Kifune M, Panjabi M M, Liu W, Arand M, Vasavada A, Oxland T
Department of Orthopaedics & Rehabilitation, Yale University School of Medicine, New Haven, Connecticut 06520-8071, USA.
J Spinal Disord. 1997 Dec;10(6):457-66.
Changes in the canal diameter during physiological motions are important considerations in the treatment of patients who have a burst fracture with the presence of bony fragments, but without neurologic deficit. In this in vitro study, the changes in the soft-canal diameter of the thoracolumbar region, when intact and after different fractures, was investigated under several different loading conditions. The soft-canal diameter was clearly identified on the lateral radiographs by attaching a series of steel balls to the posterior longitudinal ligament and ligamentum flavum in the midsagittal plane. Endplate, wedge, and burst fractures were produced incrementally in 19 three-vertebrae human cadaveric spine specimens by high-speed impacts. After each injury, a series of functional lateral radiographs were taken. The minimal canal diameter (MCD) was obtained by digitizing the images of the steel balls on radiographs using a custom-designed computer program. In the intact specimens, the MCD at the disc level changed significantly in flexion, extension, and compression, when compared with the MCD in the unloaded neutral position. However, the changes were small. The MCD after endplate and wedge fractures changed in a similar way. However, after the burst fracture, the MCD at the bone fragment level increased remarkably by a distraction force. It also significantly improved by an anterior shear force in comparison to the corresponding MCD in the neutral position. However, this change was smaller than the change due to the distraction force.
在治疗伴有骨碎片但无神经功能缺损的爆裂骨折患者时，生理运动过程中椎管直径的变化是重要的考虑因素。在这项体外研究中，在几种不同的加载条件下，研究了完整状态下以及不同骨折后胸腰段软椎管直径的变化。通过在矢状面将一系列钢球附着于后纵韧带和黄韧带来在侧位X线片上清晰识别软椎管直径。通过高速撞击在19个三节段人体尸体脊柱标本中逐步制造终板骨折、楔形骨折和爆裂骨折。每次损伤后，拍摄一系列功能性侧位X线片。使用定制的计算机程序对X线片上钢球图像进行数字化处理，从而获得最小椎管直径（MCD）。在完整标本中，与非加载中立位的MCD相比，椎间盘水平的MCD在屈曲、伸展和压缩时发生了显著变化。然而，变化很小。终板骨折和楔形骨折后的MCD变化方式类似。然而，爆裂骨折后，骨碎片水平的MCD在牵张力作用下显著增加。与中立位相应的MCD相比，在前剪切力作用下也有显著改善。然而，这种变化小于牵张力引起的变化。
