gms | German Medical Science

77th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

24.05. - 28.05.2006, Mannheim

Cochlear Implant Reliability: an analysis of more than 3000 cases over 20 years

Meeting Abstract

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  • corresponding author presenting/speaker Rolf-Dieter Battmer - HNO-Klinik, Medizinische Hochschule, Hannover, Germany
  • Birgit Linz - BfArM, Bonn, Germany
  • Thomas Lenarz - HNO-Klinik, Medizinische Hochschule, Hannover, Germany

German Society of Otorhinolaryngology, Head and Neck Surgery. 77th Annual Meeting of the German Society of Otorhinolaryngology, Head and Neck Surgery. Mannheim, 24.-28.05.2006. Düsseldorf, Köln: German Medical Science; 2006. Doc06hno013

The electronic version of this article is the complete one and can be found online at:

Published: September 7, 2006

© 2006 Battmer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: Since the beginning of the Hannover Cochlear Implant Program in 1984 all explantations and reim-plantations of cochlear implant devices have been monitored. From a population of now approximately 3100 implant users, 203 subjects had to be revised due to various reasons. These reasons can be divided into two ma-jor groups: subjects with medical problems leading to explantation and subjects with device failures. Medical problems leading to explantation are mainly infections and electrode dislocation which could be observed in 52 cases. In 151 cases the reason for explantation was a device failure.

Methods: In a retrospective study all device failures since 1984 were analyzed. Information was gathered from patient files as well as from the device failure reports of the manufacturer (Cochlear Ltd and Advanced Bionics Corp.). All these information were put into a data bank and were analyzed statistically.

Results: As result is was found that independent of the brand leakage (37%) and mechanical impact (29%) were the major reason for device failures. Other failures could be grouped into: electronic circuit failures, electrode defects and others.

Conclusions: This result lead to the development of a new leakage and impact tests, which are part of the new European standard for cochlear implants: EN 45502-1 “Active Implantable Medical Devices”. Although the manufactures of medical devices have already to comply with very specific and extended regulatory requirements this new tests may help to prevent device failures due to leakage and mechanical impact. However, it has to be stated, that the overall high cumulative survival percentage of more than 99% for the present Nucleus and Clarion devices (>36 months of observation time) demonstrates the efforts of the manufactures to produce highly reliable and save devices.

Funded by the German Federal Institute for Drugs and Medical Devices