Osseointegrated titanium implants in the temporal bone. A clinical study on bone-anchored hearing aids.

The purpose of this study is to investigate the possibilities for attaching a new type of direct bone conduction hearing aid. Using a gentle surgical technique, titanium screws were inserted into the temporal bone of fourteen patients suffering from hearing impairment. The implants became integrated with the living bone tissue and have remained so for a follow-up period of, at present, two to four years. It is therefore concluded that titanium implants may be osseointegrated in the temporal bone in a similar manner to that previously described for long bones. The bone-anchored titanium screws were connected to a permanently skin-penetrating abutment, which in turn was used for attachment to a hearing aid. In this way a direct bone conduction without obstructing soft tissue layers is secured. The permanent skin penetration caused no adverse soft tissue effects. The new system has improved pure-tone hearing threshold by about 15 dB. Further research is aimed at the construction of a new hearing aid that is better adapted to the impedance situation existing in the directly bone-anchored cases.