Highly Flexible Silicone Coated Neural Array for Intracochlear Electrical Stimulation.

We present an effective method for tailoring the flexibility of a commercial thin-film polymer electrode array for intracochlear electrical stimulation. Using a pneumatically driven dispensing system, an average 232 ± 64 µm (mean ± SD) thickness layer of silicone adhesive coating was applied to stiffen the underside of polyimide multisite arrays. Additional silicone was applied to the tip to protect neural tissue during insertion and along the array to improve surgical handling. Each array supported 20 platinum sites (180 µm dia., 250 µm pitch), spanning nearly 28 mm in length and 400 µm in width. We report an average intracochlear stimulating current threshold of 170 ± 93 µA to evoke an auditory brainstem response in 7 acutely deafened felines. A total of 10 arrays were each inserted through a round window approach into the cochlea's basal turn of eight felines with one delamination occurring upon insertion (preliminary results of the in vivo data presented at the 48th Annual Meeting American Neurotology Society, Orlando, FL, April 2013, and reported in Van Beek-King 2014). Using microcomputed tomography imaging (50 µm resolution), distances ranging from 100 to 565 µm from the cochlea's central modiolus were measured. Our method combines the utility of readily available commercial devices with a straightforward postprocessing step on the order of 24 hours.

Vibrant soundbridge in aural atresia: does severity matter?

Congenital aural atresia (CAA) poses significant challenges to surgical remediation. Both bone anchored hearing aids (BAHA) and the Vibrant Soundbridge (VSB) have been considered as alternatives or adjuncts to conventional atresiaplasty. A consensus statement on VSB implantation in children and adolescents recommended against implantation when the Jahrsdoerfer score was less than 8. More recent publications suggest that patients with Jahrsdoerfer scores between three and seven may benefit from VSB implantation. The purpose of this study was to further investigate the outcomes of VSB implantation in CAA. The study was a multi-center, retrospective review. A retrospective review of data (patient's demographic, clinical, implant and audiological information) from four collaborating centers that have performed VSB implantation in CAA was performed. Outcomes based on severity of the atresia using the Jahrsdoerfer and Yellon-Branstetter scoring systems were also evaluated. Data from 28 patients from the four centers revealed no iatrogenic facial nerve injuries or change in bone thresholds. Post-operative speech threshold and speech recognition was, respectively, 39 dB and 94%. Jahrsdoerfer and Yellon scores ranged from 4 to 9 and 4 to 12, respectively. The scores did not correlate to or predict outcomes. Three individual elements of the scores did correlate to initial, but not long-term outcomes. Atresiaplasty and BAHA in the management of CAA are not complete solutions. VSB may offer an alternative in these surgically complex patients for achieving amplification, though better metrics for patient selection need to be developed. LEVEL OF EVIDENCE : IV.