脊柱颈胸段全脊椎切除术内固定重建的生物力学

目的:研究颈胸段脊柱肿瘤在T1椎体全脊椎切除术后,前路、后路或者前后联合内固定重建方法的生物力学的优缺点。方法:使用6具颈胸段脊柱标本。在完整状态进行力学分析后,T1脊椎根据WBB脊柱肿瘤解剖区域分类依次切除。然后前路利用颈椎前路带锁Orion钢板和钛网进行固定和重建,后路利用SUMMIT方向螺钉枕颈胸钉棒系统或者联合前后路两种重建方法进行测试。在非破坏性生物力学状态下进行屈伸和左右侧屈等不同工况下测试。结果:T1脊椎全脊椎切除术后,前路钢板固定加后路短节段的椎弓根螺钉固定,其刚度优于单纯后路双节段的经椎弓根螺钉固定。前路钢板固定加后路双节段的椎弓根螺钉固定,其刚度优于前路钢板固定加后路单节段的椎弓根螺钉固定,但两者之间无显著性差异。全脊椎切除后,单纯前后钢板固定,其刚度下降明显,在肋椎关节切除后,已近失稳。结论:临床上在全脊椎切除后,尽可能采用前后联合固定,后路可以采用单节段的经椎弓根螺钉固定。临床医师应该注意的是,全脊椎切除后,单纯前路钢板固定,稳定性较差,尤其在患者肋椎关节已被肿瘤破坏的情况下,稳定性更差。

Biomechanical evaluation of spinal reconstruction for the total spondylectomy in the cervicothoracic spine

Objective:To investigate the stiffness of anterior,posterior and circumferential spinal reconstructions for different anatomic stages of tumor lesion so as to effectively treat with the tumorous lesion in the cervicothoracic spine.Methods:Six human cadaveric cervicothoracic spines were studied.The T_1 vertebral body and posterior elements were resected in sequence based on the Weinstein-Boriani-Biagini(WBB)anatomic zone classification for tumor lesion in the spine.Anterior reconstruction with titanium mesh and Orion plates systems,posterior reconstruction with the SUMMIT universal-axial transpedicular rod-screw systems or both of them were used in the reconstruction after the spondylectomy of the T_1 vertebra.Nondestructive biomechanical test was performed under different loading situations.Results:There were no statistical differences observed between the group of S AP PPS M and the group of S AP PPS S,even if the stiffness of group S AP PPS M was higher than that of the group of S PPS S.Anterior instrumentation alone for total spondylectomy did not restore stiffness to the intact level,and it was more deteriorated when the costovertebral joint were destructed by the tumor.Conclusion:The instrumentation of S AP PPS S is the optimal reconstruction method though S AP PPS M provide more stability,but they do not demonstrate statistical difference.Attention should be paid that anterior reconstruction alone could not exhibited more stability than that of the intact spine when the T_1 total spondylectomy is performed,especially when the costovertebral joints are destructed in certain circumstances.