Blue Cross Blue Shield MA IONM Coverage Update

Coverage and Medical Necessity Criteria

Medically Necessary IONM

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

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

Procedure or nerve-specific indication: Patient is undergoing intracerebral surgery or surgery with significant risk for nerve injury and one or more of the following nerve/procedure-specific indications are being monitored: cranial nerve procedures (spinal, intracranial, vascular, head and neck surgery), facial nerve procedures (neurotologic/otologic procedures such as acoustic neuroma resection, parotid tumor resection, cochlear implantation), recurrent laryngeal nerve during high-risk thyroid/parathyroid surgery (total thyroidectomy, repeat surgery, cancer, thyrotoxicosis, retrosternal/giant goiter, thyroiditis) or anterior cervical spine surgery with increased risk (prior anterior cervical surgery/revision, multilevel ACDF, preexisting RLN pathology with residual function), and other high-risk procedures (high-risk vascular procedures, brachial or lumbar plexus surgery, spinal procedures with high cord injury risk, peripheral neuroma or procedures with traction risk).

Not Medically Necessary

IONM is considered NOT MEDICALLY NECESSARY for the following specific situations:

Not medically necessary situations: IONM for cervical spine surgery that does not meet high‑risk criteria (e.g., standard anterior cervical discectomy and fusion, cervical disc arthroplasty); monitoring of epidural injections; monitoring during radiofrequency ablation/denervation procedures; monitoring during placement of spinal cord stimulator or intrathecal pain pump; and any other indication that does not meet the policy criteria.

Investigational

IONM is considered INVESTIGATIONAL when used outside specified criteria, including:

Investigational applications: Intraoperative monitoring of the recurrent laryngeal nerve during anterior cervical spine surgery that does not meet the policy criteria or during esophageal surgeries; intraoperative monitoring of visual‑evoked potentials; motor‑evoked potentials using transcranial magnetic stimulation (lack of FDA approval); intraoperative electromyography and nerve conduction velocity monitoring during peripheral nerve surgery; and other uses not meeting the above medically necessary criteria.

General medical necessity requirement for listed codes

Covered when ALL of the following are met

General coverage prerequisite: The medical necessity criteria in this policy are met for the service(s) being billed, and the codes listed are submitted for Commercial Members (Managed Care HMO/POS, PPO, Indemnity) and Medicare HMO Blue/Medicare PPO Blue.

Medical Necessity Conditions for Coverage

Covered when ALL of the following are met

MEP monitoring coverage conditions: CPT code is 95928 or 95929 or 95939; an associated listed ICD‑10 diagnosis code from the policy is submitted; and the policy's medical necessity criteria are met.

Medical Necessity Requirement for Coverage

Covered when the medical necessity criteria in this policy are met for Commercial Members across the specified product lines.

Coverage prerequisite for product lines: Medical necessity criteria in this document must be met for the listed CPT/HCPCS and ICD‑10‑PCS codes to be covered for Commercial Members (Managed Care HMO/POS, PPO, Indemnity) and Medicare HMO Blue and Medicare PPO Blue.

Thyroid/Parathyroid Surgery (High-Risk) - Covered

Covered when ALL of the following are met:

High‑risk thyroid/parathyroid surgery: Patient is undergoing high‑risk thyroid or parathyroid surgery (examples: surgery for cancer, thyrotoxicosis, retrosternal or giant goiter, thyroiditis, repeat thyroid/parathyroid surgery, or total thyroidectomy) AND intraoperative monitoring of the recurrent laryngeal nerve is performed with real‑time interpretation communicated to the surgical team.

Anterior Cervical Spine Surgery - Selective (Based on Clinical Input)

Considered medically necessary in a subgroup when ALL of the following apply (clinical input):

Selected anterior cervical spine indications: Patient meets one or more of the following risk criteria: prior anterior cervical surgery (revision), multilevel anterior cervical discectomy and fusion, or preexisting recurrent laryngeal nerve pathology with residual function; and intraoperative monitoring of the recurrent laryngeal nerve is used with continuous interpretation communicated to the surgical team.

Esophageal Surgery - Insufficient Evidence

Evidence summary:

Esophageal surgery evidence: Systematic review of mainly nonrandomized comparative studies found less recurrent laryngeal nerve palsy with IONM but evidence is not sufficiently robust to conclude improved net health outcome for esophageal surgery.

Peripheral Nerve Surgery Proximal to Nerve - Insufficient Evidence

Evidence summary:

Peripheral nerve surgery evidence: Case series and a controlled cohort study report surgical guidance and predictive ability for peripheral nerve monitoring, but no prospective comparative studies demonstrate improved patient outcomes; evidence is insufficient to determine net health benefit.

Spinal Instrumentation Requiring Screws or Distraction - Covered

Covered when monitoring is used during instrumentation procedures requiring screws or distraction:

Spinal instrumentation monitoring: IONM is used during spinal instrumentation procedures requiring screws or mechanical distraction (e.g., lumbar instrumentation, scoliosis correction) with continuous interpretation communicated to the surgical team; available evidence demonstrates high sensitivity and specificity for detecting neurologic deficits and is sufficient to support coverage.

Monitoring of epidural injections, monitoring during radiofrequency ablation/denervation procedures, and monitoring during placement of a spinal cord stimulator or intrathecal pain pump are listed in the policy as not medically necessary when the medical necessity criteria are not met. The policy further states that IONM for cervical spine surgery that does not meet the high‑risk criteria (for example, routine anterior cervical discectomy and fusion) is not medically necessary. When the policy’s medical necessity criteria are not satisfied, the monitoring may be considered investigational or not medically necessary and subject to denial.

CPT code 95941 (continuous intraoperative neurophysiology monitoring from outside the operating room or for monitoring of more than one case, per hour) is noted in the policy as investigational for Medicare HMO Blue and Medicare PPO Blue. The document advises that Medicare product rules may limit or exclude reimbursement for this code for those Medicare products.

CPT 0464T (visual evoked potential testing for glaucoma) is designated in the policy as investigational for the Commercial and Medicare product lines listed and therefore is not covered. The document also distinguishes that other VEP testing for central nervous system indications (CPT 95930) is covered when medical necessity and documentation requirements are met.

The policy classifies several applications of IONM as either not medically necessary or investigational because the evidence is insufficient or the indication is outside the defined criteria. Examples explicitly cited include monitoring for epidural injections, radiofrequency ablation/denervation, placement of spinal cord stimulators or intrathecal pumps, intraoperative visual‑evoked potential monitoring, and transcranial magnetic stimulation MEPs. For indications such as esophageal surgery and monitoring during peripheral nerve procedures proximal to the nerve, the evidence is described as insufficient to determine improved patient‑level outcomes.

The references and endnotes section provides the supporting literature and guideline citations underlying the coverage positions (for example, AAN and society guidance documents). In the excerpted endnotes there are no additional explicit coverage exclusions beyond those stated in the policy text; endnote commentary is largely expert opinion and citation support for the policy statements.

When the policy’s medical necessity criteria are not met, the document indicates the associated modalities are not medically necessary. Examples given include SSEPs, MEPs, and VEPs when used outside the specified indications. The policy separately notes VEPs are not medically necessary for routine uses such as infant screening and that MEPs and SSEPs are not medically necessary in non‑operative settings when criteria are unmet.

The policy makes clear that claims for IONM are at risk for denial when the explicit medical necessity criteria are not met. The document states that the medical necessity criteria "MUST be met" for the listed CPT/HCPCS and ICD‑10‑PCS codes to be covered for Commercial and Medicare members; billing codes submitted without meeting those criteria may therefore be denied.

Because CPT 0464T is labeled investigational for the product lines in the policy, its use for glaucoma testing is not covered and is not considered eligible for reimbursement under the policy’s medical necessity framework. The policy contrasts this investigational VEP code (0464T) with the covered CNS VEP code 95930, which requires interpretation and reporting and must meet medical necessity criteria.

The policy identifies IONM uses where current evidence is judged insufficient to demonstrate improved patient outcomes; these investigational or unproven indications include monitoring during certain esophageal procedures and intraoperative peripheral nerve monitoring proximal to the nerve. In such cases the policy treats the application as investigational or not proven rather than routinely medically necessary.

In the references/endnotes excerpted there are no standalone statements labeling additional services as "not medically necessary." That section is used to cite guidelines, position statements, and literature supporting the coverage determinations and includes an endnote indicating portions are based on expert opinion.

Billing, CPT/HCPCS, and ICD-10 Code Lists

Covered CPT CodesCPTCovered

95940	Continuous intraoperative neurophysiology monitoring in the operating room, one-on-one monitoring requiring personal attendance, each 15 minutes (List separately in addition to code for primary procedure).
95941	Continuous intraoperative neurophysiology monitoring, from outside the operating room (remote or nearby) or for monitoring of more than one case while in the operating room, per hour (List separately in addition to code for primary procedure). Note: 95941 is considered investigational for Medicare HMO Blue and Medicare PPO Blue.
95925	Short-latency somatosensory evoked potential study; upper limbs.
95926	Short-latency somatosensory evoked potential study; lower limbs.
95927	Short-latency somatosensory evoked potential study; trunk or head.
95938	Short-latency somatosensory evoked potential study; upper and lower limbs.
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); in upper and lower limbs.
95930	Visual evoked potential (VEP) checkerboard or flash testing, central nervous system except glaucoma, with interpretation and report.

Covered HCPCS CodesHCPCSCovered

G0453

Continuous intraoperative neurophysiology monitoring, from outside the operating room (remote or nearby), per patient (attention directed exclusively to one patient) each 15 minutes (list in addition to primary procedure). When EMG is utilized as part of intraoperative neurophysiologic monitoring, the appropriate EMG CPT code must be utilized in conjunction with 95940, 95941 or G0453.

Continuous IOM CPT CodesCPTCovered

95940	Continuous intraoperative neurophysiology monitoring, one-on-one, per 15 minutes.
95941	Continuous intraoperative neurophysiology monitoring, remote/outside OR or monitoring multiple cases, per hour.

Continuous IOM HCPCS CodeHCPCSCovered

G0453

Continuous intraoperative neurophysiology monitoring, remote/outside OR, per patient each 15 minutes.

SSEP CPT CodesCPTCovered

95925	SSEP upper limbs.
95926	SSEP lower limbs.
95927	SSEP trunk or head.
95938	SSEP upper and lower limbs.

ICD-10-PCS Procedure Codes for IOMICD-10Covered

4A1004G	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.
4A10X4G	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.

ICD-10 Diagnosis Codes — SSEP Related (grouped)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.

1–10 of 62

1/7

Large ICD-10 Diagnosis List (neutral)ICD-10

R40.2110	Coma scale, eyes open, never, unspecified time.
R40.2111	Coma scale, eyes open, never, in the field.
R40.2112	Coma scale, eyes open, never, at arrival to emergency department.
R40.2113	Coma scale, eyes open, never, at arrival to emergency department.
R40.2120	Coma scale, eyes open, to pain, unspecified time.
R40.2121	Coma scale, eyes open, to pain, in the field.
R40.2122	Coma scale, eyes open, to pain, at arrival to emergency department.
R40.2123	Coma scale, eyes open, to pain, at hospital admission.
R40.2124	Coma scale, eyes open, to pain, 24 hours or more after hospital admission.

Additional ICD-10 Diagnosis Codes (traumatic brain and spinal injuries)ICD-10Covered

S06.305D	Unspecified focal traumatic brain injury with loss of consciousness greater than 24 hours with return to pre-existing conscious level, subsequent encounter.
S06.305S	... sequela.
S06.306A	Unspecified focal traumatic brain injury with loss of consciousness greater than 24 hours without return to pre-existing conscious level with patient surviving, initial encounter.
S06.306D	... subsequent encounter.
S06.306S	... sequela.
S06.307A	Unspecified focal traumatic brain injury with death due to brain injury prior to regaining consciousness, initial encounter.
S06.308A	... death due to other cause prior to regaining consciousness, initial encounter.
S06.309A	Unspecified focal traumatic brain injury with loss of consciousness of unspecified duration, initial encounter.
S06.309D	... subsequent encounter.
S06.309S	... sequela.

Comprehensive ICD-10 Injury CodesICD-10Covered

S06.310D	Contusion and laceration of right cerebrum without loss of consciousness, subsequent encounter.
S06.310S	... sequela.
S06.311D	Contusion and laceration of right cerebrum with loss of consciousness of 30 minutes or less, subsequent encounter.
S06.312D	Contusion and laceration of right cerebrum with loss of consciousness of 31 minutes to 59 minutes, subsequent encounter.

Remaining ICD-10 Trauma Codes (selected)ICD-10Covered

S06.359A	Traumatic hemorrhage of left cerebrum with loss of consciousness of unspecified duration, initial encounter.
S06.360D	Traumatic hemorrhage of cerebrum, unspecified, without loss of consciousness, subsequent encounter.
S06.361A	Traumatic hemorrhage of cerebrum, unspecified, with loss of consciousness of 30 minutes or less, initial encounter.

Exhaustive ICD-10 Trauma & Injury CodesICD-10Covered

S06.370A	Contusion, laceration, and hemorrhage of cerebellum without loss of consciousness, initial encounter.
S06.371A	... with loss of consciousness of 30 minutes or less, initial encounter.
S06.372A	... with loss of consciousness of 31 minutes to 59 minutes, initial encounter.
S06.373A	... with loss of consciousness of 1 hour to 5 hours 59 minutes, initial encounter.

Extensive ICD-10 Injury Codes (brainstem and intracranial)ICD-10Covered

S06.380A	Contusion, laceration, and hemorrhage of brainstem without loss of consciousness, initial encounter.
S06.381A	... with loss of consciousness of 30 minutes or less, initial encounter.
S06.382A	... with loss of consciousness of 31 minutes to 59 minutes, initial encounter.
S06.383A	... with loss of consciousness of 1 hour to 5 hours 59 minutes, initial encounter.

Epidural/Subdural/Subarachnoid Hemorrhage CodesICD-10Covered

S06.4X0A	Epidural hemorrhage without loss of consciousness, initial encounter.
S06.5X0A	Traumatic subdural hemorrhage without loss of consciousness, initial encounter.
S06.6X0A	Traumatic subarachnoid hemorrhage without loss of consciousness, initial encounter.

Head Injury and Other Intracranial Injury CodesICD-10Covered

S06.890A	Other specified intracranial injury without loss of consciousness, initial encounter.
S06.891A	Other specified intracranial injury with loss of consciousness of 30 minutes or less, initial encounter.
S06.892A	Other specified intracranial injury with loss of consciousness of 31 minutes to 59 minutes, initial encounter.

General Head/Spine Injury CodesICD-10Covered

S06.9X0A	Unspecified intracranial injury without loss of consciousness, initial encounter.
S09.8XXA	Other specified injuries of head, initial encounter.
S09.90XA	Unspecified injury of head, initial encounter.

Cervical Spinal Cord Injury Codes (selected)ICD-10Covered

S14.101A	Unspecified injury at C1 level of cervical spinal cord, initial encounter.
S14.111A	Complete lesion at C1 level of cervical spinal cord, initial encounter.
S14.121A	Central cord syndrome at C1 level of cervical spinal cord, initial encounter.
S14.131A	Anterior cord syndrome at C1 level of cervical spinal cord, initial encounter.

Thoracic and Remaining Spinal Cord CodesICD-10Covered

S24.101A	Unspecified injury at T1 level of thoracic spinal cord, initial encounter.
S24.111A	Complete lesion at T1 level of thoracic spinal cord, initial encounter.
S24.131A	Anterior cord syndrome at T1 level of thoracic spinal cord, initial encounter.

Covered CPT Codes - Investigational/Not CoveredCPTNot Covered

0464T

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

Billing Incrementsmixed

95940	Billed per 15-minute increment for one-on-one continuous monitoring.
95941	Billed per hour for remote/multiple-case continuous monitoring (note: investigational status may apply for some products).
G0453	Billed per 15-minute increment for remote monitoring (per patient).

Authorization, Documentation, and Billing Actions for Providers

Prior Authorization

Prior Authorization Required

Prior authorization is required for intraoperative neurophysiologic monitoring (IONM) when performed inpatient for all products. For outpatient services, prior authorization is required for specified commercial products: Commercial Managed Care (HMO and POS) — outpatient prior authorization required for CPT 95940, 95941 and HCPCS G0453; Commercial PPO and Indemnity — outpatient prior authorization required for CPT 95940, 95941 and G0453. Providers should submit prior authorization requests using Authorization Manager and include facility NPI/provider ID and the servicing surgeon's NPI/provider ID. Note: historical policy revisions document prior authorization requirements applied to HMO, POS, and PPO product lines.

Inpatient: precertification/preauthorization IS REQUIRED for all products when procedure is inpatient.
Outpatient: prior authorization required for IONM codes 95940, 95941 and G0453 for specified commercial product lines.
Use Authorization Manager to submit requests; include facility NPI/provider ID and surgeon NPI/provider ID.

Documentation Required

Clinical Background and Evidence Summary

Some indications lack sufficient evidence to conclude benefit. The policy explains that intraoperative monitoring for esophageal surgery and for peripheral nerve procedures proximal to the nerve have observational or nonrandomized data but no prospective randomized evidence demonstrating improved patient outcomes, and therefore are considered to have insufficient evidence to support routine coverage.

Background: Intraoperative neurophysiologic monitoring (IONM) encompasses multiple modalities—SSEPs, MEPs, VEPs, EMG, EEG, and electrocorticography—used to provide real‑time physiologic assessment of nervous system function during surgery. The goal of IONM is to detect impending neurologic injury so the surgical team can intervene and reduce the risk of permanent deficits; interpretation is communicated to the surgical team while monitoring is ongoing.

Definitions and Terms

Definition — Intraoperative neurophysiologic monitoring (IONM)

Definition (IONM) — core modalitiesReal‑time intraoperative monitoring with continuous interpretation communicated to the surgical team using modalities such as somatosensory‑evoked potentials (SSEP), motor‑evoked potentials (MEP, transcranial electrical stimulation), brainstem auditory‑evoked potentials (BAEP), electromyography (EMG), electroencephalography (EEG), electrocorticography (ECoG), and visual‑evoked potentials (VEP)

PurposeDetect nervous system impairment intraoperatively so prompt intervention may prevent permanent deficits

Reporting requirementInterpretation must be continuously communicated to the surgical team during real‑time monitoring

Continuous intraoperative neurophysiology monitoring — billing increments and remote note

Continuous IONM (one‑on‑one) billing incrementReport per 15 minutes using CPT 95940 or HCPCS G0453 (G0453 for remote single‑patient attention)

Policy Revisions and Updates

2025-06annual_reviewLatest

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

2024-11-01material_policy_change

Policy revised to expand motor evoked potentials to include additional medically necessary indications; effective 2024-11-01.

2024-06annual_review

OpenPayer

Intraoperative Neurophysiologic Monitoring (IONM)