Stress distribution of endplate at cervicothoracic，thoracolumbar and lumbosacral junction：a biomechanical study

English Keywords:Spine  Ｊｕｎｃｔｉｏｎ  Endplate  Compressive streｓｓ  Biomechanics

English Abstract:

  【Abstract】　Objective：To investigate the stress distribution of endplate at cervicothoracic，thoracolumbar and lumbosacral junction.Method：A total of 65 vertebral bodies（125 endplates）　from 5 intact human vertebrae（C4-T1，T11-Ｌ２，Ｌ３－S1）　was used for test，49 test points at each endplate were indented by using a 1.5mm-diameter plane indenter，a continuous load was added in all specimenand，the results were processed by statistical analyses.Result：The failure load distributions of endplates varied significantly among the three sites.At cervicothoracic junction，the failure load decreased from C4 to C7，and increased from T1.At thoracolumbar junction，the failure load increased from T11 to L2，which continued to L3 and L4，but ceased in L5，and then increased again from S1.The yield load in endplates of cervicothoracic and thoracolumbar junction was lower than that in lumbosacral junction（P＜0.05）.The failure load of inferior endplates was significantly higher than that of superior endplates（P＜0.01）.As for intervertebral space，the cranial endplates had a higher yield stress than caudal endplates（P＜0.05）.The failure load increased from central to peripheral zones.At cervicothoracic and lumbosacral junction，the failure load of posterior endplates was higher than anterior regions，but on the contrary for endplates of thoracolumbar junction（P＜0.05）.Conclusion：The stress distributions of the endplates vary significantly among three junctions.It is cautious to consider their size and location when placing instrument.