Intraoperative Monitoring

Policy No: 101
Originally Created: 03/01/2011
Section: Surgery
Last Reviewed: 03/01/2019
Last Revised: 03/01/2019
Approved: 03/07/2019
Effective: 04/01/2019

This policy applies only to physicians and other qualified health care professionals.


Intraoperative monitoring (IOM)
Used to identify compromise to the central or peripheral nervous system, cardiac or vascular system, respiratory system, etc. The intent of the monitoring is to alert the surgeon in order that the surgical procedure may be altered to avoid permanent damage. Such impairments may be due to correctable factors such as a circulatory disturbance, excess compression from a retractor, bony structures or hematomas, or mechanical stretching.

Intraoperative monitoring can also:

  • Identify new systemic impairment
  • Identify separate nervous system structures, e.g., around or in a tumor
  • Demonstrate which tracts of nerves are still functional
  • Assist in reconstruction of cardiac structures
  • Aid in the identification and mapping of abnormal cardiac and brain foci

Intraoperative neurophysiological monitoring (IONM)
Subset of IOM used as adjunct for surgeries that pose risk to nervous system structures.

Policy statement

IOM/IONM is accomplished by a certified technologist in continuous attendance in the operating room; who sets up the specialized monitoring equipment including any necessary connection to the patient, and then performs the intraoperative monitoring. Monitoring oversight must be provided by the appropriate supervising physician.

Neither the surgeon (or surgical assist) performing the surgery nor the anesthesiologist performing the surgical anesthesia is not eligible for additional reimbursement for IOM/IONM as the supervising physician. IOM/IONM billed by the surgeon, assistant surgeon, or anesthesiologist will be denied as included in the surgical or anesthesia reimbursement, provider responsibility.

The IOM supervising physician (MD or DO) including IONM supervisng neurophysiologist who is dedicated to the monitoring of the patient and in constant attendance either in the operating room or at a remote location during the procedure, may be eligible for reimbursement. The site and monitoring duration must be clearly documented in the clinical records.

Remote IOM or IONM is eligible for reimbursement to the supervising physician if:

  • The recording lasts more than 30 minutes
  • The time spent performing or interpreting the baseline study is not counted as the intraoperative monitoring
  • The technologist must be in continuous attendance in the operating room performing the monitoring and communicating with the surgeon and the supervising physician.
  • The remote supervising physician must be in one-on-one real-time continuous contact with the technologist in the operating room

Reimbursement will not be allowed for charges for the technologist or by the technologist performing the IOM in the operating room as the reimbursement is included in the allowance for the supervising physician.

Professional or equipment charges billed by the surgeon, assistant surgeon, or anesthesiologist, or if billed by a non-physician or facility, are included in the global allowance of the procedure and additional reimbursement will not be allowed.

This policy applies to all intraoperative monitoring regardless of the type of monitoring.


American Medical Association (AMA). Current Procedural Terminology (CPT®). Chicago: AMA Press.

Centers for Medicare & Medicaid Services (CMS) National Correct Coding Policy Manual for Part B Medicare Carriers effective 1-1-19 Chapter XI – L

Centers for Medicare & Medicaid Services (CMS)

Cross References

Bundling Edits


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