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BioMed Research International
Volume 2015, Article ID 236364, 9 pages
http://dx.doi.org/10.1155/2015/236364
Research Article

Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

1Department of Medicine, Faculdade de Medicina, University of Sao Paulo, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil
2Department of Otorhinolaryngology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil
3Department of Radiology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil

Received 13 November 2014; Revised 23 February 2015; Accepted 4 March 2015

Academic Editor: Hung-Ching Lin

Copyright © 2015 Graziela de Souza Queiroz Martins et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane. Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation. Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arrays in situ. The resulting images were analyzed for signs of intracochlear trauma. Results. Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion. Conclusions. The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.