聴覚を守る術中持続聴覚モニタリングと蝸牛神経マッピング : 聴神経腫瘍手術と前庭神経切断術での新技術 Intraoperative Continuous Cochlear Monitoring and Electrical Cochlear Nerve Mapping for Preserving the Hearing : Advanced technology in Acoustic Neuroma Surgery and Vestibular Neurectomy
By just preserving the nerve anatomically, function of a cochlear nerve which is a central nerve cannot be saved. In order to save the function of the cochlear nerve, we thought that a highly sensitive continued stable monitoring which can visualize the change occurring in the nerve function that cannot be detected by the eye. Therefore, we produced the hearing preservation operation using new technologies called intraoperative continuous cochlear monitoring and cochlear mapping.<BR>What is most characteristic in our nerve monitoring surgery is to operate while monitoring the condition of the nerve function every several seconds without stopping the operation manipulation. The auditory brainstem response which is the traditional way of monitoring the auditory sensation is a convenient method but requires five hundred (30sec) to one thousand times in adding numbers, making is difficult for monitoring in real time. It is also susceptive to electromagnetic wave or had a flaw in that measurements could not be made in a case where the audibility level was bad.<BR>Cochlear nerve action potential was a lot sensitive than the auditory brainstem response and had a lot of improvements made to those faults on auditory brainstem response, but the stability of the electrode was not good and had a flaw in that the electrode interfered with the surgery. In order to improve the flaw in the cochlear nerve action potential, we came up with an idea to place the electrode more on the inner side at the nuclei. The electric potential obtained was named DNAP. There was a significant improvement in the hearing preservation rate by the help of DNAP and cochlear mapping.<BR>We can now check after the surgery, by reviewing the trend graph, which reactions took place at which timing. So, with more experience, the surgeon becomes aware of the needless surgical procedure and what the invasive surgical manipulations are. These really are the other significant merits for the surgeon.
- Otology Japan
Otology Japan 22(3), 191-197, 2012-07-25