Medical Devices: Evidence and Research (Feb 2019)
Robustness and lifetime of the bone conduction implant – a pilot study
Abstract
Karl-Johan Fredén Jansson,1 Bo Håkansson,1 Cristina Rigato,1 Måns Eeg-Olofsson,2 Sabine Reinfeldt1 1Department of Electrical Engineering, Chalmers University of Technology, Göteborg, Sweden; 2Department of Otorhinolaryngology, Head and Neck Surgery, Sahlgrenska University Hospital, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Objectives: The objective of this study was to develop methods for evaluating the mechanical robustness and estimating the lifetime of the novel bone conduction implant (BCI) that is used in a clinical study. The methods are intended to be applicable to any similar device.Materials and methods: The robustness was evaluated using tests originally developed for cochlear implants comprising a random vibration test, a shock test, a pendulum test, and an impact test. Furthermore, magnetically induced torque and demagnetization during magnetic resonance imaging at 1.5 T were investigated using a dipole electromagnet. To estimate the lifetime of the implant, a long-term age-accelerated test was performed.Results: Out of all the tests, the pendulum and the impact tests had the largest effect on the electro-acoustic performance of the BCI implant, even if the change in performance was within acceptable limits (<20%). In comparison with baseline data, the lower and higher resonance peaks shifted down in frequency by 13% and 18%, respectively, and with a loss in magnitude of 1.1 and 2.0 dB, respectively, in these tests.Conclusion: A complete series of tests were developed, and the BCI passed all the tests; its lifetime was estimated to be at least 26 years for patients who are using the implant for 12 hours on a daily basis. Keywords: audiology, bone conduction audiometry, electromagnetic transducer, electro-acoustics
