This is your guide to understanding the field of intraoperative neuromonitoring, from the perspective of a patient, surgeon, or potential surgical neurophysiologist. It will cover exactly what intraoperative neuromonitoring is, who can do it, how it’s done, and more.
See the IONM table of contents below to easily navigate to a portion of the page you’re most interested in.
- What is Intraoperative Neuromonitoring?
- What is IONM used for?
- What is Neuromonitoring during spinal surgery?
- What is IONM during brain surgery?
- Who uses Neuromonitoring?
- What is the purpose of IONM?
- When To Use Intraoperative Neuromonitoring?
- What are common surgeries to use intraoperative neuromonitoring?
- Is Intraoperative Neuromonitoring Effective?
- Is Intraoperative Neuromonitoring Safe?
- How Do You Do Intraoperative Neuromonitoring?
- How are nerves monitored during surgery?
- Who performs intraoperative monitoring?
- What is SSEP in surgery?
- What is EEG in surgery?
- What is tcMEP in surgery?
- What is EMG in surgery?
- What is tEMG in surgery?
- What is ABR in surgery?
- What is Train of Four in surgery?
- What are D-Waves in surgery?
- What is Motor Mapping in surgery?
- What is Phase Reversal in surgery?
- What is VEP in Surgery?
- What is Peripheral nerve monitoring in surgery?
- What is a neurophysiologist?
- What does a neuromonitoring technician do?
- How do you become an intraoperative neuromonitoring tech?
- How do I get IONM certified?
- What is a CNIM degree?
- What is the D.ABNM degree?
- Is IONM a good career?
- What Does A Day In The Life of A Surgical Neurophysiologist Look Like?
- How do traveling neurophysiologist positions differ?
- Are there part-time or per diem neuromonitoring jobs?
- Are there 1099 workers?
- How To Bill For Intraoperative Neuromonitoring?
- How much does intraoperative neuromonitoring cost?
- Does Medicare pay for 95941?
- Is Neuromonitoring covered by insurance?
What is Intraoperative Neuromonitoring?
Intraoperative neuromonitoring goes by many names. It can be called monitoring, surgical monitoring, intraoperative neuromonitoring, intraoperative neurophysiological monitoring, IONM, IOM, SSEPs, and nerve monitoring.
The same can be said for those in the neuromonitoring field. There are typically two people working on a neuromonitoring case at the same time. The first is the clinician in the room. They can go by the title of neurophysiologist, surgical neurophysiologist, neuromonitoring technician, neuromonitoring tech, surgical tech, and others. The second is a physician that is reading the waveforms collected during the case. They are either local at the hospital, or watching the case remotely. They go by the titles of oversight physician, remote physician, reading doctor, and others.
At a high level, surgical neurophysiologists use diagnostic modalities in the operating room to continuously monitor the brain, spinal cord, and nerves, as well as map neural structures. This is accomplished by applying electrical current and recording potentials. Changes in the size, shape, and timing of these potentials can help determine if the patient is at risk for injury. An oversight physician, sometimes on-site and sometimes using telemedicine, interprets the waveforms and gives a medical opinion on what, if anything, needs to be done.
What is IONM used for?
IONM stands for intraoperative neuromonitoring and can be used during surgical procedures where neural structures are at risk for injury. This might be the nerves, cranial nerves, spinal cord, brain stem, or different areas of the brain. The surgeons and the anesthesia team use the feedback from the surgical neurophysiologist as to changes in the recordings enabling better medical decision-making. The idea is to pick up deficits before they turn into injuries that would otherwise be undetectable when a patient is asleep during surgery. It acts as a safety blanket for the neural structures during surgery.
What is Neuromonitoring during spinal surgery?
During spine surgery, surgeons will use intraoperative neuromonitoring to monitor the integrity of the nervous system, as well as test for pedicle screw placement in the vertebral bones.
Any spinal procedures require removing bony or disc material, implanting graphs, straightening curves, inserting screws or other hardware, or removing tissues such as tumors or cysts. All of these maneuvers carry some level of risk to the surrounding nerves or spinal cord.
At the same time, some of these procedures require the patient to be positioned face down (prone position) for extended periods of time, anywhere from 1 to 24 hours. Some patients will suffer positional injuries from remaining in these positions, where the arms over their head or extension/flexion of the neck can be problematic. The surgical neurophysiologist monitors the brachial plexus and lumbar plexus to ensure adequate blood perfusion and limited stretch on the nerves throughout the procedure. If this were to go undetected, it has been noted in the literature that patients can have injuries in the upper and lower extremity ranging from numbness and tingling to total paralysis of the extremity.
What is IONM during brain surgery?
Brain surgery utilizes IONM in order to help prevent injury from both mechanical injuries as well as vascular insufficiencies. The modalities used help determine early warning signs so that the appropriate interventions can take place and allow for the surgery to continue without waking the patient up or aborting the surgery.
Other surgical goals are to map neural structures so the surgeon has a better approximation of that tissue to avoid injury. Brain mapping works well in tandem with navigation. This allows the neurosurgeon to better identify motor and or sensory brain material so the injury can be avoided when debulking a tumor.
Who uses Neuromonitoring?
Neuromonitoring is ordered by surgeons to help protect their patients during surgical procedures. These include orthopedic surgeons, neurosurgeons, spine surgeons, vascular surgeons, ear, nose, and throat surgeons (ENT surgeons), cardiac surgeons, and general surgeons.
Hospitals and surgical centers help facilitate the scheduling of neural monitoring companies or hire their own in-house staff in order to limit their risk of bad surgical outcomes, as well as meet the standards for providing exceptional patient care for their patients undergoing surgical procedures. Many IONM companies will deal directly with neuro coordinators and or directors for these case assignments.
Injuries coming from these surgery types range from transient sensory and motor changes that disappear in hours to days, to full-blown paralysis, paraplegia, and even death. The benefits of neural monitoring come into play when they are able to assess the function of the nervous system during the surgery and prevent these catastrophic events from occurring.
What is the purpose of IONM?
Intraoperative neuromonitoring serves 2 primary purposes.
First, it provides patient safety. If there is a physiological (not injury, but mild trauma that causes the nerves, spinal cord, or brain to not function properly… like when you hit your funny bone and you can’t make a strong fist for a couple of minutes) or pathological (injury to the neural tissue) the surgical neurophysiologist will identify changes in the recording and notify to the surgeon in a timely manner. At that point, the surgical team, the surgical neurophysiologist, and the remote oversight physician will come to a course of action to best correct the deficits.
Besides monitoring the integrity of the nervous system during surgery, IONM is also helpful to map out specific areas of the nervous system. For instance, neurosurgeons will map the brain to identify the motor cortex and motor tracks when removing tumors from around that area. This can course down from the primary motor strip to the internal capsule. They might also look to identify the sensory strip on the brain.
In otological surgery, identifying the facial nerve in the area of the brainstem allows the surgeon to map out the entire course of that cranial nerve while removing a tumor, like an acoustic neuroma.
In the spinal cord, mapping can be used to identify the location of the dorsal column medial lemniscus, which houses the sensory relays in the spinal cord. Should the surgeon look to enter between the left and right side to go in and resect a tumor within the spinal cord, they can limit the risk of damage to those posterior columns with successful mapping.
When To Use Intraoperative Neuromonitoring?
There are many different types of surgical cases to utilize intraoperative neuromonitoring. This could be due to spinal trauma, tumors, tethered cords, spinal curvature, enlarged thyroids, removing plaque from arteries, clipping aneurysms, implanting nerve or spinal cord stimulators, chronic disease of the spine requiring decompression or fusion, shoulder surgery, and hip surgery, and many others.
Surgeons will typically see their patients in their office, but sometimes it can be in the emergency room as well. After they do a full neurological assessment, they will come to a conclusion and decide on a course of action. In certain surgical procedures, including intraoperative neuromonitoring is standard practice.
The surgeon’s office or the hospital will book neuro monitoring for that patient’s surgery. The surgeon will give the pertinent details for the case, like what type of surgery, the levels, and what intraoperative monitoring modalities should be included.
Before the surgery takes place, the surgical neurophysiologist will gather pertinent information on the patient as well as do a brief history. They will then meet with the anesthesiologist and surgeon to finalize a game plan.
Many times, the surgeon and surgical neurophysiologist have performed similar procedures together many times over. Other times, there might be some new wrinkle worth mentioning pirates of the case starts. While not in every case, the neuromonitoring technologist is an important part of the surgical team in cases they are needed.
What are common surgeries to use intraoperative neuromonitoring?
The below list is an example of surgery types that will utilize intraoperative monitoring:
Spine Surgery
- Anterior cervical discectomy and fusion (ACDF)
- Iliosacral screws
- Cervical Corpectomy with Fusion and Instrumentation
- Posterior Cervical Decompression and Fusion
- Odontoid Fracture
- Cervical Laminoplasty
- Anterior thoracic Interbody fusion and instrumentation
- Thoracic corpectomy with fusion and instrumentation
- Thoracic osteotomy
- Thoracic laminectomy with or without fusion and instrumentation
- Scoliosis Spinal deformity correction
- Thoracic spinal cord tumor or AVM
- Kyphoplasty
- Anterior lumbar Interbody Fusion or Disk replacement
- Lumbar corpectomy with fusion and instrumentation
- Posterior Interbody Fusion – PLIF, TLIF
- Posterior Lateral Fusion – Pedicle Screws
- Lumbar laminectomy with fusion and instrumentation
- Spinal cord tumor or AVM
- Lateral (transpsoas) Interbody fusion – XLIF, DLIF, LLIF
- All minimally invasive procedures
- Excision of lumbar tumor
- Myelomeningocele
- Release of tethered cord
Neurosurgery
- Skull-based Tumor Resection
- Epilepsy
- Fronto-temporal Tumor Resection
- Intracranial Aneurysm Clipping
- Intracranial Arteriovenous Malformation
- Microvascular Cranial Nerve Decompression
- Peripheral Nerve
- Posterior Fossa Tumor Resection
- Tempero-parietal Tumor Resection
- Supratentorial Tumor Resection
- Chiari Malformation
- Acoustic Neuroma Resection
ENT Surgery
- Acoustic Neuroma Resection
- Facial Nerve Decompression
- Glomus Tumor
- Parotidectomy
- Revision Mastoidectomy
- Thyroidectomy
- Tympano-Mastoidectomy
Interventional Radiology
- Embolization of Cerebral and Spinal Aneurysms and Arteriovenous Malformations
- Embolization of Traumatic Cavernous Sinus Fistula
- Occlusion of Brain-Supplying Arteries
- Percutaneous Transluminal Angioplasty
- Spinal Angiography
Cardiothoracic/Vascular Surgery
- Cardiopulmonary Bypass and Hypothermia
- Correction of Coarctation
- Repair of Abdominal Aortic Aneurysm
- Carotid Endarterectomy
Orthopedic Surgery
- Acetabular Fracture
- Leg-Lengthening Procedure
- External Fixation
- Total Hip Replacement, Primary Joint Replacement with Other Risk Factors, Revision, and Reconstruction
Is Intraoperative Neuromonitoring Effective?
Using intraoperative neuromonitoring has become a standard practice for case types where there has been documented injury to the nervous system. Some cases, like scoliosis surgeries, include more provocative maneuvers as part of the surgery (derotation of the spine), as well as cover anatomical areas more prone to detrimental outcomes, should something go wrong (thoracic spine and its poor collateral circulation). Other procedures, like a lumbar microdiscectomy, have less chance have a catastrophic event occurring. Even in these more benign surgical procedures, intraoperative neuromonitoring has demonstrated cases it prevented neural injuries, such as foot drop or positional brachial plexus injuries. Since these are such debilitating injuries, the choice to reduce these risks makes monitoring beneficial when looking across large data sets. Such as been studied in lumbar laminectomies, which reduced the 30-day neurological complication rate (0.0% with vs. 1.18% without).
In other instances, such as in thyroidectomies, nerve monitoring helps surgeons identify the recurrent laryngeal nerve during times of exposure as well as ongoing monitoring of the nerve during dissection and removal of the thyroid gland or parathyroid. Such mapping is also useful in the brain and internal capsule when removing cortical tumors or cysts. There are discussions on the cost-effectiveness of neuromonitoring, especially in procedures where the rate of deficits is low. These studies are still in their infancy with limited scope, difficult to assess what outcomes would happen without intervention, and suffering from underreporting of injuries.
Is Intraoperative Neuromonitoring Safe?
Yes. The application of intraoperative neuromonitoring requires the use of needle and sticker electrodes to record potentials and activate other areas during the surgery. While there have been reports of burns on the skin and bite injuries, much has been eliminated due to improved techniques, standardized electrodes, and better regulations placed on the outputs of the new reminder ring equipment.
For instance, it has been shown that duration, or time spent with the stimulator, has a higher likelihood of causing heat buildup than intensity. As such, standardized protocols and restrictions placed on the equipment prevent those from happening end today’s surgical world.
Regular biomedical inspections are performed on the equipment and credentialing organizations ensure the neuromonitoring technicians have the appropriate knowledge. The two most recognized certifications are the CNIM and D.ABNM. A physician is also watching the case to help with troubleshooting suggestions and to give medical opinions when needed.
There are some potential complicating factors, such as pacemakers, history of epilepsy, and lose skull fragments, but these are more precautionary considerations for the surgical team than contraindications.
How Do You Do Intraoperative Neuromonitoring?
Intraoperative neuromonitoring uses electrodes to stimulate and record the peripheral and central nervous systems. The surgical neurophysiologist will hook up electrodes over the nerves or motor area of the brain and deliver electrical stimulation. They will also have other electrodes over the nerve or brain areas set to capture elicited potentials. The equipment turns this raw data into waveforms. The surgical neurophysiologist and the oversight position monitor in real-time throughout the case looking for aberrant changes in the potential or EMG activity.
Should a change be identified, a conversation between the surgical neurophysiologist technician and the oversight neurologist to decipher if it is a technical issue or a physiologic change. The surgical tech will troubleshoot within the surgical room, either on their computer, the equipment, or at the level of the electrodes on the patient. If it is a real change being expressed in the patient’s anatomy, a conversation between the tech and the remote neurologist happens over a chat log, a telephone call, or sometimes in a real person. This discussion is then relayed to the surgeon and anesthesiologist. From there, differentials are given as to what could be the cause and prioritizing what should be done in the current moment.
Some of the maneuvers to help restore function include removing hardware, doing a surgical pause and inspection, further imaging, using cold irrigation, increasing the blood pressure, decreasing anesthesia, repositioning the patient, giving more blood, giving steroids, or reducing any corrections given.
How are nerves monitored during surgery?
Your nerves work just like radio wires do. They transmit electrical signals down the wire to a receiving organ. We can mimic the signals coming from the brain with our electrical potentials to be able to monitor both sensory and motor aspects of the nerve. When we stimulate the nerve, we can see the muscles twitch, as well as the integrity of the nerve transmitting the electrical impulses. Should we see a disruption in the ability to transmit those signals, it could point to injury to the nerve.
Who performs intraoperative monitoring?
The neuromonitoring team consists of a neuromonitoring tech inside the operating room in a physician who oversees the signals in real time. The nerve monitoring tech is responsible for seeing the patient, taking a history, setting up the equipment, placing the electrodes, establishing a baseline, communicating with the oversight position, the anesthesiologist, and the surgeon, troubleshooting technical issues throughout the case, and writing preliminary reports.
The physician who is overseeing the case is responsible for interpreting the waveforms and giving a medical opinion as to the location of the issue, what could be the cause, and giving some rough guidance as to severity.
What modalities are used in Intraoperative Neuromonitoring?
What is SSEP in surgery?
SSEP – (somatosensory evoked potential) is one of the various intraoperative neurophysiological monitorings that is utilized during an operation. The SSEP testing evaluates the nerves that are responsible for sensing the sensation of pain, temperature, and so forth. These nerves send messages to the brain via electrical impulses. They involve stimulating peripheral nerve fibers (e.g., median, ulnar, radial, posterior tibial, peroneal) and recording electrical potentials in the nerve, spine, brainstem, and cortex. These recordings can then be compared to those obtained during an equivalent period of rest. Abnormalities in the conduction velocity of these pathways can be detected by comparing the latency of the evoked responses to those recorded during rest, which is referred to as the baseline data are taken prior to any surgical maneuvers. In addition, abnormalities in cortical excitability can be assessed by comparing the amplitude of the evoked responses. Monitoring these impulses allows the neuromonitorist to evaluate the condition of the nerves and provide real-time information to the surgeon. Evaluating these impulses is vital to IONM, as they help the neuromonitorist determine if a sensitive area has been damaged or is about to be damaged. Mitigating any damage to these areas helps reduce the chance of complications or injuries to the patient, such as paralysis.
During high-risk surgery, stimulating electrode pads are attached to the patient’s skin over the area where the surgeon intends to cut. Electrode wires connect these pads to a monitoring device. When the surgeon activates the cutting tool, the monitor records the electrical activity of the patient’s nervous system. This information helps determine whether the operation was successful in terms of preserving physiological function.
Monitoring techs can help surgeons monitor blood flow to the spine and brain. These signals are sent through nerves and travel along the spinal column to the brain where they are interpreted. SSEPs are used in conjunction with other types of monitors including electromyographic (EMG) recordings, electroencephalographic (EEG), evoked potentials (EPs), transcranial Doppler ultrasound (TCDU), and others.
What is EEG in surgery?
Electroencephalography is one of the oldest techniques used for intraoperative neuromonitoring. Its history goes back to the early 1900s when Hans Berger discovered the electroencephalogram (EEG) and began recording electrical activity from the human cortex. Since then, the EEG has been widely used for evaluating cerebral function during general anesthesia. In addition to being useful for detecting changes in cerebral blood flow and oxygen delivery, the EEG has also been shown to be effective for predicting postoperative cognitive dysfunction after surgery. However, despite these advances, the widespread acceptance of intraoperative EEG remains limited due to the lack of consensus regarding the optimal methodologies and criteria for interpreting the results as they relate to the depth of anesthesia.
In other surgical cases, like carotid endarterectomy or aneurysm clipping, EEG is utilized to monitor the cortical brain perfusion. Changes in blood delivery cause brain activity to change, which alters the EEG recordings. The reading physician can recognize changes in the frequency and amplitude size to determine the need for intervention to recover adequate blood supply and or reduce brain activity through increasing medications to slow the brain’s metabolic load.
What is tcMEP in surgery?
Transcranial motor evoked potentials (tcMEP) have been the most popular technique for the past decade to monitor the functional status of the corticospinal tract during neurosurgeries. Motor evoked potentials solved the problem of not being able to monitor the motor pathways directly. The results were reported as false negatives (although these aren’t true false negatives since SSEPs only monitor the sensory system.).
They are recorded by stimulating the cortex via transcranial electric current pulses and recording the resulting electromyographic signals from muscles innervated by the stimulated cortical areas. Although they are not as large as those obtained by direct peripheral nerve stimulations, MEPs can provide information about the integrity of the corticospinal projecting pathways.
tcMEP is very susceptible to anesthetic effects due to the number of synapses along the pathway, so current recommendations of using TIVA protocol with minimal to no muscle relaxation have been suggested to provide the most reliable waveforms.
What is EMG in surgery?
Intraoperative electromyography (EMG) offers useful diagnostic and prognostic info during spinal and peripheral nervous system surgeries. Basic methods include free-running EMG, and stimulus-triggered EMG. These methods can be utilized to monitor nerves during spine surgery, the facial nerves during cerebellopontine angle surgeries, recurrent laryngeal nerves during thyroidectomy or removal of the parathyroid glands, removal of a neuroma or other tumor, and peripheral nerves during brachial plexopathy exploration and repairs. However, there are several technical limitations that can lead to false positive or negative readings due t the nature of recording any electrical activity. Differentiating the patterns of EMG burst and train activity is useful in determining the severity of outcomes.
What is tEMG in surgery?
A triggered EMG response is an evoked response over a nerve and recorded in a muscle. This could either be through directly stimulating a nerve or another conducting material to look for its proximation to that neural structure. For instance, pedicle screws are often stimulated with a monopolar or bipolar probe to assess the placement within the bone. If a muscle response is picked up at an a threshold that is below acceptable levels, further exploration should be looked to see if the metal screw has breached the pedicle wall and approximating to or touching a nerve. One can also make a similar mapping claim when stimulating through surrounding tissue to identify the location of a nerve, as done when searching for a recurrent laryngeal nerve during thyroidectomy. These triggered responses use a high-frequency output from a surgical probe to induce a compound motor action potential in the corresponding muscle.
What is ABR in surgery?
Using earbuds and click sounds, surgical neurophysiologists can monitor the hearing pathway using auditory brainstem responses. There are many different surgeries to use this test, such as monitoring the auditory pathways during cerebellopontine angle surgery for removal of an acoustic neuroma and microvascular decompression. Unlike other evoked potentials, brainstem auditory evoked responses are not affected by anesthetics. They are, however, highly susceptible to noise in the room due to their small amplitude size. Great care must be taken in the operating arena to eliminate noise through filter settings and improper equipment placement. When assessing changes in auditory evoked potentials, a change in absolute latency, interpeak latency, and amplitude size is monitored. The reliable responses in Wave I (nerve), Wave III (lower brainstem), and Wave V (mid-upper brainstem) make these generators the most commonly used peaks when using BAEP in surgery.
What is Train of Four in surgery?
The ‘Train of Four’ test is a test commonly used during surgery to determine the degree of relaxation of the muscles by interpreting the muscle response. During spine surgeries, it is important for the surgeons to have a patient’s muscles relaxed as much as possible with the least possible amount of tone so that they can expose the spinal cord without causing damage. An anesthesiologist achieves this level of relaxation by administering a neuromuscular blocker. If the medication given to do this hasn’t completely left the body by the time the surgeon starts inserting the screws and rods, the intraoperative monitoring cannot be properly done. If the muscles are relaxed too much, then free-running electromyography and screw stimulation, two methods used, will not give accurate readings and the surgery could be negatively affected.
Ultimately, the goal of performing the ‘train-of four’ test before starting the surgery is to ensure the surgeon has enough relaxation on board to achieve the desired goal at that point of the surgery (like exposure) and adequate levels of EMG activity during portions of the procedure when electrical activity is required to record potentials in muscles.
Visualizing the movement of the corresponding muscles is a less sensitive alternative to recording EMG responses. Starting with the lowest electrical impulse the machine is capable of producing and allowing it to administer its four shocks will serve as the baseline. Count the number of times the patient’s pinky finger (if the ulnar nerve was activated) or eyebrow (if the facial nerve was stimulated) twitched. With the four electrical impulses, if they twitch four times, it is considered 4/4, or 4 twitches out of 4 stimulations, and the patient is at or close to fully recovered from the muscle relaxation given. Did they twitch in response to only two of the four impulses, o a recording of 2/4? This would be considered a state of partial paralysis, and tEMG and tcMEP responses might start to produce smaller CMAPs. Due to the requirement of looking for changes in the size of our amplitudes, this gives the neurophysiologist inaccurate information should there be any changes noted in this less than optimal state.
What are D-Waves in surgery?
Transcranial motor evoked potentials are used to assess the integrity of the corticospinal tracts during neurosurgery through multipulse stimulation. D-waves use the same stimulation setup with only a single pulse required to record a potential off an epidural electrode on the spinal cord. Both methods provide complementary information about the functional status of the corticospinal projecting pathways. The D wave represents the activity of the fastest conducting fibers of the corticospinal tract without any synapses at the anterior horn cell. Its amplitude reflects the number of such fibers remaining intact after an operation. A reduction in the amplitude of the D wave below a certain threshold level (30-50% reduction is significant) indicates damage to those fibers. When the D wave is reduced, the amplitude of the compound muscle action potential (CMAP), reflecting the activity of lower motor neurons, should also fall. Loss of CMAPs is indicative of damage to descending motor pathways.
What is Motor Mapping in surgery?
Resection of brain tumors involving motor areas and pathways involves the identification and preservation of certain cortical and subcortical structures involved in motor control, in order to maintain the patient’s full motor capacities. Brain mapping techniques have now been integrated into clinical practice for many years, as these tools help surgeons identify the neural structures involved with motor functions. This is done by using either a low-frequency or high-frequency approach, where a probe can be placed on and around the motor strip and fibers to the internal capsules to identify portions of the motor pathway. Electromyography recordings in the muscles corresponding topographical area are used to identify an electrical response from a motor structure. High-frequency stimulation (Taniguchi technique) delivered by monopolar probes is highly efficient in most cases, regardless of previous deficits; treatment; long seizure history; high tumor infiltration, and/or edema. The general consensus is the high-frequency technique is the most effective and safest for mapping the brain and deep white matter.
What is Phase Reversal in surgery?
Phase reversal is a method of recording SEPs directly from the cortical surfaces to identify the central sulcal region where a change in polarity occurs. Stimulation is typically performed at the wrist, using either the median or ulnar nerves. Phase reversal is a phenomenon caused by the opposite polarity of dcSSEP signals recorded across the central fissure. Recording of SEP phase reversal is considered reliable and valid. Intraoperative localization of the sensorimotor cortex using phase reversal of SEPs is an important tool for surgery in and near the peri-rolandic regions; however, unsuccessful and puzzling results have been reported. This can be due to either mass effect from the lesion or operator error. The identification of the central sulcus provides the first step in localizing the precentral and post-central gyri. If the primary motor cortex is outside the tumor resected area, further motor mapping is not needed.
What is VEP in Surgery?
Visual evoked potential (VEP) has been explored as a valid electrophysiology tool in neurological pathologies, especially in surgeries that pose a risk of vision loss in the intraoperative period. Intraoperative flash visual evoked response monitors the functionality of the optic pathways from the retina to the primary visual cortex, allowing visual impairments to be prevented or minimized. Patients are generally unconscious during surgery under general anesthesia, making flash VEP recording useful as it can objectively assess visual function.
While VEP recordings can offer some additional information when performing surgery around the visual pathway, their utility in the operating room has come under question due to the effects of anesthesia on the evoked response at P100.
What is Peripheral nerve monitoring in surgery?
Peripheral nerve injury can occur intraoperatively due to direct trauma or iatrogenic causes such as traction, compression, stretching, laceration, transection, entrapment, thermal injury, chemical exposure, electrical injury, and vascular compromise. IOM is recommended during peripheral nerve surgery to prevent postoperative neurological deficits. Nerve action potential recording is considered a standard technique for peripheral nerve monitoring because it determines whether functional axons exist in a segment of the nerve and identifies the location of functional and non-functioning fascicles. Compound muscle action potential (CMAP) recording is generally preferred to nerve action potentials (NAP) recording because it provides information about the number of functioning axons in a nerve or fascicle. The presence or absence, rather than latency, amplitude, or shape, of a CMAP is more important than its amplitude. In addition, CMAPs are easier to record than NAPs. However, CMAPs require approximately 10,000 intact or regenerating myelinated axons to be detected and they cannot be used to locate non-functioning fascicular groups. NAPs are preferred when stimulating over and recording from the same nerve allows the surgeon to better test the integrity of nerve fibers locally, like in a case where a neuroma is being removed or testing to see if a nerve has been lacerated. J-hook electrodes are useful to pull the nerve out of the surgical field and prevent the shunting of the response.
Intraoperative Neuromonitoring As A Career?
What is a neurophysiologist?
A classically trained neurophysiologist is a medical doctor that has done some additional schooling to become a neurophysiologist. They typically do not work in the operating room and perform other medical duties.
The surgical neurophysiologist is a different position altogether. While some surgical neurophysiologist does have their medical degree, it is not a requirement. Backgrounds to become a surgical neurophysiologist include chiropractors, audiologists, exercise physiologists, neuroscientists, registered EEG technicians, nurses, physician’s assistants, Physical therapists, occupational therapists, and other health-related degrees.
What does a neuromonitoring technician do?
The neuromonitoring technician will be in the operating room during surgical procedures. They meet the patient before the surgery starts and take a history, do a gross physical exam, and look through the patient’s charts for pertinent information. After discussing the monitoring plan with the surgeon and surgical team, they hook up the patient to their equipment with electrodes. They will run stimulation and record potential throughout the entire case and be in constant communication with an oversight physician who is watching the potential in real time. If there are alerts, they will relay that information to the surgical team, as well as troubleshoot any potential issues with the equipment.
How do you become an intraoperative neuromonitoring tech?
Most intraoperative neuromonitoring technicians get into the field by getting a job with on-the-job training. They come with a background that allows them to sit for the CNIM. The hospital or a private company will train them to perform the work in the operating room. It’s required to have 150 cases as the primary clinician on the case in order to sit for the CNIM examination.
There are other avenues to get into the field of neural monitoring, as well. Universities now offer degrees in intraoperative neuromonitoring. Those with degrees in neural monitoring are the minority and will still need to pass the CNIM in order to meet credentialing requirements of most hospitals and surgical centers.
How do I get IONM certified?
To get IONM certified, you will need to observe surgical cases that use intraoperative neuromonitoring for a certain amount of time, as well as learn in a didactic environment. From there, you will train in the operating room with an experienced surgical neurophysiologist as you would in an apprenticeship program.
Once that training is over, you will begin to do intraoperative neuromonitoring independently. You need 150 cases in order to sit for the examination. You have to pass the CNIM examination and then continued to upkeep it through continuing education credits. More information on how to get it as well as how to keep it can be found at www.abret.org
What is a CNIM degree?
There is no CNIM degree. There’s a degree in intraoperative neuromonitoring from schools such as the University of Michigan and Connecticut. The majority of other practitioners in the field have not gone that route. Most come in with a background in some sort of healthcare or health science degree. They then sit for and earn the CNIM for credentialing purposes.
What is the D.ABNM degree?
The D.ABNM, or diplomate of the American Board of Neurophysiologic Monitoring, is a physician-level certification identifying expertise in the field of neuromonitoring. This can act in addition to the CNIM or replace for the purposes of credentialing.
Is IONM a good career?
If you are finding out about becoming a surgical neurophysiologist, congratulations! This is one of the most niche industries in healthcare that virtually nobody knows about unless you already work in the operating room or know somebody that does. That poses a great opportunity for you to get trained in a highly sought-after skill.
With only 4,000 CNIMs working in the field, you find yourself in a small space where it’s easy to be a standout. Also, the ongoing need for cases monitored with a relatively small pool of candidates provides great job security.
There are about 200 CNIMs that pass the exam each year, but there are also some that let their certification lapse. This can be either due to retirement, going back to school (we’ve seen our share go to med school or PA school), or finding interest in another field.
Salary expectations range from $60,000 to $100,000 in the middle range, depending on the level of experience and the area you reside in. You should expect to earn less during your training, as well as understand that there are those in the field earning more than higher ranges.
Being able to participate in patient care is a fulfilling and rewarding experience. Neuromonitoring as a career is one that provides value back to society. Not every case is a life-or-death situation, but you won’t be able to speak to any surgical neurophysiologist without them having stories of preventing catastrophic events like paralysis or death.
The best piece of advice is to consider IONM as a career and not a job. This is not something you dip your toe in to see if you like it. Do your homework, understand some of the lifestyle restrictions that come along with working in a hospital setting, especially the operating room, and decide for yourself if you are personality type and life goals match up.
What Does A Day In The Life of A Surgical Neurophysiologist Look Like?
Most surgical neurophysiologists find out when they’re working the night before. That means you don’t know which hospital you’ll be at, what case type you’ll be doing, which surgeon you’ll be working with, or how long the case will actually take in order to plan out your week. Having a lifestyle that includes flexibility it’s a must for long-term success.
Once you get into the hospital, you will set your equipment up in the operating room after doing a medical check on your equipment. You would then go see the patient look over the history and come to an initial plan for what type of modalities you will use on the case.
After discussing a final plan with the surgeon, you will have a discussion with the anesthesiologist to determine what medications will work well with the modalities you will be running. Most anesthesiology teams will have a good understanding of what is required depending on what modalities are used.
After the patient rolls into the room, the anesthesia team will put the patient asleep. You will then start hooking up your electrodes and running your initial traces, called baselines. Oftentimes, some troubleshooting and tinkering will be required to optimize your baselines. Before the surgery starts, you give a rundown of what your potentials look like to the surgeon in the anesthesia team. Sometimes, baselines are difficult to obtain, and that discussion needs to be had before the case starts. If the signals are weak, the surgeon and the anesthesia team should be aware to see if there are any other strategies to better optimize those potentials. If not, the surgeon needs to be made aware of a higher risk of false positive responses, where your signals demonstrate potential physiological changes due to weak signals or become so variable that they are unreliable to interpret.
Response variability might be so bad in the beginning did the oversight physician deems the signals coming through unreliable. At that point, assuming no other troubleshooting can be done, you may have to eliminate some of the modalities being monitored, or even abort monitoring at that point.
After the case is over, the surgical neurophysiologist will write an initial report that will be finalized by the oversight position. The ongoing chat that was happening with the monitoring technician and the oversight physician, surgeon, and anesthesia team throughout the procedure is also uploaded into the document. A fee slip is left for the facility and a purchase order is created so that the facility can pay the company a fee for the services.
The surgical neurophysiologist will wait to do a post-op check on the patient for gross motor and sensory assessments. Once that is completed and the equipment is packed away, they are either off to their next case or home for the day.
Surgery isn’t a 9-5 gig. It can start or go into the night and on weekends. Most monitoring teams have a call rotation for nights and weekends. There are many different forms to this, but a general one is rotating on the weekends and taking call at night Monday through Friday, shared across the local team.
How do traveling neurophysiologist positions differ?
Most neurophysiologist work in their general location. Some will have to travel outside of their home area from time to time. There are other positions that are more travel positions. These positions tend to last in a specific region from 1 week to 6 months. Most of the time these travelers will have their travel days, their work days, and weekends free.
Are there part-time or per diem neuromonitoring jobs?
Yes, both part-time and per diem roles are available from a lot of companies.
Are there 1099 workers in neuromonitoring?
Yes. Some companies will hire contractors to cover cases. These can either be one-off cases or booked out weeks at a time. You’ll have to buy your own equipment, have your own malpractice insurance, and maybe buy and hold your own electrodes.
How To Bill For Intraoperative Neuromonitoring?
They are different payment structures out in the field, either a flat rate or hourly rate for the facilities. This fee is typically for the technician in the room, the equipment, and the supplies used for the case. This is sometimes referred to as the facility fee. The clinician will leave codes for the hospital or surgery center to bill the insurance company of the patient.
The second portion is the oversight position bill. This goes directly to the patient’s insurance.
Some companies will bill the insurance for both the technical and professional components, though this is less frequently used.
Other payment plans can be arranged, like self-pay patients, or letters of protection should be case involve an attorney and an accident.
How much does intraoperative neuromonitoring cost?
The cost of intraoperative neuromonitoring can vary considerably. Government payors typically pay less, while commercial payers use other normal billing codes like 95941. What the patient is responsible for is dependent on what their arrangement is with their insurance company, and what the payment policies of the company or hospital are for each individual circumstance.
Does Medicare pay for 95941?
No, it does not. Medicare uses its own code, the GO453.
A list of the base codes used:
- 95813 Electroencephalogram (EEG) extended monitoring; greater than 1 hour
- 95829 Electrocorticogram at the surgery
- 95864 EMG, four extremities (five or more muscles)
- 95870 Stimulated EMG (four or fewer muscles in 1 extremity), commonly used for pedicle screw testing
- 95925 Short-latency somatosensory evoked potential study, recording from the central nervous system; in upper limbs
- 95926 Short-latency somatosensory evoked potential study, recording from the central nervous system; in lower limbs
- 95927 Short-latency somatosensory evoked potential study, recording from the central nervous system; in the trunk or head
- 95928 Central motor evoked potential study (transcranial motor stimulation); upper limbs
- 95929 Central motor evoked potential study (transcranial motor stimulation); lower limbs
- 95937 Neuromuscular junction testing
- 95938 Somatosensory evoked potentials (SSEPs), upper and lower limbs
- 95939 Motor evoked potentials (MEPs), upper and lower limbs
- 95865 Needle electromyography; larynx
- 95955 Electroencephalogram (EEG) during non-intracranial surgery
Add-on codes:
- 95940 Continuous IOM intraoperative neurophysiology monitoring in the operating room, one on one monitoring requiring personal attendance, each 15 minutes
- 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
- 95885 Needle electromyography of each extremity did with nerve conduction, amplitude, and latency/velocity study.
Medicare code:
- G0453 Continuous intraoperative neurophysiology monitoring, from outside the operating room (remote or nearby), per patient, (attention directed exclusively to one patient) each 15 minutes
Is Neuromonitoring covered by insurance?
Most insurances will cover neuromonitoring. Sometimes the insurance companies will look to deny payment. Most hospitals and companies will look to work with the patients and their insurance companies to ensure proper payment. Most neuromonitoring companies will be out-of-network but will bill at in-network rates after the surprise billing legislation is passed.
