The Laryngoscope V C 2013 The American Laryngological, Rhinological and Otological Society, Inc. Nucleus N5 CI500 Series Implant Recall: Hard Failure Rate at a Major Cochlear Implantation Center Douglas M. Hildrew, MD; Timothy B. Molony, MD Objectives/Hypothesis: To compare the cumulative failure percentage of the Cochlear Nucleus N5 CI500 series implant observed, both before and after the voluntary recall of unimplanted devices, to that of the Cochlear Nucleus Freedom CI24RE series implant. Study Design: Retrospective review of 411 patients implanted with either the Nucleus Freedom or the Nucleus N5 device. Methods: Cochlear implantation was performed in standard fashion. A database was created by combining information obtained from operative case logs, an integrated clinical electronic medical records system, and an external database of devices maintained by Cochlear Corporation. Results: Of the 289 implants of the Nucleus Freedom CI24RE series device at this institution, the cumulative failure per- centage was 0%. There were 122 implants of the Nucleus N5 CI500 series device, yielding a 9.8% cumulative failure percent; 82 were manufactured before the voluntary recall and 40 were produced afterward. The 82 implants manufactured before the recall had two associated failures, while the 40 produced afterward had 10 failures. Conclusions: It is possible that the cumulative failure percentage (CFP) of the Cochlear Nucleus N5 CI500 series implant is not fully defined. While the CFP of the Nucleus Freedom CI24RE series implant at this institution was 0%, it was 9.8% for the Nucleus N5. The CFP of Nucleus N5 devices manufactured before the voluntary recall was 2.4%, while the CFP afterward was 25.0%—nearly 6-fold higher than the company-published value of 4.2% for all Nucleus N5 implants registered globally. Key Words: Cochlear implant, Nucleus N5, Nucleus Freedom, CI512, CI24RE, recall, hard failure, cumulative failure per- centage, microcrack, hermetic seal, hermeticity, diode. Level of Evidence: 3b. Laryngoscope, 123:2829–2833, 2013 INTRODUCTION From the pioneering research performed by Dr. Wil- liam House and Jack Urban in the 1960s to the modern era of medicine, cochlear implants have gone from being experimental and highly controversial to a well-estab- lished standard for those afflicted with severe to pro- found sensorineural hearing loss. The ability of the implant to provide restoration of sound awareness, speech perception, and music appreciation is widely appreciated and characterized. 1,2 It is also understood that being an implanted electronic device, there is an inherent risk that the device will necessitate revision surgery. 3 Such incidents of failure have been previously studied and are most commonly grouped into three sub- types: hardware, medical/surgical, and soft failures. 1,3,4 Recently, a manufacturing flaw has been identified by Cochlear Corporation to negatively impact the cumu- lative survival percentage (CSP) of the Nucleus N5 CI500 series cochlear implant device, thereby increasing the cumulative failure percentage (CFP). 5 The CSP is the cumulative percentage of functioning implants over time, while the CFP is the cumulative percentage of devices that are no longer functioning after a given period of time. 6 On September 11, 2011, the Cochlear Corporation announced a voluntary recall of all unim- planted Nucleus N5 CI500 series devices that were man- ufactured after January 1, 2011. While the CFP at that time was stated as being less than 1% of all devices reg- istered globally, a recent increase in the number of fail- ures had been identified. 5 On December 20, 2011, an additional report was sent to physicians in which the root cause analysis of the malfunctions was stated to be a loss in hermeticity of the device due to unexpected var- iations in the brazing process. 5 This was said to result in microcracks at the site of the braze joint (where the feedthrough to the titanium chassis exists) during subse- quent manufacturing steps, allowing for water entry, malfunction of the electronic components (typically one of four diodes), and ultimately causing spontaneous implant shutdown. 5 Additionally, the overall CFP of the Nucleus N5 implant devices was then estimated as 1.9% of implants registered globally. 5 On February 7, 2012, and August 7, 2012, similar reports were released, From the Department of Otolaryngology/ Head and Neck Surgery (D.M.H.), Tulane University School of Medicine; and the Department of Otolaryngology/ Head and Neck Surgery (T.B.M.), Ochsner Clinic Founda- tion, New Orleans, Louisiana, U.S.A. Editor’s Note: This Manuscript was accepted for publication March 20, 2013. Original Clinical Research was collected from patient data at the Ochsner Clinic Foundation. The authors have no other funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Douglas M. Hildrew, MD, 1430 Tulane Avenue, SL-59, New Orleans, LA 70112-2699. E-mail: dhildrew@tulane.edu DOI: 10.1002/lary.24149 Laryngoscope 123: November 2013 Hildrew and Molony: Nucleus N5 Cochlear Implant Recall Analysis 2829