The CPT guidelines under Intraoperative Neurophysiology (CPT codes 95940, 95941), state that when intraoperative nerve monitoring is "performed by the [primary] surgeon or anesthesiologist, it is included in the surgeon's or anesthesiologist's primary service codes and not separately reported."
If you have a second surgeon in the room who is not billing as an assistant/co-surgeon and only performing the nerve monitoring, then that surgeon can bill for the intraoperative nerve monitoring.
Hope that helps.
Jennifer M. Connell, BA, CPC, CENTC, CPCO