Facial nerve stimulation following cochlear implantation

• Published in: jibi to rinsho Vol. 42; no. 5Supplement2; pp. 717 - 725
• Main Authors: TSUBOI, Yasuhiro, TONO, Tetsuya, USHISAKO, Yasuaki, MORIMITSU, Tamotsu
• Format: Journal Article
• Language: Japanese
• Published: JIBI TO RINSHO KAI 20.09.1996
• ISSN: 0447-7227; 2185-1034
• DOI: 10.11334/jibi1954.42.5Supplement2_717

Facial nerve stimulation due to an activated electrode array is known to be a potential side effect which can occur following successful cochlear implantation. It may result in a deterioration of sound quality due to a limitation in the dynamic range of the implant. However, the precise mechanisms of this complication still remain to be clarified. Out of 26 adult patients who received the Nucleus 22-channel cochlear implant system in our department from 1990 to 1995, we observed facial nerve stimulation in 2 cases. Both patients noted facial nerve stimulation upon the activation of apical electrodes when the devices were first programmed. The low-impedance current pathways from the scala tympani to the labyrinthine and/or internal auditory canal segments of the facial nerve are apparently enhanced by osteoporotic changes due to either acoustic tumor surgery or labyrinthine syphilis. Such pathological CT findings, especially arround the cochlear capsule, may therefore help predict a greater risk for developing postimplantation facial nerve stimulation.