title: Development of cochlear-wall implants for electrical stimulation of the auditory nerve.
abstract: The aim of these experiments was to investigate the use of titanium implants for anchorage of stimulating electrodes or other clinical or experimental devices in the bony wall of the cochlea. Twenty-six cylindrical titanium fixtures, 0.6 mm in diameter, were inserted into holes drilled in the otic capsule in 8 ears in 5 nonhuman primates and then examined for stability after periods of 2 months to 2 years. Following sacrifice, the bone-metal interfaces were examined microscopically. Fourteen of the implants were firmly fixed in the bone, 6 were loosely fixed and 6 came out. Poor fixation was associated with infection in the middle ear. In uninfected ears, 90% of the implants were stable. The implants were not osseointegrated in the classic sense, but in stable implants, direct bone contact covering 5 to 60% of the titanium oxide surface of the implant shaft was observed.
authors.affiliation: Kresge Hearing Research Institute, Department of Otorhinolaryngology, University of Michigan Medical Center, Ann Arbor.
authors.forename: B E
authors.initials: BE
authors.lastname: Pfingst
authors.forename: J M
authors.initials: JM
authors.lastname: Miller
authors.forename: A
authors.initials: A
authors.lastname: Tjellström
authors.forename: T
authors.initials: T
authors.lastname: Albrektsson
authors.forename: L
authors.initials: L
authors.lastname: Carlisle
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D003051:Cochlea / Q000473:pathology; D003054:Cochlear Implants; D004867:Equipment Design; D008251:Macaca; D010865:Pilot Projects; D013701:Temporal Bone / Q000473:pathology; D014025:Titanium; D000159:Vestibulocochlear Nerve / Q000502:physiology*
chemical_list: D001672:Biocompatible Materials; D014025:Titanium