Osseointegration and growth effects of temporal bone percutaneous pedestals

The percutaneous temporal bone pedestal has shown significant utility for the attachment of bone-anchored hearing aids, attachment of cosmetic auricular prostheses, and as connector between external sound processors and implanted cochlear implants. The biological acceptance of these implants by temporal bone hosts is affected by many factors including the maturity of the bone, the design of the pedestal-fixation system, and the pedestal-construction material. The first phase of this study evaluated the effect of the pyrolized graphite pedestal fixation on maturing temporal bones. Pedestals were implanted in young swine temporal bones using single screw and multiple screw fixation systems. The effect on temporal bone growth is demonstrated with photomicrographs and gross photography showing acceptable host-tissue response to the presence of multiple and single screw attachment techniques. Osseointegration of the attaching screws occurred. The second phase of the study evaluated osseointegration of smooth, beaded, and textured titanium pedestals in feline temporal bones. High-resolution temporal bone/pedestal sectioning has been accomplished with high-performance microtomes, showing the osseointegration of the pedestal by the temporal bone. This is demonstrated with tetracycline labeling and histologic assessment. Percutaneous pedestals are of increasing importance in otologic practice. This study assists in the understanding of biologic acceptance of pedestals as influenced by the pedestal composition and fixation design. This basic understanding is essential for design improvements in percutaneous temporal bone pedestals.