to coverage consideration.

Requests for diaphragmatic/phrenic nerve stimulation for indications other than those specified in this policy are not supported by sufficient evidence and are considered not medically necessary. In particular, although the Remedé System received FDA approval for moderate to severe central sleep apnea in adults, current evidence is inadequate to establish its safety and effectiveness; therefore central sleep apnea and similar unsupported indications remain excluded under this policy.

Procedure and Supply Codes

Referenced CPT CodesCPT

64575	Open implantation of neurostimulator electrode array; peripheral nerve (excludes sacral nerve).
64580	Open implantation of neurostimulator electrode array; neuromuscular.
64590	Insertion or replacement of peripheral, sacral, or gastric neurostimulator pulse generator or receiver, requiring pocket creation and connection between electrode array and pulse generator or receiver.
64595	Revision or removal of peripheral, sacral, or gastric neurostimulator pulse generator or receiver, with detachable connection to electrode array.

Referenced HCPCS / Supply CodesHCPCS

C1778	Lead, neurostimulator (implantable).
C1816	Receiver and/or transmitter, neurostimulator (implantable).
L8680	Implantable neurostimulator electrode, each.
L8681	Patient programmer (external) for use with implantable programmable neurostimulator pulse generator, replacement only.
L8682	Implantable neurostimulator radiofrequency receiver.
L8683	Radiofrequency transmitter (external) for use with implantable neurostimulator radiofrequency receiver.
L8685	Implantable neurostimulator pulse generator, single array, rechargeable, includes extension.
L8686	Implantable neurostimulator pulse generator, single array, nonrechargeable, includes extension.
L8687	Implantable neurostimulator pulse generator, dual array, rechargeable, includes extension.
L8688	Implantable neurostimulator pulse generator, dual array, nonrechargeable, includes extension.

1–10 of 13

1/2

inv-08: Minimum independent breathing duration — operational parameter

Minimum duration requiredAt least four continuous hours per day of independent breathing without mechanical ventilator support (NeuRx RA/4 and for spinal cord injury indication)

PurposeDemonstrates that stimulation produces sufficient diaphragm activity to allow periods off the ventilator

Applicable device/indicationSpecifically required for NeuRx RA/4 spinal cord injury indication and in device-specific coverage language

inv-09: Forced Vital Capacity (FVC) threshold for ALS

FVC thresholdForced Vital Capacity (FVC) not less than 45% predicted

Applicable indicationRequired for NeuRx RA/4 use in amyotrophic lateral sclerosis (ALS) patients

Age requirement linkUsed together with the NeuRx ALS age criterion (patient must be 21 years or older)

Authorization, Documentation, and Denials

Prior Authorization

Prior Authorization Required

Prior authorization is required prior to implantation or device-specific procedures. Submit PA request with device model (e.g., Mark IV Breathing Pacemaker, Spirit Diaphragm Pacing Transmitter, NeuRx RA/4) and clinical indication. Failure to obtain prior authorization may result in claim denial or delay.

Affected devices: Mark IV Breathing Pacemaker System, Spirit Diaphragm Pacing Transmitter, NeuRx RA/4 Diaphragm Pacing System

Step Therapy

No Step Therapy

No step therapy requirements apply for diaphragmatic/phrenic nerve stimulation devices — members do not need to fail alternative therapies prior to coverage when medical necessity criteria are met.

Documentation Required

Required Clinical Documentation

Provide complete clinical documentation with the prior authorization and at time of claim submission to demonstrate medical necessity. Documentation should include:

History and diagnosis supporting severe, chronic respiratory failure (e.g., upper cervical spinal cord injury, central alveolar hypoventilation, ALS where applicable)
Objective evidence of diaphragm movement with stimulation (fluoroscopy or alternative radiographic technique such as ultrasound)
Evidence of intact and sufficient phrenic nerve, lung, and diaphragm function (nerve conduction studies, pulmonary function tests, clinical exam)
Demonstration that stimulation produces sufficient diaphragmatic contraction to support independent breathing (e.g., ability to breathe without ventilator support for at least four continuous hours per day where specified)
Documentation of normal chest anatomy, normal level of consciousness, and patient ability to participate in training/rehabilitation
For NeuRx RA/4 (HDE): age ≥21, baseline FVC ≥45% predicted and other HDE-specified criteria

Denial Risk

Denial Triggers for Unmet Criteria

Claims will be denied if medical necessity criteria are not met or well-documented. Common denial triggers include:

No prior authorization when required
No demonstrable diaphragm movement with stimulation on fluoroscopy or equivalent imaging
Insufficient phrenic nerve, lung, or diaphragm function documented
Stimulation does not produce adequate diaphragmatic activity to permit independent breathing (e.g., inability to sustain at least four continuous hours off ventilator when required)
Lack of documentation of diagnosis or indication consistent with policy (e.g., ALS criteria under HDE, upper cervical spinal cord injury at/above C3, central alveolar hypoventilation)
Incomplete clinical records or missing training/rehabilitation plan

Definitions and Regulatory Terms

inv-15: Diaphragm pacing — definition of diaphragmatic/phrenic nerve stimulation

DefinitionDiaphragmatic/phrenic nerve stimulation (diaphragm pacing): electrical stimulation of the phrenic nerves or diaphragm to produce rhythmic diaphragm contractions to enable or reduce dependence on mechanical ventilation

MechanismUses implanted electrodes or leads to deliver electrical impulses to the phrenic nerve or diaphragm muscle, causing contraction and breathing

Clinical goalAllow independent breathing or reduce ventilator time in select patients with bilateral diaphragm paralysis or severe paresis

inv-16: HDE / HUD — Humanitarian Device Exemption regulatory note

HDE / HUD explainedHumanitarian Device Exemption (HDE) / Humanitarian Use Device (HUD): an FDA pathway under which NeuRx RA/4 initially received approval for ALS and distribution was granted under HDE prior to later full approval for select spinal cord indications

Regulatory history (NeuRx RA/4)NeuRx RA/4 received HDE approval for ALS in 2011 and earlier HDE distribution in 2008; it obtained full FDA approval in 2023 for use in patients with stable, high spinal cord injuries with stimulatable diaphragms

Implication for coverageCoverage for NeuRx RA/4 is tied to the device's HDE/HUD specifications for ALS (including age and FVC limits) and to FDA-approved indications for other uses

OpenPayer

Diaphragmatic/Phrenic Nerve Stimulation

Coverage and Medical Necessity Criteria

Procedure and Supply Codes

Authorization, Documentation, and Denials

Background and Device Approvals

Definitions and Regulatory Terms