Abstract
Misplacement of the electrode array in the internal auditory canal can happen in cases of modiolus defect type inner ear malformation such as Incomplete Partition type Ⅲ （IP-Ⅲ）, which is X-linked deafness due to POU3F4 gene mutation, and common cavity cases where the internal auditory canals are widely opened. We perform fluoroscope-assisted operation to prevent electrode array misplacement. Fluoroscopy is an imaging technique that uses C-arm to obtain real-time moving images of the interior electrode. The anesthesia machine is placed on the contralateral side of the foot of the bed and the operation microscope at the head of the bed. The C-arm is placed out of the way between the anesthesia machine and the operation microscope. With this arrangement, we can perform the operation almost as usual. Because of radiation exposure, the fluoroscope beam should be narrowed and centered to see through only the temporal bone and avoid orbit penetration. It is difficult for the surgeon to confirm fluoroscope monitoring during electrode insertion, so an experienced monitoring assistant should guide the surgeon to insert the electrode in the right place.
Four patients, 1 IP-Ⅲ （13-year-old girl） and 3 common cavities （1-year-old boy, 3-year-old girl, 5-year-old girl）, underwent cochlear implantation with intraoperative fluoroscopic assistance. In the IP-Ⅲ case, gushing happened and the electrode misplacement into the internal auditory canal was confirmed by fluoroscopy at the first time. Immediately, we were able to replace the electrode in the correction location of the cochlea. In the three cases of common cavity, there was no gushing and the electrode could be placed in a good position inside the inner ear from the beginning under fluoroscopy. Fluoroscopically assisted cochlear implantation is an easy and effective technique that results in improved outcomes for cochlear implant patients with modiolus defect type inner ear deformities.
