Intraoperative Neurophysiological Testing Form

Summary Of Evidence

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Analysis of Evidence

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Intraoperative neurophysiological testing may be used to identify/prevent complications during surgery on the nervous system, its blood supply, or adjacent tissue.

Monitoring can identify new neurologic impairment, identify, or separate nervous system structures (e.g., around or in a tumor), and can demonstrate which tracts or nerves are still functional. Intraoperative neurophysiological testing may provide relative reassurance to the surgeon that no identifiable complication has been detected up to a certain point, allowing the surgeon to proceed further and provide a more thorough or careful surgical intervention than would have been provided in the absence of monitoring.

Some high-risk patients may be candidates for a surgical procedure only if monitoring is available. To establish medical necessity the following guidelines must be followed:

Intraoperative testing may be indicated with the following types of surgery:

1. Surgery of the aortic arch, its branch vessels, or thoracic aorta, including internal carotid artery surgery, when there is risk of cerebral ischemia
2. Resection of epileptogenic brain tissue or tumor
3. Resection of brain tissue close to the primary motor cortex and requiring brain mapping
4. Protection of cranial nerves:
   
   1. tumors that are optic, trigeminal, facial, auditory nerves
   2. cavernous sinus tumors
   3. oval or round window graft
   4. endolymphatic shunt for Ménière's disease
   5. vestibular section for vertigo
   6. microvascular decompression of cranial nerves
5. Correction of scoliosis or deformity of spinal cord involving traction on the cord
6. Protection of spinal cord where work is performed in close proximity to cord as in the removal of old hardware or where there have been numerous interventions
7. Spinal instrumentation requiring pedicle screws or distraction
8. Decompressive procedures on the spinal cord or cauda equina carried out for myelopathy or claudication where function of spinal cord or spinal nerves is at risk
9. Resection of:
   
   1. Spinal cord tumors
   2. Neuromas of peripheral nerves or brachial plexus, when there is risk to major sensory or motor nerves
10. Surgery for:
1. intracranial AV malformations
2. arteriovenous malformation of spinal cord
3. surgery for intractable movement disorders
4. cerebral vascular aneurysms
11. Arteriography, during which there is a test occlusion of the carotid artery
12. Circulatory arrest with hypothermia
13. Distal aortic procedures, where there is risk of ischemia to spinal cord
14. Leg lengthening procedures, where there is traction on sciatic nerve or other nerve trunks
15. Basil ganglia movement disorders
16. Surgery as a result of traumatic injury to spinal cord/brain
17. Deep brain stimulation

Limitations
For reimbursement, this test must be requested by the operating surgeon and the monitoring must be performed by a physician, other than:

The operating surgeon
The technical/surgical assistant; or
The anesthesiologist rendering the anesthesia

The benefits of intraoperative neurophysiologic testing are attainable under optimal recording and interpreting conditions.

Due to the nature of these services and the potential for significant morbidity in some procedures requiring intraoperative monitoring, Medicare expects to see these services used in the hospital setting only. As the level of anesthesia may significantly impact the ability to interpret intraoperative studies, continuous communication between the anesthesiologist and the monitoring physician is expected when medically indicated.

It is also expected that a specifically trained technician, preferably registered with one of the credentialing organizations, will be in continuous attendance in the operating room, recording and monitoring a single surgical case, with either the physical or electronic capacity for real-time communication with the supervising neurologist or other physician trained in neurophysiology.

Intraoperative monitoring is not medically necessary in situations where historical data and current practices reveal no potential for damage to neural integrity during surgery. Monitoring under these circumstances will exceed the patient's medical need.

Due to the potential risk for morbidity with many of the above noted surgeries and the need for explicit and focused attention to both the monitoring and the procedure, Medicare does not expect to see operating surgeons submitting claims for this code. Monitoring may be performed from a remote site, as long as a trained technician (see detail above) will be in continuous attendance in the operating room, with either the physical or electronic capacity for real-time communication with the supervising physician (MD/DO). Technical criteria (mandatory) include that at least 8 recording channels be available (16 if EEG is monitored) for all intraoperative neurophysiological monitoring. The remotely supervising physician must have the ability to watch the tracings as they are obtained in real-time in the operating room, as well as the baseline electrophysiological test and the monitoring tracings from earlier in the case.

Technical criteria (mandatory) for remote monitoring also include (a) routine real-time auditory or written communication between the supervising physician and the operating room and (b) the capability for telephone communications as needed between the supervising physician and the monitoring technologist, operating surgeon, and the anesthesiologist.

The equipment must also provide for all of the monitoring modalities that may be applied - auditory-evoked response, electroencephalography/electrocorticography, electromyography and nerve conduction, and somatosensory-evoked response.

Undivided attention to a unique patient may be required during some surgeries, such as during response to acute events or identification of the cerebral cortex to be resected or spared from resection. The monitoring physician must have a plan in place to transfer care to another physician of any other case during those times. When paying undivided attention to a unique patient, the physician must code and bill only for that one case during those times. For other medically necessary intraoperative neurophysiologic monitoring, a physician may monitor up to three cases simultaneously.

Medicare does not provide for reimbursement of "incident to" care in the hospital setting. More than one patient may be monitored at once; however, claims for physician services must be submitted only for the time devoted to monitoring when attention is directed exclusively to one patient.