title: Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Medicine, Faculdade de Medicina, University of Sao Paulo, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil ; Department of Otorhinolaryngology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil.
authors.forename: Graziela de Souza Queiroz
authors.initials: Gde S
authors.lastname: Martins
authors.affiliation: Department of Otorhinolaryngology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil.
authors.forename: Rubens Vuono
authors.initials: RV
authors.lastname: Brito Neto
authors.affiliation: Department of Otorhinolaryngology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil.
authors.forename: Robinson Koji
authors.initials: RK
authors.lastname: Tsuji
authors.affiliation: Department of Radiology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil.
authors.forename: Eloisa Maria Mello Santiago
authors.initials: EM
authors.lastname: Gebrim
authors.affiliation: Department of Otorhinolaryngology, Clinical Hospital, FMUSP, Avenida Dr. Eneás de Carvalho Aguiar 255, Sala 6167, 05403-000 São Paulo, SP, Brazil.
authors.forename: Ricardo Ferreira
authors.initials: RF
authors.lastname: Bento
mesh_terms: D001489:Basilar Membrane / Q000473:pathology; D003051:Cochlea / Q000000981:diagnostic imaging / Q000601:surgery; D003054:Cochlear Implants / Q000009:adverse effects*; D004432:Ear, Middle / Q000473:pathology; D004567:Electrodes, Implanted / Q000009:adverse effects*; D006801:Humans; D012405:Round Window, Ear / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D014947:Wounds and Injuries / Q000209:etiology*