Subject:
Intraoperative Neurophysiologic Monitoring
Description:
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IMPORTANT NOTE:
The purpose of this policy is to provide general information applicable to the administration of health benefits that Horizon Blue Cross Blue Shield of New Jersey and Horizon Healthcare of New Jersey, Inc. (collectively “Horizon BCBSNJ”) insures or administers. If the member’s contract benefits differ from the medical policy, the contract prevails. Although a service, supply or procedure may be medically necessary, it may be subject to limitations and/or exclusions under a member’s benefit plan. If a service, supply or procedure is not covered and the member proceeds to obtain the service, supply or procedure, the member may be responsible for the cost. Decisions regarding treatment and treatment plans are the responsibility of the physician. This policy is not intended to direct the course of clinical care a physician provides to a member, and it does not replace a physician’s independent professional clinical judgment or duty to exercise special knowledge and skill in the treatment of Horizon BCBSNJ members. Horizon BCBSNJ is not responsible for, does not provide, and does not hold itself out as a provider of medical care. The physician remains responsible for the quality and type of health care services provided to a Horizon BCBSNJ member.
Horizon BCBSNJ medical policies do not constitute medical advice, authorization, certification, approval, explanation of benefits, offer of coverage, contract or guarantee of payment.
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Intraoperative neurophysiologic monitoring (IONM) describes a variety of procedures used to monitor the integrity of neural pathways during high-risk neurosurgical, orthopedic, and vascular surgeries. It involves the detection of electrical signals produced by the nervous system in response to sensory or electrical stimuli to provide information about the functional integrity of neuronal structures. This policy does not address established neurophysiologic monitoring (ie, somatosensory-evoked potentials, motor-evoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyography of cranial nerves, electroencephalography, electrocorticography), during spinal, intracranial, or vascular procedures.
| Populations | Interventions | Comparators | Outcomes |
Individuals:
- Who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve
| Interventions of interest are:
- Intraoperative neurophysiologic monitoring
| Comparators of interest are:
- Surgery without neurophysiologic monitoring
| Relevant outcomes include:
- Morbid events
- Functional outcomes
- Quality of life
|
Individuals:
- Who are undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve
| Interventions of interest are:
- Intraoperative neurophysiologic monitoring
| Comparators of interest are:
- Surgery without neurophysiologic monitoring
| Relevant outcomes include:
- Morbid events
- Functional outcomes
- Quality of life
|
Individuals:
- Who are undergoing esophageal surgery
| Interventions of interest are:
- Intraoperative neurophysiologic monitoring
| Comparators of interest are:
- Surgery without neurophysiologic monitoring
| Relevant outcomes include:
- Morbid events
- Functional outcomes
- Quality of life
|
Individuals:
- Who are undergoing surgery proximal to a peripheral nerve
| Interventions of interest are:
- Intraoperative neurophysiologic monitoring
| Comparators of interest are:
- Surgery without neurophysiologic monitoring
| Relevant outcomes include:
- Morbid events
- Functional outcomes
- Quality of life
|
BACKGROUND
Intraoperative Neurophysiologic Monitoring
The principal goal of intraoperative neurophysiologic monitoring is the identification of nervous system impairment on the assumption that prompt intervention will prevent permanent deficits. Correctable factors at surgery include circulatory disturbance, excess compression from retraction, bony structures, hematomas, or mechanical stretching. The technology is continuously evolving with refinements in equipment and analytic techniques, including recording, with several patients monitored under the supervision of a physician who is outside the operating room.
The different methodologies of monitoring are described next.
Sensory-Evoked Potentials
Sensory-evoked potentials describes the responses of the sensory pathways to sensory or electrical stimuli. Intraoperative monitoring of sensory-evoked potentials is used to assess the functional integrity of central nervous system pathways during surgeries that put the spinal cord or brain at risk for significant ischemia or traumatic injury. The basic principles of sensory-evoked potential monitoring involve identification of a neurologic region at risk, selection and stimulation of a nerve that carries a signal through the at-risk region and recording and interpreting the signal at certain standardized points along the pathway. Monitoring of sensory-evoked potentials is commonly used in the following procedures: carotid endarterectomy, brain surgery involving vasculature, surgery with distraction compression or ischemia of the spinal cord and brainstem, and acoustic neuroma surgery. Sensory-evoked potentials can be further categorized by type of stimulation used, as follows.
Somatosensory-Evoked Potentials
Somatosensory-evoked potentials are cortical responses elicited by peripheral nerve stimulations. Peripheral nerves, such as the median, ulnar, or tibial nerves, are typically stimulated, but in some situations, the spinal cord may be stimulated directly. The recording is done either cortically or at the level of the spinal cord above the surgical procedure. Intraoperative monitoring of somatosensory-evoked potentials is most commonly used during orthopedic or neurologic surgery to prompt intervention to reduce surgically induced morbidity and/or to monitor the level of anesthesia. One of the most common indications for somatosensory-evoked potential monitoring is in patients undergoing corrective surgery for scoliosis. In this setting, somatosensory-evoked potential monitors the status of the posterior column pathways and thus does not reflect ischemia in the anterior (motor) pathways. Several different techniques are commonly used, including stimulation of a relevant peripheral nerve with monitoring from the scalp, from interspinous ligament needle electrodes, or from catheter electrodes in the epidural space.
Brainstem Auditory-Evoked Potentials
Brainstem auditory-evoked potentials are generated in response to auditory clicks and can define the functional status of the auditory nerve. Surgical resection of a cerebellopontine angle tumor, such as an acoustic neuroma, places the auditory nerves at risk, and brainstem auditory-evoked potentials have been extensively used to monitor auditory function during these procedures.
Visual-Evoked Potentials
Visual-evoked potentials (VEPs) with light flashes are used to track visual signals from the retina to the occipital cortex. Visual-evoked potential (VEP) monitoring has been used for surgery on lesions near the optic chiasm. However, visual-evoked potentials (VEPs) are very difficult to interpret due to their sensitivity to anesthesia, temperature, and blood pressure.
Motor-Evoked Potentials
Motor-evoked potentials are recorded from muscles following direct or transcranial electrical stimulation of motor cortex or pulsed magnetic stimulation provided using a coil placed over the head. Peripheral motor responses (muscle activity) are recorded by electrodes placed on the skin at prescribed points along the motor pathways. Motor-evoked potentials, especially when induced by magnetic stimulation, can be affected by anesthesia. The Digitimer electrical cortical stimulator received the U.S. Food and Drug Administration (FDA) premarket approval in 2002. Devices for transcranial magnetic stimulation have not been approved by the FDA for this use.
Multimodal intraoperative neurophysiologic monitoring, in which more than one technique is used, most commonly with somatosensory-evoked potentials and motor-evoked potentials, has also been described.
Electromyogram Monitoring and Nerve Conduction Velocity Measurements
Electromyogram (EMG) monitoring and nerve conduction velocity measurements can be performed in the operating room and may be used to assess the status of the cranial or peripheral nerves (eg, to identify the extent of nerve damage before nerve grafting or during resection of tumors). For procedures with a risk of vocal cord paralysis due to damage to the recurrent laryngeal nerve (ie, during carotid artery, thyroid, parathyroid, goiter, or anterior cervical spine procedures), monitoring of the vocal cords or vocal cord muscles has been performed. These techniques may also be used during procedures proximal to the nerve roots and peripheral nerves to assess the presence of excessive traction or other impairment. Surgery in the region of cranial nerves can be monitored by electrically stimulating the proximal (brain) end of the nerve and recording via electromyogram (EMG) activity in the facial or neck muscles. Thus, monitoring is done in the direction opposite that of sensory-evoked potentials but the purpose is similar - to verify that the neural pathway is intact.
Electroencephalogram Monitoring
Spontaneous electroencephalogram (EEG) monitoring can also be used during surgery and can be subdivided as follows:
- Electroencephalogram (EEG) monitoring has been widely used to monitor cerebral ischemia secondary to carotid cross-clamping during a carotid endarterectomy. EEG monitoring may identify those patients who would benefit from the use of a vascular shunt during the procedure to restore adequate cerebral perfusion. Conversely, shunts, which have an associated risk of iatrogenic complications, may be avoided in those patients with a normal EEG activity. Carotid endarterectomy may be done with the patient under local anesthesia so that monitoring of cortical function can be directly assessed.
- Electrocorticography is the recording of electroencephalogram (EEG) activity directly from a surgically exposed cerebral cortex. Electrocorticography is typically used to define the sensory cortex and map the critical limits of a surgical resection. Electrocorticography recordings have been most frequently used to identify epileptogenic regions for resection. In these applications, Electrocorticography does not constitute monitoring, per se.
Intraoperative neurophysiologic monitoring, including somatosensory-evoked potentials and motor-evoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyogram (EMG) of cranial nerves, EEG, and Electrocorticography, has broad acceptance, particularly for spine surgery and open abdominal aorta aneurysm repairs. These indications have long been considered the standard of care, as evidenced by numerous society guidelines, including those from the American Academy of Neurology, American Clinical Neurophysiology Society, American Association of Neurological Surgeons, Congress of Neurologic Surgeons, and American Association of Neuromuscular & Electrodiagnostic Medicine.1,2,3,4,5,6,7, Therefore, this policy focuses on monitoring of the recurrent laryngeal nerve during neck and esophageal surgeries and monitoring of peripheral nerves.
Regulatory Status
A number of EEG and electromyogram (EMG) monitors have been cleared for marketing by the FDA through the 510(k) process. FDA product code: GWQ.
Intraoperative neurophysiologic monitoring of motor-evoked potentials using transcranial magnetic stimulation does not have FDA approval.
Related Policies
- Vestibular Function Testing (Policy #089 in the Medicine Section)
- Visual-Evoked Potential (VEP)/Visual-Evoked Response (VER) (Policy #090 in the Medicine Section)
- Electromyography and Nerve Conduction Studies (Policy #082 in the Medicine Section)
Policy:
(NOTE: For Medicare Advantage, please refer to the Medicare Coverage Section below for coverage guidance.)
1. Intraoperative neurophysiologic monitoring, which includes somatosensory-evoked potentials, motor-evoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyography (EMG) of cranial nerves, electroencephalography (EEG), and electrocorticography (ECoG), is considered medically necessary during spinal, intracranial, or vascular procedures.
2. Intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve is considered medically necessary in members undergoing:
- high-risk thyroid or parathyroid surgery, including:
o total thyroidectomy
o repeat thyroid or parathyroid surgery
o surgery for cancer
o thyrotoxicosis
o retrosternal or giant goiter
o thyroiditis
- anterior cervical spine surgery associated with any of the following increased risk situations:
o prior anterior cervical surgery, particularly revision anterior cervical discectomy and fusion, revision surgery through a scarred surgical field, reoperation for pseudarthrosis or revision for failed fusion
o multilevel anterior cervical discectomy and fusion
o preexisting recurrent laryngeal nerve pathology, when there is residual function of the recurrent laryngeal nerve.
3. Intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve during anterior cervical spine surgery not meeting the criteria above or during esophageal surgeries is considered investigational.
4. Intraoperative monitoring of visual-evoked potentials is considered investigational.
5. Due to the lack of monitors approved by the U.S. Food and Drug Administration, intraoperative monitoring of motor-evoked potentials using transcranial magnetic stimulation is considered investigational.
6. Intraoperative EMG and nerve conduction velocity monitoring during surgery on the peripheral nerves is not considered medically necessary.
(NOTE: These policy statements refer only to use of these techniques as part of intraoperative monitoring. Other clinical applications of these techniques, such as visual-evoked potentials and EMG, are not considered in this policy.)
Policy Guidelines: (Information to guide medical necessity determination based on the criteria contained within the policy statements above.)
Intraoperative neurophysiologic monitoring, including somatosensory-evoked potentials and motor-evoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyography of cranial nerves, electroencephalography, and electrocorticography, has broad acceptance, particularly for spine surgery and open abdominal aorta aneurysm repairs. Therefore, this policy focuses on monitoring of the recurrent laryngeal nerve during neck surgeries and monitoring of peripheral nerves.
Constant communication among the surgeon, neurophysiologist, and anesthetist is required for safe and effective intraoperative neurophysiologic monitoring.
Medicare Coverage:
National Coverage Determination (NCD) for Electroencephalographic Monitoring During Surgical Procedures Involving the Cerebral Vasculature (160.8). Available to be accessed at CMS National Coverage Determinations (NCDs) Alphabetical Index search page: https://www.cms.gov/medicare-coverage-database/indexes/ncd-alphabetical-index.aspx.
Intraoperative Neurophysiologic Monitoring is covered when Novitas Solutions, Inc., Local Coverage Determination (LCD): Intraoperative Neurophysiological Testing (L35003) criteria and Local Coverage Article:Billing and Coding: Intraoperative Neurophysiological Testing (A56722) criteria is met. Also refer to the below Local Coverage Determinations and Articles for applicable criteria for services related to Intraoperative Neurophysiologic Monitoring.
Local Coverage Determination (LCD): Intraoperative Neurophysiological Testing (L35003).
Local Coverage Article:Billing and Coding: Intraoperative Neurophysiological Testing (A56722)
Local Coverage Determination (LCD): Neurophysiology Evoked Potentials (NEPs) (L34975).
Local Coverage Article:Billing and Coding: Neurophysiology Evoked Potentials (NEPs) (A56773)
Local Coverage Determination (LCD): Nerve Conduction Studies and Electromyography (L35081).
Local Coverage- Article:Billing and Coding: Nerve Conduction Studies and Electromyography (A54095)
Local Coverage Determination (LCD): Vestibular and Audiologic Function Studies (L35007).
Local Coverage Article:Billing and Coding: Vestibular and Audiologic Function Studies (A57434)
Novitas Solutions, Inc., LCDs and Articles available to be accessed at Novitas Solutions, Inc., Medical Policy Search page: https://www.novitas-solutions.com/webcenter/portal/MedicareJL/pagebyid?contentId=00024370.
[RATIONALE: This policy was created in 2010 and has been updated regularly with searches of the PubMed database. The most recent literature update was performed through February 11, 2020.
Early literature focused on intraoperative monitoring of cranial and spinal nerves. This policy focuses on more recently investigated techniques, including monitoring of the recurrent laryngeal nerve and peripheral nerves.
Evidence reviews assess the clinical evidence to determine whether the use of technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function, including benefits and harms. Every clinical condition has specific outcomes that are important to patients and managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.
To assess whether the evidence is sufficient to draw conclusions about the net health outcome of technology, 2 domains are examined: the relevance, and quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. RCTs are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.
Recurrent Laryngeal Nerve Monitoring During Thyroid or Parathyroid Surgery
Clinical Context and Therapy Purpose
The purpose of intraoperative neurophysiologic monitoring is to provide a treatment option that is an alternative to or an improvement on existing therapies, such as surgery without neurophysiologic monitoring, in patients who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve.
The question addressed in this policy is: Does recurrent laryngeal nerve monitoring improve the net health outcome in patients undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve?
The following PICO was used to select literature to inform this policy.
Patients
The relevant population of interest is individuals who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve.
Interventions
The therapy being considered is intraoperative neurophysiologic monitoring.
Intraoperative neurophysiologic monitoring describes a variety of procedures used to monitor the integrity of neural pathways during high-risk neurosurgical, orthopedic, and vascular surgeries. It involves the detection of electrical signals produced by the nervous system in response to sensory or electrical stimuli to provide information about the functional integrity of neuronal structures.
Patients who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve are actively managed by endocrine surgeons, neurosurgeons, and primary care providers in a surgical setting.
Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by endocrine surgeons in a surgical setting.
Outcomes
The general outcomes of interest are morbid events, functional outcomes, and quality of life.
The existing literature evaluating intraoperative neurophysiologic monitoring as a treatment for patients who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve has varying lengths of follow-up. While studies described below all reported at least one outcome of interest, longer follow-up was necessary to fully observe outcomes.
Study Selection Criteria
Methodologically credible studies were selected using the following principles:
1. To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
2. In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
3. To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
4. Studies with duplicative or overlapping populations were excluded.
Henry et al (2017) reported on a systematic review of meta-analyses published up to February 2017 that compared intraoperative neurophysiologic monitoring with direct recurrent laryngeal nerve visualization by assessing rates of vocal fold palsy.8, Reviewers included 8 meta-analyses of RCTs or observational studies (prospective or retrospective) and selected the best evidence based on the Jadad algorithm. The 8 meta-analyses differed significantly in the literature search methodology, databases included, the inclusion of quality assessment, and most did not include a study quality assessment. Pisanu et al (2014) was found to be the highest-quality meta-analysis9,; it showed no statistically significant reductions in recurrent laryngeal nerve injury between procedures using intraoperative neurophysiologic monitoring versus direct recurrent laryngeal nerve visualization. However, reviewers also noted that recent developments in intraoperative neurophysiologic monitoring technology such as continuous vagal intraoperative neurophysiologic monitoring and staged thyroidectomy might provide additional benefits, which were out of the scope of their systematic review and need to be further assessed in prospective multicenter trials.
Sun et al (2017) reported on a meta-analysis of recurrent laryngeal nerve injury during thyroid surgery with or without intraoperative neurophysiologic monitoring.10, Included were 2 prospective cohort studies and 7 retrospective cohort studies. Results are summarized in Tables 1 and 2. Intraoperative neurophysiologic monitoring was associated with a reduction in overall and permanent recurrent laryngeal nerve palsy in thyroid reoperations. Limitations included small sample sizes and study heterogeneity.
Pardal-Refoyo and Ochoa-Sangrador (2016) reported on a systematic review of recurrent laryngeal nerve injury during total thyroidectomy with or without intraoperative neurophysiologic monitoring.11, Included were 1 large (n=1000) and 1 small (n=23) RCT and 52 case series that estimated the risk to the recurrent laryngeal nerve. Twenty-nine studies used recurrent laryngeal nerve monitoring and 25 did not. Results are summarized in Tables 1 and 2. The observed differences in the subgroup analysis were imprecise because the number of observed instances of paralysis was very low.
Table 1. Characteristics of Systematic Reviews
| Study | Dates | Trials | Participants | N (Range) | Design | Duration |
| Pardal-Refoyo and Ochoa-Sangrador (2016)11, | 1987-2013 |
| Studies reporting incidence of RLN paralysis after single-stage total thyroidectomy through open cervicotomy | 30 922 (23-2546 patients) |
| NR |
| Sun et al (2017)10, | Up to Aug 2016 | 9 | Studies reporting incidence of RLN complications after thyroid surgery | 2436 nerves at risk (1109 with IONM, 1327 without IONM) | Prospective and retrospective cohort studies | NR |
| Henry et al (2017)8, | Up to Feb 2017 | 8 meta-analyses | Meta-analyses of RCTs and non-RCTs comparing IONM with direct visualization for RLNs during thyroidectomy | 8 meta-analyses (6-23 patients) | Meta-analyses | NR |
IONM: intraoperative neurophysiologic monitoring; NR: not reported; RCT: randomized controlled trial; RLN: recurrent laryngeal nerve.
Table 2. Results of Systematic Reviews
| Study | Risk of Bilateral RLN Paralysis | Transient RLN Palsy | Permanent RLN Palsy |
| Pardal-Refoyo and Ochoa-Sangrador (2016)11, |
| ARR (95% CI) | 2.75% (NR)a | NR | NR |
| NNT (95% CI) | 364 (NR)a | NR | NR |
| I2 (p) | 8%a (NR) | NR | NR |
 | Overall RLN Palsy | | |
| Sun et al (2017)10, |
| With IONM | 4.69% | 3.98%b | 1.26%b |
| Without IONM | 9.27% | 6.63%b | 2.78%b |
| RR (95% CI) (p) | 0.434 (0.206 to 0.916) (0.029) | 0.607 (0.270 to 1.366) (0.227)b | 0.426 (0.196 to 0.925) (0.031)b |
| NNT (95% CI) | NR | NRb | NRb |
| I2 (p) | 70.2% (NR) | 67.4%b(NR) | 13.7%b(NR) |
ARR: absolute risk reduction; CI: confidence interval; IONM: intraoperative neurophysiologic monitoring NNT: number needed to treat; NR: not reported; RLN: recurrent laryngeal nerve; RR: relative risk.
a Sample size of 11947 patients.
b Sample of 7 studies.
Barczynski et al (2009) reported results of the largest RCT evaluating recurrent laryngeal nerve as summarized in Tables 3 and 4.12,recurrent laryngeal nerve monitoring was performed with electrodes on the vocal muscles through the cricothyroid ligament, which may not be the method currently used in the United States In high-risk patients, defined as those undergoing surgery for cancer, thyrotoxicosis, retrosternal or giant goiter, or thyroiditis, the prevalence of transient recurrent laryngeal nerve paresis was 2.9% lower in patients who had recurrent laryngeal nerve monitoring (p=0.011) compared with those who received visual identification only. In low-risk patients, there was no significant difference in recurrent laryngeal nerve injury rates between monitoring and no monitoring. Notably, high-risk patients with prior thyroid or parathyroid surgery were excluded from this trial. A benefit of recurrent laryngeal nerve monitoring was also shown in patients undergoing high-risk total thyroidectomy.13,
Table 3. Summary of Key Trial Characteristics
| Study | Countries | Sites | Dates | Participants | Active | Comparator |
| Barczynski et al (2009)12, | Poland | 1 | 2006-2007 | Patients undergoing bilateral neck surgery | 500 | 500 |
Table 4. Summary of Key RCT Results
| Study | RLN Injury | RLN Paresis | Permanent RLN Palsy |
| Barczynski et al (2009)12, | | | |
| RLN visualization alone, n/N | 8/500 | NR | NR |
| RLN visualization plus monitoring, n/N | NR | NR | NR |
| ARR (95% CI) (p) | 2.3% (NR) (0.007) | 1.9% (NR) (0.011) | 0.4% (NR) (NS) |
| NNT (95% CI) | NR | NR | NR |
ARR: absolute risk reduction; CI: confidence interval; NNT: number needed to treat; NR: not reported; NS: not significant RCT: randomized controlled trial; RLN: recurrent laryngeal nerve.
Section Summary: Recurrent Laryngeal Nerve Monitoring During Thyroid or Parathyroid Surgery
The evidence on the use of intraoperative neurophysiologic monitoring in reducing recurrent laryngeal nerve injury includes a large RCT and systematic reviews assessing thyroid and parathyroid surgery. The strongest evidence derives from an RCT of 1,000 patients undergoing thyroid surgery. This RCT found minimal effect of intraoperative neurophysiologic monitoring overall but a significant reduction in recurrent laryngeal nerve injury in patients at high risk for injury. High-risk in this trial was defined as surgery for cancer, thyrotoxicosis, retrosternal or giant goiter, or thyroiditis. The high-risk category may also include patients with prior thyroid or parathyroid surgery or total thyroidectomy.
Recurrent Laryngeal Nerve Monitoring During Cervical Spine Surgery
Clinical Context and Therapy Purpose
The purpose of intraoperative neurophysiologic monitoring is to provide a treatment option that is an alternative to or an improvement on existing therapies, such as surgery without neurophysiologic monitoring, in patients who are undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve.
The question addressed in this policy is: Does recurrent laryngeal nerve monitoring improve the net health outcome in patients undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve and peripheral nerves?
The following PICO was used to select literature to inform this policy.
Patients
The relevant population of interest is individuals who are undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve.
Interventions
The therapy being considered is intraoperative neurophysiologic monitoring.
Intraoperative neurophysiologic monitoring describes a variety of procedures used to monitor the integrity of neural pathways during high-risk neurosurgical, orthopedic, and vascular surgeries. It involves the detection of electrical signals produced by the nervous system in response to sensory or electrical stimuli to provide information about the functional integrity of neuronal structures.
Patients who are undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve are actively managed by neurosurgeons, orthopedic surgeons, and primary care providers in an inpatient surgical setting.
Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by neurosurgeons, orthopedic surgeons, and primary care providers in an inpatient surgical setting.
Outcomes
The general outcomes of interest are morbid events, functional outcomes, and quality of life.
The existing literature evaluating intraoperative neurophysiologic monitoring as a treatment for patients who are undergoing anterior cervical spine surgery and are at high risk of injury to the recurrent laryngeal nerve has varying lengths of follow-up. While studies described below all reported at least one outcome of interest, longer follow-up was necessary to fully observe outcomes.
Study Selection Criteria
Methodologically credible studies were selected using the principles described in the first indication.
Ajiboye et al (2017) reported on the results of a systematic review that included 10 studies (total n=26 357 patients).14, All studies were of low methodologic quality but had a low risk of bias. Only studies that compared the risk of nerve injury using intraoperative neurophysiologic monitoring with no intraoperative neurophysiologic monitoring were included. Based on data from these 2 studies, there was no statistically significant difference in the risk of neurologic injury with or without intraoperative neurophysiologic monitoring (odds ratio [OR], 0.726; 95% confidence interval [CI], 0.287 to 1.833; p=0.498) (see Tables 5 and 6).
Erwood et al (2016) reported on the results of a meta-analysis that summarized the relative rate of recurrent laryngeal nerve injury following revision anterior cervical discectomy and fusion.15, The meta-analysis did not report recurrent laryngeal nerve injury rate with intraoperative neurophysiologic monitoring versus without intraoperative neurophysiologic monitoring. Based on pooled data from 3 prospective cohort studies and 5 retrospective series (total n=238 patients), reviewers reported an overall recurrent laryngeal nerve injury rate of 14.1% (95% CI, 9.8% to 19.1%)(see Tables 5 and 6).
Daniel et al (2018) published a literature review and meta-analysis evaluating intraoperative neurophysiologic monitoring during spinal operative surgical procedures16,. Six retrospective studies, published between 2006 and 2016, with a total of 335 458 patients (range, 74 - 231,067) were included. Pooled OR for neurological events with and without intraoperative neurophysiologic monitoring was 0.72 (95% CI, 0.71–1.79; p=0.4584), and sensitivity analysis, which included only 2 studies, had a pooled OR of 0.199 (95% CI, 0.038–1.035; p=0.055). The review was limited by the lack of prospective studies, by only 3 of the included studies being considered to have high methodological quality assessment, and by many heterogeneous spinal procedures with different rates of neurological events and wide CIs being included.
Table 5. Systematic Review Characteristics
| Study | Dates | Trials | Participants | N (Range) | Design | Duration |
| Ajiboye et al (2017)14, | NR | 10 | Studies reporting IONM use for ACSS | 26,357 (16-22,768) | · 9 retrospective
· 1 prospective | NR |
| Erwood et al (2016)15, | 1998-2015 | 8 | Studies reporting reoperative ACSS for RLN | 238 (13-63) | · 5 prospective
· 3 retrospective | 2 wk to 24 mo |
| Daniel et al (2018)16, | 2006-2016 | 6 | Studies reporting IONM use for spinal surgical procedures | 335,458 (74-231,067) | · 2 cohort
·4 retrospective | NR |
ACSS: anterior cervical spine surgery; IONM: intraoperative neurophysiologic monitoring; NR: not reported; RLN: recurrent laryngeal nerve.
Table 6. Systematic Review Results
| Study | Risk of Neurologic Injury |
| Ajiboye et al (2017)14, | |
| OR (95% CI) (p)a | 0.726 (0.287 to 1.833) (0.44)b |
| NNT (95% CI) | NR |
| I2 (p) | 0% (NR) |
| Erwood et al (2016)15, | |
| Estimate (95% CI) (p)a | 0.14 (0.10 to 0.19) |
| NNT (95% CI) | NR |
| I2 (p) | 10.7% (NR) |
| Daniel et al (2018)16, | |
| OR (95% CI) (p) | 0.72 (0.71 to 1.79) (0.4584) |
CI: confidence interval; NNT: number needed to treat; NR: not reported; OR: odds ratio.
a Risk of neurologic injury after anterior cervical discectomy and fusion with or without intraoperative neurophysiologic monitoring.
b Included 2 studies.
Section Summary: Recurrent Laryngeal Nerve Monitoring During Cervical Spine Surgery
The evidence on the use of intraoperative neurophysiologic monitoring in reducing recurrent laryngeal nerve injury during cervical spinal surgery includes a 2017 systematic review and a meta-analysis. Of the 10 studies included in the systematic review, 2 compared the risk of nerve injury using intraoperative neurophysiologic monitoring with no intraoperative neurophysiologic monitoring and found no difference.
Recurrent Laryngeal Nerve Monitoring During Esophageal Surgery
Clinical Context and Therapy Purpose
The purpose of intraoperative neurophysiologic monitoring is to provide a treatment option that is an alternative to or an improvement on existing therapies, such as surgery without neurophysiologic monitoring, in patients who are undergoing esophageal surgery.
The question addressed in this policy is: Does recurrent laryngeal nerve monitoring improve the net health outcome in patients undergoing esophageal surgery during surgeries that could damage their recurrent laryngeal nerve or peripheral nerves?
The following PICO was used to select literature to inform this policy.
Patients
The relevant population of interests individuals who are undergoing esophageal surgery.
Interventions
The therapy being considered is intraoperative neurophysiologic monitoring.
Intraoperative neurophysiologic monitoring describes a variety of procedures used to monitor the integrity of neural pathways during high-risk neurosurgical, orthopedic, and vascular surgeries. It involves the detection of electrical signals produced by the nervous system in response to sensory or electrical stimuli to provide information about the functional integrity of neuronal structures.
Patients who are undergoing esophageal surgery are actively managed by neurosurgeons, thoracic surgeons and primary care providers in a surgical setting.
Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by thoracic surgeons and primary care providers in a surgical setting.
Outcomes
The general outcomes of interest are morbid events, functional outcomes, and quality of life.
The existing literature evaluating intraoperative neurophysiologic monitoring as a treatment for patients who are undergoing esophageal surgery has varying lengths of follow-up. While studies described below all reported at least one outcome of interest, longer follow-up was necessary to fully observe outcomes.
Study Selection Criteria
Methodologically credible studies were selected using the principles described in the first indication.
Zhong et al (2014) published a comparative study from Asia evaluating recurrent laryngeal nerve monitoring during surgery for esophageal cancer.17, One hundred fifteen patients with esophageal cancer were enrolled in this prospective study. In 54 patients, the left recurrent laryngeal nerve was found and underwent monitoring. In the remainder (n=61), the recurrent laryngeal nerve was not located. No recurrent laryngeal nerve injury was reported during surgery in either group, but 6 (10%) of 61 patients who did not receive monitoring had notable recurrent laryngeal nerve injury identified postoperatively. It is unclear whether the difference in outcomes was due to monitoring or to the inability to identify the recurrent laryngeal nerve during surgery.
Section Summary: Recurrent Laryngeal Nerve Monitoring During Esophageal Surgery
One nonrandomized comparative study on surgery for esophageal cancer was identified. Interpretation of this study is confounded because only the patients who had visual identification of the nerve underwent intraoperative neurophysiologic monitoring. Current evidence does not support conclusions on whether intraoperative neurophysiologic monitoring reduces recurrent laryngeal nerve injury in patients undergoing surgery for esophageal cancer.
Monitoring Peripheral Nerves
Clinical Context and Therapy Purpose
The purpose of intraoperative neurophysiologic monitoring is to provide a treatment option that is an alternative to or an improvement on existing therapies, such as surgery without neurophysiologic monitoring, in patients who are undergoing surgery proximal to a peripheral nerve.
The question addressed in this policy is: Does neurophysiologic monitoring improve the net health outcome in patients during surgeries that could damage their peripheral nerves?
The following PICO was used to select literature to inform this policy.
Patients
The relevant population of interest is individuals who are undergoing surgery proximal to a peripheral nerve.
Interventions
The therapy being considered is intraoperative neurophysiologic monitoring.
intraoperative neurophysiologic monitoring describes a variety of procedures used to monitor the integrity of neural pathways during high-risk neurosurgical, orthopedic, and vascular surgeries. It involves the detection of electrical signals produced by the nervous system in response to sensory or electrical stimuli to provide information about the functional integrity of neuronal structures.
Patients who are undergoing surgery proximal to a peripheral nerve are actively managed by neurosurgeons and primary care providers in an inpatient surgical setting.
Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by neurosurgeons and primary care providers in an inpatient surgical setting.
Outcomes
The general outcomes of interest are morbid events, functional outcomes, and quality of life.
The existing literature evaluating intraoperative neurophysiologic monitoring as a treatment for patients who are undergoing surgery proximal to a peripheral nerve has varying lengths of followup. While studies described below all reported at least one outcome of interest, longer follow-up was necessary to fully observe outcomes.
Study Selection Criteria
Methodologically credible studies were selected using the principles described in the first indication.
Kneist et al (2013) assessed monitoring peripheral nerves during surgery in a case-control study of 30 patients.18, In patients undergoing total mesorectal excision, impaired anorectal function was observed in 1 (7%) of 15 patients who had intraoperative neurophysiologic monitoring compared with 6 (40%) of 15 without. Kneist et al (2013) also reported on erectile function following low anterior rectal resection in a pilot study with 17 patients.19, In this study, the combined intraoperative measurement of the bladder and internal anal sphincter innervation was a strong predictor of postoperative erectile function, with a sensitivity of 90%, specificity of 86%, positive predictive value of 90%, and negative predictive value of 86%. The possibility of intervention during surgery was not addressed.
Clarkson et al (2011) described the use of intraoperative nerve recording for suspected brachial plexus root avulsion.20, Included in this retrospective review were 25 consecutive patients who underwent intraoperative nerve recording during surgery for unilateral brachial plexus injury. Of 55 roots thought to be avulsed preoperatively, 14 (25%) were found to be intact using intraoperative nerve recording. Eleven of them were then used for reconstruction, of which 9 (82%) had a positive functional outcome. Electrophysiologic monitoring has also been reported to guide selective rhizotomy for glossopharyngeal neuralgia in a series of 8 patients.21,
Use of intraoperative neurophysiologic monitoring of peripheral nerves has also been reported in patients undergoing orthopedic procedures, including tibial/fibular osteotomies, hip arthroscopy for femoroacetabular impingement, and shoulder arthroplasty.22,23,24,
Section Summary: Monitoring Peripheral Nerves
Surgical guidance with peripheral intraoperative neurophysiologic monitoring has been reported in case series and one case-control study. Other case series have reported on the predictive ability of monitoring of peripheral nerves. No prospective comparative studies identified have assessed whether outcomes are improved with neurophysiologic monitoring.
Summary of Evidence
For individuals who are undergoing thyroid or parathyroid surgery and are at high risk of injury to the recurrent laryngeal nerve who receive intraoperative neurophysiologic monitoring, the evidence includes a large randomized controlled trial and systematic reviews. Relevant outcomes are morbid events, functional outcomes, and quality of life. The strongest evidence on neurophysiologic monitoring derives from a randomized controlled trial of 1000 patients undergoing thyroid surgery. This randomized controlled trial found a significant reduction in recurrent laryngeal nerve injury in patients at high-risk for injury. High-risk in this trial was defined as surgery for cancer, thyrotoxicosis, retrosternal or giant goiter, or thyroiditis. The high-risk category may also include patients with prior thyroid or parathyroid surgery or total thyroidectomy. A low volume of surgeries might also contribute to a higher risk for recurrent laryngeal nerve injury. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.
For individuals who are undergoing anterior cervical spine surgery and are at high-risk of injury to the recurrent laryngeal nerve who receive intraoperative neurophysiologic monitoring, the evidence includes systematic reviews of case series and cohort studies. Relevant outcomes are morbid events, functional outcomes, and quality of life. The evidence on the use of intraoperative neurophysiologic monitoring to reduce recurrent laryngeal nerve injury during cervical spinal surgery includes a 2017 systematic review and a meta-analysis. Of the 10 studies assessed in the systematic review, 2 compared the risk of nerve injury with use of intraoperative neurophysiologic monitoring versus no intraoperative neurophysiologic monitoring and found no difference. The evidence is insufficient to determine the effects of the technology on health outcomes.
For individuals who are undergoing esophageal surgery who receive intraoperative neurophysiologic monitoring, the evidence includes a nonrandomized comparative study. Relevant outcomes are morbid events, functional outcomes, and quality of life. One nonrandomized comparative study on surgery for esophageal cancer was identified. Interpretation of this study is confounded because only those patients who had visual identification of the nerve underwent neurophysiologic monitoring. Current evidence is not sufficiently robust to determine whether neurophysiologic monitoring reduces recurrent laryngeal nerve injury in patients undergoing surgery for esophageal cancer. The evidence is insufficient to determine the effects of the technology on health outcomes.
For individuals who are undergoing surgery proximal to a peripheral nerve who receive intraoperative neurophysiologic monitoring, the evidence includes case series and a controlled cohort study. Relevant outcomes are morbid events, functional outcomes, and quality of life. Surgical guidance with peripheral intraoperative neurophysiologic monitoring and the predictive ability of monitoring of peripheral nerves have been reported. No prospective comparative studies were identified that assessed whether outcomes are improved with neurophysiologic monitoring. The evidence is insufficient to determine the effects of the technology on health outcomes.
Clinical Input
Objective
In 2017, clinical input was sought for intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve to determine whether monitoring improves health outcomes when used during cervical spine surgery.
Respondents
Clinical input was provided by the following medical specialty societies (listed alphabetically):
- American Academy of Neurological Surgeons and Congress of Neurological Surgeons (AANS/CNS)
- American Academy of Orthopaedic Surgeons and North American Spine Society (AAOS/NASS combined response)
- American Academy of Otolaryngology- Head and Neck Surgery (AAO-HNS)
Clinical input provided by the specialty society at an aggregate level is attributed to the specialty society. Clinical input provided by a physician member designated by the specialty society or health system is attributed to the individual physician and is not a statement from the specialty society or health system. Specialty society and physician respondents participating in the Evidence Street® clinical input process provide a review, input, and feedback on topics being evaluated by Evidence Street®. However, participation in the clinical input process by a special society and/or physician member designated by the specialty society or health system does not imply an endorsement or explicit agreement with the Evidence Opinion published by BCBSA or any Blue Plan.
Clinical Input Responses
Additional Comments
- “While there is little evidence to support the use of intraoperative monitoring of the recurrent laryngeal nerve during primary anterior cervical spine surgery, it has been well-studied in soft-tissue surgery of the neck, including thyroidectomy. Given the increased difficulty, scarring and aberrant anatomy sometimes associated with revision anterior cervical surgery, we extrapolate from the available literature that monitoring of the recurrent laryngeal nerve may increase patient safety in these revision situations. Thus, each case and use of monitoring would be up to the surgeons’ discretion.” (AAOS/NASS)
- “We feel that it is generally at the surgeon's discretion whether neurophysiologic monitoring of the recurrent laryngeal nerve is indicated in patients undergoing cervical spine surgery. As referenced above, for monitoring of the recurrent laryngeal nerve, there are certain circumstances where this nerve is at much higher risk of injury, and perhaps monitoring of this nerve may play a role in preventing injuries to it.” (AANS/CNS)
- “If there is a pre-existing injury to the recurrent laryngeal nerve and there is no nerve function it would seem that monitoring that side has no value. If the included definition of recurrent laryngeal nerve pathology was partial and not complete there would be value in monitoring the affected nerve. However, if they are talking about the contralateral recurrent laryngeal nerve that was currently working well, the answer should be high confidence and monitored in every situation. Monitoring the contralateral recurrent laryngeal nerve in the presence of ipsilateral pathology would be yes with high confidence. However, monitoring the already damaged recurrent laryngeal nerve would not be valuable as described above.” (AAO-HNS)
See Appendices 1 and 2 for details of the clinical input.
SUPPLEMENTAL INFORMATION
Clinical Input From Physician Specialty Societies and Academic Medical Centers
While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process, through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.
2017 Input
In response to requests, clinical input on intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve for individuals undergoing cervical spine surgery was received from 5 specialty society-level response while this policy was under review in 2017.
Based on the evidence and independent clinical input, the clinical input supports that the following indication provides a clinically meaningful improvement in the net health outcome and is consistent with generally accepted medical practice:
- Use of intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve for individuals undergoing cervical spine surgery with:
- prior anterior cervical surgery, particularly revision anterior cervical discectomy and fusion, revision surgery through a scarred surgical field, reoperation for pseudarthrosis, or revision for failed fusion;
- multilevel anterior cervical discectomy and fusion; and
- preexisting recurrent laryngeal nerve pathology, when there is residual function of the recurrent laryngeal nerve
2014 Input
In response to requests, input was received from 5 physician specialty societies (7 responses) and 2 academic medical centers while this policy was under review in 2014. Input agreed that intraoperative neurophysiologic monitoring with somatosensory-evoked potentials, motor-evoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyography of cranial nerves, electroencephalography, or electrocorticography might be medically necessary during spinal, intracranial, or vascular procedures. There was general agreement that intraoperative neurophysiologic monitoring of visual-evoked potentials and motor-evoked potentials using transcranial magnetic stimulation is investigational. Input was mixed on whether intraoperative neurophysiologic monitoring of peripheral nerves would be considered medically necessary. Some reviewers recommended monitoring some peripheral nerves during spinal surgery (eg, nerve roots, percutaneous pedicle screw placement, lateral transpsoas approach to the lumbar spine). Other reviewers suggested using intraoperative neurophysiologic monitoring during resection of peripheral nerve tumors or surgery around the brachial plexus or facial/cranial nerves.
Practice Guidelines and Position Statements
American Association of Neurological Surgeons and Congress of Neurological Surgeons
In 2018, the American Association of Neurological Surgeons (AANS) and Congress of Neurological Surgeons updated their position statement on intraoperative neurophysiologic monitoring during routine spinal surgery.25, They stated that intraoperative neurophysiologic monitoring, especially motor evoked potential, “is a reliable diagnostic tool for assessment of spinal cord integrity during surgery” (Level 1 evidence). Intraoperative motor evoked potentials may also “predict recovery in traumatic cervical spinal cord injury.” However, AANS and Congress of Neurological Surgeons found no evidence that such monitoring provides a therapeutic benefit.The statement also recommends that intraoperative neurophysiologic monitoring should be used when the operating surgeon believes it is warranted for diagnostic value, such as with “deformity correction, spinal instability, spinal cord compression, intradural spinal cord lesions, and when in proximity to peripheral nerves or roots.” In addition, they recommend spontaneous and evoked electromyography “for minimally invasive lateral retroperitoneal transpsoas approaches to the lumbar spine" and during pedicle screw insertion.
American Association of Neuromuscular & Electrodiagnostic Medicine
In 2017, the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) updated their position statement on electrodiagnostic medicine.7,The recommendations indicated that intraoperative sensory-evoked potentials have demonstrated usefulness for monitoring of spinal cord, brainstem, and brain sensory tracts. The AANEM stated that intraoperative sensory-evoked potential monitoring is indicated for select spine surgeries in which there is a risk of additional nerve root or spinal cord injury. Indications for sensory-evoked potential monitoring may include, but are not limited to, complex, extensive, or lengthy procedures, and when mandated by hospital policy. However, intraoperative sensory-evoked potential monitoring may not be indicated for routine lumbar or cervical root decompression.
American Clinical Neurophysiology Society
In 2009, the American Clinical Neurophysiology Society (ACNS) recommended standards for intraoperative neurophysiologic monitoring.4, Guideline 11A included the following statement26,:
“The monitoring team should be under the direct supervision of a physician with training and experience in neurophysiologic intraoperative monitoring. The monitoring physician should be licensed in the state and privileged to interpret neurophysiologic testing in the hospital in which the surgery is being performed. He/she is responsible for real-time interpretation of neurophysiologic intraoperative monitoring data. The monitoring physician should be present in the operating room or have access to intraoperative neurophysiologic monitoring data in real-time from a remote location and be in communication with the staff in the operating room. There are many methods of remote monitoring, however any method used must conform to local and national protected health information guidelines. The monitoring physician must be available to be in the operating room, and the specifics of this availability (ie, types of surgeries) should be decided by the hospital credentialing committee. In order to devote the needed attention, it is recommended that the monitoring physician interpret no more than three cases concurrently.”
American Academy of Neurology
In 1990 (updated in 2012), the American Academy of Neurology (AAN) published an assessment of intraoperative neurophysiologic monitoring, with an evidence-based guideline update by the AAN and ACNS (2012).1,2, The 1990 assessment indicated that monitoring requires a team approach with a well-trained physician-neurophysiologist to provide or supervise monitoring. Electroencephalogram (EEG) monitoring is used during carotid endarterectomy or for other similar situations in which cerebral blood flow is at high risk. Electrocorticography from surgically exposed cortex can help to define the optimal limits of surgical resection or identify regions of greatest impairment, while sensory cortex somatosensory-evoked potentials can help to localize the central fissure and motor cortex. Auditory-evoked potentials, along with cranial nerve monitoring can be used during posterior fossa neurosurgical procedures. Spinal cord somatosensory-evoked potentials are frequently used to monitor the spinal cord during orthopedic or neurosurgical procedures around the spinal cord, or cross-clamping of the thoracic aorta. Electromyographic monitoring during procedures near the roots and peripheral nerves can be used to warn of excessive traction or other impairment of motor nerves. At the time of the 1990 assessment, motor-evoked potentials were considered investigational by many neurophysiologists. The 2012 update, which was endorsed by the AANEM, concluded that the available evidence supported intraoperative neurophysiologic monitoring using somatosensory-evoked potentials or motor-evoked potentials when conducted under the supervision of a clinical neurophysiologist experienced with intraoperative neurophysiologic monitoring. Evidence was insufficient to evaluate intraoperative neurophysiologic monitoring when conducted by technicians alone or by an automated device.
In 2012, the AAN published a model policy on principles of coding for intraoperative neurophysiologic monitoring and testing.27, The background section of this document provides the following information on the value of intraoperative neurophysiologic monitoring in averting neural injuries during surgery:
1. "Value of EEG Monitoring in Carotid Surgery. Carotid occlusion, incident to carotid endarterectomies, poses a high-risk for cerebral hemispheric injury. Electroencephalogram (EEG) monitoring is capable of detecting cerebral ischemia, a serious prelude to injury. Studies of continuous monitoring established the ability of electroencephalogram EEG to correctly predict risks of postoperative deficits after a deliberate, but necessary, carotid occlusion as part of the surgical procedure. The surgeon can respond to adverse EEG events by raising blood pressure, implanting a shunt, adjusting a poorly functioning shunt, or performing other interventions.
2. Multicenter Data in Spinal Surgeries. An extensive multicenter study conducted in 1995 demonstrated that [intraoperative neurophysiologic monitoring] using [sensory-evoked potentials] reduced the risk of paraplegia by 60% in spinal surgeries. The incidence of false negative cases, wherein an operative complication occurred without having been detected by the monitoring procedure, was small: 0.06%.
3. Technology Assessment of Monitoring in Spinal Surgeries. A technology assessment by the McGill University Health Center...reviewed 11 studies and concluded that spinal [intraoperative neurophysiologic monitoring] is capable of substantially reducing injury in surgeries that pose a risk to spinal cord integrity. It recommended combined sensory-evoked potentials/motor-evoked potential monitoring, under the presence or constant availability of a monitoring physician, for all cases of spinal surgery for which there is a risk of spinal cord injury.
4. Value of Combined Motor and Sensory Monitoring. Numerous studies of post-surgical paraparesis and quadriparesis have shown that both sensory-evoked potentials and motor-evoked potential monitoring had predicted adverse outcomes in a timely fashion. The timing of the predictions allowed the surgeons the opportunity to intervene and prevent adverse outcomes. The 2 different techniques (sensory-evoked potentials and motor-evoked potential) monitor different spinal cord tracts. Sometimes, one of the techniques cannot be used for practical purposes, for anesthetic reasons, or because of preoperative absence of signals in those pathways. Thus, the decision about which of these techniques to use needs to be tailored to the individual patient’s circumstances.
5. Protecting the Spinal Cord from Ischemia during Aortic Procedures. Studies have shown that [intraoperative neurophysiologic monitoring] accurately predicts risks for spinal cord ischemia associated with clamping the aorta or ligating segmental spinal arteries. [intraoperative neurophysiologic monitoring] can assess whether the spinal cord is tolerating the degree of relative ischemia in these procedures. The surgeon can then respond by raising blood pressure, implanting a shunt, re-implanting segmental vessels, draining spinal fluid, or through other interventions...
6. Value of EMG [electromyogram] monitoring. Selective posterior rhizotomy in cerebral palsy significantly reduces spasticity, increases range of motion, and improves functional skills. Electromyography during this procedure can assist in selecting specific dorsal roots to transect. Electromyogram (EMG) can also be used in peripheral nerve procedures that pose a risk of injuries to nerves...
7. Value of Spinal Monitoring using somatosensory-evoked potentials and motor-evoked potentials. According to a recent review of spinal monitoring using somatosensory-evoked potential and motor-evoked potentials by the Therapeutics and Technology Assessment Subcommittee of AAN and ACNS, [intraoperative neurophysiologic monitoring] is established as effective to predict an increased risk of the adverse outcomes of paraparesis, paraplegia, and quadriplegia in spinal surgery (4 Class I and 7 Class II studies). Surgeons and other members of the operating team should be alerted to the increased risk of severe adverse neurologic outcomes in patients with important [intraoperative neurophysiologic monitoring] changes (Level A)."
The AAN model policy also offered guidance on personnel and monitoring standards for intraoperative neurophysiologic monitoring] and somatosensory-evoked potential.
American Society of Neurophysiological Monitoring
In 2018, the American Society of Neurophysiological Monitoring (ASNM) published practice guidelines for the supervising professional on intraoperative neurophysiologic monitoring.28, The ASNM (2013) position statement on intraoperative motor-evoked potential monitoring indicated that motor-evoked potentials are an established practice option for cortical and subcortical mapping and monitoring during surgeries risking motor injury in the brain, brainstem, spinal cord or facial nerve.29,
National Institute for Health and Care Excellence
In 2008, a guidance from the National Institute for Health and Care Excellence on intraoperative neurophysiologic monitoring during thyroid surgery found no major safety concerns.30, Regarding efficacy, intraoperative neurophysiologic monitoring was indicated as helpful “in performing more complex operations such as reoperative surgery and operations on large thyroid glands.”
U.S. Preventive Services Task Force Recommendations
Not applicable.
Ongoing and Unpublished Clinical Trials
Some currently unpublished trials that might influence this policy are listed in Table 7.
Table 7. Summary of Key Trials
| NCT No. | Trial Name | Planned Enrollment | Completion Date |
| Ongoing | | | |
| NCT03773120 | Effectiveness of Intraoperative Neuromonitoring of the External Branch of the Superior Laryngeal Nerve During Thyroid Surgery | 126 | Jun 2020 |
| of the External Branch of the Superior Laryngeal Nerve (EBSLN) During Thyroid Surgery: Does it Improve Voice Preservation? | | |
| of the Pelvic Autonomic Nerves During Total Mesorectal Excision (TME) for the Prevention of Urogenital and Anorectal Dysfunction in Patients With Rectal Cancer (NEUROS) | | |
| NCT01630785 | Neurophysiological Monitoring IONM Retrospective Data Analysis of Neurophysiological Data for Intraoperative or Epilepsy Monitoring | 5000 | Dec 2025 |
| Unpublished | | | |
| NCT02395146 | Intra-operative Monitoring of the External Branch of the Superior Laryngeal Nerve (EBSLN) During Thyroid Surgery: Does it Improve Voice Preservation? | 60 | Oct 2018
(updated 06/19/19) |
| NCT01585727 | Continuous Intraoperative Monitoring of the Pelvic Autonomic Nerves During Total Mesorectal Excision (TME) for the Prevention of Urogenital and Anorectal Dysfunction in Patients With Rectal Cancer (NEUROS) | 188 | Dec 2018
(updated 02/27/19) |
NCT: national clinical trial.]
________________________________________________________________________________________
Horizon BCBSNJ Medical Policy Development Process:
This Horizon BCBSNJ Medical Policy (the “Medical Policy”) has been developed by Horizon BCBSNJ’s Medical Policy Committee (the “Committee”) consistent with generally accepted standards of medical practice, and reflects Horizon BCBSNJ’s view of the subject health care services, supplies or procedures, and in what circumstances they are deemed to be medically necessary or experimental/ investigational in nature. This Medical Policy also considers whether and to what degree the subject health care services, supplies or procedures are clinically appropriate, in terms of type, frequency, extent, site and duration and if they are considered effective for the illnesses, injuries or diseases discussed. Where relevant, this Medical Policy considers whether the subject health care services, supplies or procedures are being requested primarily for the convenience of the covered person or the health care provider. It may also consider whether the services, supplies or procedures are more costly than an alternative service or sequence of services, supplies or procedures that are at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of the relevant illness, injury or disease. In reaching its conclusion regarding what it considers to be the generally accepted standards of medical practice, the Committee reviews and considers the following: all credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, physician and health care provider specialty society recommendations, the views of physicians and health care providers practicing in relevant clinical areas (including, but not limited to, the prevailing opinion within the appropriate specialty) and any other relevant factor as determined by applicable State and Federal laws and regulations.
___________________________________________________________________________________________________________________________
Index:
Intraoperative Neurophysiologic Monitoring
Intraoperative Neurophysiologic Monitoring (Sensory-Evoked Potentials, Motor-Evoked Potentials, EEG Monitoring)
BAEP Intraoperative Monitoring
Brainstem Auditory-Evoked Potential Intraoperative Monitoring
EEG Intraoperative Monitoring
Electroencephalogram Intraoperative Monitoring
Electromyogram Intraoperative Monitoring
EMG Intraoperative Monitoring
INM (Intraoperative Neurophysiologic Monitoring)
MEP Intraoperative Monitoring
Monitoring, Intraoperative Neurophysiologic
Motor-Evoked Potential Intraoperative Monitoring
Sensory-Evoked Potential Intraoperative Monitoring
SEP Intraoperative Monitoring
Somatosensory-Evoked Potential Intraoperative Monitoring
SSEP Intraoperative Monitoring
VEP Intraoperative Monitoring
Visual-Evoked Potential Intraoperative Monitoring
References:
1. American Academy of Neurology. Assessment: intraoperative neurophysiology. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. Nov 1990;40(11):1644-1646. PMID 2234418
2. Nuwer MR, Emerson RG, Galloway G, et al. Evidence-based guideline update: intraoperative spinal monitoring with somatosensory and transcranial electrical motor evoked potentials: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the American Clinical Neurophysiology Society. Neurology. Feb 21 2012;78(8):585-589. PMID 22351796
3. Skinner SA, Cohen BA, Morledge DE, et al. Practice guidelines for the supervising professional: intraoperative neurophysiological monitoring. J Clin Monit Comput. Apr 2014;28(2):103-111. PMID 24022172
4. American Clinical Neurophysiology Society. ACNS Guidelines and Consensus Statements. Updated February 13, 2020. http://www.acns.org/practice/guidelines. Accessed March 5, 2020.
5. American Association of Neurological Surgeons (AANS)/Congress of Neurological Surgeons (CNS). AANS/CNS Joint Section on disorders of the spine and peripheral Nerves. Updated Position Statement: Intraoperative electrophysiological monitoring. 2014; http://www.spinesection.org/files/pdfs/IOM%20Position%20Statement%2004.24.2014.pdf. Accessed March 23, 2018.
6. Resnick DK, Choudhri TF, Dailey AT, et al. Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: electrophysiological monitoring and lumbar fusion. J Neurosurg Spine. Jun 2005;2(6):725-732. PMID 16028743
7. American Association of Neuromuscular & Electrodiagnostic Medicine. Position Statement: Recommended Policy for Electrodiagnostic Medicine. 2014; http://www.aanem.org/getmedia/884f5b94-a0be-447e-bdae- 20d52aaf8299/Recommended-Policy-for-Electrodiagnostic-Medicine.pdf. Accessed March 5, 2020.
8. Henry BM, Graves MJ, Vikse J, et al. The current state of intermittent intraoperative neural monitoring for prevention of recurrent laryngeal nerve injury during thyroidectomy: a PRISMA-compliant systematic review of overlapping meta-analyses. Langenbecks Arch Surg. Jun 2017;402(4):663-673. PMID 28378238
9. Pisanu A, Porceddu G, Podda M, et al. Systematic review with meta-analysis of studies comparing intraoperative neuromonitoring of recurrent laryngeal nerves versus visualization alone during thyroidectomy. J Surg Res. May 1 2014;188(1):152-161. PMID 24433869
10. Sun W, Liu J, Zhang H, et al. A meta-analysis of intraoperative neuromonitoring of recurrent laryngeal nerve palsy during thyroid reoperations. Clin Endocrinol (Oxf). Nov 2017;87(5):572-580. PMID 28585717
11. Pardal-Refoyo JL, Ochoa-Sangrador C. Bilateral recurrent laryngeal nerve injury in total thyroidectomy with or without intraoperative neuromonitoring. Systematic review and meta-analysis. Acta Otorrinolaringol Esp. Mar-Apr 2016;67(2):66-74. PMID 26025358
12. Barczynski M, Konturek A, Cichon S. Randomized clinical trial of visualization versus neuromonitoring of recurrent laryngeal nerves during thyroidectomy. Br J Surg. Mar 2009;96(3):240-246. PMID 19177420
13. Vasileiadis I, Karatzas T, Charitoudis G, et al. Association of intraoperative neuromonitoring with reduced recurrent laryngeal nerve injury in patients undergoing total thyroidectomy. JAMA Otolaryngol Head Neck Surg. Oct 1 2016;142(10):994-1001. PMID 27490310
14. Ajiboye RM, Zoller SD, Sharma A, et al. ntraoperative neuromonitoring for anterior cervical spine surgery: What is the evidence? Spine (Phila Pa 1976). Mar 15 2017;42(6):385-393. PMID 27390917
15. Erwood MS, Hadley MN, Gordon AS, et al. Recurrent laryngeal nerve injury following reoperative anterior cervical discectomy and fusion: a meta-analysis. J Neurosurg Spine. Aug 2016;25(2):198-204. PMID 27015129
16. Daniel JW, Botelho RV, Milano JB, et al. Intraoperative Neurophysiological Monitoring in Spine Surgery: A Systematic Review and Meta-Analysis. Spine (Phila Pa 1976). 2018 Aug;43(16):1154-1160. PMID: 30063222
17. Zhong D, Zhou Y, Li Y, et al. Intraoperative recurrent laryngeal nerve monitoring: a useful method for patients with esophageal cancer. Dis Esophagus. Jul 2014;27(5):444-451. PMID 23020300
18. Kneist W, Kauff DW, Juhre V, et al. Is intraoperative neuromonitoring associated with better functional outcome in patients undergoing open TME? Results of a case-control study. Eur J Surg Oncol. Sep 2013;39(9):994-999. PMID 23810330
19. Kneist W, Kauff DW, Rubenwolf P, et al. Intraoperative monitoring of bladder and internal anal sphincter innervation: a predictor of erectile function following low anterior rectal resection for rectal cancer? Results of a prospective clinical study. Dig Surg. Feb 2013;30(4-6):459-465. PMID 24481247
20. Clarkson JH, Ozyurekoglu T, Mujadzic M, et al. An evaluation of the information gained from the use of intraoperative nerve recording in the management of suspected brachial plexus root avulsion. Plast Reconstr Surg. Mar 2011;127(3):1237-1243. PMID 21364425
21. Zhang W, Chen M, Zhang W, et al. Use of electrophysiological monitoring in selective rhizotomy treating glossopharyngeal neuralgia. J Craniomaxillofac Surg. Jul 2014;42(5):e182-185. PMID 24095216
22. Ochs BC, Herzka A, Yaylali I. Intraoperative neurophysiological monitoring of somatosensory evoked potentials during hip arthroscopy surgery. Neurodiagn J. Dec 2012;52(4):312-319. PMID 23301281
23. Jahangiri FR. Multimodality neurophysiological monitoring during tibial/fibular osteotomies for preventing peripheral nerve injuries. Neurodiagn J. Jun 2013;53(2):153-168. PMID 23833842
24. Nagda SH, Rogers KJ, Sestokas AK, et al. Neer Award 2005: Peripheral nerve function during shoulder arthroplasty using intraoperative nerve monitoring. J Shoulder Elbow Surg. May-Jun 2007;16(3 Suppl):S2-8. PMID 17493556
25. AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves updated position statement: intraoperative electrophysiological monitoring. SpineSection.org. January 2018. https://www.spinesection.org/statement-detail/intraoperative-electrophysiological-monitoring. Accessed March 3, 2020.
26. American Clinical Neurophysiology Society. Guideline 11A: Recommended Standards for Neurophysiologic Intraoperative Monitoring Principles. 2009; https://www.acns.org/pdf/guidelines/Guideline-11A.pdf. Accessed March 5, 2020.
27. American Academy of Neurology. Model Coverage Policy: Principles of Coding for Intraoperative Neurophysiologic Monitoring (IOM) and Testing. 2012; https://www.aan.com/siteassets/home-page/tools-and- resources/practicing-neurologist--administrators/billing-and-coding/model-coverage- policies/16iommodelpolicy_tr.pdf. Accessed March 5, 2020.
28. Gertsch JH, Moreira JJ, Lee GR, et al. Practice guidelines for the supervising professional: intraoperative neurophysiological monitoring. J Clin Monit Comput. 2018 Oct 30. PMID: 30063222
29. Macdonald DB, Skinner S, Shils J, et al. Intraoperative motor evoked potential monitoring - A position statement by the American Society of Neurophysiological Monitoring. Clin Neurophysiol. Dec 2013;124(12):2291-2316. PMID 24055297
30. National Institute for Health and Care Excellence (NICE). Intraoperative nerve monitoring during thyroid surgery [IPG255]. 2008; https://www.nice.org.uk/guidance/ipg255/chapter/1-guidance. Accessed March 5, 2020.
31. Centers for Medicare & Medicaid Services. National Coverage Determination (NCD) for Electroencephalographic Monitoring During Surgical Procedures Involving the Cerebral Vasculature (160.8). 2006; https://www.cms.gov/medicare-coverage-database/details/ncd- details.aspx?NCDId=77&ncdver=2&CoverageSelection=National&KeyWord=monitoring&KeyWordLookUp=Title &KeyWordLookUp=Title&KeyWordLookUp=Title&KeyWordSearchType=And&KeyWordSearchType=And&KeyW ordSearchType=And&bc=gAAAACAAAAAA&. Accessed March 5, 2020.
32. Centers for Medicare & Medicaid Services. Billing Medicare for Remote Intraoperative Neurophysiology Monitoring in CY 2013. 2012; https://www.cms.gov/Medicare/Medicare-Fee-for-Service- Payment/PhysicianFeeSched/Downloads/FAQ-Remote-IONM.pdf. Accessed March 5, 2020.
Codes:
(The list of codes is not intended to be all-inclusive and is included below for informational purposes only. Inclusion or exclusion of a procedure, diagnosis, drug or device code(s) does not constitute or imply authorization, certification, approval, offer of coverage or guarantee of payment.)
CPT*
92585
92586
95829
95865
95867
95868
95907
95908
95909
95910
95911
95912
95913
95925
95926
95927
95928
95929
95930
95940
95941
95955
HCPCS
* CPT only copyright 2020 American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.
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Medical policies can be highly technical and are designed for use by the Horizon BCBSNJ professional staff in making coverage determinations. Members referring to this policy should discuss it with their treating physician, and should refer to their specific benefit plan for the terms, conditions, limitations and exclusions of their coverage.
The Horizon BCBSNJ Medical Policy Manual is proprietary. It is to be used only as authorized by Horizon BCBSNJ and its affiliates. The contents of this Medical Policy are not to be copied, reproduced or circulated to other parties without the express written consent of Horizon BCBSNJ. The contents of this Medical Policy may be updated or changed without notice, unless otherwise required by law and/or regulation. However, benefit determinations are made in the context of medical policies existing at the time of the decision and are not subject to later revision as the result of a change in medical policy
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