[Titanium as an implant material for rods of transpedicular instrumentation of the lumbar spine].
OBJECTIVE
Titanium alloys are increasingly being used as an implant material in orthopaedics and for spinal instrumentation. In this study a metallographic analysis and mechanical testing were performed to evaluate the resistance of rods of Ti-A16-V4 in particular to tensile forces.


METHODS
The surface texture of unprepared Ti-A16-V4 and a rod of the same material for spinal instrumentation were evaluated in a metallographic analysis using light microscopy and electron microscopy. Tensile strength measurements were performed on 2 rods, and the strength of the connection between rod and pedicle screws was tested in 9 cases. An electron microscopic analysis of surface changes of the connections between rod and pedicle screws after loading was performed.


RESULTS
The titanium alloy Ti-A16-V4 has a mill-annealed appearance, which has a high resistance to tearing under stress. Titanium rods show high tensile strength before failure under loading. The connection between rod and pedicle screws also as high resistance to tensile loads (> 27 kN) with only little deformation of the connecting surface and no tearing.


CONCLUSIONS
The titanium alloy Ti-A16-V4 is an appropriate material for dorsal spinal instrumentation rods because of its low weight, high biocompability and high tensile strength.
von Knoch
M
M
Klinik und Poliklinik für Orthopädie, Universität Duisburg-Essen. mariusvonknoch@yahoo.com
Saxler
G
G
Quint
U
U
D000497:Alloys; D001672:Biocompatible Materials / Q000737:chemistry*; D001858:Bone Nails; D019544:Equipment Failure Analysis / Q000379:methods*; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D008422:Materials Testing / Q000379:methods*; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium