Neuromonitoring During Surgery

Intraoperative electrophysiological monitoring is performed during all surgeries at The Center for Acoustic Neuroma. Neuromonitoring is performed to help localize important structures, such as the facial nerve, and also to monitor hearing and brain function during the removal of the tumor. At The Center for Acoustic Neuroma, a specially trained technician and neurologist are involved in all surgeries to continually monitor the cranial nerves and also the brainstem function during the entire surgical removal of the tumor. The surgeon is alerted if there is any irritation to the cranial nerves or to the brainstem and the dissection of tumor is adjusted to minimize risk to the important structure.

Nerves that may be monitored during the surgery include the facial nerve, hearing nerve, swallowing nerve, voice nerve, jaw muscle nerves, tongue nerve, or other nerves. In addition, often the brainstem is monitored by following evoked potentials in the upper and lower extremities.

Intraoperative monitoring of hearing is performed by Brainstem Auditory Evoked Response (BAER) testing during hearing preservation surgeries.  Delivery of auditory stimulus is by conformable ear foams connected to transducer by means of plastic tubing.  BAERs are very small auditory evoked potentials in response to an auditory stimulus, which are recorded by electrodes placed on the scalp.  This test is performed continually during tumor surgery to monitor the hearing and the surgeon is alerted if any change in the waveforms is identified by the technician and neurologist that are monitoring the surgery.