Cochlear Implant Surgery

Audiology and Neurotology, 2006

tile only ( 1 85-110 dB HL, 250-500 Hz). In the remaining 7 cases, residual hearing was maintained up to at least 6 months after operation with minor changes. Insertion depth angles in these cases ranged from 285 to 420°. For these subjects, the mean preoperative score for words presented at 65 dB SPL was 22%. Mean postoperative scores were 56% for CI alone, and 68% for CI plus ipsilateral hearing aid (p ! 0.05, paired t). For sentences presented in multitalker babble noise at 5 dB SNR, mean scores were 61% CI alone, and 75% CI+IpsiHA (p ! 0.01, paired t). Conclusions: Hearing was conserved during surgery and over time in 70% of conventional candidates implanted with the Nucleus 24 Contour Advance CI who had significant levels of preoperative low-frequency residual hearing ( ^ 60 dB HL). These conventional candidates for CI also benefited from improved speech recognition in noise when using combined ipsilateral electrical and acoustic stimulation.

The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 2012

The cochlear implant (CI) is the first effective treatment for deafness and severe losses in hearing. As such, the CI is now widely regarded as one of the great advances in modern medicine. This article reviews the key events and discoveries that led up to the current CI systems, and we review and present some among the many possibilities for further improvements in device design and performance. The past achievements include: (1) development of reliable devices that can be used over the lifetime of a patient; (2) development of arrays of implanted electrodes that can stimulate more than one site in the cochlea; and (3) progressive and large improvements in sound processing strategies for CIs. In addition, cooperation between research organizations and companies greatly accelerated the widespread availability and use of safe and effective devices. Possibilities for the future include: (1) use of otoprotective drugs; (2) further improvements in electrode designs and placements; (3) further improvements in sound processing strategies; (4) use of stem cells to replace lost sensory hair cells and neural structures in the cochlea; (5) gene therapy; (6) further reductions in the trauma caused by insertions of electrodes and other manipulations during implant surgeries; and (7) optical rather electrical stimulation of the auditory nerve. Each of these possibilities is the subject of active research. Although great progress has been made to date in the development of the CI, including the first substantial restoration of a human sense, much more progress seems likely and certainly would not be a surprise.

Anatomical record (Hoboken, N.J. : 2007), 2012

This review covers the most recent clinical and surgical advances made in the development and application of cochlear implants (CIs). In recent years, dramatic progress has been made in both clinical and basic science aspect of cochlear implantation. Today's modern CI uses multi-channel electrodes with highly miniaturized powerful digital processing chips. This review article describes the function of various components of the modern multi-channel CIs. A selection of the most recent clinical and surgical innovations is presented. This includes the preliminary results with electro-acoustic stimulation or hybrid devices and ongoing basic science research that is focused on the preservation of residual hearing post-implantation. The result of an original device that uses a binaural stimulation mode with a single implanted receiver/stimulator is also presented. The benefit and surgical design of a temporalis pocket technique for the implant's receiver stimulator is discussed. Ad...

Journal of the Association for Research in Otolaryngology

Cochlear implants (CIs) are the world’s most successful sensory prosthesis and have been the subject of intense research and development in recent decades. We critically review the progress in CI research, and its success in improving patient outcomes, from the turn of the century to the present day. The review focuses on the processing, stimulation, and audiological methods that have been used to try to improve speech perception by human CI listeners, and on fundamental new insights in the response of the auditory system to electrical stimulation. The introduction of directional microphones and of new noise reduction and pre-processing algorithms has produced robust and sometimes substantial improvements. Novel speech-processing algorithms, the use of current-focusing methods, and individualised (patient-by-patient) deactivation of subsets of electrodes have produced more modest improvements. We argue that incremental advances have and will continue to be made, that collectively th...

BioMed Research International, 2015

Acta Oto-Laryngologica, 2005

Conclusions. Hearing may be conserved in adults after implantation with the Nucleus Contour Advance perimodiolar electrode array. The degree of hearing preservation and the maximum insertion depth of the electrode array can vary considerably despite a defined surgical protocol. Residual hearing combined with electrical stimulation in the same ear can provide additional benefits even for conventional candidates for cochlear implantation. Objectives. We present preliminary results from a prospective multicentre study investigating the conservation of residual hearing after implantation with a standard-length Nucleus Contour Advance perimodiolar electrode array and the benefits of combined electrical and acoustic stimulation. Material and methods. The subjects were 12 adult candidates for cochlear implantation recruited according to national selection criteria. A ''soft'' surgery protocol was defined, as follows: 1 Á/1.2-mm cochleostomy hole anterior and inferior to the round window; Nucleus Contour Advance electrode array inserted using the ''Advance-off-stylet'' technique; and insertion depth controlled by means of three square marker ribs left outside the cochleostomy hole. These procedures had been shown to reduce insertion forces in temporal bone preparations. Variations in surgical techniques were monitored using a questionnaire. Pure-tone thresholds were measured pre-and postoperatively. Patients who still retained thresholds B/90 dB HL for frequencies up to 500 Hz were re-fitted with an in-the-ear (ITE) hearing aid. Word recognition was tested in quiet and sentence perception in noise for the cochlear implant alone and in combination with an ipsilateral hearing aid. Results. Hearing threshold level data were available for 12 patients recruited from 6 of the centres. Median increases in hearing threshold levels were 23, 27 and 33 dB for the frequencies 125, 250 and 500 Hz, respectively. These median increases include the data for two patients who had total loss of residual hearing due to difficulties encountered during surgery. ''Cochlear view'' X-ray images indicated that the depth of insertion varied between 300 and 4308, despite modest variations in the length of the electrode inserted (17 Á/19 mm). The insertion angle had some influence on the preservation of residual hearing at frequencies of 250 Á/500 Hz. Six of the 12 patients retained sufficient hearing for effective use of an ipsilateral ITE hearing aid (5/80 dB HL at 125 and 250 Hz; 5/90 dB HL at 500 Hz). Word recognition scores in quiet were improved from 10% to 30% with the cochlear implant plus ipsilateral hearing aid in 3 patients who had at least 3 months postoperative experience. Signal:noise ratio thresholds for sentence recognition were improved by up to 3 dB. Patients reported that they experienced greatly improved sound quality and preferred to use the two devices together.

2013

Introduction Recent advances in cochlear implant technology have resulted in the relaxation of the selection criteria for their use. [1] As the benefits of implantation have been more widely demonstrated, there has been increasing emphasis not only on implanting individuals who are totally deaf, but also those with residual hearing at low frequencies. [2] Moreover, recent studies have shown that residual hearing can be preserved after cochlear implantation. [3] They suggested that the use of a hearing aid and a cochlear implant in the same ear can result in better hearing and speech perception than when using either device alone. This concept, known as electric-acoustic stimulation (EAS), was later successfully realized in practice. [4-7] EAS is based on the concept that electric stimulation of the basal cochlear regions generates high-frequency percepts while the residual low-frequency regions of the cochlea are acoustically amplified by way of a conventional hearing aid. [8] The c...

Cochlear Implants International, 2004

Cochlear Implants International, 2011

Objectives: Clinicians traditionally advise patients that implantation with a conventional full cochlear implant array will lead to loss of any remaining hearing in the implanted ear. We sought to assess the extent to which 'standard' insertion of a full electrode array affects cochlear function. Methods: Air conduction pure tone audiometry was performed as part of the routine 6-month postimplantation audiological assessment for 81 adult patients who preoperatively had identifiable pure tone thresholds. All patients were implanted with the nucleus CI24 device, with complete insertion of a straight array in 68 and a contour array in 13 patients. A separate cochleostomy was fashioned anterior to the round window using a 1 mm diamond burr, and the array inserted without lubrication. The operating surgeon was blinded to the inclusion of patients in this study at the time of surgery. Results: Of 81 patients, 58 preserved some residual hearing at 6 months. The rate of preservation of hearing was higher in the low frequencies. At 500 Hz 77 patients had an identifiable preoperative pure tone threshold, still identifiable postoperatively in 48. At 4 kHz only 25 patients had an identifiable preoperative threshold, preserved in 9, and at 8 kHz 6 of 13 patients still had identifiable pure tone thresholds postoperatively. There was no correlation between the depth of insertion and hearing preservation, both groups having a mean of 5 stiffening rings inserted in addition to the 22 active electrodes. The mean deterioration in threshold in those who had residual hearing was 15 dB at 500 Hz, and in 29 patients the deterioration in the threshold was less than 15 dB. Conclusion: Insertion of a full conventional electrode array is not as damaging to cochlear function as often assumed. Residual low-frequency hearing may be preserved in approximately two-thirds of patients 6 months postoperatively. This study supports our counselling patients that despite the delicate nature of the inner ear there is a significant chance that their air conduction hearing will not be lost.

The Journal of Rehabilitation Research and Development, 2008

The cochlear implant is the most successful of all neural prostheses developed to date. It is the most effective prosthesis in terms of restoration of function, and the people who have received a cochlear implant outnumber the recipients of other types of neural prostheses by orders of magnitude. The primary purpose of this article is to provide an overview of contemporary cochlear implants from the perspective of two designers of implant systems. That perspective includes the anatomical situation presented by the deaf cochlea and how the different parts of an implant system (including the user's brain) must work together to produce the best results. In particular, we present the design considerations just mentioned and then describe in detail how the current levels of performance have been achieved. We also describe two recent advances in implant design and performance. In concluding sections, we first present strengths and limitations of present systems and then offer some possibilities for further improvements in this technology. In all, remarkable progress has been made in the development of cochlear implants but much room still remains for improvements, especially for patients presently at the low end of the performance spectrum.