This policy covers multiple IONM modalities: SSEP (somatosensory‑evoked potentials), MEP (motor‑evoked potentials), BAEP (brainstem auditory‑evoked potentials), EMG (electromyography), EEG, and electrocorticography. These techniques are described as methods to assess the functional integrity of sensory and motor pathways and cranial/peripheral nerves during procedures that put the spinal cord, brain, or cranial/peripheral nerves at risk.
Evoked potential testing covered by the policy includes VEP (visual‑evoked potentials), SSEP, and MEP. VEPs may be medically necessary for diagnostic evaluation or monitoring of optic pathway disorders (for example multiple sclerosis or suspected optic nerve/chiasm/radiation disorders not explained by imaging), while SSEP and MEP testing are considered medically necessary when the results will be used to guide clinical management in specified conditions (e.g., acute anoxic encephalopathy, coma following diffuse brain injury, unexplained myelopathy, demyelinating disease, suspected brain death, and spinal cord lesions when surgical decisions depend on testing).
Policy intent: IONM and evoked potential testing are intended to be used when monitoring/testing will influence intraoperative or perioperative management or when monitoring can help prevent nerve injury in high‑risk surgical settings (examples listed include spinal instrumentation requiring screws or distraction, intracranial/spinal/vascular procedures, high‑risk thyroid/parathyroid surgery with risk to the recurrent laryngeal nerve, and selected head and neck or cranial nerve surgeries). The policy specifies real‑time monitoring with continuous communication to the surgical team as a requirement for medical necessity and identifies uses considered not medically necessary or investigational when criteria are not met.