Grid Monitoring and Intraoperative Electroencephalography

Aetna covers intraoperative scalp EEG for monitoring cerebral function during carotid artery surgery, intracranial vascular procedures, and parietal/eloquent‑cortex tumor or lesion resections (ICD‑10s C71.3, C79.31, D33.0, D43.0, D49.6, G93.89), and covers grid monitoring (ECoG) to localize an epileptogenic focus for possible resection in intractable seizures when seizures involve functionally important areas, scalp EEG is nonlocalizing, or there is discordance with other neurodiagnostic studies. EEG used for anesthetic depth monitoring (including BIS/one‑ or two‑channel modules) is considered integral to the anesthesia service and not separately reimbursable, and intraoperative EEG or grid monitoring for indications not listed (e.g., open‑heart surgery, prediction of postoperative delirium) is experimental/investigational and not covered.

"Intraoperative scalp EEG is medically necessary for monitoring cerebral function during carotid artery surgery."