CAM 70158

Intraoperative Neurophysiologic Monitoring

Category:Surgery   Last Reviewed:January 2020
Department(s):Medical Affairs   Next Review:January 2021
Original Date:January 2013    

Description 
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 evidence review 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.

For individuals who are undergoing thyroid or parathyroid surgery and are at high-risk of injury to the recurrent laryngeal nerve (RLN) who receive IONM, the evidence includes a large randomized controlled trial and systematic reviews. Therelevant outcomes are morbid events, functional outcomes, and quality of life (QOL). 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 RLN 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 RLN 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 RLN who receive IONM, the evidence includes systematic reviews of case series and cohort studies. Therelevant outcomes are morbid events, functional outcomes, and QOL. The evidence on the use of IONM to reduce RLN injury during cervical spinal surgery includes a 2017 systematic review and a meta-analysis. Of the ten studies assessed in the systematic review, two compared the risk of nerve injury with use of IONM vs no IONM 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 IONM, the evidence includes a nonrandomized comparative study. Therelevant outcomes are morbid events, functional outcomes, and QOL. One nonrandomized comparative study on surgery for esophageal cancerwas 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 RLN 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 IONM, the evidence includes case series and a controlled cohort study. Therelevant outcomes are morbid events, functional outcomes, and QOL. Surgical guidance with peripheral IONM 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 obtained in 2014 and professional society guidelines have supported the use of IONM during spinal, intracranial, or vascular procedures. There was general agreement that IONM of visual-evoked potentials and motor-evoked potentials using transcranial magnetic stimulation is investigational. It should be noted there is controversy about the utility of IONM in some surgical procedures. Most of the published literature is from Europe, and, while many articles have reported the sensitivity and specificity of motor-evoked potentials for predicting postsurgical neurologic deficits, few have reported intraoperative interventions undertaken in response to information from monitoring.

Clinical input obtained in 2017 supports that the following indication provides a clinically meaningful improvement in net health outcome and is consistent with generally accepted medical practice:

  • Use of IONM of the RLN 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 RLN pathology, when there is residual function of the RLN.

Thus, the above indication may be considered medically necessary considering the suggestive evidence and clinical input support.

Background
INTRAOPERATIVE NEUROPHYSIOLOGIC MONITORING
The principal goal of intraoperative neurophysiologic monitoring (IONM) is 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 potential (SEP) describes the responses of the sensory pathways to sensory or electrical stimuli. Intraoperative monitoring of SEPs is used to assess the functional integrity of central nervous system (CNS) pathways during surgeries that put the spinal cord or brain at risk for significant ischemia or traumatic injury. The basic principles of SEP 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 interpretation of the signal at certain standardized points along the pathway. Monitoring of SEPs is commonly used during 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. SEPs can be further broken down into the following categories by type of simulation used.

Somatosensory-Evoked Potentials
Somatosensory-evoked potentials (SSEPs) 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. Recording is done either cortically or at the level of the spinal cord above the surgical procedure. Intraoperative monitoring of SSEPs 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 SSEP monitoring is in patients undergoing corrective surgery for scoliosis. In this setting, SSEP 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 (BAEPs) 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 BAEPs 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. VEP monitoring has been used for surgery on lesions near the optic chiasm. However, VEPs are very difficult to interpret due to their sensitivity to anesthesia, temperature, and blood pressure.

Motor-Evoked Potentials
Motor-evoked potentials (MEPs) are recorded from muscles following direct or transcranial electrical stimulation of motor cortex or by pulsed magnetic stimulation provided by 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. MEPs, especially when induced by magnetic stimulation, can be affected by anesthesia. The Digitimer electrical cortical stimulator received U.S. Food and Drug Administration (FDA) premarket approval in 2002. Devices for transcranial magnetic stimulation have not been approved by FDA for this use.

Multimodal IONM, in which more than 1 technique is used, most commonly with SSEPs and MEPs, has also been described.

Electromyogram Monitoring and Nerve Conduction Velocity Measurements
Electromyography (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 EMG activity in the facial or neck muscles. Thus, monitoring is done in the direction opposite that of SEPs, but the purpose is similarto verify that the neural pathway is intact. 

Electroencephalogram Monitoring
Spontaneous electroencephalography (EEG) monitoring can also be used during surgery and can be subdivided as follows: 

  • 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. Carotid endarterectomy may be done with the patient under local anesthesia so that monitoring of cortical function can be directly assessed.
  • Electrocorticography (ECoG) is the recording of the EEG directly from a surgically exposed cerebral cortex. ECoG is typically used to define the sensory cortex and map the critical limits of a surgical resection. ECoG recordings have been most frequently used to identify epileptogenic regions for resection. In these applications, ECoG does not constitute monitoring, per se. 

Intraoperative neurophysiologic monitoring, including SSEPs and MEPs using transcranial electrical stimulation, BAEPs, EMG of cranial nerves, EEG, and ECoG, has broad acceptance, particularly for spine surgery and open abdominal aorta aneurysm repairs. These indications have long been considered 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.1-7 Therefore, this evidence review focuses on monitoring of the recurrent laryngeal nerve during neck and esophageal surgeries and monitoring of peripheral nerves.

Related Policies
20190 Navigated Transcranial Magnetic Stimulation

Policy
Intraoperative neurophysiologic monitoring, which includes somatosensory-evoked potentials, motorevoked potentials using transcranial electrical stimulation, brainstem auditory-evoked potentials, electromyography (EMG) of cranial nerves, electroencephalography, and electrocorticography, may be considered MEDICALLY NECESSARY during spinal, intracranial, or vascular procedures. 

Intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve may be considered MEDICALLY NECESSARY in patients undergoing: 

  • high-risk thyroid or parathyroid surgery, including: 
    • total thyroidectomy
    • repeat thyroid or parathyroid surgery 
    • surgery for cancer
    • thyrotoxicosis 
    • retrosternal or giant goiter 
    • thyroiditis 
  • anterior cervical spine surgery associated with any of the following increased risk situations: 
    • 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 
    • preexisting recurrent laryngeal nerve pathology, when there is residual function of the recurrent laryngeal nerve. 

Intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve during anterior cervical spine surgery not meeting the criteria above or during esophageal surgeries is considered investigatonal and/or unproven and therefore considered NOT MEDICALLY NECESSARY.

NOTE: laryngeal nerve and facial nerve monitoring are not separately allowable if the provider rendering the service is part of the operating room team (including but not limited to surgeon, surgical assistant, scrub and circulating nurses and anesthesia).

Intraoperative monitoring of visual-evoked potentials is considered investigational and/or unproven and therefore considered NOT MEDICALLY NECESSARY.

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 and/or unproven and therefore considered NOT MEDICALLY NECESSARY.

Intraoperative EMG and nerve conduction velocity monitoring during surgery on the peripheral nerves is considered NOT 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
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 evidence review focuses on monitoring of the recurrent laryngeal nerve during neck surgeries and monitoring of peripheral nerves.

Constant communication between surgeon, neurophysiologist, and anesthetist are required for safe and effective intraoperative neurophysiologic monitoring.

CODING
Effective in 2013, there is new CPT coding for this service:

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).

In 2013, the Centers for Medicare and Medicaid Services also established a new HCPCS code for this type of monitoring:

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).

Codes 95040 and 95941 would be reported in conjunction with the code(s) for the testing performed, ie, 92585, 95822, 95860-95870, 95907-95913, and 95925-95939.

Benefit Application
BlueCard/National Account Issues
Intraoperative monitoring is considered reimbursable as a separate service only when a licensed healthcare practitioner, other than the operating surgeon, interprets the monitoring. The monitoring is performed by a healthcare practitioner or technician who is in attendance in the operating room throughout the procedure.

Implementation of a local policy on this technology may also involve discussions about credentialing of those providing the intraoperative monitoring services, as well as on-site versus remote real-time review and interpretation.

Coding for intraoperative monitoring uses time-based codes; they are not based on the number (single vs. multiple) of modalities used.

Rationale
Early literature focused on intraoperative monitoring of cranial and spinal nerves. This evidence review focuses on more recently investigated techniques, including monitoring of the recurrent laryngeal nerve (RLN) 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 the of life, quality of life (QOL), and ability to function—including benefits and harms. Every clinical condition has specific outcomes that are important to patients andmanaging 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 two domains are examined: the relevance, and quality and credibility. To be relevant, studies must represent one or more intended clinical uses 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.

RLN Monitoring During Thyroid or Parathyroid Surgery
Clinical Context and Therapy Purpose

The purpose of intraoperative neurophysiologic monitoring (IONM) is to provide a treatment option that is an alternative to or an improvement on existing therapies, such assurgery without neurophysiologic monitoring, in patients who are undergoing thyroid or parathyroid surgery and are at high-risk of injury to the RLN.

The question addressed in this evidence review is: does neurophysiologic monitoring improve the net health outcome in patients during surgeries that could damage their RLN or peripheral nerves?

The following PICOTS were used to select literature to inform this review.

Patients
The relevant population of interest are individuals who are undergoing thyroid or parathyroid surgery and are at high-risk of injury to the RLN.

Interventions
The therapy being considered is IONM.

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.

Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by endocrine surgeons and primary care providers in an outpatient surgical setting.

Outcomes
The general outcomes of interest are morbid events, functional outcomes, and QOL.

Timing
The existing literature evaluating IONM as a treatment for patients who are undergoing thyroid or parathyroid surgery and are at high-risk of injury to the RLN 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.

Setting
Patients who are undergoing thyroid or parathyroid surgery and are at high-risk of injury to the RLN are actively managed by endocrine surgeons, neurosurgeons, and primary care providers in an outpatient surgical setting.

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 comparedIONM with direct RLN visualization by assessing rates of vocal fold palsy.8, Reviewers included eight meta-analyses of RCTs or observational studies (prospective or retrospective) and selected the best evidence based on the Jadad algorithm. The eight8 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. Using the Jadad algorithm, reviewers determined the meta-analysis by Pisanu et al (2014)9, to have the highest quality; it found that concluded no statistically significant reductions in RLN injury between procedures using IONM vs direct RLN visualization. However, reviewers also noted that recent developments in IONM technology such as continuous vagal IONM and staged thyroidectomy might provide additional benefits, which were out of the scope of their systematic review and need to be assessed in further assessment in prospective multicenter trials.

Sun et al (2017) reported on a meta-analysis of RLN injury during thyroid surgery with or without IONM.10, Included were two prospective cohort studies and seven retrospective cohort studies. Results are summarized in Tables 1 and 2. The absolute risk reduction was 2.75%, with a number needed to treat of 364.13. Observed differences in the subgroup analysis were very imprecise because the number of observed paralyses was very low. IONM was associated with a reduction in overall and permanent RLN palsy in thyroid reoperations. Limitations included small sample sizes and study heterogeneity.

Pardal-Refoyo and Ochoa-Sangrador (2016) reported on a systematic review of RLN injury during total thyroidectomy with or without IONM.11, Included were 1 large (n=1000) and 1 small (n=23) RCT and 52 case series that estimated the risk to the RLN. Twenty-nine studies used RLN monitoring and 25 did not. Results are summarized in Table 1 and 2. The absolute risk reduction was 2.75%, with a number needed to treat of 364.13. The observed differences in the subgroup analysis were very 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

  • 2 RCTs
  • 52 case series

Studies reporting incidence of RLN paralysis after single- stage

30,922

  • RCT
  • Case series

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/ 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 (range, 6-23 patients)

Meta-analysis

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

 

 

NNT (95% CI)

364 (NR)a

 

 

I2 (p)

8%a

 

 

 

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%

67.4%b

13.7%b

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.
aSample size of 11,947 patients.
bSample of 7 studies.

The largest RCT evaluating RLN neuromonitoring for thyroid surgery was reported by Barczynski et al (2009) and is summarized in Tables 3 and 4.12 RLN 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 RLN paresis was 2.9% lower in patients who had RLN monitoring (p=0.011) compared with those who received visual identification only. In low-risk patients, there was no significant difference in RLN 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 RLN 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; RLN: recurrent laryngeal nerve. 

Section Summary: RLN Monitoring During Thyroid or Parathyroid Surgery
The evidence on the use of IONM in reducing RLN injury includes a large RCT and systematic reviews assessing thyroid and parathyroid surgery. The strongest evidence derives from an RCT of 1000 patients undergoing thyroid surgery. This RCT found minimal effect of IONM overall but a significant reduction in RLN 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.

RLN Monitoring During Cervical Spine Surgery
Clinical Context and Therapy Purpose
The purpose of IONM 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 RLN.

The question addressed in this evidence review is: does neurophysiologic monitoring improve the net health outcome in patients during surgeries that could damage their RLN or peripheral nerves?

The following PICOTS were used to select literature to inform this review.

Patients
The relevant population of interest are individuals who are undergoing anterior cervical spine surgery and are at high-risk of injury to the RLN.

Interventions
The therapy being considered is IONM.

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.

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 QOL.

Timing
The existing literature evaluating IONM as a treatment for patients who are undergoing anterior cervical spine surgery and are at high-risk of injury to the RLN 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.

Setting
Patients who are undergoing anterior cervical spine surgery and are at high-risk of injury to the RLN are actively managed by neurosurgeons, orthopedic surgeons, and primary care providers in an inpatient surgical setting.

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.

Ajiboye et al (2017) reported on the results of a systematic review that included 10 studies (totaln=26357 patients).14, All studies were of low methodologic quality but had a low-risk of bias. Only studies compared the risk of nerve injury using IONM with no IONM. Based on data from these 2 studies, there was no statistically significant difference in the risk of neurologic injury with or without IONM (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 RLN injury following revision anterior cervical discectomy and fusion.15, The meta-analysis did not report RLN injury rate with IONM vs without IONM. Based on pooled data from 3 prospective cohort studies and 5 retrospective series (totaln=238 patients), reviewers reported an overall RLN 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 evaluatingIONM during spinal operative surgical procedures16,. Six retrospective studies, published between 2006 and 2016, with a total of 335458 patients (range, 74–231067) were included. Pooled OR for neurological events with and without IONM 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 three 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: RLN Monitoring During Cervical Spine Surgery
The evidence on the use of IONM in reducing RLN injury during cervical spinal surgery includes a 2017 systematic review and a meta-analysis. Of the ten studies included in the systematic review, two compared the risk of nerve injury using IONM with no IONM and found no difference.

RLN Monitoring During Esophageal Surgery
Clinical Context and Therapy Purpose
The purpose of IONM 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 evidence review is: does neurophysiologic monitoring improve the net health outcome in patients during surgeries that could damage their RLM or peripheral nerves?

The following PICOTS were used to select literature to inform this review.

Patients
The relevant population of interest are individuals who are undergoing esophageal surgery.

Interventions
The therapy being considered is IONM.

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.

Comparators
Comparators of interest include surgery without neurophysiologic monitoring. This operation is managed by thoracic surgeons and primary care providers in an outpatient surgical setting.

Outcomes
The general outcomes of interest are morbid events, functional outcomes, and QOL.

Timing
The existing literature evaluating IONM 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.

Setting
Patients who are undergoing esophageal surgery are actively managed by neurosurgeons, thoracic surgeons and primary care providers in an outpatient surgical setting.

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.

A comparative study from Asia by Zhong et al (2014) evaluated RLN 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 RLN was found and underwent monitoring. In the remainder (n=61), the RLN was not located. No RLN injury was reported during surgery in either group but 6 (10%) of 61 patients who did not receive monitoring had notable RLN injury identified postoperatively. It is unclear whether the difference in outcomes was due to monitoring or to the inability to identify the RLN during surgery.

Section Summary: RLN Monitoring During Esophageal Surgery
One nonrandomized comparative study on surgery for esophageal cancerwas identified. Interpretation of this study is confounded because only the patients who had visual identification of the nerve underwent IONM. Current evidence does not support conclusions on whether IONM reduces RLN injury in patients undergoing surgery for esophageal cancer.

Monitoring Peripheral Nerves
Clinical Context and Therapy Purpose
The purpose of IONM 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 evidence review is: does neurophysiologic monitoring improve the net health outcome in patients during surgeries that could damage their RLN or peripheral nerves?

The following PICOTS were used to select literature to inform this review.

Patients
The relevant population of interest are individuals who are undergoing surgery proximal to a peripheral nerve.

Interventions
The therapy being considered is IONM.

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.

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 QOL.

Timing
The existing literature evaluating IONM as a treatment for patients who are undergoing surgery proximal to a peripheral 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.

Setting
Patients who are undergoing surgery proximal to a peripheral nerve are actively managed by neurosurgeons and primary care providers in an inpatient surgical setting.

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.

Monitoring peripheral nerves during surgery was assessed by Kneist et al (2013) 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 IONM 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.

A report by 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 eight8 patients.21,

Use of IONM 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 IONM 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 RLN who receive IONM, the evidence includes a large RCT and systematic reviews. Therelevant outcomes are morbid events, functional outcomes, and QOL. The strongest evidence on neurophysiologic monitoring derives from a RCT of 1000 patients undergoing thyroid surgery. This RCT found a significant reduction in RLN 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 RLN 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 RLN who receive IONM, the evidence includes systematic reviews of case series and cohort studies. Therelevant outcomes are morbid events, functional outcomes, and QOL. The evidence on the use of IONM to reduce RLN injury during cervical spinal surgery includes a 2017 systematic review and a meta-analysis. Of the ten studies assessed in the systematic review, two compared the risk of nerve injury with use of IONM vs no IONM 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 IONM, the evidence includes a nonrandomized comparative study. Therelevant outcomes are morbid events, functional outcomes, and QOL. One nonrandomized comparative study on surgery for esophageal cancerwas 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 RLN 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 IONM, the evidence includes case series and a controlled cohort study. Therelevant outcomes are morbid events, functional outcomes, and QOL. Surgical guidance with peripheral IONM 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 (RLN) 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

Figure 1:

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 RLN and there is no nerve function it would seem that monitoring that side has no value. If the included definition of RLN pathology was partial and not complete there would be value in monitoring the affected nerve. However, if they are talking about the contralateral RLN that was currently working well, the answer should be high confidence and monitored in every situation. Monitoring the contralateral RLN in the presence of ipsilateral pathology would be yes with high confidence. However, monitoring the already damaged RLN would not be valuable as described above.” (AAO-HNS)

See Appendices 1 and 2 for details of the clinical input.

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 (IONM) of the recurrent laryngeal nerve (RLN) 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 IONM of the RLN 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 RLN pathology, when there is residual function of the RLN

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 IONM 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 IONM of visual-evoked potentials and motor-evoked potentials using transcranial magnetic stimulation is investigational. Input was mixed on whether IONM 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 IONM 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
The position statement onIONM during routine spinal surgery by theAANS andCNS (2012), updated in 2014, has stated that IONM may assist in diagnosing the neurologic injury.5, However, AANS and CNS found no evidence that such monitoring either (1) reduces the incidence of neurologic injury or (2) mitigates the severity of it. The position taken by AANS and CNS indicated that routine use of IONM is neither warranted nor recommended, although IONM should be performed if the diagnostic information gained is of value, particularly in high-risk cases such as deformity, gross instability, navigation through or around peripheral nerves, or intramedullary procedures. In the 2014 update, the AANS and CNS found no evidence that would conflict with their previous recommendations for IONM for lumbar fusion.25, TheeSocieties found no evidence that IONM can prevent injury to the nerve roots. They found limited evidence that IONM can indicate a medial pedicle breach by a pedicle screw, but once a nerve root injury has taken place, changing the direction of the screw does not alter the outcome.

American Association of Neuromuscular & Electrodiagnostic Medicine
A position statement on somatosensory-evoked potentials (SSEPs) from the AANEM(2014) has indicated that intraoperative sensory-evoked potentials (SEPs) have demonstrated usefulness for monitoring of spinal cord, brainstem, and brain sensory tracts.7The AANEM stated that intraoperative SEP monitoring is indicated for select spine surgeries in which there is a risk of additional nerve root or spinal cord injury. Indications for SEP monitoring may include, but not limited to, complex, extensive, or lengthy procedures, and when mandated by hospital policy. However, intraoperative SEP monitoring may not be indicated for routine lumbar or cervical root decompression.

American Clinical Neurophysiology Society
The ACNS(2009) recommended standards for IONM.4, Guideline 11A included the following statement26,:

“The monitoring team should be under the direct supervision of a physician with training and experience in NIOM [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 NIOM data. The monitoring physician should be present in the operating room or have access to NIOM 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
The AAN(1990) published an assessment of IONM, 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. Electroencephalography (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 SSEPs 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 SSEPs 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 (MEPs) were considered investigational by many neurophysiologists. The 2012 update, which was endorsed bythe AANEM, concluded that the available evidence supported IONM using SSEPs or MEPs when conducted under the supervision of a clinical neurophysiologist experienced with IONM. Evidence was insufficient to evaluate IONM when conducted by technicians alone or by an automated device.

The AAN (2012) published a model policy on principles of coding for IONM and testing.27, The background section of this document provides the following information on the value of IONM 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. EEG monitoring is capable of detecting cerebral ischemia, a serious prelude to injury. Studies of continuous monitoring established the ability of 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 IOM (intraoperative neurophysiologic monitoring) using SEP 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 IOM is capable of substantially reducing injury in surgeries that pose a risk to spinal cord integrity. It recommended combined SEP/MEP 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 SEP and MEP 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 two different techniques (SEP and MEP) 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 IOM accurately predicts risks for spinal cord ischemia associated with clamping the aorta or ligating segmental spinal arteries. IOM 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 [electromyography] 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. EMG can also be used in peripheral nerve procedures that pose a risk of injuries to nerves.
  7.  Value of Spinal Monitoring using SSEP and MEPs. According to a recent review of spinal monitoring using SSEP and MEPs by the Therapeutics and Technology Assessment Subcommittee of AAN and ACNS, IOM 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 IOM changes (Level A).”

The AAN model policy also offered guidance on personnel and monitoring standards for IONM and SSEP.

American Society of Neurophysiological Monitoring
The American Society of Neurophysiological Monitoring (2018) published practice guidelines on the supervising professional on IONM.28, The Society’s (2013) position statement on intraoperative MEP monitoring indicated that MEPs 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
A guidance from the National Institute for Health and Care Excellence (2008) on IONM during thyroid surgery found no major safety concerns.30,Regarding efficacy, IONM 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 review are listed in Table 7.

Table 7. Summary of Key Trials

NCT No.

Trial Name

Planned Enrollment

Completion Date

Ongoing

     

NCT02395146

Intra-operative Monitoring of the External Branch of the Superior Laryngeal Nerve (EBSLN) During Thyroid Surgery: Does it Improve Voice Preservation?

60

Aug 2017
(unknown)

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

NCT01630785

Observation of Neurosurgical Interventions With Intraoperative Neurophysiological Monitoring IONM

5,000

Dec 2023

Unpublished

     

NCT02187653a

Spine Registry Exposure for Lumbar and Cervical Surgery Utilizing IOM

10,000

Dec 2016
(unknown)

NCT: national clinical trial.
a Denotes industry-sponsored or cosponsored trial.

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. 2009; http://www.acns.org/practice/guidelines. Accessed March 23, 2018.
  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 23, 2018.
  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. Sharan A, Groff MW, Dailey AT, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: electrophysiological monitoring and lumbar fusion. J Neurosurg Spine. Jul 2014;21(1):102-105. PMID 24980592.
  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 23, 2018.
  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 23, 2018.
  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 23, 2018.
  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 23, 2018.
  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 23, 2018.

Coding Section

Codes Number Description
CPT 92585

Auditory evoked potentials for evoked responseaudiometry and/or testing of the central nervous system; comprehensive

  95829

Electrocardiogram at surgery (separate procedure)

  95867-95868

Needle electromyography of cranial nerve suppliedmuscle(s) code range

  95905 Nerve Conduction Test
  95907  Nerve conduction studies; 1-2 studies
  95908 Nerve conduction studies; 3-4 studies
  95909  Nerve conduction studies; 5-6 studies
  95910  Nerve conduction studies; 7-8 studies
  95911  Nerve conduction studies; 9-10 studies
  95912  Nerve conduction studies; 11-12 studies
  95913  Nerve conduction studies; 13 or more studies
  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)

  95925-95927

Somatosensory-evoked potentials code range

  95930

Visual evoked potential (VEP) testing central nervous system, checkerboard or flash

  95955

Electroencephalogram (EEG) during non-intracranial surgery (e.g., carotid surgery)icd-9n ICD

ICD-9 Porocedure 38.12

Carotid endarterectomy

  89.14

Electroencephalogram

  89.15

Other non-operative neurologic function tests (includes SEP, VEP, BAEP, motor- evoked potentials, and nerve conduction study)

  93.08

Electromyography

ICD-9 Diagnosis 191.6

Malignant neoplasm of brain, occipital lobe

  198.3

Secondary malignant neoplasm of brain and spinal cord

  225.0

Benign neoplasm of brain

  225.1

Benign neoplasm of cranial nerves (includes acoustic neuroma)

  237.5 Neoplasm of uncertain behavior, brain and spinal cord
  239.6

Neoplasm of unspecified behavior, brain 

  441

Aortic aneurysm and dissection 

  722.0

Intervertebral disc disorders 

  723.0-723.3 Other disorders of cervical region code range
  724.09

Other and unspecified disorders of back 

  737.0-737.39 

Curvature of spine (i.e., scoliosis) code range 

   433.1

Occlusion and stenosis of carotid artery 

HCPCS   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)
ICD-10-CM (effective 10/01/2015)  C71.0-C71.9  Malignant neoplasm of brain; code range
  C79.31-C79.32 Secondary malignant neoplasm of brain and cerebral meninges; code range
  D33.0-D33.9

Benign neoplasm of brain and other parts of central nervous system; code range 

  D43.0-D43.9

Neoplasm of uncertain behavior of brain and central nervous system; code range

  D49.6

Neoplasm of unspecified behavior of brain 

  I171.00-I171.9 

Aortic aneurysm and dissection; code range 

  M50.00-M50.93

Cervical disc disorders; code range 

  M48.00-M48.08

Spinal stenosis; code range 

  M40.00-M40.57

Kyphosis and lordosis; code range 

  M41.00-M41.9

Scoliosis; code range 

  I65.01-I65.9 Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction; code range
ICD-10-PCS (effective 10/01/15)  4A0002Z  Measurement of Central Nervous Conductivity, Open Approach
  4A0004Z

Measurement of Central Nervous Electrical Activity, Open Approach

  4A000BZ Measurement of Central Nervous Pressure, Open Approach
  4A00X2Z  Measurement of Central Nervous Conductivity, External Approach
  4A00X4Z 

Measurement of Central Nervous Electrical Activity, External Approach

  4A01029 

Measurement of Peripheral Nervous Conductivity, Sensory, Open Approach

  4A0102B 

Measurement of Peripheral Nervous Conductivity, Motor, Open Approach

  4A01329 

Measurement of Peripheral Nervous Conductivity, Sensory, Percutaneous Approach

  4A0132B

Measurement of Peripheral Nervous Conductivity, Motor, Percutaneous Approach

  0A01X29

Measurement of Peripheral Nervous Conductivity, Sensory, External Approach

  4A01X2B Measurement of Peripheral Nervous Conductivity, Motor, External Approach
  4A1002Z Monitoring of Central Nervous Conductivity, Open Approach
  4A1004Z

Monitoring of Central Nervous Electrical Activity, Open Approach

  4A100BZ

Monitoring of Central Nervous Pressure, Open Approach

  4A10X2Z

Monitoring of Central Nervous Conductivity, External Approach

  4A10X4Z

Monitoring of Central Nervous Electrical Activity, External Approach

  4A11029

Monitoring of Peripheral Nervous Conductivity, Sensory, Open Approach

  4A1102B

Monitoring of Peripheral Nervous Conductivity, Motor, Open Approach

  4A11329

Monitoring of Peripheral Nervous Conductivity, Sensory, Percutaneous Approach

  4A1132B

Monitoring of Peripheral Nervous Conductivity, Motor, Percutaneous Approach

  4A11X29 

Monitoring of Peripheral Nervous Conductivity, Sensory, External Approach 

  4A11X2B 

Monitoring of Peripheral Nervous Conductivity, Motor, External Approach  

  4B00XVZ 

Measurement of Central Nervous Stimulator, External Approach

  4B01XVZ Measurement of Peripheral Nervous Stimulator, External Approach
  4B0FXVZ

Measurement of Musculoskeletal Stimulator, External Approach 

  F01Z77Z 

Facial Nerve Function Assessment using Electrophysiologic Equipment 

  F01Z87Z

Neurophysiologic Intraoperative Assessment using Electrophysiologic Equipment  

  F01Z8JZ 

Neurophysiologic Intraoperative Assessment using Somatosensory Equipment 

  F01Z9JZ 

Somatosensory Evoked Potentials Assessment using Somatosensory Equipment 

Type of Service  Surgery  
Place of Service Inpatient   

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

Appendix
Appendix 1: Clinical Input

Appendix Table 1. Respondent Profile

 

Specialty Society

 

No.

Name of Organization

Clinical Specialty

1

American Academy of Neurological Surgeons / Congress of Neurological Surgeons

Neurosurgery

2

American Academy of Otolaryngology-Head and Neck Surgery

Otolaryngology, Head and Neck Surgery

3

American Academy of Orthopaedic Surgeons / North American Spine Society

Orthopaedic Surgery, Spine Disorders

Appendix Table 2. Respondent Conflict of Interest Disclosure

No.

1. Research support related to the topic where clinical input is beingsought

2. Positions, paid or unpaid, related to the topic where clinical input is beingsought

3. Reportable,morethan$1000,healthcare-relatedassetsorsourcesofincomeformyself, my spouse, or my dependent children related to the topic where clinical input is beingsought

4. Reportable, more than $350, gifts or travel reimbursements for myself, myspouse, or my dependent children related to the topic where clinical input is beingsought

No.

Yes/No

Explanation

Yes/No

Explanation

Yes/No

Explanation

Yes/No

Explanation

1

No

 

No

 

No

 

No

 

2

3 No

1 Yes

1 NR

1 Yes = Triological Society Career Development Award recipient. Topic of research is the study of laryngeal motor neuropathy through the evaluation of transcranial magnetic stimulation-evoked myogenic potentials

4 No

1 NR

 

4 No

1 NR

 

4 No

1 NR

 

No.

Conflict of Interest Policy Statement

3

The North American Spine Society (NASS) employs rigorous checks and balances to ensure that its comments and recommendations on payors’ coverage policies/clinical evidence reports are scientifically sound and unbiased. These checks and balances include requiring all individuals involved in drafting, reviewing, revising and approving the comments to disclose any conflicts of interest he or she may have. Using an evidence-based approach when possible, the multi-disciplinary team works together to develop the comments which requires multiple levels of review. The individuals who provide the final reviews and approvals are further required to divest themselves of most financial interests in any medical industry-related concerns. For more information on NASS’ Level 1 disclosure policy, please visit NASS website.

Individual physician respondents answered at individual level. Specialty Society respondents provided aggregate information that may be relevant to the group of clinicians who provided input to the Society-level response.
NR: not reported.

Appendix 2: Clinical Input Responses
Objective
Clinical input is sought for intraoperative neurophysiologic monitoring of the recurrent laryngeal nerve to determine whether monitoring improves health outcomes when used during cervical spine surgeries.

Responses

1.     For patients undergoing cervical spine surgery, are there patient factors and/or surgical factors that would increase the risk of recurrent laryngeal nerve injury?

No.

Yes/No

Explanation

1

Yes

A meta-analysis by Erwood from 2016 was performed to determine the rate of recurrent laryngeal nerve (RLN) injuries after recurrent ACDF's. They report a rate of RLN injury after reoperative ACDF of 14.1% (95% confidence interval [CI] 9.8%-19.1%). This number is much greater than what is reported for routine ACDF's, and as such we must take into account that monitoring of the RLN may be indicated in patients undergoing revision ACDF procedures. Tan et al (2014 Spine J) also confirm that there is significant evidence that revision ACDF increase the risk of laryngeal palsy. An article from Dimopoulos (2009) reviewed the role of laryngeal intraoperative electromyography (IEMG) in predicting the development of postoperative recurrent laryngeal nerve (RLN) palsy in patients undergoing anterior cervical discectomy and fusion (ACDF). They found significantly increased IEMG activity in patients with previous surgical intervention, patients undergoing multilevel procedures, long-lasting procedures, and cases in which self-retained retractors were used. They therefore conclude that IEMG can provide real-time information and can potentially minimize the risk of operative RLN injury.

Refs:

  • 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. 2016 Aug;25(2):198-204. PMID: 27015129
  • Tan TP, Govindarajulu AP, Massicotte EM, et al. Vocal cord palsy after anterior cervical spine surgery: a qualitative systematic review. Spine J. 2014 Jul 1; 14(7):1332-42. PMID: 24632183
  • Dimopoulos VG, Chung I, Lee GP, et al. Quantitative estimation of the recurrent laryngeal nerve irritation by employing spontaneous intraoperative electromyographic monitoring during anterior cervical discectomy and fusion. J Spinal Disord Tech. 2009 Feb;22(1):1-7. PMID: 19190427

2

Yes

1.     Revision surgery through a scarred surgical field

  • Beutler WJ, Sweeney CA, Connolly PJ. Recurrent laryngeal nerve injury with anterior cervical spine surgery risk with laterality of surgical approach. Spine (Phila Pa 1976). 2001 Jun 15; 26(12):1337-42. PMID: 11426148
  • Dimopoulos VG, Chung I, Lee GP, et al. Quantitative estimation of the recurrent laryngeal nerve irritation by employing spontaneous intraoperative electromyographic monitoring during anterior cervical discectomy and fusion. J Spinal Disord Tech. 2009 Feb;22(1):1-7. PMID: 19190427

2.     Preexisting recurrent laryngeal nerve pathology

  • Jung A, Schramm J, Lehnerdt K, et al. Recurrent laryngeal nerve palsy during anterior cervical spine surgery: a prospective study. J Neurosurg Spine. 2005 Feb;2(2):123-7. PMID: 15739522
  • Paniello RC, Martin-Bredahl KJ, Henkener LJ, et al. Preoperative laryngeal nerve screening for revision anterior cervical spine procedures. Ann Otol Rhinol Laryngol. 2008 Aug; 117(8):594-7. PMID: 18771076

3.     Lower level cervical spine surgery:

  • Apfelbaum RI, Kriskovich MD, Haller JR. On the incidence, cause, and prevention of recurrent laryngeal nerve palsies during anterior cervical spine surgery. Spine (Phila Pa 1976). 2000 Nov 15; 25(22):2906-12. PMID: 11074678
  • Razfar A, Sadr-Hosseini SM, Rosen CA, et al. Prevention and management of dysphonia during anterior cervical spine surgery. Laryngoscope. 2012 Oct; 122(10):2179-83. PMID: 22898808

4.     Right-sided approach:

  • While most approaches are done from the left, some surgeons do prefer a right sided approach. There is a known incidence of non-recurrent laryngeal nerve on the right of ~1% (Kamani D, Potenza AS, Cernea CR, et al. The nonrecurrent laryngeal nerve: anatomic and electrophysiologic algorithm for reliable identification. Laryngoscope. 2015 Feb;125(2):503-8. PMID: 25042210). Dissection on this side, without monitoring, almost certainly results in right RLN injury. Review of 16 cases of vocal fold paralysis at a single institution showed 15/16 were secondary to right sided approach (Netterville JL, Koriwchak MJ, Winkle M, et al. Vocal fold paralysis following the anterior approach to the cervical spine. Ann Otol Rhinol Laryngol. 1996 Feb; 105(2):85-91. PMID: 8659941).

3

Yes

Increased risk for injury to the recurrent laryngeal nerve havebeen found in patients with prior anterior cervical surgery as well as patients undergoing re-operation for pseudarthrosis or failed fusion.

2.     For each situation you described in Question 1:

a.     Please fill in the first column of the table below with each indication you reported.
b.     Please respond YES or NO whether the use of intraoperative neurophysiologic monitoring would be expected to improve health outcomes by reducing nerve injury and postoperative morbidity.
c.     Please use the 1 to 5 scale outlined below to indicate your level of confidence that there is adequate evidence that supports your conclusions.

No.

Fill in the blanks below with each indication you reported in Question 1

Yes/No

Low Confidence

 

Intermediate Confidence

 

High Confidence

     

1

2

3

4

5

1

Revision anterior cervical discectomy and fusion

Yes

       

X

1

Multilevel anterior cervical discectomy and fusion

Yes

   

X

   

1

Time consuming anterior cervical discectomy and fusion (eg, tumor)

Yes

   

X

   

2

Revision surgery through a scarred surgical field

Yes

       

X

2

Preexisting recurrent laryngeal nerve pathology

Yes

     

X

 

2

Lower level cervical spine surgery

Yes

 

X

     

2

Right-sided approach

Yes

X

       

3

Prior anterior cervical surgery

Yes

   

X

   

3

Reoperation for pseudarthrosis or revision for failed fusion

Yes

   

X

   

3.     For each situation you described in Question 1:

a.     Please fill in the first column of the table below with each indication you reported.
b.     Please respond YES or NO whether this clinical use is in accordance with generally accepted medical practice.
c.     Please use the 1 to 5 scale outlined below to indicate your level of confidence that this clinical use is in accordance with generally accepted medical practice.

No.

Fill in the blanks below with each indication you reported in Question 1

Yes/No

Low Confidence

 

Intermediate Confidence

 

High Confidence

     

1

2

3

4

5

1

Revision anterior cervical discectomy and fusion

Yes

     

X

 

1

Multilevel anterior cervical discectomy and fusion

Yes

 

X

     

1

Time consuming anterior cervical discectomy and fusion (eg, tumor)

Yes

 

X

     

2

Revision surgery through a scarred surgical field

Yes

       

X

2

Preexisting recurrent laryngeal nerve pathology

No

   

X

   

2

Lower level cervical spine surgery

No

   

X

   

2

Right-sided approach

Yes

X

       

3

Prior anterior cervical surgery

No

     

X

 

3

Reoperation for pseudarthrosis or revision for failed fusion

No

     

X

 

4.     Additional comments and/or any citations supporting your clinical input on the clinical use of intraoperative neurophysiologic monitoring in patients undergoing cervical spine surgery. 

No.

Additional Comments

1

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.

On the broader topic of general intraoperative neurophysiologic monitoring in patients undergoing cervical spine surgery, the AANS has made guidelines as follows:

  • Multimodality intraoperative monitoring (IOM), including somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) recording during spinal cord/spinal column surgery is a reliable and valid diagnostic adjunct to assess spinal cord integrity and is recommended if utilized for this purpose.
  • Motor evoked potential recordings are superior to SSEP recordings during spinal cord/spinal column surgery as diagnostic adjuncts for assessment of spinal cord integrity and are recommended if utilized for this purpose.
    • SSEP recordings during spinal cord/spinal column surgery are reliable and valid diagnostic adjuncts to describe spinal cord integrity and are recommended if utilized for this purpose.

2

1.     Revision surgery through a scarred surgical field

  • Beutler WJ, Sweeney CA, Connolly PJ. Recurrent laryngeal nerve injury with anterior cervical spine surgery risk with laterality of surgical approach. Spine (Phila Pa 1976). 2001 Jun 15; 26(12):1337-42. PMID: 11426148
  • Dimopoulos VG, Chung I, Lee GP, et al. Quantitative estimation of the recurrent laryngeal nerve irritation by employing spontaneous intraoperative electromyographic monitoring during anterior cervical discectomy and fusion. J Spinal Disord Tech. 2009 Feb;22(1):1-7. PMID: 19190427

2.     Preexisting recurrent laryngeal nerve pathology

  • Jung A, Schramm J, Lehnerdt K, et al. Recurrent laryngeal nerve palsy during anterior cervical spine surgery: a prospective study. J Neurosurg Spine. 2005 Feb;2(2):123-7. PMID: 15739522
  • Paniello RC, Martin-Bredahl KJ, Henkener LJ, et al. Preoperative laryngeal nerve screening for revision anterior cervical spine procedures. Ann Otol Rhinol Laryngol. 2008 Aug; 117(8):594-7. PMID: 18771076
  • Preexisting recurrent laryngeal nerve pathology:
    • If there is a pre-existing injury to the RLN and there is no nerve function it would seem that monitoring that side has no value. If the included definition of RLN pathology was partial and not complete there would be value in monitoring the affected nerve. However, if they are talking about the contralateral RLN that was currently working well, the answer should be high confidence and monitored in every situation.
    • Monitoring the contralateral RLN in the presence of ipsilateral pathology would be yes with high confidence. However, monitoring the already damaged RLN would not be valuable as described above.

3.     Lower level cervical spine surgery

  • Apfelbaum RI, Kriskovich MD, Haller JR. On the incidence, cause, and prevention of recurrent laryngeal nerve palsies during anterior cervical spine surgery. Spine (Phila Pa 1976). 2000 Nov 15; 25(22):2906-12. PMID: 11074678
  • Razfar A, Sadr-Hosseini SM, Rosen CA, et al. Prevention and management of dysphonia during anterior cervical spine surgery. Laryngoscope. 2012 Oct; 122(10):2179-83. PMID: 22898808
  • Ebraheim NA, Lu J, Skie M, et al. Vulnerability of the recurrent laryngeal nerve in the anterior approach to the lower cervical spine. Spine (Phila Pa 1976). 1997 Nov 15; 22(22):2664-7. PMID: 9399453

3

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.

5.     Is there any evidence missing from the attached draft review of evidence?

No.

Yes/No

Citations of Missing Evidence

1

Yes

  • In 2010 Fehlings et al offered a systematic review of the literature on IOM recordings during spinal surgery. They screened 103 articles and reviewed 32 that met rigid inclusion criteria. The authors concluded that “high level” medical evidence supports the use of IOM as a sensitive and specific means to monitor spinal cord function and integrity and to detect intraoperative neurological injury during spinal surgery. (Fehlings MG, Brodke DS, Norvell DC, et al. The evidence for intraoperative neurophysiological monitoring in spine surgery: does it make a difference? Spine (Phila Pa 1976). 2010 Apr 20; 35(9 Suppl):S37-46. PMID: 20407350)
  • May et al, JNS, 1996 (May DM, Jones SJ, Crockard HA. Somatosensory evoked potential monitoring in cervical surgery: identification of pre- and intraoperative risk factors associated with neurological deterioration. J Neurosurg. 1996 Oct; 85(4):566-73. PMID: 8814157.)
    • Case series of SSEP monitoring in 191 cervical spine procedures (24 for trauma). Broad spectrum of cervical pathology. I SSEP changes were noted in 33 cases while 10 patients had new neurological deficits post-surgery. Sensitivity was 99% but specificity low, 27%. False positives exceeded true positives 3:1.
  • Hilibrandet al, JBJS, 2004 (Hilibrand AS, Schwartz DM, Sethuraman V, et al. Comparison of transcranial electric motor and somatosensory evoked potential monitoring during cervical spine surgery. J Bone Joint Surg Am. 2004 Jun; 86-A(6):1248-53. PMID: 15173299.)
    • Retrospective review of 427 cervical spine procedures for broad-spectrum pathology monitored with SSEP and TcMEP, comparing both modalities to neurological outcome. I TcMEP sensitivity and specificity were 100%. SSEP was 100% specific but only 25% sensitive. TcMEPs superior to SSEPs to detect motor tract deficits.
  • Eggspuehler et al, Eur Spine J, 2007 (Eggspuehler A, Sutter MA, Grob D, et al. Multimodal intraoperative monitoring (MIOM) during cervical spine surgical procedures in 246 patients. Eur Spine J. 2007 Nov; 16 Suppl 2:S209-15. PMID: 17610090.)
    • Prospective series of 246 patients undergoing cervical spine surgery with multimodal IOM. I Multimodal IOM sensitivity and specificity were 83% and 99%. Only 7 cases were performed for fracture/ instability.
  • Kelleher MO, Tan G, Sarjeant R, et al. Predictive value of intraoperative neurophysiological monitoring during cervical spine surgery: a prospective analysis of 1055 consecutive patients. J Neurosurg Spine. 2008 Mar;8(3):215-21. PMID: 18312072.
    • Prospective series of 1055 cervical spine procedures performed with multimodal intraoperative monitoring (IOM). I/II SSEP (n=1055) was 52% sensitive and 100% specific while TcMEP (n=26) was 100% sensitive and 96% specific in predicting new post-op deficits. True comparison of monitoring modalities not offered.
  • Kim et al, Spine, 2007 (Kim DH, Zaremski J, Kwon B, et al. Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy. Spine (Phila Pa 1976). 2007 Dec 15;32(26):3041-6. PMID: 18091499.)
  • oRetrospective series of 52 consecutive patients undergoing surgery for cervical myelopathy with SSEP and TcMEP monitoring. I/II TcMEP sensitivity and specificity were 100% and 90% vs. 0% and 100% for SSEP. TcMEP positive predictive value was 17% (ie, five of six alerts were false positive).
    • Class I: TcMEPs superior to SSEP.
    • Class II: Limited to small CSM population.

2

Yes

  • 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. 2016 Aug;25(2):198-204. PMID: 27015129
  • Beutler WJ, Sweeney CA, Connolly PJ. Recurrent laryngeal nerve injury with anterior cervical spine surgery risk with laterality of surgical approach. Spine (Phila Pa 1976). 2001 Jun 15; 26(12):1337-42. PMID: 11426148
  • Dimopoulos VG, Chung I, Lee GP, et al. Quantitative estimation of the recurrent laryngeal nerve irritation by employing spontaneous intraoperative electromyographic monitoring during anterior cervical discectomy and fusion. J Spinal Disord Tech. 2009 Feb;22(1):1-7. PMID: 19190427
  • Jung A, Schramm J, Lehnerdt K, et al. Recurrent laryngeal nerve palsy during anterior cervical spine surgery: a prospective study. J Neurosurg Spine. 2005 Feb;2(2):123-7. PMID: 15739522
  • Paniello RC, Martin-Bredahl KJ, Henkener LJ, et al. Preoperative laryngeal nerve screening for revision anterior cervical spine procedures. Ann Otol Rhinol Laryngol. 2008 Aug; 117(8):594-7. PMID: 18771076
  • Razfar A, Sadr-Hosseini SM, Rosen CA, et al. Prevention and management of dysphonia during anterior cervical spine surgery. Laryngoscope. 2012 Oct; 122(10):2179-83. PMID: 22898808
  • Apfelbaum RI, Kriskovich MD, Haller JR. On the incidence, cause, and prevention of recurrent laryngeal nerve palsies during anterior cervical spine surgery. Spine (Phila Pa 1976). 2000 Nov 15; 25(22):2906-12. PMID: 11074678
  • Kriskovich MD, Apfelbaum RI, Haller JR. Vocal fold paralysis after anterior cervical spine surgery: incidence, mechanism, and prevention of injury. Laryngoscope. 2000 Sep; 110(9):1467-73. PMID: 10983944
  • Jellish WS, Jensen RL, Anderson DE, et al. Intraoperative electromyographic assessment of recurrent laryngeal nerve stress and pharyngeal injury during anterior cervical spine surgery with Caspar instrumentation. J Neurosurg. 1999 Oct; 91(2 Suppl):170-4. PMID: 10505500
  • Kamani D, Potenza AS, Cernea CR, et al. The nonrecurrent laryngeal nerve: anatomic and electrophysiologic algorithm for reliable identification. Laryngoscope. 2015 Feb;125(2):503-8. PMID: 25042210
  • Mehra S, Heineman TE, Cammisa FP Jr, et al. Factors predictive of voice and swallowing outcomes after anterior approaches to the cervical spine. Otolaryngol Head Neck Surg. 2014 Feb; 150(2):259-65. PMID: 24367048
  • Netterville JL, Koriwchak MJ, Winkle M, et al. Vocal fold paralysis following the anterior approach to the cervical spine. Ann Otol Rhinol Laryngol. 1996 Feb; 105(2):85-91. PMID: 8659941
  • Zeng JH, Li XD, Deng L, et al. Lower cervical levels: Increased risk of early dysphonia following anterior cervical spine surgery. Clin Neurol Neurosurg. 2016 Oct; 149:118-21. PMID: 27513980

3

No

 

Index
EEG monitoring
EMG monitoring
Intra-operative monitoring
Monitoring, intra-operative
Motor-evoked potentials
Sensory-evoked potentials
Somatosensory-evoked potentials
Visual-evoked potentials

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association.  All Rights Reserved" 

History From 2013 Forward     

01/21/2020 

Annual review, no change to policy intent. Updating rationale, references and description. 

05/21/2019 

Corrected last review date. No other changes made. 

01/30/2019 

Annual review, updating rationale and references. 

11/14/2018 

Interim review updating note section to include facial nerve monitoring and adding specificity to the providers included in the note. No other changes made.

09/11/2018 

Interim review, updating coding. No other changes made. 

02/15/2018 

Annual review, adding policy verbiage regarding the medical necessity of laryngeal nerve monitoring. Also updating title, background, description, guidelines, rationale and references. 

01/04/2017 

Annual review, no change to policy intent. 

01/13/2016 

Annual review, no change to policy intent. Updating background, description, rationale and references. 

01/29/2015

Annual review, no change to policy intent. Added coding & related policy. Updated guidelines, rationale and references.

01/14/2014

Annual review. Updated rationale and references. Added benefit applications. No change to policy intent.


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