Blue Cross Blue Shield MA IONM Coverage Update

Coverage Criteria and Medical Necessity

Intraoperative Neurophysiologic Monitoring — Medically Necessary

IONM may be considered MEDICALLY NECESSARY when ALL of the following are met:

Real-time monitoring: Monitoring is being conducted in real-time and interpretation is continuously communicated to the surgical team

Requires continuous intraoperative interpretation and communication

Monitored nerves and indicated surgical scenarios: The individual is having one or more of the following nerves/modalities monitored in the setting of indicated high‑risk surgical scenarios: cranial nerves for intracranial/spinal/vascular procedures (including spinal instrumentation requiring screws or distraction); facial nerve monitoring for skull base, head and neck, neurotologic procedures (eg, acoustic neuroma, parotid tumor, cochlear implantation); recurrent laryngeal nerve monitoring for high‑risk thyroid/parathyroid procedures (eg, total thyroidectomy, reoperation, surgery for cancer, retrosternal/giant goiter) and for selected anterior cervical spine procedures with increased RLN risk (multilevel ACDF, prior anterior cervical surgery, scarred field, preexisting RLN pathology with residual function); brachial or lumbar plexus and other peripheral nerve monitoring for procedures at high risk of nerve injury; high‑risk vascular and interventional neuroradiology procedures; spinal procedures with high risk of cord injury (eg, spinal cord tumor, fracture with cord compression, mechanical distraction, scoliosis correction).

See detailed lists of nerves and scenarios in source

Visual Evoked Potential Testing

Visual evoked potentials (VEPs):

VEP indications: May be considered MEDICALLY NECESSARY for diagnosis, evaluation, or monitoring of: multiple sclerosis, neuromyelitis optica (NMO) or other demyelinating disorders; suspected disorder of the optic nerve, optic chiasm, or optic radiations not explained by MRI, CT, infection, or metabolic disorder

VEPs are not medically necessary for other uses (eg, routine infant screening)

Somatosensory Evoked Potential Testing

Somatosensory evoked potentials (SSEPs):

SSEP indications: May be considered MEDICALLY NECESSARY when results will be used to guide clinical management for: acute (within 72 hours) anoxic encephalopathy; unexplained CNS deficit when not explained by imaging; coma following traumatic, hypoxic‑ischemic or other diffuse brain injuries; demyelinating disease when diagnosis is uncertain; spinocerebellar degeneration (eg, Friedreich's ataxia); unexplained myelopathy; spinal cord lesions secondary to trauma when need for surgery is uncertain; suspected brain death

SSEPs are not medically necessary for other uses

Motor Evoked Potential Testing

Motor evoked potentials (MEPs):

MEP indications: May be considered MEDICALLY NECESSARY when results will be used to guide clinical management for: acute (within 72 hours) anoxic encephalopathy; unexplained CNS deficit when not explained by imaging; coma following traumatic, hypoxic‑ischemic or other diffuse brain injuries; demyelinating disease when diagnosis is uncertain; spinocerebellar degeneration; unexplained myelopathy; spinal cord lesions secondary to trauma when need for surgery is uncertain; suspected brain death. MEPs are MEDICALLY NECESSARY for evaluation of suspected hysterical/factitious paralysis.

MEPs are not medically necessary for other uses; non‑operative use is not medically necessary when criteria not met

Investigational Uses

Investigational/not covered uses:

Investigational IONM uses: IONM is considered INVESTIGATIONAL when criteria above are not met. Examples include: IONM of the recurrent laryngeal nerve during anterior cervical spine surgery that does not meet the specified high‑risk criteria or during esophageal surgeries; intraoperative monitoring of visual evoked potentials; intraoperative MEP monitoring using transcranial magnetic stimulation (lack of FDA approval); intraoperative EMG and nerve conduction velocity monitoring during peripheral nerve surgery.

Listed investigational items per source

Not Medically Necessary / NMN

Not medically necessary statements:

Not medically necessary: IONM is NOT MEDICALLY NECESSARY for cervical spine surgery that does not meet the listed high‑risk criteria (eg, standard anterior cervical discectomy and fusion). Intraoperative VEPs and other listed uses when criteria are not met are considered investigational/not medically necessary.

See source for additional examples

Coverage with medical necessity and code/diagnosis match

Covered when ALL of the following are met

Billing and diagnosis: The specific IOM procedure codes (CPT/HCPCS/ICD‑10‑PCS) are billed and the submitted ICD‑10 diagnosis code is one of the diagnoses listed as medically necessary in the policy.

Medical necessity criteria must be met for coverage

Medical necessity: The medical necessity criteria described elsewhere in the policy are met for the procedure(s)

Coverage contingent on meeting medical necessity criteria

EMG pairing when used: When EMG is utilized as part of intraoperative neurophysiologic monitoring, the appropriate EMG CPT code must be reported in conjunction with codes 95940, 95941, or G0453 as applicable.

Coding and documentation pairing required

Coverage for IONM motor evoked potentials

Covered when ALL of the following are met

Coverage prerequisites for MEP CPTs: CPT code billed is one of 95928, 95929, or 95939; an ICD‑10 diagnosis code from the enumerated list for these CPT codes is submitted; and the policy's medical necessity criteria for IONM are met.

Claims without meeting these conditions are not covered

Coverage by Indication

Coverage determinations summarized by procedure/location and evidence strength:

Thyroid/parathyroid (recurrent laryngeal nerve) high‑risk: Covered when IONM is used for thyroid or parathyroid surgery in patients at high risk of recurrent laryngeal nerve injury (eg, reoperation, total thyroidectomy, retrosternal or giant goiter, surgery for cancer, low surgeon volume); evidence includes a large RCT showing reduced RLN injury.high‑risk defined per trial (eg, reoperation, total thyroidectomy, low surgeon volume)

Evidence sufficient to show improvement in net health outcome

Anterior cervical spine (selected high‑risk): IONM of the recurrent laryngeal nerve for anterior cervical spine surgery may be considered for selected high‑risk subgroups (multilevel ACDF, revision through scarred field, prior anterior cervical surgery, preexisting RLN pathology with residual function) based on clinical input; overall evidence insufficient for routine use.patient selection per expert input

Supported by clinical expert opinion for selected patients

Policy statements and historical indication changes

Policy statements and indications have been reviewed and updated historically; the excerpt documents changes in indications and clarifications but states policy statements remained unchanged in several updates.

Policy updates summary: Multiple reviews and clarifications recorded in policy history include: expansion of MEP indications effective 11/1/2024; addition of spinal instrumentation indication (procedures requiring screws or distraction) in 6/2023; coding clarifications and cross‑reference to related policy #701 for EMG coding and requirement to report EMG CPT codes in conjunction with IONM codes; changes in investigational/coverage status for intraoperative EMG/NCV for peripheral nerve surgery in 6/2022. Many annual reviews noted references updated with policy statements unchanged.

See policy history entries in source

Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) are not medically necessary for uses beyond the indications listed in this policy. The policy specifies clinical situations in which SSEPs and MEPs may be considered medically necessary (for example, acute anoxic encephalopathy within 72 hours, unexplained CNS deficit not explained by imaging, coma after diffuse brain injury, demyelinating disease when diagnosis is uncertain, unexplained myelopathy, spinal cord lesions after trauma when surgical decision is uncertain, and suspected brain death). Use of SSEPs or MEPs outside those listed indications is considered not medically necessary and is not supported by the policy.

Additionally, certain intraoperative monitoring applications are specifically identified as investigational (for example, monitoring of MEPs using transcranial magnetic stimulation and monitoring of visual-evoked potentials) and are excluded when the investigational criteria apply.

CPT and HCPCS codes referenced in this policy will not be covered unless the policy's medical necessity criteria are met and an appropriate ICD-10 diagnosis code from the enumerated list is submitted. The policy explicitly states that the medical necessity criteria MUST be met for coverage across specified member types including Commercial Managed Care (HMO and POS), Commercial PPO, Indemnity, Medicare HMO Blue and Medicare PPO Blue.

When billed with motor-evoked potential CPT codes (e.g., 95928, 95929, 95939) or other IONM procedure codes, claims require both an allowed procedure code and a matching medically necessary ICD-10 diagnosis code from the policy's listed set for the service to be considered covered.

CPT code 0464T (visual evoked potential testing for glaucoma with interpretation and report) is designated in the policy as investigational for Commercial Members and therefore is not covered for those members.

Medicare-specific local coverage determinations and related Medicare references were removed from this policy in January 2021 and are handled separately; the policy directs users to the Medicare policy management process (see MP #132) for current Medicare LCD/NCD guidance.

Intraoperative monitoring of motor-evoked potentials using transcranial magnetic stimulation is considered investigational because of lack of U.S. Food and Drug Administration approval and insufficient evidence to support routine clinical use; as such this technique is excluded from coverage under the investigational provisions of the policy.

The policy identifies several indications for which the evidence is insufficient or not established to support improved net health outcome, and therefore are considered investigational or not established. Examples include intraoperative monitoring of the recurrent laryngeal nerve during anterior cervical spine surgery that does not meet specified high‑risk criteria, intraoperative visual‑evoked potential monitoring, and certain uses of IONM in esophageal or peripheral nerve surgeries where available studies are nonrandomized or limited in quality.

Policy history documents that the status of intraoperative electromyography (EMG) and nerve conduction velocity monitoring during peripheral nerve surgery was changed: in June 2022 the policy position for these services was revised from "not medically necessary" to investigational. Subsequent history entries note coding clarifications and cross-references to related EMG policy guidance.

Procedure and Diagnosis Codes

ICD-10-PCS Procedure CodesICD-10

4A1O04G	Monitoring of Central Nervous Electrical Activity, Intraoperative, Open Approach
4A1034G	Monitoring of Central Nervous Electrical Activity, Intraoperative, Percutaneous Approach
4A1074G	Monitoring of Central Nervous Electrical Activity, Intraoperative, Via Natural or Artificial Opening
4A1084G	Monitoring of Central Nervous Electrical Activity, Intraoperative, Via Natural or Artificial Opening, Endoscopic
4A1OX4G	Monitoring of Central Nervous Electrical Activity, Intraoperative, External Approach
4A1104G	Monitoring of Peripheral Nervous Electrical Activity, Intraoperative, Open Approach
4A1134G	Monitoring of Peripheral Nervous Electrical Activity, Intraoperative, Percutaneous Approach
4A1174G	Monitoring of Peripheral Nervous Electrical Activity, Intraoperative, Via Natural or Artificial Opening
4A1184G	Monitoring of Peripheral Nervous Electrical Activity, Intraoperative, Via Natural or Artificial Opening, Endoscopic
4A11X4G	Monitoring of Peripheral Nervous Electrical Activity, Intraoperative, External Approach

HCPCS CodesHCPCS

G0453

Continuous intraoperative neurophysiology monitoring; from outside the operating room (remote or nearby), per patient; each 15 minutes

HCPCS Billing Notemixed

When EMG is used as part of IONM, appropriate EMG CPT code must also be billed (see policy).

CPT Codes (SSEP)CPTCovered

95926	Short-latency somatosensory evoked potential study, upper limbs
95927	Short-latency somatosensory evoked potential study, trunk or head
95938	Short-latency somatosensory evoked potential study, upper and lower limbs

CPT Codes (MEP)CPTCovered

95928	Central motor evoked potential study (transcranial motor stimulation); upper limbs
95929	Central motor evoked potential study (transcranial motor stimulation); lower limbs
95939	Central motor evoked potential study (transcranial motor stimulation); upper and lower limbs
95930	Visual evoked potential (VEP) testing, central nervous system

CPT Codes (IONM time-based)CPT

95940	Continuous intraoperative neurophysiology monitoring in the operating room, one-on-one monitoring requiring personal attendance, each 15 minutes
95941	Continuous intraoperative neurophysiology monitoring from outside the operating room or for monitoring more than one case, per hour

Investigational CPTCPTExperimental

0464T

Visual evoked potential testing for glaucoma with interpretation and report (considered investigational for Commercial Members)

ICD-10 Diagnosis Codes (Neoplasms and Related)ICD-10Covered

C41.2	Malignant neoplasm of vertebral column
C70.0	Malignant neoplasm of cerebral meninges
C70.1	Malignant neoplasm of spinal meninges
C71.0	Malignant neoplasm of cerebrum, except lobes and ventricles
C71.1	Malignant neoplasm of frontal lobe
C71.2	Malignant neoplasm of temporal lobe
C71.3	Malignant neoplasm of parietal lobe
C71.4	Malignant neoplasm of occipital lobe
C71.5	Malignant neoplasm of cerebral ventricle
C71.6	Malignant neoplasm of cerebellum

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ICD-10 Diagnosis Codes (Neurologic, Sensory, and Other)ICD-10Covered

F44.4	Conversion disorder with motor symptom or deficit
F68.10	Factitious disorder imposed on self, unspecified
F68.11	Factitious disorder imposed on self, predominantly psychological signs
F68.12	Factitious disorder imposed on self, predominantly physical signs
F68.13	Factitious disorder imposed on self, combined signs
F68.8	Other specified disorders of adult personality and behavior
G11.0	Congenital nonprogressive ataxia
G11.10	Early-onset cerebellar ataxia, unspecified
G11.11	Friedreich ataxia
G11.2	Late-onset cerebellar ataxia

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ICD-10 Diagnosis Codes (Glasgow/Coma and Related)ICD-10Covered

R40.20	Unspecified coma
R40.2313	Coma scale, best motor response none, at hospital admission
R40.2314	Coma scale, best motor response none, 24 hours or more after hospital admission
R40.2320	Coma scale, best motor response extension, unspecified time
R40.2321	Coma scale, best motor response extension, in the field
R40.2322	Coma scale, best motor response extension, at arrival to ED
R40.2323	Coma scale, best motor response extension, at hospital admission
R40.2324	Coma scale, best motor response extension, 24 hours or more after admission
R40.2330	Coma scale, best motor response abnormal flexion, unspecified time
R40.2331	Coma scale, best motor response abnormal flexion, in the field

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Authorization, Documentation, and Billing Instructions

Note

Provider actions summary

No denial rules are present in this section. There are no explicit authorization triggers or denial triggers stated here. This section does not specify any authorization or denial requirements. It contains ICD-10 diagnosis code listings only. No documentation requirements are stated in this module section. There is no step therapy information or step therapy requirements described in these chunks.

Provides ICD-10 diagnosis code lists related to intraoperative neurophysiologic monitoring (IONM) and associated CPT/HCPCS codes.
Notes prior authorization processes elsewhere in the policy (Authorization Manager) but does not impose authorization rules within this section.
Clarifies that providers should report services using up-to-date procedure, revenue, and diagnosis codes; however, no specific documentation requirements are given here.
States that inclusion/exclusion of a code does not guarantee coverage and refers readers to member contract benefits for coverage determination.

Background and Scope

Background: Intraoperative neurophysiologic monitoring (IONM) comprises real‑time electrophysiologic techniques (including somatosensory‑evoked potentials, motor‑evoked potentials, brainstem auditory‑evoked potentials, electromyography, electroencephalography, and electrocorticography) that are continuously interpreted and communicated to the surgical team during procedures with risk of neural injury. The principal goal of IONM is to identify nervous system impairment intraoperatively so the surgical team can take immediate steps to prevent or limit permanent neurologic injury.

Definition — Intraoperative neurophysiologic monitoring (IONM)

DefinitionReal-time monitoring during surgery including SSEPs, MEPs, BAEPs, EMG, EEG, and electrocorticography with continuous interpretation communicated to the surgical team

PurposeIdentify nervous system impairment intraoperatively to allow prompt intervention to prevent permanent deficits

Continuous interpretation requirementMonitoring must be conducted in real-time with continuous communication of interpretation to the surgical team

Definition — Evoked Potential Testing (VEP, SSEP, MEP)

Policy History and Updates

2025-06annual_reviewLatest

Annual policy review with literature update through February 27, 2025; references updated and policy statements unchanged.

2024-11-01indication_expansion

Motor evoked potentials expanded to include additional medically necessary indications effective 11/1/2024.

2023-06new_indication

OpenPayer

Intraoperative Neurophysiologic Monitoring (IONM) and Evoked Potential Testing — Coverage Criteria

Coverage Criteria and Medical Necessity

Procedure and Diagnosis Codes

Authorization, Documentation, and Billing Instructions

Background and Scope

Policy History and Updates