ModifiedPremera Blue Cross of WashingtonPolicy N/A

Navigated Transcranial Magnetic Stimulation for Preoperative Brain Mapping

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Coverage of navigated transcranial magnetic stimulation for preoperative motor or language mapping in individuals undergoing surgery for brain tumors or other intracranial lesions near eloquent cortex.

Policy Summary

PayerPremera Blue Cross of Washington

PolicyNavigated Transcranial Magnetic Stimulation for Preoperative Brain Mapping

Policy CodePolicy N/A

Change TypeNew policy

Effective DateFebruary 5, 2027

Next Review DateN/A

Key ActionDo not expect coverage for preoperative nTMS motor or language mapping because it is considered investigational.

SourceLink

POLICY UPDATE CHANGES

A new policy was created stating that navigated repetitive transcranial magnetic stimulation for preoperative motor or language mapping is investigational.

InvestigationalCoverage stance

1CPT code identified

2FDA clearance milestones

NoneMedicare national coverage determination

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ModifiedPremera Blue Cross of WashingtonPolicy N/A

Navigated Transcranial Magnetic Stimulation for Preoperative Brain Mapping

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Policy Summary

PayerPremera Blue Cross of Washington

PolicyNavigated Transcranial Magnetic Stimulation for Preoperative Brain Mapping

Policy CodePolicy N/A

Change TypeNew policy

Effective DateFebruary 5, 2027

Next Review DateN/A

Key ActionDo not expect coverage for preoperative nTMS motor or language mapping because it is considered investigational.

SourceLink

POLICY UPDATE CHANGES

A new policy was created stating that navigated repetitive transcranial magnetic stimulation for preoperative motor or language mapping is investigational.

InvestigationalCoverage stance

1CPT code identified

2FDA clearance milestones

NoneMedicare national coverage determination

Coverage Criteria

Preoperative motor or language mapping

The service is considered investigational.

Investigational preoperative nTMS: Navigated transcranial magnetic stimulation of the brain using an FDA-cleared device and modality is considered investigational when used for preoperative motor or language mapping in individuals undergoing surgery for brain tumors or other intracranial lesions near eloquent cortex, such as with Nexstim Navigated Brain Stimulation Systems.

No coverage criteria establish medical necessity because the service is classified as investigational.

Evidence insufficient for routine coverage

The evidence is insufficient to establish improved net health outcomes.

Evidence basis for investigational status: Evidence limitations include nonrandomized designs, historical or matched controls, single-center expertise, heterogeneous tumor populations and mapping tasks, variable follow-up, inconsistent outcome definitions, different devices, and multimodal surgical workflows that make it difficult to isolate the independent effect of nTMS.

The policy concludes that routine nTMS for presurgical motor or language mapping remains investigational.

Coding Information

Investigational Navigated Transcranial Magnetic StimulationCPTExperimental

64999

Unlisted procedure, nervous system

Provider Action Required

Denial Risk

Investigational nTMS is not covered

Coverage is denied because navigated transcranial magnetic stimulation (nTMS), including use with an FDA-cleared device and modality for preoperative motor or language mapping in individuals undergoing surgery for brain tumors or other intracranial lesions near eloquent cortex, is considered investigational.

Applicable to preoperative motor or language mapping for brain tumors or other intracranial lesions near eloquent cortex.
The evidence is insufficient to establish improved net health outcomes compared with standard presurgical planning and intraoperative mapping.
CPT 64999 is identified for investigational navigated transcranial magnetic stimulation (unlisted procedure, nervous system).

Denial Risk

Investigational preoperative mapping

Preoperative navigated repetitive transcranial magnetic stimulation of the brain using an FDA-cleared device and modality is considered investigational for motor or language mapping in individuals undergoing surgery for brain tumors or other intracranial lesions near eloquent cortex; this investigational status is a basis for noncoverage.

Clinical Background

Navigated transcranial magnetic stimulation (nTMS) is a noninvasive technique that combines transcranial magnetic stimulation with MRI-based neuronavigation to map functional cortical areas before neurosurgery. It may identify motor-related sites through motor evoked potentials and language-related sites during tasks such as object naming. Mapping information may support surgical planning for tumors or other intracranial lesions involving or located near eloquent cortex, including assessment of surgical risk, approach, and potential extent of resection.

nTMS is an adjunctive preoperative method rather than a replacement for intraoperative direct cortical or direct electrical stimulation, which remains commonly used to confirm functional boundaries when clinically indicated. Although studies report correspondence between nTMS and intraoperative mapping and possible effects on surgical planning, the evidence is limited by nonrandomized designs, heterogeneous populations and mapping protocols, variable follow-up, and multimodal surgical workflows. The policy therefore concludes that evidence is insufficient to establish improved net health outcomes from routine presurgical nTMS compared with standard planning and intraoperative mapping.

Definitions

Navigated transcranial magnetic stimulation (nTMS)

DefinitionA noninvasive method of mapping functional cortical areas before neurosurgery.

MRI-based neuronavigationThe Nexstim navigated brain stimulation system integrates transcranial magnetic stimulation with magnetic resonance imaging (MRI)-based neuronavigation to localize motor- or language-related cortical sites.

Planning useMapping data may be exported for surgical planning, neuronavigation, and diffusion tensor imaging tractography.

Eloquent cortex

DefinitionBrain regions involved in important functions such as movement or language.

Clinical significanceSurgical injury to eloquent cortex may cause neurologic deficits.

Policy Summary

PayerPremera Blue Cross of Washington

PolicyNavigated Transcranial Magnetic Stimulation for Preoperative Brain Mapping

Policy CodePolicy N/A

Change TypeNew policy

Effective DateFebruary 5, 2027

Next Review DateN/A

Key ActionDo not expect coverage for preoperative nTMS motor or language mapping because it is considered investigational.

SourceLink

On This Page

The policy was approved October 13, 2026.
The policy is effective for dates of service on or after February 5, 2027, following 90-day provider notification.

Surgical contextLesions involving motor or language areas require individualized planning to balance resection goals against the risk of permanent neurologic deficit.

Direct cortical stimulation/direct electrical stimulation (DCS/DES)

DefinitionIntraoperative direct cortical stimulation or direct electrical stimulation are methods used to identify functional cortical boundaries.

Reference standardIntraoperative direct cortical stimulation or direct electrical stimulation is generally considered the reference standard for identifying eloquent cortex.

Relationship to preoperative mappingPreoperative mapping may provide information before surgery, but intraoperative stimulation is still commonly used to confirm functional boundaries when clinically indicated.

Navigated transcranial magnetic stimulation

Device-related definitionA noninvasive diagnostic technique cleared for preprocedural mapping uses under the evoked response electrical stimulator classification.

Motor cortex mappingThe Nexstim eXimia and NBS System 4 systems were cleared for noninvasive mapping of the primary motor cortex for preprocedural planning.

NEXSPEECH contextNEXSPEECH, used with the NBS System 4, was cleared to localize cortical areas that do not contain essential speech function and to provide information for presurgical planning in patients undergoing brain surgery.

Intraoperative limitationThe localization information provided by NEXSPEECH is intended to be verified by direct cortical stimulation, and the device is not intended for use during a surgical procedure.

Preprocedural mapping

IndicationThe Nexstim device indication for motor and speech mapping is for preprocedural or presurgical planning.

Motor mapping purposeThe NBS System 4 is indicated for noninvasive mapping of the primary motor cortex for preprocedural planning.

Speech mapping purposeNEXSPEECH provides information for presurgical planning by localizing cortical areas that do not contain essential speech function.

Not for intraoperative useThe device is not intended for use during a surgical procedure; NEXSPEECH localization is intended to be verified by direct cortical stimulation.