Endoscopic cochlear implantation: Call for caution.

OBJECTIVES/HYPOTHESIS To assess whether transcanal endoscopic access to the basal turn of the cochlea for cochlear implantation is appropriate. STUDY DESIGN Case series study. METHODS We reviewed 100 consecutive computed tomographic studies of the sinuses and temporal bone in our institution. We excluded studies that demonstrated evidence of congenital anomalies, chronic ear disease, or inadequate visualization of the cochlea. On axial sections, the angles of the basal turn of the cochlea and of the ear canal in reference to the sagittal plane were recorded as a function of age. RESULTS Eighty-four studies were included and 16 were excluded. There was significant variability in the relationship between the ear canal and the basal turn of the cochlea in reference to the sagittal plane. A clear majority of images demonstrated the basal turn of the cochlea to align with a more posterior angle than that of the ear canal. CONCLUSION The trajectory provided by posterior tympanotomy aligns more favorably with the basal turn of the cochlea than transcanal access. Endoscopic technique, primarily an ear canal intervention, may not be useful in cochlear implant surgery. LEVEL OF EVIDENCE 4. Laryngoscope, 126:689-692, 2016.