Intraoperative Neuromonitoring

What intraoperative neuromonitoring is

IONM is performed by a trained neurophysiologist who records several types of signals throughout the operation: somatosensory evoked potentials (SSEP) that reflect sensory pathways, motor evoked potentials (MEP) that reflect motor pathways, and electromyography (EMG) that watches individual nerve roots.

Electrodes placed before incision establish a baseline; any meaningful change during surgery is communicated to Dr. Choi immediately, while correction is still possible.

How it supports precision

The spinal cord cannot signal pain under anesthesia, so without monitoring the team has no direct way to know how it is tolerating retraction, repositioning, or correction. IONM provides that missing feedback — an early warning when cord or nerve function changes during a maneuver.

When signals change, the surgeon can pause, adjust, revise a correction, or check blood pressure and positioning — turning what might have been an unrecognized injury into a reversible moment.

When it is used

IONM is matched to risk, not used by default. It is most valuable in cases that work near the spinal cord — cervical myelopathy decompressions, deformity corrections, tumor resections, and complex revisions — where retraction or repositioning could affect cord function. Cases farther from the cord, or straightforward cases where risk is low, may gain nothing from monitoring.

What it does not do is prevent injury. It reports changes and buys the team a chance to respond, but the correction still depends on the surgeon’s hands and judgment. A quiet monitor is reassuring, not a guarantee — and careful technique remains the foundation.

Its limits

Monitoring reports function; it does not prevent injury on its own. Its value depends entirely on the team recognizing a change quickly and knowing which responses are likely to restore the signal. Anesthesia choices and body temperature also affect the readings and must be managed so the data stays trustworthy.

Not every operation requires IONM. Its use is matched to the case — the level, the proximity to the cord, and the type of correction — rather than applied by default.

What it does

Under anesthesia, the spinal cord and nerves cannot signal distress — the team has no direct way to know how neural tissue is tolerating retraction, repositioning, or correction. IONM fills that gap. A trained neurophysiologist tracks electrical signals traveling through the cord and nerves throughout the operation — sensory pathways, motor pathways, and individual nerve roots — against a baseline established before incision. Any meaningful change is communicated to the surgeon immediately, while correction is still possible.

What actually changes in the operation is feedback. A maneuver that is quietly stressing the cord becomes visible the moment the signals shift — so the surgeon can pause, ease a retraction, revise a correction, or check positioning and blood pressure before a reversible change becomes a permanent one.

How Dr. Choi uses it

IONM is matched to risk, not used by default. It is most valuable in operations that work near the spinal cord — cervical myelopathy decompressions, deformity corrections, tumor resections, and other cases where the cord or critical nerve roots are directly in the working zone. For routine decompressions at lower risk, it may add little, and it is not ordered reflexively.

When it is used, the monitoring runs continuously from incision to closure, and signal changes are treated as information, not alarms — a prompt to reassess the field, the position, and the plan in real time.

What it means for you

For patients, IONM means the most delicate structures in the operating field are being watched electrically, moment by moment, even though you are asleep and cannot feel anything. It does not make surgery risk-free — no technology does — but it gives the team an early warning system for the exact injuries everyone most wants to avoid, and a chance to act while action still helps. It is one more layer of vigilance around the nerves, alongside the microscope's magnification and the surgeon's judgment. Read more about Dr. Choi and his approach to complex cases.