title: Safety, reliability, and operability of cochlear implant electrode arrays coated with biocompatible polymer.
abstract: CONCLUSIONS
  Polymer-coated electrodes can reduce surgically-induced trauma associated with the insertion of a cochlear implant (CI) electrode array.
  
  
  OBJECTIVE
  To evaluate if insertion trauma in CI surgery can be reduced by using electrode arrays coated with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer.
  
  
  METHODS
  We analyzed characteristics of the Contour Advance electrode arrays coated with MPC polymer. To assess surgical trauma during electrode insertion, polymer-coated or uncoated (n = 5 each) animal electrode arrays were implanted in guinea pig cochleae and operability and electrophysiological and histological changes were assessed.
  
  
  RESULTS
  Under light and scanning electron microscopy, polymer-coated electrodes did not appear different from uncoated electrodes, and no change was observed after mechanical stressing of the arrays. Electrode insertion was significantly easier when polymer-coated electrodes were used. Auditory brainstem response (ABR) thresholds did not differ between groups, but p1-n1 amplitudes of the coated group were larger compared with the uncoated group at 32 kHz at 28 days after surgery. The survival of outer hair cells and spiral ganglion cells was significantly greater in the polymer-coated group.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Yayoi S
authors.initials: YS
authors.lastname: Kikkawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Kondo
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Konno
authors.forename: Nick
authors.initials: N
authors.lastname: Pawsey
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible; D003051:Cochlea / Q000293:injuries*; D019929:Cochlear Implantation / Q000009:adverse effects* / Q000295:instrumentation; D003054:Cochlear Implants / Q000009:adverse effects*; D004195:Disease Models, Animal; D004867:Equipment Design; D016057:Evoked Potentials, Auditory, Brain Stem; D006168:Guinea Pigs; D006309:Hearing; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008689:Methacrylates; D010767:Phosphorylcholine / Q000031:analogs & derivatives*; D015203:Reproducibility of Results
chemical_list: D020099:Coated Materials, Biocompatible; D008689:Methacrylates; D010767:Phosphorylcholine; C070638:2-methacryloyloxyethyl phosphorylcholine
keywords: Auditory brainstem response; cochlear implantation; electrical acoustic stimulation; guinea pig; hair cell; organ of Corti; scanning electron microscope; spiral ganglion