A MECHANICAL MODEL OF HUMAN SPINAL MOTION SEGMENTS

A modular mechanical model of the spine was developed which can be ada pted to approximate the mechanical properties of various spinal levels and pathologic conditions in single-or multisegmental forms. The char acteristics of the model were compared with those of human L4-5 specim ens in flexion and extension, axial rotation and lateral bending. The model showed comparable ranges of motion to those of human specimens i n all directions and likewise was characterized by increasing stiffnes s with increasing load as well as hysteresis. This model can be used a s a standard for the comparison of different spine testers. As a subst itute for cadaveric specimens in implant testing, these models provide the advantages of availability, consistent properties, and adaptabili ty, and avoid the risks associated with handling human tissue.