This retrospective study is conducted to gain more knowledge on use and complications of 3mm long implants used in percutaneous (through the skin) bone-anchored hearing system (BAHS) surgeries in adults. Patients included have already been treated and recieved an implant with the wide diameter (Ø: 4.5 mm) design, either of 3- or 4mm length. The main purpose of the study is to investigate implant survival three months after implantation.

BAHS systems are intended for patients with conductive or mixed hearing loss, and for patients with single-sided deafness. In BAHS surgery, an implant - coupled to a skin-penetrating abutment - is implanted in the bone behind the ear and is later loaded with a sound processor. The sound processor transforms sound waves to sound vibrations that are transferred through the skull bone to the inner ear(s)/cochlea. Thus, sound can be transmitted directly to the cochlea and bypass any problems in the ear canal or middle ear. Today, more than 400,000 implantations have been made around the world and the long-term success rate of BAHS surgery is high, with a low rate of major complications.

Over the years, both implant design and surgical techniques have developed, with improved patient outcomes as a result. Wider diameter implants, 4.5mm in diameter, increased the implant stability and have become standard. The implants exist in two different lengths, 3- and 4mm, to accomodate for different bone thickness. The shorter implant has primarily been used for (young) children and for adults with thinner bone. The aim of this restrospective study is to investigate the outcomes after implantation of a 3mm implant in an adult population.

Inclusion Criteria:

• Adult patient (≥19 years) receiving percutaneous BAHS treatment using an implant with the wide diameter (Ø: 4.5 mm) design.

Exclusion Criteria:

• Patient undergoing re-implantation due to previous failure of osseointegration or other spontaneous implant loss.
• Patient undergoing conversions from passive transcutaneous devices (i.e. BAHA Attract) to active percutaneous devices (using an abutment), using the same implant for attachment.

Patients that have already obtained surgical intervention with a percutaneous bone anchored hearing system.