ARE SHEEP SPINES A VALID BIOMECHANICAL MODEL FOR HUMAN SPINES

Study Design. Range of motion, neutral zone, and stiffness parameters of the complete cervical, thoracic, and lumbar sheep spine were determ ined in flexion and extension, axial left/right rotation, and right/le ft lateral bending. Objectives. To determine quantitative biomechanica l properties of the sheep spine and compare them with those from the h uman spine. Summary of Background Data. Sheep spines often serve as a model for experimental in vivo and in vitro studies in spine research, but few quantitative biomechanical data from sheep spines for compari son with human specimens are available. Methods. Complete spines were sectioned into Single-joint segments and tested in a spine tester unde r : pure moments in the three main anatomic planes. Results. The crani ocaudal variation in range of motion in all load directions was qualit atively similar between sheep spines and values reported in the litera ture for human specimens. Conclusions. Based on the biomechanical simi larities of sheep and human spines demonstrated in this study, it appe ars that the use of the sheep spine, which already includes evaluation of surgical techniques and bone healing processes, might be extended to spinal implants.