Development of an intracochlear navigated electrode array for cochlear implantation

Research question: The exact positioning of the Ci electrode in the cochlea is essential in the context of cochlear implantation. The insertion process of the electrode array during cochlear implantation represents a "black box", as direct optical visualisation is not possible. To solve this problem, a computer-assisted and image-guided system was developed to provide accurate real-time visualisation of the position of the electrode array during insertion.

Methods The system is based on an electromagnetic tracking system and modified ENT navigation software and was evaluated on human petrous bone specimens. A flat-panel volume CT with a slice thickness of 100 μm was used for imaging. To validate the system, a cochlear implantation surgery was simulated. Radio-Opaque markers were inserted around the mastoid cavity for registration and accuracy measurement. After insertion, the electrode array was fixed in the cochlea and re-imaging was performed.

Results In a first pilot study, the fiducial registration error (FRE) was 0.24 mm ± 0.20 mm. The prototype electrode array could be inserted into the cochlea and placed with an accuracy of 1.1 mm ± 0.40 mm. A maximum insertion angle of 120° could be achieved.

Conclusion The experiments were the first step in the development of a navigated cochlear implant electrode array, which will allow intracochlear navigation to be performed. Such a system could contribute to improved control of the insertion process into the cochlea, the preoperatively defined insertion depth and avoidance of electrode malposition.

Publication History

Article published online:
12 May 2023