Neuromonitoring in operations in the skull base.

Methods to monitor the integrity of cranial motor nerves during operations on skull base tumors have been developed over the past decade. These methods can help the surgeon to identify cranial motor nerves that are located in the surgical field but which may not be visible directly. Methods have also been developed that allow monitoring of the function of sensory systems such as the auditory system and it has been shown that brainstem auditory evoked potentials can provide important information about the integrity of the auditory nervous system. It has been shown in several studies that such neuromonitoring, when performed during operations in the skull base, can help reduce the incidence of permanent neurological deficits that may occur with the removal of large tumors. We have also shown that such monitoring can be performed routinely without interfering noticeably with the actual surgical procedures.