Navigation-guided transmodiolar approach for auditory nerve implantation via the middle ear in humans

The aim of this study was to assess the surgical feasibility of a transmodiolar approach via the middle ear cavity for an auditory nerve implantation in humans. In the first part of the study, 6 adult human temporal bones underwent a navigator-guided transmodiolar implantation via the middle ear space after a radical mastoidectomy. In the second part, 122 temporal bone CT scans were analyzed for anatomical parameters relevant to this approach. The nerve implantation was feasible in all temporal bones in laboratory conditions, with a mean target registration error of 0.065 ± 0.0583 mm (n = 6). Evaluation of anatomical parameters on CT scans also supported the feasibility. There was a significant interindividual variation of the modiolar axis and the entry point in relation to visible anatomical landmarks, highlighting the necessity for surgical preplanning.