[Determination of bone quality before spinal instrumentation--value of different in vivo methods].
OBJECTIVE
The present investigation should elucidate which assessment technique for bone quality is most appropriate to estimate preoperatively fixation strength of instrumental spine fusions.


METHODS
VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pullout force assessment. Bone quality was assessed by Dual Energy X-ray Absorptiometry (DEXA), Quantitative Computed Tomography (QCT), MRT and histomorphometry. For each of these techniques, correlation with axial pull out force strength was investigated.


RESULTS
Highest correlation was found for cancellous bone density (QCT) (r = 0.72; p < 0.001) and DEXA (r = 0.70; p < 0.001). MRT, cortical bone density (QCT) and histomorphometry just slightly correlated with pullout force strength.


CONCLUSIONS
Absorptiometrical techniques like QCT and DEXA are most appropriate to estimate VDS-screw fixation strength preoperatively.
Schwitalle
M
M
Orthopädische Klinik, Klinikum der Johannes Gutenberg-Universität, Mainz.
Eysel
P
P
Oberstein
A
A
Degreif
J
J
Kirkpatrick
C J
CJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology*; D001863:Bone Screws; D003952:Diagnostic Imaging; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013123:Spinal Fusion / Q000295:instrumentation*