Relationship between different levels of energy impaction and changes of geometric parameters and biomechanics in thoracolumbar spinal segments
Abstract：AIM: To explore the relationship between the different levels of impact energy and geometric parameters,variations of such parameters and their biomechanics to provide an objective standard for evaluation of the extent of injury to the spine and the stability variations and to provide an accurate experimental basis for selecting a proper biomechanical management method in handling such injuries.METHODS: Eighteen human thoracolumbar spines taken from cadavers were impacted with different levels of energy.Then,models of L1 vertebrae burst injuries of different levels were established.Based on the three dimensional spinal stability test,the analysis of geometric parameter changes of the vertebrae and the biomechanical changes was conducted.RESULTS: Structural" laxity" appeared after low energy impaction.Merely the angle parameters took a change among those geometric parameters(P< 0.05),which indicates no apparent destruction to the vertebrae body in spite of some loosening between the vertebras.But significant changes of the vertebrae geometric parameters were observed after medium or high energy impaction.In the medium energy impaction group,at the position of posterior extension,anterior vertebral height(AVH),and deformation ratio(DR) could get restored to normality on the whole,while posterior vertebrae height(PVH) and vertebrae diameter(VD) couldn't get restored to normality(P< 0.05).In the high energy group,although AVH and DR got could recover to their normality at the position of posterior extension,there existed a significant difference compared with the normal PVH and VD(P< 0.01).After extension,all the linear and angle parameters could get restored to their normality on the whole in medium and high energy groups except for VD,indicating that extension could restore the spinal body well.CONCLUSION:AVH,DR and angle parameters can be taken as indexes for evaluation of injured spine's stability.When PVH and posterior unite height(PUH) are less than 85% of the normal value,it indicates a severe destruction to the vertebrae structure.That is a severe burst fracture happens. Traction is an effective biomechanical method to restore vertebrae geometric parameters.Risks follow when posterior extension manipulation is applied to these severe burst fractures.
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Publication Date：2004-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 363-366 )