A database system for the registration of complications and failures in cochlear implant surgery applied to over 1000 implantations performed in Nijmegen, The Netherlands H J THEUNISSE, J J MULDER, R J E PENNINGS, H P M KUNST, E A M MYLANUS Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Center, Nijmegen, and Centre for Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands Abstract Objective: To create a system for the uniform registration and classification of complications and failures in cochlear implant surgery, and apply it to all the patients who underwent implantation in our clinic. Method: The definition of a medical complication was established, and data for all cochlear implantations performed between 1987 and 2012 were entered into a custom-made database system. Results: One or more medical complications were registered in 19.0 per cent of 1003 cochlear implantations. The incidence of ‘hard failure’ was 2.3 per cent. Findings revealed a decrease in device failures over the years; the rate of medical complications remained constant. Conclusion: Our database system, which is available free of charge, enables fast and accurate data entry. There were a relatively high number of (minor) complications in our series, but comparison with the relevant literature is difficult. This emphasises the need for a uniform definition of ‘complication’ as it relates to cochlear implant surgery, and an appropriate classification system for such complications. Key words: Cochlear Implantation; Postoperative Complications; Equipment Failure; Database Management Systems Introduction There is a growing demand for quality assessment in medicine. Indicators of outcome include: patient satis- faction, quality of life, mortality and complications. The uniform registration and classification of compli- cations is essential in order to compare results between medical centres. Responsibility for the regis- tration of complications lies with the medical centres and the medical personnel. The key to successful com- plication registration is to create an infrastructure that warrants an easy, fast and safe means of recording the information. Strict registration of negative outcomes is necessary for the evaluation of new surgical procedures and new devices, and for determining the best policy regarding other management options, such as the necessity of post-operative antibiotic therapy. Fortunately, severe complications in cochlear implant patients are rare. Therefore, a large number of patients are needed to detect statistically significant differences in complication rates between groups. This can be accomplished by pooling data from differ- ent clinics. However, all of the involved centres would need to be able to use the same system for the registra- tion of negative outcomes. A distinction must be made between complications, sequelae and failures. Complications are unexpected events not intrinsic to the procedure, whereas sequelae are inherent to the procedure; complications and seque- lae both add new problems to the underlying disease. Failures are events in which the purpose of the proced- ure is not fulfilled. 1 In the case of cochlear implant- ation, the procedure itself may be a failure (i.e. a correctly functioning device is implanted without benefit for the patient) or the device may be malfunc- tioning. Device failures are further divided in ‘hard fail- ures’ (i.e. a device with characteristics outside the manufacturer’s specification, resulting in a loss of clin- ical benefit) and ‘soft failures’ (i.e. a device malfunc- tion is suspected but cannot be proven using currently available in vivo methods). Furthermore, a device may have measured characteristics outside the Professor E A M Mylanus is one of the JLO 2014 Visiting Professors Accepted for publication 12 February 2014 First published online 2 October 2014 The Journal of Laryngology & Otology (2014), 128, 952–957. MAIN ARTICLE © JLO (1984) Limited, 2014 doi:10.1017/S0022215114002126