Titanium metal release after posterior cervical spine plate placement in a canine model.

The local tissue concentration of released titanium from Ti-6Al-4V posterior cervical spine plates in canines was determined using inductively coupled plasma atomic emission spectroscopy. The plates were also evaluated for percentage of surface area damage. The highest titanium levels (> 100 ppm dry weight) and most severe surface damage were associated with screw-plate interfaces. A model to explain the metal release mechanisms was proposed, consisting of a combination of fretting wear, diffusion through the passive oxide layer, and dissolution of this layer.