Resultados del implante coclear Nurotron en población anciana

Abstract

Introduction: The efficacy of cochlear implantation (CI) in severe profound bilateral postlocutive hearing loss in the elderly population is perfectly validated at the present time. There are no age limits for indicating this surgery, when the patient's state of health allows it. In our CI unit we participated in the prospective multicentre study of the efficacy and safety of the Nurotron Venus cochlear implantation system for Spain. Its use in Europe was authorised in 2012. It is an implant with 26 electrodes (2 extracochlear), 22 mm long. There are also 3 other thinner leads available: long, medium and short; ranging from 17.5-25.5mm. These electrodes are slightly pre-curved to facilitate their insertion, but are positioned laterally in the tympanic ramp. Previous studies show that their insertion into the cochlea is easy, and an incidence of severe trauma after insertion of 12.5%.

Method: 7 patients over 65 years of age, on the waiting list for CI, were randomly selected. All patients had severe-deep bilateral hearing loss as adults. Surgeries were performed between October and December 2019, in the ear with worse hearing, using contralateral acoustic stimulation.

Results: The surgeries were performed by a single surgeon, with no change in duration or difficulty in achieving complete implantation in the cases treated. The surgical procedure and postoperative care were performed in the same manner as other CIs. We evaluated the hearing outcomes by means of liminal tonal and open-field speech audiometry with hearing aid alone, cochlear implant alone and both prostheses simultaneously. The mean gain in tonal audiometry was 46.4dB (37.5-48.7). The mean gain in maximum speech discrimination with implant alone was 50% (0-90) and with CI and hearing aid 67.1% (40-100%).

Discussion: Hearing and speech discrimination results are comparable to other brands, varying according to the etiology of the hearing loss. One patient had a 20-year-old hearing loss of unknown etiology, with low intelligibility, who had undergone CI surgery twice with other brands with low gain, and was therefore included in the study. This patient showed the least benefit from CI. On the other hand, two patients suffering from poorly controlled bilateral Ménière's disease had fluctuations in understanding. The hearing outcomes with this implant, evaluated at least 48 months, have been satisfactory. The tonal thresholds with the implant alone were 46.4 dB and the speech discrimination 67.1%, which is comparable to other results in the elderly population. In relation to surgery, it does not present any changes compared to other brands: the receiver bed is shallower due to its reduced thickness, it does not have screws for fixation to the bone and the electrode array allows an acceptable insertion.

Conclusions: The Nurotron implant has similar surgical placement and hearing outcomes to other brands, taking into account age, sound deprivation and etiology of deafness. Positive elements are its lower price, as well as its 15-year warranty, compared to 10 years for other implants.