P. Neumann et al., FLEXION-DISTRACTION INJURY OF THE LUMBAR SPINE - INFLUENCE OF LOAD, LOADING RATE, AND VERTEBRAL MINERAL-CONTENT, Journal of spinal disorders, 9(2), 1996, pp. 89-102
The biomechanical response of the lumbar spine to combined flexion-she
ar loading was determined experimentally The injury model simulated fl
exion-distraction trauma to the lumbar spine. Forty-eight lumbar funct
ional spinal units (FSUs) were subjected to dynamic loading to injury
with six different load types. The reactive forces and moments and res
ulting deformity were determined. Static physiologic loading was perfo
rmed before and after the injurious loading to assess residual injury.
The biomechanical response of FSUs was dependent on the amount of loa
d and loading rate. The vertebral bone mineral content explained most
of the biologic variation of the results. An osteoporotic or severely
degenerated spine will be more easily rendered unstable after trauma w
ith lower deformity. Injury at high loading rates will create instabil
ity with lower deformity. In vitro experiments should be performed on
entire spinal units and with combined loads.