Magnetic Guidance of Cochlear Implants: Proof-of-Concept and Initial Feasibility Study

Cochlear implants have become a standard treatment for many with severe to profound sensorineural hearing loss. However, delicate cochlear structures can be damaged during surgical insertion, which can lead to loss of residual hearing and decreased implant effectiveness. We propose a magnetic guidance concept in which a magnetically tipped cochlear implant is guided as it is inserted into the cochlea. In a scaled in vitro experimental study, we record insertion forces for nonguided and magnetically guided insertion experiments and compare the results. Results indicate that magnetic guidance reduced insertion forces by approximately 50%. Using first principles, we discuss the effects of scaling down our in vitro experiments, and account for realistic clinical dimensions. We conclude that scale-down effects are negligible, but to produce the same field strength as in our experiments and provide sufficient clearance between the patient and the manipulator, the magnet dimensions should be increased by approximately four times.