Clinical Policy Title: Somatosensory evoked potentials (SEPs or SSEPs) test

Transcription

1 Clinical Policy Title: Somatosensory evoked potentials (SEPs or SSEPs) test Clinical Policy Number: Effective Date: January 1, 2016 Initial Review Date: June 16, 2013 Most Recent Review Date: September 21, 2017 Next Review Date: September 2018 Policy contains: Somatosensory evoked potentials (SEPs or SSEPs) test. Related policies: None. ABOUT THIS POLICY: Select Health of South Carolina has developed clinical policies to assist with making coverage determinations. Select Health of South Carolina s clinical policies are based on guidelines from established industry sources, such as the Centers for Medicare & Medicaid Services (CMS), state regulatory agencies, the American Medical Association (AMA), medical specialty professional societies, and peerreviewed professional literature. These clinical policies along with other sources, such as plan benefits and state and federal laws and regulatory requirements, including any state- or plan-specific definition of medically necessary, and the specific facts of the particular situation are considered by Select Health of South Carolina when making coverage determinations. In the event of conflict between this clinical policy and plan benefits and/or state or federal laws and/or regulatory requirements, the plan benefits and/or state and federal laws and/or regulatory requirements shall control. Select Health of South Carolina s clinical policies are for informational purposes only and not intended as medical advice or to direct treatment. Physicians and other health care providers are solely responsible for the treatment decisions for their patients. Select Health of South Carolina s clinical policies are reflective of evidence-based medicine at the time of review. As medical science evolves, Select Health of South Carolina will update its clinical policies as necessary. Select Health of South Carolina s clinical policies are not guarantees of payment. Coverage policy Select Health of South Carolina considers the use of short-latency somatosensory evoked potential (SEPs or SSEPs) testing to be clinically proven and therefore, medically necessary when the following criteria are met (Liu 2017, Thirumala 2017&2016, Hayes 2016, Tanaka 2016, Achouh 2007): To assess any neurologic decline which may warrant emergent surgery in unconscious spinal cord injury members who show specific structural damage to the somatosensory system, and who are candidates for emergency spinal cord surgery (Tanaka 2016). For diagnosis and management of specific neurologic diseases which involve the somatosensory system, conditions such as multiple sclerosis (MS), spinal cord trauma, myoclonus and pelizaeusmerzbacher disease. Intraoperative monitoring during surgeries that place parts of the somatosensory pathways at risk ((Liu 2017, Thirumaia 2017, Thirumaia 2016 a,b,c,d, Hayes 2016, Achouh 2007) To evaluate members with sensory symptoms that might be psychogenic. To localize the cause of a central nervous system deficit seen on exam, but not explained by lesions seen on computerized tomography (CT) or magnetic resonance imaging (MRI). 1

2 To manage members with spinocerebellar degeneration (e.g., Friedreichs ataxia, olivopontocerebellar [OPC] degeneration). Unexplained myelopathy. To evaluate members with suspected brain death. All medical necessity criteria must be clearly documented in the member's medical record and made available upon request. Limitations: Select Health of South Carolina considers all other uses of somatosensory evoked potentials testing not medically necessary. Note: SSEP studies are appropriate only when a detailed clinical history, neurologic examination and appropriate diagnostic tests, such as imaging studies, electromyogram, and nerve conduction studies make a lesion (or lesions) of the central somatosensory pathways a likely and reasonable differential diagnostic possibility. Alternative covered services: Conventional nerve conduction studies or needle electromyography (EMG), as ordered, under care of a primary care physician or neurologist. Background SSEP studies the relay of body sensations to the brain and how the brain receives those sensations. A stimulating electrode is placed on the arm or leg, and it generates an electrical signal. Recording electrodes are placed on the head and/or spine. The information received from these electrodes can help to diagnose a problem. The test evaluates the health of peripheral nerves and the spinal cord. It also tests how the spinal cord and/or brain transmit information about body sensations through peripheral nerves. It can localize a "signal blockage" either in the relay system, (peripheral nerves act like telephone wires) or in the interpretive center (the brain and spinal cord act like a telephone receiver). Evoked potentials studies involve three major tests that measure response to visual, auditory and electrical stimuli. Visual evoked response (VER) test. This test can diagnose problems with the optic nerves that affect sight. Electrodes are placed along the scalp. The patient is asked to watch a checkerboard pattern flash for several minutes on a screen and the electrical responses in the brain are recorded. 2

3 Brainstem auditory evoked response (BAER) test. This test can diagnose hearing ability and can indicate the presence of brain stem tumors and multiple sclerosis. Electrodes are placed on the scalp and earlobes. Auditory stimuli, such as clicking noises and tones, are delivered to one ear. Somatosensory evoked response (SSER) test. This test can detect problems with the spinal cord as well as numbness and weakness of the extremities. For this test, electrodes are attached to the wrist, the back of the knee, or other locations. A mild electrical stimulus is applied through the electrodes. Electrodes on the scalp then determine the amount of time it takes for the current to travel along the nerve to the brain. A related procedure that may be performed is an electroencephalogram (EEG). An EEG measures spontaneous electrical activity of the brain. Please see this procedure for additional information. Evoked potential studies may be used to assess hearing or sight, especially in infants and children, to diagnose disorders of the optic nerve, and to detect tumors or other problems affecting the brain and spinal cord. The tests may also be performed to assess brain function during a coma. A disadvantage of these tests is that they detect abnormalities in sensory function, but usually do not produce a specific diagnosis about what is causing the abnormality. However, the evoked potentials test can sometimes confirm a diagnosis of multiple sclerosis. Searches Select Health of South Carolina searched PubMed and the databases of: UK National Health Services Centre for Reviews and Dissemination. Agency for Healthcare Research and Quality s National Guideline Clearinghouse and other evidence-based practice centers. The Centers for Medicare & Medicaid Services (CMS). We conducted searches on August 18, Search terms were: evoked potentials (MeSH), intraoperative (MeSH), spinal cord (MeSH), Neuropathy (MeSH) and plexopathy (MeSH). We included: Systematic reviews, which pool results from multiple studies to achieve larger sample sizes and greater precision of effect estimation than in smaller primary studies. Systematic reviews use predetermined transparent methods to minimize bias, effectively treating the review as a scientific endeavor, and are thus rated highest in evidence-grading hierarchies. Guidelines based on systematic reviews. Economic analyses, such as cost-effectiveness, and benefit or utility studies (but not simple cost studies), reporting both costs and outcomes sometimes referred to as efficiency studies which also rank near the top of evidence hierarchies. Findings 3

4 SSEPs are used for clinical diagnosis in patients with neurologic diseases, to evaluate patients with sensory symptoms that might be psychogenic, for prognostication in comatose patients, and for intraoperative monitoring during surgeries, that place parts of the somatosensory pathways at risk. Abnormal SEPs can result from dysfunction at the level of the peripheral nerve, plexus, spinal root, spinal cord, brain stem, thalamocortical projections, or primary somatosensory cortex. Since individuals have multiple parallel afferent somatosensory pathways, (e.g., the anterior spinothalamic tract and the dorsal column tracts within the spinal cord), SEPs can be normal in patients with significant sensory deficits. However, an abnormal SEP result demonstrates that there is dysfunction within the somatosensory pathways. Subjects cannot volitionally make their SEPs; abnormal SEPs are useful in identifying clinically in apparent abnormalities and lesions causing only vague or equivocal signs or symptoms, and offer a noninvasive, often quantifiable, method of assessing known lesions. SEPs may also be useful for certain conditions in which the diagnosis is uncertain, by indicating involvement of central somatosensory pathways, as well as suggesting the type of involvement (e.g., demyelination). For patients with cervical root disease, electromyography and nerve conduction studies remain the gold standard diagnostic test, though their prognostic value is limited. For patients with suspected cervical myelopathy, SEP tests are more accurate in differentiating anterior horn cell diseases from myelopathy. For patients with diabetes peripheral neuropathy, adding motor evoked potentials (MEP) testing is useful. Policy updates: A systematic review (Liu 2017) evaluated the intraoperative warning criteria for monitoring evoked potential. Current guidelines recommend a decrease in SEP amplitude by 50 percent and MEP amplitude by 50 percent through 100 percent as warning signals for injury to the ascending sensory and descending motor pathways. Of significance, 0.1 percent through 4.1 percent of monitored patients in the review suffered postoperative neurologic deficit despite apparently normal intraoperative recordings. The authors argue that until a threshold that predicts spinal cord injury can be accurately determined, it remains difficult to define the clinical utility of intraoperative neurophysiologic monitoring. A systematic review (Thirumala 2017) sought to determine the efficacy of intraoperative transcranial motor evoked potential (TcMEP) in patients (n=2102) undergoing surgery for scoliosis, and found an observed incidence of neurological deficits of 1.38 percent (29/2102). The diagnostic odds ratio indicated that it is 250 times more likely to observe significant MEP changes intra-operatively in patients who experience a new-onset motor deficit immediately after scoliosis surgery. A systematic review (Thirumala 2016a) studied the predictive value of combined multimodality SSEP and TcMEP monitoring in detecting impending neurological injury during surgery for idiopathic scoliosis. 4

5 Seven studies (n=2052) established the incidence of neurological deficit in this cohort was 0.93 percent. The pooled sensitivity, specificity, and diagnostic odds ratio were 82.6 percent (95% CI 56.7%-94.5%), 94.4 percent (95% CI 85.1%-98.0%), and (95% CI ), respectively. The authors reported that patients who experience a new neurological deficit discovered postoperatively are times more likely to have had an SSEP and/or TcMEP change during corrective procedures, and that these results demonstrate that combined multimodality SSEP and TcMEP monitoring are advantageous in this clinical setting. A contemporary meta-analysis (Tanaka 2016) found MEP monitoring intra-operatively to be high in sensitivity and specificity at predicting postoperative paraplegia in patients undergoing thoracic (TA) or thoracoabdominal aortic aneurysm (TAAA) surgery. A systematic review (Thirumala 2016b) considered the ability of intraoperative SSEP to predict perioperative neurological outcome in patients undergoing spinal deformity surgery to correct adolescent idiopathic scoliosis (AIS). Fifteen studies (n=4763) documented new postoperative neurological deficits in 1.11 percent (53/4763) of the sample population. Among this population, 75.5 percent (40/53) showed significant SSEP changes, and 24.5 percent (13/53) did not show significant change (average 84%, 95% confidence interval 59-95%) and specificity (average 98%, 95% confidence interval 97-99%). The diagnostic odds ratio was 340 (95% confidence interval ). The authors concluded that SSEP is a highly sensitive and specific test, and that iatrogenic spinal cord injury resulting in new neurological deficits was 340 times more likely to have changes in SSEP compared to those without any new deficits. A systematic review (Thirumala 2016c) sought to determine whether intraoperative changes in SSEP during cerebral aneurysm clipping are predictive of perioperative stroke. A total of 14 articles (n=2015) found SSEP demonstrated a strong mean specificity of 84.5% (95% confidence interval [95% CI] to 90.3); however, there was significantly less sensitivity of 56.8% (95% CI ) for predicting stroke. A diagnostic odds ratio of (95% CI ) suggested that the odds of observing an SSEP change among those with a postoperative neurologic deficit were 7 to 8 times greater than those without a neurologic deficit. A systematic review (Thirumala 2016d) studied SSEP, transcranial motor evoked potentials (TME) and electromyography as monitoring activities in anterior cervical procedures for cervical spondylotic myelopathy. The authors identified a total of only 2 studies (n=173) that met inclusion criteria for the review. In both studies procedures done without monitoring found worsening myelopathy and/or quadriplegia: 2.71 percent of patients without monitoring and 0.91 percent of patients with monitoring. The authors opined that insufficient evidence exists to make recommendations regarding the use of different monitoring modalities to reduce neurological complications during anterior cervical procedures. A clinical trial (Achouh 2007) found intraoperative SSEP monitoring was reliable (though low in sensitivity) in ruling out spinal injury in descending TA and TAAA repair; moreover, the modality was an 5

6 independent predictor of mortality and correlated well with low preoperative glomerular filtration rate. A Hayes review of multimodal intraoperative monitoring during cervical spinal surgery found low-quality evidence suggesting both sensitivity and specificity in predicting postoperative injury, which included immediate C5 nerve root damage (Hayes 2016). The overall quality of the evidence pertaining to the diagnostic accuracy (i.e., clinical validity) of MIOM in detecting neurological deficits was rated as low. Only 2 of the included studies were considered to be of fair quality, with 7 considered to be of poor quality. The overall quality of the evidence related to the clinical utility of MIOM was rated as very low because all 3 studies directly measuring clinical utility had serious limitations in terms of study design and conduct, which may have introduced important differences between the groups, affecting the results observed. Hayes established a rating of C (potential but unproven benefit) for this technology. Moderate-quality evidence suggests that monitoring during corrective surgery for scoliosis is accurate in identifying patients who experience neurological decline during surgery, and is assumed to have clinical utility (Hayes 2016). It is in contemporary practice a useful adjunct to prevent permanent neurological damage. Hayes has established a rating of B (some proven benefit) for this intervention. Summary of clinical evidence: Citation Liu (2017) Warning criteria for intraoperative neurophysiologic monitoring. Thirumala (2017) Diagnostic accuracy of motor evoked potentials to detect neurological deficit during idiopathic scoliosis correction: a systematic review. Thirumala (2016a) Content, Methods, Recommendations A systematic review evaluated the intraoperative warning criteria for intraoperative evoked potential. Current guidelines recommend a decrease in SEP amplitude by 50 percent and MEP amplitude by 50 percent through 100 percent as warning signals for injury to the ascending sensory and descending motor pathways. Of significance, 0.1 percent through 4.1 percent of monitored patients in the review suffered postoperative neurologic deficit despite apparently normal intraoperative recordings. The authors argue that until a threshold that predicts spinal cord injury can be accurately determined, it remains difficult to define the clinical utility of intraoperative neurophysiologic monitoring. A systematic review sought to determine the efficacy of intraoperative MEP in patients (n=2102) undergoing surgery for scoliosis, and found an observed incidence of neurological deficits of 1.38 percent (29/2102). The diagnostic odds ratio indicated that it is 250 times more likely to observe significant MEP changes in patients who experience a new-onset motor deficit immediately after scoliosis surgery. 6

7 Citation Diagnostic accuracy of combined multimodality somatosensory evoked potential and transcranial motor evoked potential intraoperative monitoring in patients with idiopathic scoliosis Thirumala (2016b) Diagnostic accuracy of somatosensory evoked potential monitoring during scoliosis fusion. Thirumala (2016c) Diagnostic value of somatosensory-evoked potential monitoring during cerebral aneurysm clipping Thirumala (2016d) Value of intraoperative neurophysiological monitoring to reduce neurological complications in patients undergoing anterior cervical spine procedures for cervical spondylotic myelopathy. Hayes (2016) Content, Methods, Recommendations Systematic review of 7 publications (total sample 2,052) on patients with surgery for idiopathic scoliosis resulted in a diagnostic odds ratio of (95% CI , ). Interpretation: those with a new neurological deficit were about 106 times as likely to have had intrasurgical changes in SSEP or TcMEP. Conclusion: combined monitoring shows an advantage over single mode monitoring, and intrasurgical monitoring may be valuable in predicting a new neurological deficit. A systematic review considered the ability of intraoperative SSEP to predict perioperative neurological outcome in patients undergoing spinal deformity surgery to correct adolescent idiopathic scoliosis (AIS). Fifteen studies (n=4763) documented new postoperative neurological deficits in 1.11 percent (53/4763) of the sample population. Among this population, 75.5 percent (40/53) showed significant SSEP changes, and 24.5 percent (13/53) did not show significant change (average 84%, 95% confidence interval 59-95%) and specificity (average 98%, 95% confidence interval 97-99%). The diagnostic odds ratio was 340 (95% confidence interval ). The authors concluded that SSEP is a highly sensitive and specific test, and that iatrogenic spinal cord injury resulting in new neurological deficits was 340 times more likely to have changes in SSEP compared to those without any new deficits. Systematic review of 14 publications (total sample 2,015) on SSEP monitoring during cerebral aneurism clipping resulted in a diagnostic odds ratio of (95% CI -76.3, 90.3). Interpretation: among those with a neurologic deficit, the odds of observing a change in SSEP were nearly 8 times more than among those without a neurologic deficit. Conclusion: among patients undergoing surgery for clipping of cerebral aneurisms, SSEP monitoring during surgery is highly specific for predicting neurologic outcome. A systematic review studied SSEP, TME and electromyography as monitoring modalities in anterior cervical procedures for cervical spondylotic myelopathy. A total of only 2 studies (n=173). In both studies procedures done without monitoring found worsening myelopathy and/or quadriplegia as seen in 2.71 percent of patients for studies without monitoring and 0.91 percent of patients for studies with monitoring. The authors opined that insufficient evidence exists to make recommendations regarding the use of different monitoring modalities to reduce neurological complications during anterior cervical procedures. 7

8 Citation Multimodality Intraoperative Monitoring (MIOM) During Corrective Surgery for Scoliosis and Spinal Deformities Hayes (2016) Multimodal Intraoperative Monitoring (MIOM) During Cervical Spinal Surgery Tanaka (2016)\ Motor evoked potentials monitoring during TAA/TAAA surgery Achouh (2007) Role of somatosensory evoked potentials in predicting outcome during thoracoabdominal aortic repair. Content, Methods, Recommendations Moderate-quality evidence in an Hayes review suggests that monitoring during corrective surgery for scoliosis is accurate in identifying patients who experience neurological decline during surgery It is in contemporary practice a useful adjunct to prevent permanent neurological damage. Hayes established a rating of B (some proven benefit). A Hayes review of multimodal intraoperative monitoring during cervical spinal surgery found low-quality evidence suggesting both sensitivity and specificity in predicting postoperative injury, which included immediate C5 nerve root damage. The overall quality of the evidence pertaining to the diagnostic accuracy (i.e., clinical validity) of MIOM in detecting neurological deficits was rated as low. The overall quality of the evidence related to the clinical utility of MIOM was rated as very low because all 3 studies directly measuring clinical utility had serious limitations in terms of study design and conduct, which may have introduced important differences between the groups, affecting the results observed. Hayes established a rating of C (potential but unproven benefit) for this technology. Meta-analysis including 19 studies resulted in findings of 89.1 % sensitivity (95% CI, %) and 99.3 % specificity (95% CI %) in predicting postoperative paraplegia. A clinical trial (n=444) examined the use of SSEP during descending thoracic and thoracoabdominal aortic repair. There were 270 thoracoabdominal aorta and 174 descending thoracic aorta diagnoses. SSEP changes were classified as (1) no change, (2) transient changes that returned to baseline by the end of the procedure, or (3) persistent changes that did not return to baseline by the end of the procedure. Changes occurred in 87 (19.6%) patients; 22 (25%) of these did not return to baseline. Immediate neurologic deficit occurred in 8 of 444 patients (1.8%); five deficits (5 of 87; 5.8%) occurred in patients with SSEP changes, compared with three deficits (3 of 357; 0.8%) in patients without changes. The odds ratio for this comparison was 7.2 (p < 0.002). Somatosensory evoked potential was a poor screening tool for neurologic deficit, with a sensitivity of 62.5% and specificity 81.2%. Negative predictive value was 99.2%, indicating a very low event probability in the absence of SSEP changes. Delayed neurologic deficit occurred in 3.2% and was not related to SSEP changes. Somatosensory evoked potential changes were also associated with increased 30-day mortality and low glomerular filtration rate. The authors concluded that intraoperative SSEP monitoring was reliable in ruling out spinal injury in descending thoracic and thoracoabdominal aortic repair, but had a low 8

9 Citation Content, Methods, Recommendations sensitivity and did not predict delayed neurologic deficit. Spinal SSEP change was an independent predictor of mortality and correlated with low preoperative glomerular filtration rate. References Professional society guidelines/other: Hayes Medical Technology Directory. Multimodal Intraoperative Monitoring (MIOM) During Cervical Spinal Surgery. Lansdale, Pa. Hayes Inc.; October Hayes Medical Technology Directory. Multimodality Intraoperative Monitoring (MIOM) During Corrective Surgery for Scoliosis and Spinal Deformities. Lansdale, Pa. Hayes Inc.; October Peer-reviewed references: Achouh PE, Estrera AL, Miller CC 3rd, Azizzadeh A, Irani A, Wegryn TL, Safi HJ. Role of somatosensory evoked potentials in predicting outcome during thoracoabdominal aortic repair. Ann Thorac Surg. 2007;84(3):782-7; discussion Kamen, Gary. Electromyographic Kinesiology. In Robertson, DGE et al. Research Methods in Biomechanics. Champaign, IL: Human Kinetics Publ.; Liu Q, Wang Q, Liu H, Wu WKK, Chan MTV. Warning criteria for intraoperative neurophysiologic monitoring. Curr Opin Anaesthesiol. 2017;30(5): Niedermeyer E. and da Silva F.L. (2004). Electroencephalography: Basic Principles, Clinical Applications, and Related Fields. Lippincot Williams & Wilkins. ISBN Tanaka Y, Kawaguchi M, Noguchi Y, et al. Systematic review of motor evoked potentials monitoring during thoracic and thoracoabdominal aortic aneurysm open repair surgery: a diagnostic meta-analysis. J Anesth. 2016;30(6): Thirumala PD, Cheng HL, Loke YK, Kojo Hamilton D, Balzer J, Crammond DJ. Diagnostic accuracy of somatosensory evoked potential monitoring during scoliosis fusion. J Clin Neurosci. 2016b;30:8-14. Thirumala PD, Crammond DJ, Loke YK, Cheng HL, Huang J, Balzer JR. Diagnostic accuracy of motor evoked potentials to detect neurological deficit during idiopathic scoliosis correction: a systematic review. J Neurosurg Spine. 2017;26(3): Thirumala PD, Huang J, Thiagarajan K, Cheng H, Balzer J, Crammond DJ. Diagnostic Accuracy of 9

10 Combined Multimodality Somatosensory Evoked Potential and Transcranial Motor Evoked Potential Intraoperative Monitoring in Patients With Idiopathic Scoliosis. Spine. 2016a;41(19):E Thirumala P, Muralidharan A, Loke YK, Habeych M, Crammond D, Balzer J. Value of intraoperative neurophysiological monitoring to reduce neurological complications in patients undergoing anterior cervical spine procedures for cervical spondylotic myelopathy. J Clin Neurosci. 2016d;25: Thirumala PD, Udesh R, Muralidharan A, et al. Diagnostic Value of Somatosensory-Evoked Potential Monitoring During Cerebral Aneurysm Clipping: A Systematic Review. World Neurosurgery. 2016c;89: CMS National Coverage Determinations (NCDs): National Coverage Determination (NCD) for Evoked Response Tests (160.10), Effective: 1/15/ &CoverageSelection=Both&ArticleType=All&PolicyType=Final&s=New+York+- +Upstate&CptHcpcsCode=36514&bc=gAAAABAAAgAA&. Accessed August 18, Local Coverage Determinations (LCDs): No LCDs identified as of the writing of this policy. Commonly submitted codes Below are the most commonly submitted codes for the service(s)/item(s) subject to this policy. This is not an exhaustive list of codes. Providers are expected to consult the appropriate coding manuals and bill accordingly. CPT Code Description Comment Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in upper limbs Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in lower limbs Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in the trunk or head Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in upper and lower limbs 10

11 ICD 10 Code Description Comment G11.0 G11.9 Hereditary ataxia G23.0 G23.9 Other degenerative diseases of the basal ganglia G25.3 Myoclonus G32.0 Subacute combined degeneration of spinal cord in diseases classified elsewhere G32.81 Cerebellar ataxia in diseases classified elsewhere G35 Multiple sclerosis G36.0 G36.9 Other acute disseminated demyelination G37.0 G37.9 Other demyelinating diseases of central nervous system E75.23 Krabbe disease E75.25 Metachromatic leukodystrophy E75.29 Other sphingolipidosis G82.20 Paraplegia, unspecified G82.21 Paraplegia, complete G82.22 Paraplegia, incomplete G90.3 Multi-system degeneration of the autonomic nervous system G93.0 Cerebral cysts G93.1 Anoxic brain damage, not elsewhere classified G93.40 G93.49 Other and unspecified encephalopathy G93.5 Compression of brain G93.6 Cerebral edema G93.82 Brain death G93.89 Other specified disorders of brain G93.9 Disorder of brain, unspecified G95.0 Syringomyelia and syringobulbia G95.20 Unspecified cord compression G95.29 Other cord compression G95.9 Disease of spinal cord, unspecified I67.83 Posterior reversible encephalopathy syndrome P11.5 Birth injury to spine and spinal cord S06.1x0A S06.1x9S Traumatic cerebral edema HCPCS Level II Code G0453 Description Continuous intraoperative neurophysiology monitoring, from outside the operating room (remote or nearby), per patient, (attention directed Comment 11

12 exclusively to one patient) each 15 minutes (list in addition to primary procedure 12