健康成人下颈椎在体三维瞬时运动特点研究

IN VIVO THREE-DIMENSIONAL TRANSIENT MOTION CHARACTERISTICS OF THE SUBAXIAL CERVICAL SPINE IN HEALTHY ADULTS

目的 观察并测定健康成人生理载荷下下颈椎在体三维瞬时运动特点。方法 纳入17名无颈椎疾患的健康志愿者男8名,女9名;年龄23~41岁平均26岁。通过CT扫描联合Rhinoceros 4.0造模软件获得下颈椎三维模型,将该模型匹配到双X线透视影像系统（dual fluoroscopic imaging system,DFIS）捕获的前屈-后伸、左-右侧弯、左-右旋转体位时颈椎双斜位X线图像上,重现生理载荷下不同活动体位时颈椎三维瞬时运动状态通过在椎体几何中心建立三维坐标系定义X轴位于冠状面并指向左侧,Y轴位于矢状面并指向后侧,Z轴垂直于X-Y平面指向头侧。沿X、Y、Z轴的旋转角度分别定义为屈-伸旋转角度（α）、侧弯旋转角度（β）和左-右旋转角度（γ）,沿X,Y,Z轴的位移分别定义为左-右位移（x）、前-后位移（Y）和上-下位移（z）从而获得健康成人下颈椎在体三维运动6自由度数据。结果屈伸活动：除C_（6、7）节段前-后位移显著小于其余各节段（P〈0.05）外,其余各节段间前-后、左-右、上-下位移比较差异均无统计学意义（P〉0.05）;屈-伸旋转角度在C_（4、5）和C_（5、6）节段最大（P〈0.05）、C_（6、7）节段最小（P〈0.05）左-右旋转角度C_（4,5）节段明显大于C_（5、6）和C_（6、7）节段（P〈0.05）;各节段间侧弯旋转角度比较差异均无统计学意义（P〉0.05）。侧弯活动：除C_（3、4）节段前-后位移显著大于C_（4,5）节段,C_（6、7）节段上-下位移显著小于C_（3、4）和C_（4、5）节段（P〈0.05）外,其余各节段间各项位移间比较差异均无统计学意义（P〉0.05）;除C_（3、4）节段左-右旋转角度显著大于C_（5、6）及C_（6、7）节段（P〈0.05）外其余各节段间各项旋转角度比较差异均无统计学意义（P〉0.05）。旋转活动：除C_（3、4）节段左-右旋转角度显著大于C_（4、5）和C_（6、7）节段（P〈0.05）外,其余各节段间各项位移及旋转角度比较差异均无统计学意义（P〉0.05）。结论健康成人下颈椎在体三维瞬时运动具有不同特点,为进一步了解颈椎的生理活动功能提供了参考。

Objective To observe the in vivo three-dimensional （3-D） transient motion characteristics of the subaxial cervical spine in healthy adults. Methods Seventeen healthy volunteers without cervical spine related diseases were recruited for this study, including 8 males and 9 females with a mean age of 26 years （range, 23-41 years）. The vertebral segment motion of each subject was reconstructed with CT, and Rhinoceros 4.0 solid modeling software were used for 3-D reconstruction model of the subaxial cervical spine. In vivo cervical vertebral motion in flexion- extension, left and right bending, left and right rotation was observed with dual fluoroscopic imaging system （DHS）. Coordinate systems were established at the vertebral center of C3-7 to obtain the intervertebral range of motion （ROM） and displacement at C3.4, C4. 5, C5.6, and C6. r. The X-axis pointed to the left along the coronal plane, the Y-axis pointed to the back along the sagittal plane, and the Z-axis perpendicular to the X-Y plane pointed to the head. The ROM along X, Y, and Z axises were represented by rotation in flexion-extension （ct）, in left-right bending （13）, and in left-right twisting （γ） respectively, and the displacement in left-right direction （x）, in anterior-posterior direction （y）, and in proximaldistal direction （z）, respectively. Results In flexion and extension, the displacement in anterior-posterior direction of C6, 7 was significantly less that of other segments （P〈0.05）, but the displacements in left-right direction and in proximal- distal direction showed no significant difference between segments （P〉0.05）; the ROM values in flexion-extension of C4. 5 and C5, 6 were significantly larger than those of C3, 4 and C6, 7 （P〈0.05）, and the ROM value in left-right twisting of C4. 5 was significantly larger than those of C5, 6 and C6, 7 （P〈0.05）, but the ROM value in left-right bending showed no significant difference between segments （P〉0.05）. In left and right bending, there was no significant difference in the displacement between other segments （P〉0.05） except that the displacement in anterior-posterior direction of C3, 4 was significantly larger than that of C4, 5 （P〈0.05）, and that the displacement in proximal-distal direction of C6. 7 was significantly less than that of C3, 4 and C4, 5 （P〈0.05）; no significant difference was shown in the ROM value between segments （P〉0.05）, except that the ROM value in left-right twisting of C3, 4 was significantly larger than that of C5, 6 and C6, 7 （P〈0.05）. In left and right rotation, the ROM value in left-right twisting of C3, 4 was significantly larger than that of C4. 5 and C6, 7 （P〈0.05）, and the displacement and ROM value showed no significant differece between other segments （P〉0.05）. Conclusion The intervertebral motions of the cervical spine show different characters at different levels. And the 6-degree-of-freedom data of the cervical vertebrae are obtained, these data may provide new information for the in vivo kinematics of the cervical spine.