Vol.:(0123456789) 1 3 European Archives of Oto-Rhino-Laryngology https://doi.org/10.1007/s00405-020-06290-3 OTOLOGY Binaural hearing restoration with a bilateral fully implantable middle ear implant Domenico Cuda 1  · Alessandra Murri 1  · Anna Mainardi 1  · Francesca Forli 2  · Stefano Berrettini 2  · Luca Bruschini 2 Received: 11 May 2020 / Accepted: 11 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Aim The fully implantable middle ear implant (C-FI-MEI) is designed for patients with moderate-to-severe sensorineural hearing loss or those with mixed hearing loss. To analyze the audiological post-operative results of subjects bilaterally implanted with C-FI-MEI. Materials and methods Retrospective study: 14 patients with bilateral, moderate-to-severe, sensorineural or mixed hear- ing loss were treated. This clinical sample included 14 cases bilaterally implanted (13 sequentially, 1 simultaneously). The evaluation at each follow-up after surgery included otologic examination, a structured interview, and diferent audiological tests composed of pure tone audiometry, speech in quiet and in noise test, and localization task. The mean follow-up was 67.2 ± 33 months. Results There were no signifcant diferences between pre and post-operative pure tone averages. The patients showed no signifcant diferences between pre-operatively aided and C-FI-MEI implant-aided conditions in terms of word recognition score. Speech perception in noise under diferent loudspeaker arrangements and localization tests demonstrated a binaural advantage in bilaterally implanted patients. The mean daily use time was 17.4 and 16.7 h, respectively, for right and left side. Conclusion The results for the 14 patients, bilaterally implanted with C-FI-MEI, suggest that bilateral implantation of fully implantable middle ear hearing devices is an efective procedure. Level of evidence 4. Keywords Fully implantable middle ear implant · Middle ear · Implant · Bilateral Introduction Middle ear implants (MEIs) are increasingly applied in cases of moderate-to-severe sensorineural or mixed hearing loss (SNHL or MHL). There are semi-implantable and fully implantable MEIs (FI-MEI). The frsts have the electronic components, battery and the microphone housed in an audio processor worn by the patient while the transducer is sur- gically implanted, conducting the vibratory energy to the ossicular chain and the cochlea. Two FI-MEIs were available on the market at the time of writing. In one the microphone is placed under the ret- roauricular skin. It captures sounds and sends them to the implant for processing. The signals are then converted into mechanical vibrations by an electromechanical transducer (actuator) appropriately secured by a special fxation system. The tip of the actuator is coupled to one of the ossicles or to the middle ear windows. This system includes a recharge- able battery, and if charged daily, the estimated life span is more than 10 years. The other one takes advantage of the eardrum as a micro- phone: a piezoelectric transducer (sensor) coupled to the malleus converts the vibrations into an electrical signal which is amplifed by the sound processor placed under the retroauricular skin. The signal is then converted into mechanical vibrations by another piezoelectric transducer coupled to the stapes (driver). In contrast to the frst one, the second includes a non-rechargeable battery with a life span of between 4.5 and 9 years. * Alessandra Murri alessandra_murri@libero.it 1 Department of Otorhinolaryngology, “Guglielmo da Saliceto” Hospital of Piacenza, Via Cantone del Cristo 40, 29121 Piacenza, Italy 2 ENT Audiology and Phoniatric Unit, University Hospital of Pisa, Pisa, Italy