Biocompatibility of vitallium as ossicular reconstruction material in the middle ear: experimental animal study

Although long-term data will be necessary for confirmation, the result of this preliminary study indicates that vitallium may be a good alternative material for ossicular replacement prostheses in the middle ear.

To investigate the biocompatibility of vitallium (Co-Cr-Mo) as ossicular reconstruction material in the rabbit middle ear, and to compare the results with those obtained with titanium, well known as a highly biocompatible material, and non-implanted control groups.

Eighteen female New Zealand White rabbits were anesthetized. The tympanomeatal flap was elevated and 12 vitallium and 12 titanium implants were placed in the bulla away from the ossicles in 24 middle ears. Six rabbits were used as non-implanted controls. All animals were sacrificed under general anesthesia on the 180th day after implantation. The temporal bones were removed, fixed in 10% buffered paraformaldehyde and decalcified for a week in EDTA. Tissue samples were then prepared using an Autotechnicon and embedded in paraffin. Sections (30-microm thick) were cut with a microtome, stained with hematoxylin-eosin, von Gieson's stain and fibroblast growth factor (FGF) and examined under a light microscope. The numbers of lymphocytes, collagen fibers and FGF-positive cells were determined in all three groups.

There was no significant difference in the numbers of collagen fibers between the groups (p > 0.05). No significant differences were found in the numbers of lymphocytes and FGF-positive cells between the titanium and vitallium groups (p > 0.05). The differences in the numbers of lymphocytes and FGF-positive cells between the control and other groups were found to be significant (p <0.05).