Electrode insertion mechanics and outer wall forces with the Nucleus 24 Contour Advance™ electrode

Abstract

Table 1: Width at half maximum for average NRT tuning curves. The widths were obtained by fitting Gaussian curves to the tuning curves. For electrodes 1 and 20 the half-width-at-half-maximum is indicated. For electrodes 6, 11 and 16, full-width-at-half-maximum is indicated. Widths are indicated in number of electrode distances. The reduction of width due to modiolus hugging was significant for electrodes 1, 6 and 20 Electrode numberTuning width before Tuning width after (base to apex) modiolus hugging modiolus hugging 18 .9 (± 0.6) 6.2 (± 0.6) 61 0.9 (± 0.3) 9.4 (± 0.3) 11 12.3 (± 0.6) 11.2 (± 0.8) 1613.4 (± 0.5) 12.8 (± 0.6) 20 8.5 (± 0.3) 6.6 (± 0.4) Discussion and conclusionModiolus hugging gave a small but significant reduction of spread of neural excitation on the basal and apical apart of the Nucleus CI24R(CS) cochlear implant. There was no significant effect on the mid-section of the implant array. To our knowledge, our results are the first within-subject demonstration of the effect of modiolus hugging. Our intra-operative measurements had to be performed at a high stimulus level. At lower stimulation levels, closer to those an implant user would typically use, the reduction of the spread of excitation may be more pronounced, as is also suggested by Cohen et al. (2003). We conclude that modiolus hugging improves stimulation selectivity. This may improve speech discrimination and be beneficial for implant users.

The Effects of Insertion Speed on Inner Ear Function during Cochlear Implantation: A Comparison Study

“…A possible explanation is, especially when considering previous findings, that the slow electrode insertion reduces intracochlear pressure peaks and facilitates pressure equalisation by allowing time for perilymph egress while the electrode enters the confined fluid-filled intracochlear space [Roland et al, 2005;Todd et al, 2007]. This would result in a net reduction of intracochlear volume displacement with potentially less mechanical effects and trauma on the basilar membrane and the organ of Corti [Todd et al, 2007].…”

“…There are a number of variables related to hearing preservation that need to be clarified and investigated. These variables include electrode design, the use of hair cell protection, electrode insertion depth and the method of electrode insertion, which should be as atraumatic as possible [Ishii et al, 1995;Roland et al, 2005;Rebscher et al, 2008;Verbist et al, 2009]. Until recently, the electrode insertion speed and its impact on insertion characteristics has not been examined in detail, especially in the clinical setting [Majdani et al, 2010].…”

Dexamethasone Is One of the Factors Minimizing the Inner Ear Damage from Electrode Insertion in Cochlear Implantation

“…There are a number of variables to be considered for HP apart from the use of an otoprotective drug: surgical strategies related to an atraumatic technique and electrode array design Roland et al, 2005; Verbist et al, 2009]. An atraumatic surgical procedure maximizes the chances of survival of neural cochlear structures.…”

Exploration of factors influencing the preservation of residual hearing following cochlear implantation

“…The Contour Advance electrode is the only perimodiolar array in the industry and is pre-curved for complete insertion, with Softip that enables atraumatic insertion (Roland, Shelva, Gibson, & Treaba, 2005).…”