title: A vibration investigation of a flat surface contact to skull bone for direct bone conduction transmission in sheep skulls in vivo.
abstract: OBJECTIVE
  Bone conduction implant (BCI) attached with a flat surface contact will offer efficient and linear vibration transmission over time.
  
  
  BACKGROUND
  Despite that percutaneous bone conduction devices (PBCD) are successful in treating patients with conductive hearing loss, there are some drawbacks related to the need of a permanent skin penetration. The BCI system is designed as an alternative to the PBCD because it leaves the skin intact.
  
  
  METHODS
  BCI dummy implants were installed in 3 sheep skulls in vivo to study the vibration transmission characteristics over time. Mechanical point impedances and vibration transfer response functions of the BCI implants were measured at the time of surgery and after a healing period of 8 months.
  
  
  RESULTS
  In 1 sheep both implants healed without complications. In the other 2 sheep, the implants were either partially loose or lost to follow up. In the sheep with stable implants, it was found by the resonance frequency shift of the mechanical point impedance that a firmer integration between the implant and bone tissue as seen in osseointegrated surfaces developed over time. It was also shown that the transcranial vibration transmission remains stable and linear. Providing bone chips in the contact between the implant and the bone did not enhance vibration transmission. The surgical procedure for installing the BCI dummy implants was uneventful.
  
  
  CONCLUSIONS
  The mechanical point impedances and vibration transfer response functions indicate that the BCI implants integrate and that transmission conditions remain stable over time.
authors: Division of Signal Processing and Biomedical Engineering, Department of Signals and Systems, Chalmers University of Technology, Göteborg, Sweden. taghavi@chalmers.se
authors: Hamidreza
authors: H
authors: Taghavi
authors: Bo
authors: B
authors: Håkansson
authors: Måns
authors: M
authors: Eeg-Olofsson
authors: Carina B
authors: CB
authors: Johansson
authors: Anders
authors: A
authors: Tjellström
authors: Sabine
authors: S
authors: Reinfeldt
authors: Tomas
authors: T
authors: Bergqvist
authors: Joakim
authors: J
authors: Olsson
mesh_terms: D000818:Animals; D001844:Bone Conduction / Q000502:physiology*; D005260:Female; D006310:Hearing Aids; D006314:Hearing Loss, Conductive / Q000503:physiopathology / Q000601:surgery*; D016348:Osseointegration / Q000502:physiology*; D019919:Prosthesis Implantation / Q000379:methods; D012756:Sheep; D012886:Skull / Q000502:physiology / Q000601:surgery*; D013701:Temporal Bone / Q000502:physiology / Q000601:surgery*; D014732:Vibration; D014945:Wound Healing / Q000502:physiology