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 cosmet ic auricular prostheses, and as connector between external sound proce ssors and implanted cochlear implants. The biological acceptance of th ese implants by temporal bone hosts is affected by many factors includ ing the maturity of the bone, the design of the pedestal-fixation syst em, and the pedestal-construction material. The first phase of this st udy evaluated the effect of the pyrolized graphite pedestal fixation o n maturing temporal bones. Pedestals were implanted in young swine tem poral bones using single screw and multiple screw fixation systems. Th e 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. Osseointe gration of the attaching screws occurred. The second phase of the stud y evaluated osseointegration of smooth, beaded, and textured titanium pedestals in feline temporal bones. High-resolution temporal bone/pede stal sectioning has been accomplished with high-performance microtomes , showing the osseointegration of the pedestal by the temporal bone. T his is demonstrated with tetracycline labeling and histologic assessme nt. Percutaneous pedestals are of increasing importance in otologic pr actice. This study assists in the understanding of biologic acceptance of pedestals as influenced by the pedestal composition and fixation d esign. This basic understanding is essential for design improvements i n percutaneous temporal bone pedestals.