胸腰椎爆裂型骨折椎管内骨折块产生的组织结构基础

A Structural Analysis of Bone Fragments in Spinal Canal After Thoracolumbar Burst Fracture

目的：揭示胸腰椎爆裂型骨折的发生机制及造成脊髓损伤的骨折块来源部位及产生机理。方法：本研究从造成脊柱损伤的实际过程出发，利用ＢＩＭ－Ｉ型立式自由落体生物撞击机，在准静态加载下对尸体脊柱标本复制爆裂型骨折模型及应用体视显微镜观测正常及撞击后终板软骨、小梁骨形态和损伤情况。结果：（１）终板软骨为盘状结构，中央区薄弱厚约０．３～０．４ｍｍ。终板软骨下及椎基静脉孔壁为１～２层板层状结构，终板之间为垂直柱状结构。（２）撞击标本均伴有终板中央或中央偏后部位破裂，椎体后上缘骨折并突向椎管内。结论：终板软骨形态、厚度，椎体骨小梁密度、排列顺序及椎基静脉孔的解剖结构是爆裂型骨折及椎管内骨折块产生的组织结构基础。

To explore the mechanism of thoracolumbar burst fractures and the original location of the intracanal fractured fragments which injuried the spinal cord. Methods: A model of thoracolumbar burst fracture was produced by using the BIM-Ⅰ falling weight impact machine, and the anatomical and pathological changes of the cartilaginous end plate and trabeculae were studied. Results: the cartilaginous end plate was disc shaped and its central part was 0.3 to 0.4 mm. in thickness. A single or double plate structure of the trabeculae were found beneath the end plates and around intervertebral foramina; a vertical columnar trabecula was aligned between the end plates. The fractures occurred at the central and posteriocentral portion of the end plate as well as the posterio-superior margin of vertebral body. Conclusions: The shape and thickness of the end plate, the density and arrangement of the trabecula and the structure of vertebral foramina are the anatomic basis for burst fracture and intracanal bone fragments.