Vibration test for evaluating the spinal stability following fixation of thoracolumbar burst fracture in pigs / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the feasibility of vibration test in evaluation of spinal stability after instrument fixation of thoracolumbar burst fracture in pigs.</p><p><b>METHODS</b>Twenty-one porcine spines (T11 to L5) were impacted longitudinally with different energy levels to simulate thoracolumbar burst fracture. The fractures were fixed by Luque, Harrington, Steffee and Kaneda techniques, and the anterior-posterior, lateral and vertical spinal stability was analyzed using vibration test.</p><p><b>RESULTS</b>In the mild injury group, vibration test showed that only the first order frequency showed marked anterior shift in the vertical direction (P<0.05) but the main frequency did not, suggesting loosening between the vertebrae. In moderate- or high-energy impact groups, the main frequency markedly shifted forward in the vertical and anterior-posterior directions (P<0.05 or P<0.01), and obvious lateral shift was observed only in high-energy impact group.</p><p><b>CONCLUSION</b>The dynamical characteristics of the spine indicate that the main frequency markedly shift after instrument fixation (except for Luque) of thoracolumbar burst fracture, suggesting the feasibility of vibration test for evaluating spinal injury severity and instrument fixation.</p>