Abstract: The invention relates to a hearing aid device of the bone conduction type, i.e. a hearing aid device in which the sound is mechanically transmitted via the skull bone directly into the inner ear of a person with impaired hearing. The hearing aid device is divided into an implantable part (5) which comprises a vibrator (7) for generating vibrations correponding to the received sound information and an external part (1) with microphone (7) and electronic circuitry (3). The entire implantable part (5), including the vibrator (7), is housed in a unit which is arranged partly outside the skull bone and anchored by means of osseointegration. The power to the implantable part (5) is transmitted by induction from the external part (1) when the device is used.

Abstract: The invention relates to a screw-shaped anchoring element (fixture) (1) for permanent anchorage of hearing aid devices or ear and orbital prostheses in the skull bone. The main body (8) of the anchoring element which is intended to be inserted into the skull bone is shorter than 5 mm. The apical part of the anchoring element is self-tapping with at least one cavity (4) with a cutting edge (2). The cavity or cavities have been designed in such a way that their total volume corresponds to at least half of the bone tissue material which is cut-off by the cutting edge (2) when the anchoring element is screwed down into a hole drilled in the skull bone with a diameter corresponding to the inner diameter of the screw thread. The cavities (4) are extending along the apical, bottom half of the main body (8) of the fixture which is intended to be inserted in the skull bone and the cavities are deep enough to make room for said cut-off bone tissue material.