Vol.:(0123456789) 1 3 European Archives of Oto-Rhino-Laryngology https://doi.org/10.1007/s00405-018-4901-z OTOLOGY Risk factors for complications in cochlear implant surgery Henricus J. Theunisse 1,2,3  · Ronald J. E. Pennings 2,3  · Henricus P. M. Kunst 2,4  · Jef J. Mulder 2,3  · Emmanuel A. M. Mylanus 2,3 Received: 10 October 2017 / Accepted: 5 February 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Purpose The objective of this study was to achieve uniform reporting of complications and failures in cochlear implanta- tion, to analyze complications and failures and to identify risk factors for complications in a series of over 1300 cochlear implantations. Methods In a retrospective chart review and observational study, data from all cochlear implantations from 1987 to 2015 were entered in a custom-made database. Complications were classifed using the contracted form of the Clavien–Dindo system and risk factors were identifed by statistical analysis. Results A complication rate of 18.4% and a device failure rate of 2.9% were found. There was a higher rate of hematoma in patients with a clotting disorder and when a subtotal petrosectomy was performed, a higher rate of wound infections in patients who were not vaccinated against Streptococcus pneumoniae and a higher rate of meningitis in patients with an inner ear malformation. Conclusions The use of a strict defnition of a medical complication and device failure—in combination with the Clavien– Dindo classifcation system—enables uniform and objective registration of adverse events and prevents any tendency to downgrade complications. Complication and failure rates in this series are comparable to those reported in the literature. These results stress the need for pneumococcal vaccination, which may prevent general wound infections, but is especially important for patients with inner ear malformation, who have an increased risk of (postoperative) meningitis. Keywords Cochlear implantation · Postoperative complications · Equipment failure · Risk factors Introduction Cochlear implantation is very successful in restoring hear- ing in patients with profound sensorineural hearing loss, but surgical complications are reported in 6–63% of the cases [1–5]. This complication rate is comparable to that of active middle ear implantation (16–21% [6, 7]), but is higher than in other felds of otology such as cholesteatoma surgery (6–17%, although reports are sparse [8, 9]). The frst step in reducing these complications is identif- cation of the most common and most severe complications. Although there are many reports on complication rates, these results are hard to compare since there is no consensus on reporting them (except for meningitis [10] and device failure [11, 12]). Hansen et al. have proposed a useful overview of defnitions and criteria, which was elaborated by Jeppesen et al. [3, 5], but unfortunately, this has not yet been widely used. Similar problems arise with classifcation: most studies diferentiate between major and minor complications, but the use is inconsistent and a clear defnition is rarely given. Hansen et al. have also addressed this problem, but their defnition still leaves room for interpretation (e.g., ‘a signif- cant medical problem’ is considered a major complication). To tackle this problem in general surgery, Clavien et al. developed a classifcation system (modifed by Dindo et al.), based on the therapy used to treat the complication [13, 14]. * Henricus J. Theunisse e.theunisse@cwz.nl 1 Department of Otorhinolaryngology, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands 2 Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Center, Nijmegen, The Netherlands 3 Centre for Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands 4 Radboud Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands