Intraoperative Neurophysiologic Monitoring (IONM)

This policy covers intraoperative neurophysiologic monitoring (IONM)—including SSEPs, transcranial electrical MEPs, BAEPs, cranial nerve EMG, EEG, and electrocorticography—to assess neural pathway integrity during high‑risk spinal, intracranial, vascular, and select neck/thyroid/parathyroid procedures (including recurrent laryngeal nerve monitoring for total/repeat thyroidectomy, cancer, thyrotoxicosis, giant/retrosternal goiter, thyroiditis, and certain anterior cervical spine revisions and multilevel ACDF). Coverage is subject to the member’s benefit plan and state contract, with major limitations that RLN monitoring for anterior cervical surgery is covered only when increased‑risk criteria are met and that VEPs, TMS‑induced MEPs, peripheral nerve EMG/NCV, and other specified uses/devices are considered experimental, investigational, or unproven.

"Somatosensory-evoked potentials (SSEPs) during spinal, intracranial, or vascular procedures."